
Wavelength Medicine
In this chapter, we will explore wavelength as medicine and the amazing, seemingly magical optical window of red light therapy. Our goal is clear – discover the most beneficial and healing wavelengths of light to use in photobiomodulation. Let’s look at wavelengths as the "medicine," or "active ingredient," powering red light therapy. While we can consider other parameters like intensity, time and overall energy the “dose,” we also need to have the correct “active ingredients,” or wavelengths, to treat our troubling condition(s).
In the red and near infrared range of wavelengths (600-1100nm), some penetrate powerfully, while others offer more therapeutic value. Some wavelengths target key chromophores like cytochrome c oxidase while other wavelengths do not have much of an effect. Also some wavelengths have been more thoroughly researched than others giving them more proven validation. We also need to know the emission spectra, aka the spread, of the LEDs, crucial because LEDs (without exception) emit a wide range of wavelengths. Putting this all together and wrapping it in a proverbial bow gives us clarity about the most favorable wavelengths to utilize in red and near infrared LED light therapy. Whether we run a busy clinic for patients excited about its potential, or simply want the best LED device for ourselves and our family - the wavelength, intensity/irradiance and dose are critical factors in obtaining enduring results with red and near infrared light therapy. Not surprisingly, there is a great deal of MISINFORMATION floating around the industry – nonsense like “more irradiance is better.” If we take to heart the exciting information in these next three chapters, we’ll be flush with knowledge that will help us sift through all the lies and marketing hype so we can examine the science without distraction.
In this chapter, we will explore wavelength as medicine and the amazing, seemingly magical optical window of red light therapy. Our goal is clear – discover the most beneficial and healing wavelengths of light to use in photobiomodulation. Let’s look at wavelengths as the "medicine," or "active ingredient," powering red light therapy. While we can consider other parameters like intensity, time and overall energy the “dose,” we also need to have the correct “active ingredients,” or wavelengths, to treat our troubling condition(s).
In the red and near infrared range of wavelengths (600-1100nm), some penetrate powerfully, while others offer more therapeutic value. Some wavelengths target key chromophores like cytochrome c oxidase while other wavelengths do not have much of an effect. Also some wavelengths have been more thoroughly researched than others giving them more proven validation. We also need to know the emission spectra, aka the spread, of the LEDs, crucial because LEDs (without exception) emit a wide range of wavelengths. Putting this all together and wrapping it in a proverbial bow gives us clarity about the most favorable wavelengths to utilize in red and near infrared LED light therapy. Whether we run a busy clinic for patients excited about its potential, or simply want the best LED device for ourselves and our family - the wavelength, intensity/irradiance and dose are critical factors in obtaining enduring results with red and near infrared light therapy. Not surprisingly, there is a great deal of MISINFORMATION floating around the industry – nonsense like “more irradiance is better.” If we take to heart the exciting information in these next three chapters, we’ll be flush with knowledge that will help us sift through all the lies and marketing hype so we can examine the science without distraction.

Biological Windows
To better understand the therapeutic range of wavelengths and intensities of red and near infrared light of maximal benefit to our body, let’s introduce the idea of biological windows.
The word “window” has its origins and derives its meaning from “Wind Eye” or “Eye Door,” signifying an opening or range. A window is always transparent to a wide range of parameters. A biological window is a spectrum of electromagnetic energies that our bodies readily accept and convert to dynamic physiological responses. Signals that fall outside the biological window can have no, minimal or detrimental effect. The three main windows, or therapeutic value, in photobiomodulation are the wavelength windows (which we will explore in this chapter) and the irradiance and dosage windows, which we will focus on in Chapters 11 and 12.
To better understand the therapeutic range of wavelengths and intensities of red and near infrared light of maximal benefit to our body, let’s introduce the idea of biological windows.
The word “window” has its origins and derives its meaning from “Wind Eye” or “Eye Door,” signifying an opening or range. A window is always transparent to a wide range of parameters. A biological window is a spectrum of electromagnetic energies that our bodies readily accept and convert to dynamic physiological responses. Signals that fall outside the biological window can have no, minimal or detrimental effect. The three main windows, or therapeutic value, in photobiomodulation are the wavelength windows (which we will explore in this chapter) and the irradiance and dosage windows, which we will focus on in Chapters 11 and 12.

"Optical Window" and the Optimal Wavelengths for RLT
Studies make it clear - the “optical window” of ideal red and near infrared light wavelengths fall between roughly 600nm to 1150nm [1]. Our bodies are most transparent to these wavelengths, paving the way for them to penetrate the furthest. The reality that red and near infrared are the DEEPEST penetrating of ALL wavelengths of biologically active light illuminates the overall picture even further. Most wavelengths barely get past our skin if at all, while red and near infrared ones penetrate up to five centimeters, benefiting our cells, tissues, organs and even our bones more profoundly than other wavelengths of light.
Studies make it clear - the “optical window” of ideal red and near infrared light wavelengths fall between roughly 600nm to 1150nm [1]. Our bodies are most transparent to these wavelengths, paving the way for them to penetrate the furthest. The reality that red and near infrared are the DEEPEST penetrating of ALL wavelengths of biologically active light illuminates the overall picture even further. Most wavelengths barely get past our skin if at all, while red and near infrared ones penetrate up to five centimeters, benefiting our cells, tissues, organs and even our bones more profoundly than other wavelengths of light.

Part 1 - Optical Windows and Penetration Depth
As kids, many of us played the game of putting the lighted end of a flashlight in our mouth while looking at a mirror in the dark. Those of us who were slightly less adventurous simply placed a flashlight over our hand, hoping to see a crazy light show on our skin. The reason we only see a darker red is that our skin immediately absorbs the other colors so they don't pass through. Since the white light of a normal flashlight contains all the beautiful colors of the rainbow, the fact that red is the only color that pops through proves that it is indeed the deepest penetrating visible wavelength. In the spirit of learning, find a bright flashlight and bring it into a darkened room to engage in an experiment. Yep! We are indeed more transparent to light than we think, especially RED LIGHT! As we'll see, near infrared penetrates even further, but we cannot see it due to the limitations of the human eye.
As kids, many of us played the game of putting the lighted end of a flashlight in our mouth while looking at a mirror in the dark. Those of us who were slightly less adventurous simply placed a flashlight over our hand, hoping to see a crazy light show on our skin. The reason we only see a darker red is that our skin immediately absorbs the other colors so they don't pass through. Since the white light of a normal flashlight contains all the beautiful colors of the rainbow, the fact that red is the only color that pops through proves that it is indeed the deepest penetrating visible wavelength. In the spirit of learning, find a bright flashlight and bring it into a darkened room to engage in an experiment. Yep! We are indeed more transparent to light than we think, especially RED LIGHT! As we'll see, near infrared penetrates even further, but we cannot see it due to the limitations of the human eye.

Tissue Optics 101
Seeing red light on the other side of our hand when we hold a flashlight up to it offers a remarkable demonstration of the wonderful world of tissue optics. Tissue optics is the science of light propagation (including all electromagnetic waves) through biological tissues that strictly adheres to the physics of light's natural behavior. For our purposes, let’s focus on the tissue optics of red and near infrared wavelengths. Applying red or near infrared light to the tissue yields some intriguing results. Part of that light will be reflected, while other parts will be scattered, absorbed and possibly even transmitted. Here briefly are the four core ideas in tissue optics.
1) Reflection- Reflected light is light that bounces off the surface of the skin and never enters the body. The only reason we can see red light on the skin is because light is reflected off it. There is an intense amount of reflection in the red and near infrared range. Studies inform us that between 50-80% of red light hitting our skin will be reflected. It’s crucial for us to minimize reflection because reflected light essentially has no therapeutic value. One of the benefits of a full body red light therapy bed is that the light surrounds us 360, and high-quality red light beds like Spectra and Novothor have reflective coating to keep the light "in the bed" helping to maximum light absorption into the body.
Seeing red light on the other side of our hand when we hold a flashlight up to it offers a remarkable demonstration of the wonderful world of tissue optics. Tissue optics is the science of light propagation (including all electromagnetic waves) through biological tissues that strictly adheres to the physics of light's natural behavior. For our purposes, let’s focus on the tissue optics of red and near infrared wavelengths. Applying red or near infrared light to the tissue yields some intriguing results. Part of that light will be reflected, while other parts will be scattered, absorbed and possibly even transmitted. Here briefly are the four core ideas in tissue optics.
1) Reflection- Reflected light is light that bounces off the surface of the skin and never enters the body. The only reason we can see red light on the skin is because light is reflected off it. There is an intense amount of reflection in the red and near infrared range. Studies inform us that between 50-80% of red light hitting our skin will be reflected. It’s crucial for us to minimize reflection because reflected light essentially has no therapeutic value. One of the benefits of a full body red light therapy bed is that the light surrounds us 360, and high-quality red light beds like Spectra and Novothor have reflective coating to keep the light "in the bed" helping to maximum light absorption into the body.

2) Scattering and Anisotrophy- Scattering occurs when light photons shift direction based on a tissue's refractive index. A crucial property of tissue scattering is the anisotropy factor, or how much light scatters forward or backwards. The values of this factor range from zero (scattering in all directions) up to one, which is only forward scattering, which in free space is like a lightbulb (closer to zero) vs a laser (closer to one). The closer the value is to one, the deeper the penetration of light. The image here shows a zero value (maximum scattering or isotropic) at the far left - where light shoots in all directions - versus a one value to the far right, where it travels in a single direction, with no scattering. The values with lasers and LEDs usually range from ~(.7 to .95) depending on the light source, wavelength, angle of contact, etc. If all this is a bit mind-boggling, let’s visualize it this way. A scattered photon is a like a pinball that bounces around from side to side. When the scattering has an anisotropy factor close to one, that is akin to the ball dropping straight down versus scattering all around and bouncing off the bumpers. Why is this important? If light is randomly bouncing around, it’s more likely to be absorbed superficially than penetrate deeper. Longer wavelengths have a higher anisotropic value than shorter ones so they will indeed penetrate deeper! This process naturally connects to the particle wave duality, in which shorter wavelengths are more particle-like so they will bounce around more. Longer wavelengths are more wave-like, so they keep heading in the same direction. Another important aspect is that heating tissue decreases this factor - one of many reasons why tissue heating is undesirable (and why more irradiance is NOT better).

3) Absorption - Following scattering and reflection, most of the remaining light is absorbed by a chromophore. Light energy that is absorbed can either drive metabolic reactions, be re-radiated or be transformed into heat. The goal of red light therapy is to drive the metabolic process, like ATP production or NO release, but not generate heat. The KEY chromophores behind most of the red light magic is cytochrome c oxidase (CCO) and, secondarily, water. While we want to "hit" CCO with our red light photons, other chromophores like melanin in the skin and hemoglobin in the blood often obstruct the process. By tapping into the right wavelengths with the perfect amount of power, we can vastly improve our chances of increasing CCO absorption and activation.
4) Transmission and Transmittance - Transmission is simply light that passes through and emerges from the other side, much like light through a window. With transmitted light, nothing happens because a chromophore does not absorb it. While this usually doesn't happen in the human body as a whole, it CAN sometimes occur in the extremities like the hands/fingers and feet/toes. When we put a flashlight to our hand in the dark – we’ll see transmitted light blazing through. Transmittance (T) is the fraction of incidental transmitted light. It's the amount of light that “successfully” passes through the substance and comes out the other side. If 10% of the light from our flashlight came out the other side of our hand, the transmittance (T) would be 10%.
4) Transmission and Transmittance - Transmission is simply light that passes through and emerges from the other side, much like light through a window. With transmitted light, nothing happens because a chromophore does not absorb it. While this usually doesn't happen in the human body as a whole, it CAN sometimes occur in the extremities like the hands/fingers and feet/toes. When we put a flashlight to our hand in the dark – we’ll see transmitted light blazing through. Transmittance (T) is the fraction of incidental transmitted light. It's the amount of light that “successfully” passes through the substance and comes out the other side. If 10% of the light from our flashlight came out the other side of our hand, the transmittance (T) would be 10%.
The absorption spectrum of a human hand - Key Study #1
To best demonstrate how these elements join forces to yield the deepest penetrating wavelengths, we should check out a study by Karl Norris on the tissue optics of the human hand. The hand was the prime choice because it is not very thick and light can pass all the way through, as we have all amused ourselves demonstrating. Using a very sensitive spectrophotometer, Norris demonstrated that our hands are transparent to light of wavelengths between 650 and 900 nm and again past like 1050nm, as shown in the figure below. Visible light does not penetrate very deeply until we hit red! The graphic compellingly shows why we only see red light when we put a flashlight to our hand. Notice that the best penetrating wavelengths are 720nm (visible as dark red), 810nm and around 1100nm. [2]
To best demonstrate how these elements join forces to yield the deepest penetrating wavelengths, we should check out a study by Karl Norris on the tissue optics of the human hand. The hand was the prime choice because it is not very thick and light can pass all the way through, as we have all amused ourselves demonstrating. Using a very sensitive spectrophotometer, Norris demonstrated that our hands are transparent to light of wavelengths between 650 and 900 nm and again past like 1050nm, as shown in the figure below. Visible light does not penetrate very deeply until we hit red! The graphic compellingly shows why we only see red light when we put a flashlight to our hand. Notice that the best penetrating wavelengths are 720nm (visible as dark red), 810nm and around 1100nm. [2]
So how far does the deepest penetrating wavelengths of red light (~808-810nm) penetrate?
C.E. Tedford and others embarked on one of the most enlightening studies on penetration depth with red and near infrared light. They did their research using human unfixed cadaver brain tissue. Tedford and his team compared 660nm, 808nm and 940nm laser penetration. 808 nm achieved the best penetration, and they concluded that 808nm wavelength light penetrates the scalp, skull and brain to a depth of approximately 40 mm = 4cm or 1.57 inches. [3] It's clear why we see 808-810nm, in so many red light therapy systems!
A crucial question we might ask is: Why isn't 720nm a popular wavelength used in red light therapy as well? As we'll see next, there are wavelengths of red that may penetrate deep and are totally safe, yet don't activate CCO to create more ATP - and therefore, fail to generate much benefit. This is why we need to know the action spectra of the target chromophore, which in red light therapy is mainly CCO (and water, which we'll look at later in this chapter).
C.E. Tedford and others embarked on one of the most enlightening studies on penetration depth with red and near infrared light. They did their research using human unfixed cadaver brain tissue. Tedford and his team compared 660nm, 808nm and 940nm laser penetration. 808 nm achieved the best penetration, and they concluded that 808nm wavelength light penetrates the scalp, skull and brain to a depth of approximately 40 mm = 4cm or 1.57 inches. [3] It's clear why we see 808-810nm, in so many red light therapy systems!
A crucial question we might ask is: Why isn't 720nm a popular wavelength used in red light therapy as well? As we'll see next, there are wavelengths of red that may penetrate deep and are totally safe, yet don't activate CCO to create more ATP - and therefore, fail to generate much benefit. This is why we need to know the action spectra of the target chromophore, which in red light therapy is mainly CCO (and water, which we'll look at later in this chapter).

Part 2 - Action Spectra of CCO
The action spectra describes the wavelength that results in prime physiological activity based on the absorption of light by the photoacceptor [4]. Just as the most action spectra in plants revolves around chlorophyll, in humans (and animals) the most essential action spectra revolves around cytochrome c oxidase (CCO).
CCO is a complex protein composed of 13 different polypeptide subunits, along with the crucial porphyrin-based heme centers and two copper centers. These different units can be either oxidized or reduced, resulting in 16 different oxidation states [5].
In this case the action spectra is the range of wavelengths absorbed by cytochrome c oxidase that most effectively activates one or more of these 16 states to increase ATP production, DNA transcription and other wildly beneficial effects, like energy ATP. Essentially, we want wavelengths of light that lead to this all-important photochemical reaction, instead of generating a mere thermal effect. Recall from Chapter 2 that these are the wavelengths of light with the ideal amount of energy to bump or nudge an electron in CCO to an excited state and transfer electrons to oxygen, creating more ATP. Two of the most quoted action spectra studies come to us courtesy of Tina Karu and Margaret Wong-Riley. They showcase the wavelengths of light that BEST activate CCO (its action spectra) to create more ATP [5,6].
The action spectra describes the wavelength that results in prime physiological activity based on the absorption of light by the photoacceptor [4]. Just as the most action spectra in plants revolves around chlorophyll, in humans (and animals) the most essential action spectra revolves around cytochrome c oxidase (CCO).
CCO is a complex protein composed of 13 different polypeptide subunits, along with the crucial porphyrin-based heme centers and two copper centers. These different units can be either oxidized or reduced, resulting in 16 different oxidation states [5].
In this case the action spectra is the range of wavelengths absorbed by cytochrome c oxidase that most effectively activates one or more of these 16 states to increase ATP production, DNA transcription and other wildly beneficial effects, like energy ATP. Essentially, we want wavelengths of light that lead to this all-important photochemical reaction, instead of generating a mere thermal effect. Recall from Chapter 2 that these are the wavelengths of light with the ideal amount of energy to bump or nudge an electron in CCO to an excited state and transfer electrons to oxygen, creating more ATP. Two of the most quoted action spectra studies come to us courtesy of Tina Karu and Margaret Wong-Riley. They showcase the wavelengths of light that BEST activate CCO (its action spectra) to create more ATP [5,6].
Wong-Riley Action and Absorption Spectra Study - Key Study #1
We see in this diagram the results of a study done by Margaret Wong-Riley, an expert on the mitochondria. By looking at the light absorption spectra (black circular dots) of cytochrome c oxidase (CCO), she demonstrated that there are high levels of absorption in the red from 630-680 (peak at 670nm). Notice that it takes a dip in the 700s, then returns in the 800s (another peak at 830nm) and takes a dive again in the 900s and does not come back. We can see the correspondence of effective wavelengths (especially the peaks at 670 and 830 nm) with the absorption spectrum of oxidized cytochrome c oxidase and the non-correspondence of the least effective wavelength (728 nm). [6,7]
Below is the absorption spectra of CCO. The squares at the top show the ATP production at various wavelengths, while the triangles reveal cytochrome c oxidase activity. The peaks and valleys of both ATP production and cytochrome c oxidase activity adhere closely to the absorption spectra. It is a molecular biologist's dream when the absorption spectra matches the action spectra - which is very much the case in CCO. When light is ABSORBED by cytochrome c oxidase, we get CCO activation and more ATP! This is literally like a solar panel that is nearly 100% efficient.
We see in this diagram the results of a study done by Margaret Wong-Riley, an expert on the mitochondria. By looking at the light absorption spectra (black circular dots) of cytochrome c oxidase (CCO), she demonstrated that there are high levels of absorption in the red from 630-680 (peak at 670nm). Notice that it takes a dip in the 700s, then returns in the 800s (another peak at 830nm) and takes a dive again in the 900s and does not come back. We can see the correspondence of effective wavelengths (especially the peaks at 670 and 830 nm) with the absorption spectrum of oxidized cytochrome c oxidase and the non-correspondence of the least effective wavelength (728 nm). [6,7]
Below is the absorption spectra of CCO. The squares at the top show the ATP production at various wavelengths, while the triangles reveal cytochrome c oxidase activity. The peaks and valleys of both ATP production and cytochrome c oxidase activity adhere closely to the absorption spectra. It is a molecular biologist's dream when the absorption spectra matches the action spectra - which is very much the case in CCO. When light is ABSORBED by cytochrome c oxidase, we get CCO activation and more ATP! This is literally like a solar panel that is nearly 100% efficient.
Now we can answer the question of why we don’t use 720nm red light even though it is one of the deepest penetrating wavelengths. It should be clear - although 720nm has a maximal penetration depth, it is not absorbed well by CCO and hence does a poor job stimulating CCO to produce more ATP! Actually, most of the wavelengths between 700-770nm do a poor job with CCO activation and ATP production, which is why we rarely if ever see any of these wavelengths used in red light therapy! Quite frankly, they’re just not up to the task.

Karu 1999 Study - The Action Spectra Study that forever Changed Red light therapy! - Key Study #2
Tina Karu’s ability to define the action spectra and absorption spectrum of CCO in 1999 marked a a pivotal development in our understanding of photobiomodulation. In this seminal research, Karu notes the absorption peaks at the following wavelengths: "with well-pronounced maxima at 620, 680, 760 and 825 nm." [5]
More importantly, each peak corresponds to a specific oxidized or reduced state of the iron (heme) or copper (Cu) molecules in CCO. For example, 760nm corresponds to the reduced state of CuB. Although 760nm has an absorption peak, this wavelength range in the 700's is often found ineffective. This is possibly due to this particular Cu state failing to utilize the absorbed energy in an advantageous and useful way. "Low biochemical activity occurs in wavelengths in the range of 700–770 nm." [8] We need to find the absorption peak that corresponds to the optimal biological response.
Another study describes the unique configuration of the molecules as follows, corresponding to their absorption peaks: "CCO has absorption peaks in the red (Heme a, 605 nm; CuA reduced, 620 nm; heme a3/CuB, 655 nm; CuB oxidized, 680 nm) and the NIR spectral regions (CuB reduced, 760 nm; CuA oxidized, 825 nm). When light is shone on CCO, photon energy is absorbed by the various metal centers of CCO and their electrons are excited from the ground state to upper excited states." [9]
Researchers have illuminated the reality that targeting the CuA in the oxidized state leads to tremendous response and benefits - which is at the 825nm peak but also includes wavelengths around it, like 810. Oxidized states are likely more active because absorbed light can boost electrons to reduce them. We can see why many subsequent studies have specifically chosen 830nm for its superior absorption peak in CCO and action mechanism. We are now ready to combine tissue optics studies and penetration depth with the action spectra of CCO to determine what the best wavelengths are to ensure ATP activation!
Tina Karu’s ability to define the action spectra and absorption spectrum of CCO in 1999 marked a a pivotal development in our understanding of photobiomodulation. In this seminal research, Karu notes the absorption peaks at the following wavelengths: "with well-pronounced maxima at 620, 680, 760 and 825 nm." [5]
More importantly, each peak corresponds to a specific oxidized or reduced state of the iron (heme) or copper (Cu) molecules in CCO. For example, 760nm corresponds to the reduced state of CuB. Although 760nm has an absorption peak, this wavelength range in the 700's is often found ineffective. This is possibly due to this particular Cu state failing to utilize the absorbed energy in an advantageous and useful way. "Low biochemical activity occurs in wavelengths in the range of 700–770 nm." [8] We need to find the absorption peak that corresponds to the optimal biological response.
Another study describes the unique configuration of the molecules as follows, corresponding to their absorption peaks: "CCO has absorption peaks in the red (Heme a, 605 nm; CuA reduced, 620 nm; heme a3/CuB, 655 nm; CuB oxidized, 680 nm) and the NIR spectral regions (CuB reduced, 760 nm; CuA oxidized, 825 nm). When light is shone on CCO, photon energy is absorbed by the various metal centers of CCO and their electrons are excited from the ground state to upper excited states." [9]
Researchers have illuminated the reality that targeting the CuA in the oxidized state leads to tremendous response and benefits - which is at the 825nm peak but also includes wavelengths around it, like 810. Oxidized states are likely more active because absorbed light can boost electrons to reduce them. We can see why many subsequent studies have specifically chosen 830nm for its superior absorption peak in CCO and action mechanism. We are now ready to combine tissue optics studies and penetration depth with the action spectra of CCO to determine what the best wavelengths are to ensure ATP activation!
The Best of Both Worlds - Combining Tissue Penetration with The Top Two CCO Action Spectra Studies
Putting this elaborate, intricate puzzle together, we see why the most popular wavelengths used to stimulate energy and ATP production with red and near infrared light are between 630 and 680nm and also 808 to around 850nm**. They represent wavelengths that have BOTH maximal penetration AND maximal CCO absorption, in addition to the most exciting action spectra – all of which leads to increased ATP production!! The image here makes this crystal clear, combining the Norris study of penetration depth with the Wong-Riley study (and Karu study) of CCO absorption, activation and ATP generation.
Putting this elaborate, intricate puzzle together, we see why the most popular wavelengths used to stimulate energy and ATP production with red and near infrared light are between 630 and 680nm and also 808 to around 850nm**. They represent wavelengths that have BOTH maximal penetration AND maximal CCO absorption, in addition to the most exciting action spectra – all of which leads to increased ATP production!! The image here makes this crystal clear, combining the Norris study of penetration depth with the Wong-Riley study (and Karu study) of CCO absorption, activation and ATP generation.
Part 3 - The Most Researched Wavelengths in nm (Survey of 5000+ Studies)
To truly understand the science behind red and near infrared light, we first need to ignore EVERYTHING that other red light panel and red light bed companies have claimed. It’s crucial to get our facts straight from science and research studies (and studies, and studies!), not marketing propaganda employed to sell largely inefficient products. Sadly typical of our social media age, where gullible people believe anything they see posted on Facebook or Instagram, many people quote misleading information they read on manufacturer blogs, in articles and videos. Let’s cut through the absolutely mind-boggling marketing hype with a critical question: Which wavelengths are used the most in research studies?
Vladimir Heiskanen’s photobiomodulation database of 7931 peer-reviewed articles (at the time of this writing 2/17/2024) published in the literature is an extremely valuable resource in the annals of red light therapy research. We embarked on several extensive searches on 2/17/2024 across 5508 studies listing the wavelengths used. We went through an extensive range of wavelengths from 600-1400nm and created this table, which features the most common wavelengths employed in order of most frequent occurrences (and a bar graph below to summarize).
To truly understand the science behind red and near infrared light, we first need to ignore EVERYTHING that other red light panel and red light bed companies have claimed. It’s crucial to get our facts straight from science and research studies (and studies, and studies!), not marketing propaganda employed to sell largely inefficient products. Sadly typical of our social media age, where gullible people believe anything they see posted on Facebook or Instagram, many people quote misleading information they read on manufacturer blogs, in articles and videos. Let’s cut through the absolutely mind-boggling marketing hype with a critical question: Which wavelengths are used the most in research studies?
Vladimir Heiskanen’s photobiomodulation database of 7931 peer-reviewed articles (at the time of this writing 2/17/2024) published in the literature is an extremely valuable resource in the annals of red light therapy research. We embarked on several extensive searches on 2/17/2024 across 5508 studies listing the wavelengths used. We went through an extensive range of wavelengths from 600-1400nm and created this table, which features the most common wavelengths employed in order of most frequent occurrences (and a bar graph below to summarize).
We can see 660 is by far the most often utilized, with 830 in second place and then 808, 633 and 810 bunched as the next most regularly researched groups in that order. Combining 808 and 810, it’s clear that 660 and 808/810nm are the top two wavelengths. Combining 630 and 633, we find that is in those upper reaches too, as is putting together 660 and 670. It seems obvious we would want AT LEAST 630 (or 633), 660 (or 670), and 810 (or 808) and 830. Does this mean that these are the best wavelengths to use for PBM? Not necessarily. It’s just that we have a lot of studies and hence great deal of data to justify their use.
Combining these well-known wavelengths with the most relevant action spectra studies, we would be wise to choose 660 or 670nm along with 810 or especially 830nm. The most essential to include is 830nm. Let’s award an honorable mention to 630 or 633nm based on the sheer number of studies. 680nm from the Karu study sounds amazing but lacks experimental research, as I could only find five studies with 680nm. As we'll soon see, we don't need the EXACT wavelength because LEDs spread out a bit (but we do need to be close). This means 808 and 810 are basically the same, as are 630 and 633.
Combining these well-known wavelengths with the most relevant action spectra studies, we would be wise to choose 660 or 670nm along with 810 or especially 830nm. The most essential to include is 830nm. Let’s award an honorable mention to 630 or 633nm based on the sheer number of studies. 680nm from the Karu study sounds amazing but lacks experimental research, as I could only find five studies with 680nm. As we'll soon see, we don't need the EXACT wavelength because LEDs spread out a bit (but we do need to be close). This means 808 and 810 are basically the same, as are 630 and 633.
The Chart Below Shows a Meaningful Sampling of Various Conditions and Which Wavelengths of Light Have the Most evidence for Each Condition. Again notice 630, 660, 810 and 830 dominate as the most research proven wavelengths!
Part 4 - Coherence and LED Emission spectra
(LEDs are Quasimonochromatic)
(LEDs are Quasimonochromatic)
Despite its appearance as rays coming from a massive yellow ball of gas, sunlight is considered white light because it contains all the colors of the rainbow, along with infrared and UV. We could say sunlight is polychromatic (meaning "many-colored"), signifying that it has a wide range of wavelengths. Yet it is also wildly scattered and incoherent, as the light darts in all directions.
LED (light emitting diode) light is different. The primary difference between LED light and sunlight is that LEDs are more monochromatic, which means "one color." It offers a very narrow spectra of wavelengths of light versus a multitude. Technically, LEDs are quasimonochromatic ("quasi-" means "partly" or "almost") because they have a range of wavelengths, albeit a very narrow range compared to sunlight. Light from the sun has a spread, or range, of almost 2000nm while most LEDs run a gamut closer to 20 to 30 nm. LEDs are also quasi-coherent because the light photons move "almost" in the same direction, with a slight divergence.
LASER light is both monochromatic and coherent. It has only one dominant wavelength, meaning that we won't get a range (with a small error margin). The benefits of LEDs are identical to those of lasers, with one fundamental therapeutic difference. Lasers tend to concentrate their energy in a tiny area while LEDs have less power spread over a wider area. LEDs also have a greater range of wavelengths. In some ways this is a fine thing, because they can cover a broader spectrum of therapeutically beneficial wavelengths. There is a place for both in a clinical setting, but full body LED beds and panels are much safer and easier to use, making them ideally suited for homes (and clinics looking for an easy to apply therapy).
LED (light emitting diode) light is different. The primary difference between LED light and sunlight is that LEDs are more monochromatic, which means "one color." It offers a very narrow spectra of wavelengths of light versus a multitude. Technically, LEDs are quasimonochromatic ("quasi-" means "partly" or "almost") because they have a range of wavelengths, albeit a very narrow range compared to sunlight. Light from the sun has a spread, or range, of almost 2000nm while most LEDs run a gamut closer to 20 to 30 nm. LEDs are also quasi-coherent because the light photons move "almost" in the same direction, with a slight divergence.
LASER light is both monochromatic and coherent. It has only one dominant wavelength, meaning that we won't get a range (with a small error margin). The benefits of LEDs are identical to those of lasers, with one fundamental therapeutic difference. Lasers tend to concentrate their energy in a tiny area while LEDs have less power spread over a wider area. LEDs also have a greater range of wavelengths. In some ways this is a fine thing, because they can cover a broader spectrum of therapeutically beneficial wavelengths. There is a place for both in a clinical setting, but full body LED beds and panels are much safer and easier to use, making them ideally suited for homes (and clinics looking for an easy to apply therapy).

Why LEDs cover a range of wavelengths (not just one!)
Johann Carl Friedrich Gauss (1777-1855), was a German mathematician, astronomer, geodesist and physicist who contributed to many fields in math and science. For our purposes, he’s the guy whose concept of Gaussian distribution is a type of continuous probability distribution for real valued random variables.
LEDs are quasimonochromatic because they have a wider spectra or Gaussian distribution, though it’s still quite narrow compared to most light sources. While LEDs are laser focused on their rated wavelength compared to regular light sources, there’s a clear spread or range, which is roughly +/- 10nm for reds (600-700nm) and +/- 15nm for NIR (800-900nm). For example, a 660nm LED will have a range of wavelengths from about 650-670nm and a 830nm LED from 815-845nm, both following the Gaussian distribution model very closely. (Note: these +/- ranges are for full width half maximum as to insure therapeutic value over the entire range - SEE NEXT SECTION).
This broader spectra of LEDs offer the advantage of covering a wider range of known therapeutic wavelengths. With approximately seven different wavelength LEDs, we can blanket the entire therapeutic range of the action spectra of cytochrome c oxidase (600-680nm) and (780-850nm). Four red LEDs can cover 600-680, while three NIR LEDs can cover 800-860. We should definitely add a 900+ like 980nm or 1064 for water as a chromophore and perhaps even a green and blue for other specialized applications (Appendix A).
Johann Carl Friedrich Gauss (1777-1855), was a German mathematician, astronomer, geodesist and physicist who contributed to many fields in math and science. For our purposes, he’s the guy whose concept of Gaussian distribution is a type of continuous probability distribution for real valued random variables.
LEDs are quasimonochromatic because they have a wider spectra or Gaussian distribution, though it’s still quite narrow compared to most light sources. While LEDs are laser focused on their rated wavelength compared to regular light sources, there’s a clear spread or range, which is roughly +/- 10nm for reds (600-700nm) and +/- 15nm for NIR (800-900nm). For example, a 660nm LED will have a range of wavelengths from about 650-670nm and a 830nm LED from 815-845nm, both following the Gaussian distribution model very closely. (Note: these +/- ranges are for full width half maximum as to insure therapeutic value over the entire range - SEE NEXT SECTION).
This broader spectra of LEDs offer the advantage of covering a wider range of known therapeutic wavelengths. With approximately seven different wavelength LEDs, we can blanket the entire therapeutic range of the action spectra of cytochrome c oxidase (600-680nm) and (780-850nm). Four red LEDs can cover 600-680, while three NIR LEDs can cover 800-860. We should definitely add a 900+ like 980nm or 1064 for water as a chromophore and perhaps even a green and blue for other specialized applications (Appendix A).
The Gaussian Distribution of LEDs (Optional Reading)
These +/- ranges of LED wavelengths are best described using the full-width, half- maximum (FWHM) of each analyzed LED. For red and NIR, this is in the ballpark of 20-30 nm, while the FWHM of a laser is on the order 2 nm. FWHM is an engineering acronym denoting the range of wavelengths where there is at least half the power as that peak (hence, the full width of wavelengths that have at least half the maximum power). The major bonus of LEDs over lasers is that we get AT LEAST half power across a range of 20-30nm. This represents 76% of the total output of the LED. This is helpful in calculating irradiance and dosage across different wavelengths of LEDs.
Note: it makes no sense to include BOTH 808 and 810 OR to include both 630 and 633. Because of the LED spread of -/+ 10-15nm, both pairs are essentially the same UNLESS a laser diode is used - which is not the case for full body LED therapy, the focus of this book.
These +/- ranges of LED wavelengths are best described using the full-width, half- maximum (FWHM) of each analyzed LED. For red and NIR, this is in the ballpark of 20-30 nm, while the FWHM of a laser is on the order 2 nm. FWHM is an engineering acronym denoting the range of wavelengths where there is at least half the power as that peak (hence, the full width of wavelengths that have at least half the maximum power). The major bonus of LEDs over lasers is that we get AT LEAST half power across a range of 20-30nm. This represents 76% of the total output of the LED. This is helpful in calculating irradiance and dosage across different wavelengths of LEDs.
Note: it makes no sense to include BOTH 808 and 810 OR to include both 630 and 633. Because of the LED spread of -/+ 10-15nm, both pairs are essentially the same UNLESS a laser diode is used - which is not the case for full body LED therapy, the focus of this book.

All LEDs cover a wide range of wavelengths.
This example is an accurate illustration from a Hopocolor spectroradiometer to test a popular red light therapy bed. We can see that the half maximum on both their 660nm and 850nm LEDs is half the height (which is the irradiance). When we scan through, it is roughly +/- 10nm for 660nm and +/- 15nm for 850nm.
This example is an accurate illustration from a Hopocolor spectroradiometer to test a popular red light therapy bed. We can see that the half maximum on both their 660nm and 850nm LEDs is half the height (which is the irradiance). When we scan through, it is roughly +/- 10nm for 660nm and +/- 15nm for 850nm.

Important Note: We should demand from any reputable red light bed or panel company a verification of the specific wavelengths they claim in their marketing. (We need a spectroradiometer for this - more on this in the next chapter). One company we found claimed to have 660nm, but when we tested it, it was only 630nm!!
Also, it is important to note that wavelength shifts with temperature - typically 0.3nm per 1 ºC (the diode temperature may rise in a treatment session 5 - 20º). We have seen as much as 10nm higher than listed, for example 670nm peak, instead of reported 660nm peak. This is an even more significant problem with high irradiance beds and red light beds that are not properly cooled down.
Also, it is important to note that wavelength shifts with temperature - typically 0.3nm per 1 ºC (the diode temperature may rise in a treatment session 5 - 20º). We have seen as much as 10nm higher than listed, for example 670nm peak, instead of reported 660nm peak. This is an even more significant problem with high irradiance beds and red light beds that are not properly cooled down.
Which Wavelengths are best for Cytochrome C Oxidase Activation?
Taking into account all FOUR factors: Penetration depth, action spectra, research studies and LED emission spectrums, we can now rank (Olympic style) the top wavelengths to use in red and near infrared Light therapy (Drum roll please!).
#1 - 830nm (Winner) - Gold
Top action spectra wavelength, close to best penetration, and second most studies
#2 - 660nm (Runner Up) - Silver
#2 Because of the sheer volume of research, proven and with +/- spread easily covers peak absorption at 670, plus it’s close enough to cover heme absorption at 655. 670nm would work well, too!
#3 - 810/808nm (3rd Place) - Bronze
Deepest penetrating and lots of research. Close to peak action wavelength 825nm.
#4 - 630/633nm (4th Place) - Honorable mention (good to use to balance 600s/800s)
Mainly because of research and proven wavelength. Close to 620nm absorption.
#5 - 850nm - This wavelength also has much research and is a solid choice to include. I would not recommend any 800's above 850 as this gets outside the CCO action spectra (one red light bed company uses 880nm which is in no mans land between CCO and water activation). This is why it is important to demand to know all the wavelengths used!
Taking into account all FOUR factors: Penetration depth, action spectra, research studies and LED emission spectrums, we can now rank (Olympic style) the top wavelengths to use in red and near infrared Light therapy (Drum roll please!).
#1 - 830nm (Winner) - Gold
Top action spectra wavelength, close to best penetration, and second most studies
#2 - 660nm (Runner Up) - Silver
#2 Because of the sheer volume of research, proven and with +/- spread easily covers peak absorption at 670, plus it’s close enough to cover heme absorption at 655. 670nm would work well, too!
#3 - 810/808nm (3rd Place) - Bronze
Deepest penetrating and lots of research. Close to peak action wavelength 825nm.
#4 - 630/633nm (4th Place) - Honorable mention (good to use to balance 600s/800s)
Mainly because of research and proven wavelength. Close to 620nm absorption.
#5 - 850nm - This wavelength also has much research and is a solid choice to include. I would not recommend any 800's above 850 as this gets outside the CCO action spectra (one red light bed company uses 880nm which is in no mans land between CCO and water activation). This is why it is important to demand to know all the wavelengths used!

Part 5 - Why it is important to include 900nm+ Wavelengths!
(900nm-1070nm Wavelengths for EZ Water)!
Thus far, we have focused on cytochrome c oxidase (CCO) and how red light therapy (RLT) stimulates its action spectra to improve mitochondrial function. Once it receives this additional light energy in the known absorption bands (630-680nm and 810-850nm), CCO can stimulate ATP production, lower inflammation and ROS and create beneficial signaling for tissue healing, repair and regeneration - along with increased cellular antioxidants and vastly improved resiliency. [10]
There is more than a single predominate chromophore at play in red and near infrared light therapy. Research illuminates the fact that water is secondarily a very significant chromophore for wavelengths above 800nm, mainly from 900-1100nm. We now have dozens of peer reviewed studies to validate their mechanisms and efficacy.
Water absorption into interstitial mitochondrial areas produces EZ Water (structured water or liquid crystalline water) in the cells, which we introduced in chapters 5 and 6. The salient point is that near infrared light creates EZ when water is adjacent to a hydrophilic (water loving) surface. Proteins, carbohydrates and DNA are all hydrophilic, and as a result, more than 90% of the dry weight of our cells are hydrophilic. They have the potential to create EZ water in the presence of near infrared light. In this section, we will focus on how this EZ Water improves cellular functions in similar ways to CCO absorption. Its five research-proven benefits arise from the distinct physical changes that occur with EZ water, mainly the movement in viscosity, pH and charge separation [11-14]. The much-respected LLLT Handbook, co-authored by the esteemed Dr. Hamblin, includes a chapter about how water is a primary photoacceptor for photobiomodulation. [15] These mechanisms we are about to discuss are firmly established in the photobiomodulation (PBM) and red light therapy research communities and in the mainstream textbooks on the subject.
Since the EZ water layers occur on intracellular membranes, it is logical to suggest that ion channels embedded within these membranes (for instance, in mitochondria) may be triggered by these physical shifts resulting from EZ water creation. Let's look at these five well-researched benefits of using 900-1100nm LEDs, which targets water as a chromophore.
5 Research-Proven Benefits of 900-1100nm near infrared therapy
1) Increases cellular voltage directly
2) Clears ROS and lowers inflammation
3) Improves ATP Synthase activity and hence ATP production
4) Enhances TRPV channels for Proper Calcium Modulation
5) Activates Singlet Oxygen for improved ATP
(900nm-1070nm Wavelengths for EZ Water)!
Thus far, we have focused on cytochrome c oxidase (CCO) and how red light therapy (RLT) stimulates its action spectra to improve mitochondrial function. Once it receives this additional light energy in the known absorption bands (630-680nm and 810-850nm), CCO can stimulate ATP production, lower inflammation and ROS and create beneficial signaling for tissue healing, repair and regeneration - along with increased cellular antioxidants and vastly improved resiliency. [10]
There is more than a single predominate chromophore at play in red and near infrared light therapy. Research illuminates the fact that water is secondarily a very significant chromophore for wavelengths above 800nm, mainly from 900-1100nm. We now have dozens of peer reviewed studies to validate their mechanisms and efficacy.
Water absorption into interstitial mitochondrial areas produces EZ Water (structured water or liquid crystalline water) in the cells, which we introduced in chapters 5 and 6. The salient point is that near infrared light creates EZ when water is adjacent to a hydrophilic (water loving) surface. Proteins, carbohydrates and DNA are all hydrophilic, and as a result, more than 90% of the dry weight of our cells are hydrophilic. They have the potential to create EZ water in the presence of near infrared light. In this section, we will focus on how this EZ Water improves cellular functions in similar ways to CCO absorption. Its five research-proven benefits arise from the distinct physical changes that occur with EZ water, mainly the movement in viscosity, pH and charge separation [11-14]. The much-respected LLLT Handbook, co-authored by the esteemed Dr. Hamblin, includes a chapter about how water is a primary photoacceptor for photobiomodulation. [15] These mechanisms we are about to discuss are firmly established in the photobiomodulation (PBM) and red light therapy research communities and in the mainstream textbooks on the subject.
Since the EZ water layers occur on intracellular membranes, it is logical to suggest that ion channels embedded within these membranes (for instance, in mitochondria) may be triggered by these physical shifts resulting from EZ water creation. Let's look at these five well-researched benefits of using 900-1100nm LEDs, which targets water as a chromophore.
5 Research-Proven Benefits of 900-1100nm near infrared therapy
1) Increases cellular voltage directly
2) Clears ROS and lowers inflammation
3) Improves ATP Synthase activity and hence ATP production
4) Enhances TRPV channels for Proper Calcium Modulation
5) Activates Singlet Oxygen for improved ATP
1) Increases Cellular Voltage Directly
Dr. Gerald Pollack and his research team made the revolutionary discovery that simply adding light to water next to a protein (or any hydrophilic surface) not only increases EZ water creation and expansion, but also generates a charge separation. This process resembles the initial step of photosynthesis. In that process, energy from the sun splits a water molecule, separating positive and negative charges. This charge separation allows water to store energy like a battery, or in this case a bio-battery, where the stored energy can further power cellular processes! [8] Dr. Pollack has demonstrated that radiant energy can generate an exclusion zone (EZ) in a water interface able to store electrical charges while also releasing up to 70% of the input energy! This energy can be tapped to power and enhance all cellular functions and activities, like increased cellular voltage. [8,9]
Important Note: Dr. Gerald Pollack in his well-researched books Cells, Gels and the Engines of Life and The Fourth Phase of Water provides compelling evidence that near infrared light creates EZ water, which can store voltage energy via charge separation (like a battery). He also proves that EZ water and ATP are two main sources of overall cellular energy storage. Pollack cites many researchers that support his conclusions. While it is beyond the scope of this book to get into all the details, the reader can further explore his theories of EZ water in the recommended readings on EZ water at the end of this chapter. The major punchline is that EZ water (liquid crystalline or structured water) in the cells plays a HUGE role in the intricate process of creating ATP and cellular voltage.
Dr. Gerald Pollack and his research team made the revolutionary discovery that simply adding light to water next to a protein (or any hydrophilic surface) not only increases EZ water creation and expansion, but also generates a charge separation. This process resembles the initial step of photosynthesis. In that process, energy from the sun splits a water molecule, separating positive and negative charges. This charge separation allows water to store energy like a battery, or in this case a bio-battery, where the stored energy can further power cellular processes! [8] Dr. Pollack has demonstrated that radiant energy can generate an exclusion zone (EZ) in a water interface able to store electrical charges while also releasing up to 70% of the input energy! This energy can be tapped to power and enhance all cellular functions and activities, like increased cellular voltage. [8,9]
Important Note: Dr. Gerald Pollack in his well-researched books Cells, Gels and the Engines of Life and The Fourth Phase of Water provides compelling evidence that near infrared light creates EZ water, which can store voltage energy via charge separation (like a battery). He also proves that EZ water and ATP are two main sources of overall cellular energy storage. Pollack cites many researchers that support his conclusions. While it is beyond the scope of this book to get into all the details, the reader can further explore his theories of EZ water in the recommended readings on EZ water at the end of this chapter. The major punchline is that EZ water (liquid crystalline or structured water) in the cells plays a HUGE role in the intricate process of creating ATP and cellular voltage.

2) Clears ROS and lowers Inflammation
In a peer-reviewed article titled "Aging Is a Sticky Business," the authors lay out a mechanism of mitochondrial dysfunction where ROS (reactive oxygen species) accumulation in the mitochondria causes a reduction of ATP production. The ROS causes an increase in viscosity (or stickiness, as implied by the title), and the absorption of near infrared light (900nm-1100nm) eliminates the ROS and improves and elevates ATP production again.[16]
Reactive oxygen species (ROS) are more than electron hungry free radicals that can damage or "rust" the cells organelles and components (proteins, etc.). They also have a unique villainous superpower - to make water thicker and stickier, which gums up and slows down cellular energetics like ATP production. Studies have shown that the near infrared wavelengths reduce both ROS and the viscosity of water, causing water to flow better and, as much as is possible, actually become wetter. [17] This is especially important in ATP synthase activity and function, which leads us to yet another benefit of creating EZ water in the cells.
In a peer-reviewed article titled "Aging Is a Sticky Business," the authors lay out a mechanism of mitochondrial dysfunction where ROS (reactive oxygen species) accumulation in the mitochondria causes a reduction of ATP production. The ROS causes an increase in viscosity (or stickiness, as implied by the title), and the absorption of near infrared light (900nm-1100nm) eliminates the ROS and improves and elevates ATP production again.[16]
Reactive oxygen species (ROS) are more than electron hungry free radicals that can damage or "rust" the cells organelles and components (proteins, etc.). They also have a unique villainous superpower - to make water thicker and stickier, which gums up and slows down cellular energetics like ATP production. Studies have shown that the near infrared wavelengths reduce both ROS and the viscosity of water, causing water to flow better and, as much as is possible, actually become wetter. [17] This is especially important in ATP synthase activity and function, which leads us to yet another benefit of creating EZ water in the cells.
3) Improves ATP Synthase activity and hence ATP production
When the membranes of the mitochondria are "sticky," or glue-like, from ROS, the gooeyness naturally hinders the production of ATP and the mitochondrial ATP synthase rotary motor.[18] Researcher Andrei Sommer and his team have found that the decrease in viscosity of water in the mitochondrial membranes caused by red and near infrared light is sufficient to restore the ATP synthase rotor back to its full functionality. [18] Recall from Chapter 6 that ATP synthase is the fifth and most critical complex/enzyme in the electron transport chain. Using its molecular rotor, ATP synthase harnesses the flow of water from the proton gradients to generate tons of energy, much like a water turbine does at a dam. Imagine if the turbine, or "water-wheel," axis was not lubricated and failed to turn easily. It would generate less electricity due to the added friction. Likewise with ROS and "sticky," or high viscosity, water. It clogs and slows down the ATP synthase molecular turbine.
Near infrared light over 900nm (most notably 980nm, used extensively in research) helps enhance ATP synthase activity by lowering the viscosity of EZ water surrounding the mitochondrial membrane, which allows protons to more easily flow downstream. This lower viscosity makes water "wetter" and more slippery, akin to "greasing the wheels" of the ATP synthase molecular rotor and allowing the proverbial wheels of life to spin more rapidly, not to mention effortlessly. This in turn generates even more ATP! [16-19]
When the membranes of the mitochondria are "sticky," or glue-like, from ROS, the gooeyness naturally hinders the production of ATP and the mitochondrial ATP synthase rotary motor.[18] Researcher Andrei Sommer and his team have found that the decrease in viscosity of water in the mitochondrial membranes caused by red and near infrared light is sufficient to restore the ATP synthase rotor back to its full functionality. [18] Recall from Chapter 6 that ATP synthase is the fifth and most critical complex/enzyme in the electron transport chain. Using its molecular rotor, ATP synthase harnesses the flow of water from the proton gradients to generate tons of energy, much like a water turbine does at a dam. Imagine if the turbine, or "water-wheel," axis was not lubricated and failed to turn easily. It would generate less electricity due to the added friction. Likewise with ROS and "sticky," or high viscosity, water. It clogs and slows down the ATP synthase molecular turbine.
Near infrared light over 900nm (most notably 980nm, used extensively in research) helps enhance ATP synthase activity by lowering the viscosity of EZ water surrounding the mitochondrial membrane, which allows protons to more easily flow downstream. This lower viscosity makes water "wetter" and more slippery, akin to "greasing the wheels" of the ATP synthase molecular rotor and allowing the proverbial wheels of life to spin more rapidly, not to mention effortlessly. This in turn generates even more ATP! [16-19]

4) Enhances TRPV channels for Proper Calcium Modulation
The fourth research-proven benefit of near infrared light in creating EZ water is also related to its viscosity/stickiness lowering effect. The research targets the way 980nm is used to enhance heat/light gated ion channels (called TRPV channels) that modulate calcium levels. When these channels have a lowered water viscosity, healthy calcium levels in the cells can normalize. Calcium is a critical ion for cellular energetics and calcium signaling is an essential pathway inherent in many cell types. Ill health results when calcium levels are out of whack. By making water wetter, near infrared light facilitates the opening of these channels and allows calcium to better flow where it is needed. [20]
The fourth research-proven benefit of near infrared light in creating EZ water is also related to its viscosity/stickiness lowering effect. The research targets the way 980nm is used to enhance heat/light gated ion channels (called TRPV channels) that modulate calcium levels. When these channels have a lowered water viscosity, healthy calcium levels in the cells can normalize. Calcium is a critical ion for cellular energetics and calcium signaling is an essential pathway inherent in many cell types. Ill health results when calcium levels are out of whack. By making water wetter, near infrared light facilitates the opening of these channels and allows calcium to better flow where it is needed. [20]

5) Activates Singlet Oxygen for improved ATP
The fifth well-researched benefit of near infrared light is specifically with 1064nm, the peak absorption converting ground state oxygen to singlet oxygen so it may help to enhance ATP activity. Boosting electrons in oxygen to a higher state helps electrify the electron transport chain, which facilitates the pumping out of H+ ions to hasten the production of ATP. Other wavelengths in the red and near infrared can directly affect ground state oxygen to singlet oxygen as well, but there is a peak at 1063/1064. [21]
The fifth well-researched benefit of near infrared light is specifically with 1064nm, the peak absorption converting ground state oxygen to singlet oxygen so it may help to enhance ATP activity. Boosting electrons in oxygen to a higher state helps electrify the electron transport chain, which facilitates the pumping out of H+ ions to hasten the production of ATP. Other wavelengths in the red and near infrared can directly affect ground state oxygen to singlet oxygen as well, but there is a peak at 1063/1064. [21]

What are the Best 900nm-11oonm wavelengths to use?
Now that we have seen all the benefits of employing at least one 900nm-1100nm wavelength in our red and near infrared full body device, we arrive naturally at a thoughtful question: What are the foremost wavelengths for creating EZ water in the cells and mitochondria?
Just like cytochrome c oxidase, it turns the action spectra of water in the same manner as a chromophore closely follows its absorption spectra. The creation of EZ water (action spectra) increases in proportion to the amount of light absorbed at a given wavelength (absorption spectra). Water has a peak absorption of approximately 3100nm, and Dr. Gerald Pollack and his team of researchers found this wavelength to also be the maximum for EZ water generation and expansion. Extra EZ water translates to an elevated cellular energy and more of the five benefits we just discussed.
Note in the above image: In this study, due to technical limitations, the researches had to use a lower intensity infrared (IR) light source for the wavelengths above 1000nm. When compared to the wavelengths, the projected values are between 200-700nm. We should also note the gap between 700 and 1800nm. Yet because the absorption matches the action spectra, we can look at the absorption of water in this range and feel free to interpolate (see image below).
Now that we have seen all the benefits of employing at least one 900nm-1100nm wavelength in our red and near infrared full body device, we arrive naturally at a thoughtful question: What are the foremost wavelengths for creating EZ water in the cells and mitochondria?
Just like cytochrome c oxidase, it turns the action spectra of water in the same manner as a chromophore closely follows its absorption spectra. The creation of EZ water (action spectra) increases in proportion to the amount of light absorbed at a given wavelength (absorption spectra). Water has a peak absorption of approximately 3100nm, and Dr. Gerald Pollack and his team of researchers found this wavelength to also be the maximum for EZ water generation and expansion. Extra EZ water translates to an elevated cellular energy and more of the five benefits we just discussed.
Note in the above image: In this study, due to technical limitations, the researches had to use a lower intensity infrared (IR) light source for the wavelengths above 1000nm. When compared to the wavelengths, the projected values are between 200-700nm. We should also note the gap between 700 and 1800nm. Yet because the absorption matches the action spectra, we can look at the absorption of water in this range and feel free to interpolate (see image below).

In this image, we see an increase in water absorption going up from 810 with a LOCAL peak at 980nm and a dip at 1064nm, then rising and falling slightly numerous times up to the peak at 3100nm. There is a reason 980nm and 1064nm are the best two for the 900nm+ near infrared LED therapy. They have the perfect blend of DEEP penetration optimized with absorption and minimal tissue heating. All three factors are essential to be optimized. If absorption was the only factor, everyone would use 3100nm.
There are two reasons we do NOT use 3100nm. First, when we compare this to the Norris penetration depth study, the 3100nm simply does not penetrate well; in fact, its penetration rate is as poor as blue and UV, which hardly penetrate a millimeter. Second, it has more heating effects, and studies show that when we elevate the temperature of the tissue, it largely stunts the impact of near infrared light therapy. Heat limits both penetration depth and cytochrome c oxidase activity. It is noteworthy that solar panels are also less efficient as they heat up; their peak efficiency is in the winter. Thermal vibrations disrupt the absorption of light by CCO, just as they impede the absorption of light on solar cells in solar panels. This explains why we don't see red light panels, lasers or beds with any LEDs above 1064nm (refer to our survey of wavelengths in the last section and the link to the myriad studies).
There are two reasons we do NOT use 3100nm. First, when we compare this to the Norris penetration depth study, the 3100nm simply does not penetrate well; in fact, its penetration rate is as poor as blue and UV, which hardly penetrate a millimeter. Second, it has more heating effects, and studies show that when we elevate the temperature of the tissue, it largely stunts the impact of near infrared light therapy. Heat limits both penetration depth and cytochrome c oxidase activity. It is noteworthy that solar panels are also less efficient as they heat up; their peak efficiency is in the winter. Thermal vibrations disrupt the absorption of light by CCO, just as they impede the absorption of light on solar cells in solar panels. This explains why we don't see red light panels, lasers or beds with any LEDs above 1064nm (refer to our survey of wavelengths in the last section and the link to the myriad studies).
While 810 and 830nm are great wavelengths because of their penetration depths, 980 and 1064nm will generate at least TWICE the amount of EZ water as 810 and 830, according to Dr. Gerald Pollack's research (and even more than red in the 600-680nm range). 810 and 830 will still create EZ water in addition to activating CCO, making them the most versatile wavelengths [22]. This is the reason that it’s best to use multiple wavelengths is best and why we want at least a 980nm or 1064nm wavelength in our bed or panel. By doing so, we are blessed with the best of both worlds of CCO activation and EZ water expansion/creation. [23]
Which Wavelengths are best for EZ Water Activation?
Taking into account all FOUR factors - penetration depth, action spectra, research studies and LED emission spectrums - we can rank (Olympic style, again!) the top 900nm+ wavelengths to use in red and near infrared light therapy (Drum roll please).
#1 - 980nm (Winner) - Gold
980nm edges out 1064nm because it is better at creating EZ water. This wavelength was specifically used in the studies showing enhanced ATP synthase activity and better function of TRPV channels (#2,#3 and #4 on our list of five benefits). 980nm also has the second most studies, closely behind 1064nm.
#2 - 1064nm (Runner Up) - Silver
1064nm is a very close second due to the sheer volume of research, and because it is the deepest penetrating. This wavelength is the peak for creating singlet oxygen as well.
#3 - 940nm (3rd Place) - Bronze
940nm is a distant but solid third place, mainly because it has been part of numerous studies (third most behind 1064 and 980).
Conclusion: While the action spectra for cytochrome c oxidase (630-680nm and 800-850nm) yields excited electrons that can pass on to oxygen as the crucial step in ATP production, the action spectra for water (900-1100nm ideally) yields what Gerald Pollack calls EZ water. This creates all manner of dynamic benefits in the cells, including increased cellular voltage, improved ATP production via ATP synthase activation, accelerated ion transport in calcium channels, reduced ROS and inflammation and increased singlet oxygen for better electron flow in the electron transport chain. The most thorough research and evidence suggests that 980nm and 1064nm are the most effective and powerful 900nm+ near infrared wavelengths to use. Everyone should look for a panel or bed with at least one 900nm+ wavelength, especially 980nm/1064nm.
Which Wavelengths are best for EZ Water Activation?
Taking into account all FOUR factors - penetration depth, action spectra, research studies and LED emission spectrums - we can rank (Olympic style, again!) the top 900nm+ wavelengths to use in red and near infrared light therapy (Drum roll please).
#1 - 980nm (Winner) - Gold
980nm edges out 1064nm because it is better at creating EZ water. This wavelength was specifically used in the studies showing enhanced ATP synthase activity and better function of TRPV channels (#2,#3 and #4 on our list of five benefits). 980nm also has the second most studies, closely behind 1064nm.
#2 - 1064nm (Runner Up) - Silver
1064nm is a very close second due to the sheer volume of research, and because it is the deepest penetrating. This wavelength is the peak for creating singlet oxygen as well.
#3 - 940nm (3rd Place) - Bronze
940nm is a distant but solid third place, mainly because it has been part of numerous studies (third most behind 1064 and 980).
Conclusion: While the action spectra for cytochrome c oxidase (630-680nm and 800-850nm) yields excited electrons that can pass on to oxygen as the crucial step in ATP production, the action spectra for water (900-1100nm ideally) yields what Gerald Pollack calls EZ water. This creates all manner of dynamic benefits in the cells, including increased cellular voltage, improved ATP production via ATP synthase activation, accelerated ion transport in calcium channels, reduced ROS and inflammation and increased singlet oxygen for better electron flow in the electron transport chain. The most thorough research and evidence suggests that 980nm and 1064nm are the most effective and powerful 900nm+ near infrared wavelengths to use. Everyone should look for a panel or bed with at least one 900nm+ wavelength, especially 980nm/1064nm.
This brings us to the concluding topic of this chapter - why using more proven wavelengths is BETTER than using fewer, provided we can create an even spread of light for each wavelength across the area of application (this is done by adjusting the beam angle and a proper distance away). For example, 830nm is fantastic, but 830/660 together is better, and 830/810/660/630 is even more amazing. Ideally, it’s good to balance the 600s with the 800s, as with the stellar combination 830/810/660/630, and add at least one 980nm or 1064nm.
Part 6 - Multi-light-a-min Approach
A Compelling Case for Multiple Wavelengths
A Compelling Case for Multiple Wavelengths

The next question we need to ask when considering a full body red light panel or bed is: How many wavelengths does the bed have? Just two, four, five or six or more? All whole-body light beds and panels on the market have between two to ten wavelengths. The astute reader probably has surmised by now that it’s most ideal to use multiple wavelengths to better "blanket" these therapeutic ranges. Our research backs this up!
There is compelling evidence suggesting that Cytochrome C Oxidase (CCO) is the MAIN chromophore (light harnessing molecule) responsible for the multitude of wonderful, life-affirming mechanisms and healing benefits of red light therapy. CCO has 16 different configurations. Due to the 2 copper and 2 heme centers, each has an oxidized and reduced state - and EACH of these configurations boasts a different band gap, which gives CCO a broad spectrum of 16 wavelengths to absorb, NOT JUST ONE! Studies by Wong-Riley and others have shown that this range peaks around 605-680 and 800-880. Having multiple wavelengths increases the "odds" of light being absorbed by the mitochondria to create not only energy but all the other wonderful benefits red light therapy provides. Since we don’t know exactly what “state” our copper and porphyrin heme molecules are in during treatment, it may be wise to "hedge our bets" and cover the full range of wavelengths that can absorb into a variety of the 16 possibilities. Ideally, we want a bed with the BROADEST spectrum of wavelengths in the 605-680 and 800-880 range, with at least ONE 900-1100nm to activate EZ water for extra cellular energy and reduced water viscosity! Many red light bed and panel companies have failed to receive the proverbial memo so far, but thankfully, we continue to spot a hopeful trend towards using more proven wavelengths.
The analogy we make is: It’s like consuming "just" Vitamin A and Vitamin D vs. taking a full spectrum multivitamin with A, B1,B2, B3, B5, B6, B12, C, E, D and additional minerals and other antioxidants. A state-of-the-art red light therapy system with 5 - 10 different wavelengths gives us very rich spectral content, akin to an all-purpose "multi-light-a-min" that provides everything our bodies need ALL AT once. A bare minimum would be five with 630-660-810-830/850-980. Those are THE most effective five, but we can add some extras like 600/605 for the skin, 640, 670, 850 and possibly a blue and a green as well.
There are many studies showing that multiple wavelengths together work better [24-33]!
There is compelling evidence suggesting that Cytochrome C Oxidase (CCO) is the MAIN chromophore (light harnessing molecule) responsible for the multitude of wonderful, life-affirming mechanisms and healing benefits of red light therapy. CCO has 16 different configurations. Due to the 2 copper and 2 heme centers, each has an oxidized and reduced state - and EACH of these configurations boasts a different band gap, which gives CCO a broad spectrum of 16 wavelengths to absorb, NOT JUST ONE! Studies by Wong-Riley and others have shown that this range peaks around 605-680 and 800-880. Having multiple wavelengths increases the "odds" of light being absorbed by the mitochondria to create not only energy but all the other wonderful benefits red light therapy provides. Since we don’t know exactly what “state” our copper and porphyrin heme molecules are in during treatment, it may be wise to "hedge our bets" and cover the full range of wavelengths that can absorb into a variety of the 16 possibilities. Ideally, we want a bed with the BROADEST spectrum of wavelengths in the 605-680 and 800-880 range, with at least ONE 900-1100nm to activate EZ water for extra cellular energy and reduced water viscosity! Many red light bed and panel companies have failed to receive the proverbial memo so far, but thankfully, we continue to spot a hopeful trend towards using more proven wavelengths.
The analogy we make is: It’s like consuming "just" Vitamin A and Vitamin D vs. taking a full spectrum multivitamin with A, B1,B2, B3, B5, B6, B12, C, E, D and additional minerals and other antioxidants. A state-of-the-art red light therapy system with 5 - 10 different wavelengths gives us very rich spectral content, akin to an all-purpose "multi-light-a-min" that provides everything our bodies need ALL AT once. A bare minimum would be five with 630-660-810-830/850-980. Those are THE most effective five, but we can add some extras like 600/605 for the skin, 640, 670, 850 and possibly a blue and a green as well.
There are many studies showing that multiple wavelengths together work better [24-33]!
Conclusion - Look for a full red light panel or bed that blankets the therapeutic ranges with at least half maximum. Make sure to include at least one 900nm+ LED ideally 980nm and / or 1064nm. Based on easy calculations using FWHM of 600s and 800s and including the most researched wavelengths, we need a bare minimum of five wavelengths (like 630-660-810-830/850-980). Add an additional 600 and 830/850 to fully blanket the biologically active windows of 600-680 and 800-860. Other excellent wavelengths we can add are blue for acne and green for its many benefits, outlined in chapter 9 and Appendix B. If there are only 2-4 wavelengths, we are likely missing major “chunks” of therapeutic ranges. If we use the wrong wavelengths, say the way one company substitutes 880nm as their only 800, we are completely missing the 800s, as 880 is outside the therapeutic window for cytochrome C oxidase.
Demand Verification of Wavelengths Claimed.
Only two companies - Novothor and Spectra Red Light - can send test reports verifying the touted wavelengths as accurate and legitimate. Buyer Beware: If a company claims to have a proprietary blend yet fails to disclose the precise wavelengths they use - MOVE ON! If they cannot disclose one of the two most important parameters of a full body red light bed or panel (wavelength and irradiance), that is unacceptable and most likely a scam. It’s like a multi-vitamin bottle or container without a label listing the active ingredients. We must know the lab verified wavelengths. Remember, more wavelengths are better, providing that the light is spread uniformly.
In the next chapter, we will examine irradiance, the intensity of light given off by a red light bed or panel. Along with the wavelengths used, this is the other KEY parameter we must fully understand via lab certified testing! We'll see that incorrect irradiance measurements and listings comprise the largest scale scam in the entire red light industry. This chapter and the next two are probably THE most important, offering details of exactly what we need to look for in a full body red light panel or bed.
******END OF CHAPTER*****
NO MORE EDITING OR ILLUSTRATIONS PAST THIS POINT
Demand Verification of Wavelengths Claimed.
Only two companies - Novothor and Spectra Red Light - can send test reports verifying the touted wavelengths as accurate and legitimate. Buyer Beware: If a company claims to have a proprietary blend yet fails to disclose the precise wavelengths they use - MOVE ON! If they cannot disclose one of the two most important parameters of a full body red light bed or panel (wavelength and irradiance), that is unacceptable and most likely a scam. It’s like a multi-vitamin bottle or container without a label listing the active ingredients. We must know the lab verified wavelengths. Remember, more wavelengths are better, providing that the light is spread uniformly.
In the next chapter, we will examine irradiance, the intensity of light given off by a red light bed or panel. Along with the wavelengths used, this is the other KEY parameter we must fully understand via lab certified testing! We'll see that incorrect irradiance measurements and listings comprise the largest scale scam in the entire red light industry. This chapter and the next two are probably THE most important, offering details of exactly what we need to look for in a full body red light panel or bed.
******END OF CHAPTER*****
NO MORE EDITING OR ILLUSTRATIONS PAST THIS POINT
References Chapter 10
[1] S. L. Jacques, “Optical properties of biological tissues: a review,” Phys. Med. Biol. 58(11), R37–61 (2013).
[2] The spectrum was recorded with a very sensitive spectrophotometer with the hand in close juxtaposition with the photocathode (unpublished data of Karl H. Norris, from The Science of Photobiology (KC Smith, ed., Plenum Press, 1977; p. 400).
[3] Tedford, C.E., DeLapp, S., Jacques, S., Anders, J., 2015. Quantitative analysis of transcranial and intraparenchymal light penetration in human cadaver brain tissue. Lasers Surg. Med. 47, 312322. Available from: https://doi.org/10.1002/lsm.22343.
[4] Hartman, K.M., 1983. Action spectroscopy. In: Hoppe, W., Lohmann, W., Marke, H., Ziegler, H. (Eds.), Biophysics. Springer-Verlag, Heidelberg.
[5] Karu, T., 1999a. Primary and secondary mechanisms of action of visible to near-IR radiation on cells. J. Photochem. Photobiol. B 49, 117.
http://photobiology.info/Karu.html
[6] Wong-Riley, M.T., Liang, H.L., Eells, J.T., Chance, B., Henry, M.M., Buchmann, E., et al., 2005. Photobiomodulation directly benefits primary neurons functionally inactivated by toxins: role of cytochrome c oxidase. J. Biol. Chem. 280, 47614771. Read the full article here: https://www.jbc.org/article/S0021-9258(20)76125-9/fulltext
[7] Cooper, C.E., Springett, R., 1997. Measurement of cytochrome oxidase and mitochondrial energetic by near-infrared spectroscopy. Philos. Trans. R. Soc. Lond. B Biol. Sci. 352, 669676.
[8] Dompe, Claudia et al. “Photobiomodulation-Underlying Mechanism and Clinical Applications.” Journal of clinical medicine vol. 9,6 1724. 3 Jun. 2020
[9] Salehpour, Farzad et al. “Brain Photobiomodulation Therapy: a Narrative Review.” Molecular neurobiology vol. 55,8 (2018): 6601-6636.
[10] Chung H, Dai T, Sharma SK, Huang YY, Carroll JD, Hamblin MR. The nuts and bolts of low-level laser (light) therapy. Ann Biomed Eng. 2012;40(2):516-533.
[11]Pollack, G.H., 2003. The role of aqueous interfaces in the cell. Adv. Colloid Interface Sci. 103 (2), 173196
[12] Pollack, G.H., Reitz, F.B., 2001. Phase transitions and molecular motion in the cell. Cell Mol. Biol. (Noisy-le-grand). 47 (5), 885900.
[13] Trevors, J.T., Pollack, G.H., 2012. Origin of microbial life hypothesis: a gel cytoplasm lacking a bilayer membrane, with infrared radiation producing
exclusion zone (EZ) water, hydrogen as an energy source and thermosynthesis for bioenergetics. Biochimie 94 (1), 258262.
[14] Pollack GH. Cell electrical properties: reconsidering the origin of the electrical potential. Cell biology international. 2015;39(3):237–242
[15] Hamblin M, Pires de Sousa MV, Agrawal T. Handbook of Low-Level Laser Therapy 2017 Pan Stanford Publishing Pte. Ltd.
[16] Sommer AP. Aging Is a Sticky Business. Photomed Laser Surg. 2018 May;36(5):284-286.
[17] Andrei P. Sommer.Photobiomodulation, Photomedicine, and Laser Surgery.Jun 2019.336-341.
[18] Sommer AP. Mitochondrial cytochrome c oxidase is not the primary acceptor for near infrared light-it is mitochondrial bound water: the principles of low-level light therapy. Ann Transl Med. 2019;7(Suppl 1):S13.
[19] Sommer AP, Haddad MK, Fecht H-J. Light effect on water viscosity: implication for ATP biosynthesis. Sci Rep 2015;5:12029.
[20]. Wang Y, et al. Photobiomodulation of human adipose-derived stem cells using 810nm and 980nm lasers operates via different mechanisms of action. Biochim Biophys Acta. 2016
[21] Alfonso Blázquez-Castro, Direct 1O2 optical excitation: A tool for redox biology, Redox Biology, Volume 13, 2017, Pages 39-59,
[22] Tsai SR, Hamblin MR. Biological effects and medical applications of infrared radiation. J Photochem Photobiol B. 2017 May;170:197-207
[23] Dompe C, Moncrieff L, Matys J, Grzech-Leśniak K, Kocherova I, Bryja A, Bruska M, Dominiak M, Mozdziak P, Skiba THI, Shibli JA, Angelova Volponi A, Kempisty B, Dyszkiewicz-Konwińska M. Photobiomodulation-Underlying Mechanism and Clinical Applications. J Clin Med. 2020 Jun 3;9(6):1724.
[24] Lima, Andrezza & Sergio, Luiz Philippe & Fonseca, Adenilson. (2020). Photobiomodulation via multiple-wavelength radiations. Lasers in Medical Science. 35
[25] Tsai SR, Hamblin MR. Biological effects and medical applications of infrared radiation. J Photochem Photobiol B. 2017 May;170:197-207. doi: 10.1016/j.jphotobiol.2017.04.014. Epub 2017 Apr 13. PMID: 28441605; PMCID: PMC5505738.
[26] Ferraresi C, Huang YY, Hamblin MR. Photobiomodulation in human muscle tissue: an advantage in sports performance? J Biophotonics. 2016 Dec;9(11-12):1273-1299
[27] Pope NJ, Powell SM, Wigle JC, Denton ML. Wavelength- and irradiance-dependent changes in intracellular nitric oxide level. J Biomed Opt. 2020 Aug;25(8):1-20.
[28] Ferraresi C, Huang YY, Hamblin MR. Photobiomodulation in human muscle tissue: an advantage in sports performance? J Biophotonics. 2016 Dec;9(11-12):1273-1299
[29] Yang M, Yang Z, Wang P, Sun Z. Current application and future directions of photobiomodulation in central nervous diseases. Neural Regen Res. 2021 Jun;16(6):1177-1185
[30] Lee SY, Park KH, Choi JW, Kwon JK, Lee DR, Shin MS, Lee JS, You CE, Park MY. A prospective, randomized, placebo-controlled, double-blinded, and split-face clinical study on LED phototherapy for skin rejuvenation: clinical, profilometric, histologic, ultrastructural, and biochemical evaluations and comparison of three different treatment settings. J Photochem Photobiol B. 2007 Jul 27;88(1):51-67.
[31] Fekrazad R, Sarrafzadeh A, Kalhori KAM, Khan I, Arany PR, Giubellino A. Improved Wound Remodeling Correlates with Modulated TGF-beta Expression in Skin Diabetic Wounds Following Combined Red and Infrared Photobiomodulation Treatments. Photochem Photobiol. 2018 Jul;94(4):775-779.
[32] Zein R, Selting W, Hamblin MR. Review of light parameters and photobiomodulation efficacy: dive into complexity. J Biomed Opt. 2018 Dec;23(12):1-17.
[33] Kuryliszyn-Moskal A, Kita J, Dakowicz A, Chwieśko-Minarowska S, Moskal D, Kosztyła-Hojna B, Jabłońska E, Klimiuk PA. The influence of Multiwave Locked System (MLS) laser therapy on clinical features, microcirculatory abnormalities and selected modulators of angiogenesis in patients with Raynaud's phenomenon. Clin Rheumatol. 2015 Mar;34(3):489-96.
[1] S. L. Jacques, “Optical properties of biological tissues: a review,” Phys. Med. Biol. 58(11), R37–61 (2013).
[2] The spectrum was recorded with a very sensitive spectrophotometer with the hand in close juxtaposition with the photocathode (unpublished data of Karl H. Norris, from The Science of Photobiology (KC Smith, ed., Plenum Press, 1977; p. 400).
[3] Tedford, C.E., DeLapp, S., Jacques, S., Anders, J., 2015. Quantitative analysis of transcranial and intraparenchymal light penetration in human cadaver brain tissue. Lasers Surg. Med. 47, 312322. Available from: https://doi.org/10.1002/lsm.22343.
[4] Hartman, K.M., 1983. Action spectroscopy. In: Hoppe, W., Lohmann, W., Marke, H., Ziegler, H. (Eds.), Biophysics. Springer-Verlag, Heidelberg.
[5] Karu, T., 1999a. Primary and secondary mechanisms of action of visible to near-IR radiation on cells. J. Photochem. Photobiol. B 49, 117.
http://photobiology.info/Karu.html
[6] Wong-Riley, M.T., Liang, H.L., Eells, J.T., Chance, B., Henry, M.M., Buchmann, E., et al., 2005. Photobiomodulation directly benefits primary neurons functionally inactivated by toxins: role of cytochrome c oxidase. J. Biol. Chem. 280, 47614771. Read the full article here: https://www.jbc.org/article/S0021-9258(20)76125-9/fulltext
[7] Cooper, C.E., Springett, R., 1997. Measurement of cytochrome oxidase and mitochondrial energetic by near-infrared spectroscopy. Philos. Trans. R. Soc. Lond. B Biol. Sci. 352, 669676.
[8] Dompe, Claudia et al. “Photobiomodulation-Underlying Mechanism and Clinical Applications.” Journal of clinical medicine vol. 9,6 1724. 3 Jun. 2020
[9] Salehpour, Farzad et al. “Brain Photobiomodulation Therapy: a Narrative Review.” Molecular neurobiology vol. 55,8 (2018): 6601-6636.
[10] Chung H, Dai T, Sharma SK, Huang YY, Carroll JD, Hamblin MR. The nuts and bolts of low-level laser (light) therapy. Ann Biomed Eng. 2012;40(2):516-533.
[11]Pollack, G.H., 2003. The role of aqueous interfaces in the cell. Adv. Colloid Interface Sci. 103 (2), 173196
[12] Pollack, G.H., Reitz, F.B., 2001. Phase transitions and molecular motion in the cell. Cell Mol. Biol. (Noisy-le-grand). 47 (5), 885900.
[13] Trevors, J.T., Pollack, G.H., 2012. Origin of microbial life hypothesis: a gel cytoplasm lacking a bilayer membrane, with infrared radiation producing
exclusion zone (EZ) water, hydrogen as an energy source and thermosynthesis for bioenergetics. Biochimie 94 (1), 258262.
[14] Pollack GH. Cell electrical properties: reconsidering the origin of the electrical potential. Cell biology international. 2015;39(3):237–242
[15] Hamblin M, Pires de Sousa MV, Agrawal T. Handbook of Low-Level Laser Therapy 2017 Pan Stanford Publishing Pte. Ltd.
[16] Sommer AP. Aging Is a Sticky Business. Photomed Laser Surg. 2018 May;36(5):284-286.
[17] Andrei P. Sommer.Photobiomodulation, Photomedicine, and Laser Surgery.Jun 2019.336-341.
[18] Sommer AP. Mitochondrial cytochrome c oxidase is not the primary acceptor for near infrared light-it is mitochondrial bound water: the principles of low-level light therapy. Ann Transl Med. 2019;7(Suppl 1):S13.
[19] Sommer AP, Haddad MK, Fecht H-J. Light effect on water viscosity: implication for ATP biosynthesis. Sci Rep 2015;5:12029.
[20]. Wang Y, et al. Photobiomodulation of human adipose-derived stem cells using 810nm and 980nm lasers operates via different mechanisms of action. Biochim Biophys Acta. 2016
[21] Alfonso Blázquez-Castro, Direct 1O2 optical excitation: A tool for redox biology, Redox Biology, Volume 13, 2017, Pages 39-59,
[22] Tsai SR, Hamblin MR. Biological effects and medical applications of infrared radiation. J Photochem Photobiol B. 2017 May;170:197-207
[23] Dompe C, Moncrieff L, Matys J, Grzech-Leśniak K, Kocherova I, Bryja A, Bruska M, Dominiak M, Mozdziak P, Skiba THI, Shibli JA, Angelova Volponi A, Kempisty B, Dyszkiewicz-Konwińska M. Photobiomodulation-Underlying Mechanism and Clinical Applications. J Clin Med. 2020 Jun 3;9(6):1724.
[24] Lima, Andrezza & Sergio, Luiz Philippe & Fonseca, Adenilson. (2020). Photobiomodulation via multiple-wavelength radiations. Lasers in Medical Science. 35
[25] Tsai SR, Hamblin MR. Biological effects and medical applications of infrared radiation. J Photochem Photobiol B. 2017 May;170:197-207. doi: 10.1016/j.jphotobiol.2017.04.014. Epub 2017 Apr 13. PMID: 28441605; PMCID: PMC5505738.
[26] Ferraresi C, Huang YY, Hamblin MR. Photobiomodulation in human muscle tissue: an advantage in sports performance? J Biophotonics. 2016 Dec;9(11-12):1273-1299
[27] Pope NJ, Powell SM, Wigle JC, Denton ML. Wavelength- and irradiance-dependent changes in intracellular nitric oxide level. J Biomed Opt. 2020 Aug;25(8):1-20.
[28] Ferraresi C, Huang YY, Hamblin MR. Photobiomodulation in human muscle tissue: an advantage in sports performance? J Biophotonics. 2016 Dec;9(11-12):1273-1299
[29] Yang M, Yang Z, Wang P, Sun Z. Current application and future directions of photobiomodulation in central nervous diseases. Neural Regen Res. 2021 Jun;16(6):1177-1185
[30] Lee SY, Park KH, Choi JW, Kwon JK, Lee DR, Shin MS, Lee JS, You CE, Park MY. A prospective, randomized, placebo-controlled, double-blinded, and split-face clinical study on LED phototherapy for skin rejuvenation: clinical, profilometric, histologic, ultrastructural, and biochemical evaluations and comparison of three different treatment settings. J Photochem Photobiol B. 2007 Jul 27;88(1):51-67.
[31] Fekrazad R, Sarrafzadeh A, Kalhori KAM, Khan I, Arany PR, Giubellino A. Improved Wound Remodeling Correlates with Modulated TGF-beta Expression in Skin Diabetic Wounds Following Combined Red and Infrared Photobiomodulation Treatments. Photochem Photobiol. 2018 Jul;94(4):775-779.
[32] Zein R, Selting W, Hamblin MR. Review of light parameters and photobiomodulation efficacy: dive into complexity. J Biomed Opt. 2018 Dec;23(12):1-17.
[33] Kuryliszyn-Moskal A, Kita J, Dakowicz A, Chwieśko-Minarowska S, Moskal D, Kosztyła-Hojna B, Jabłońska E, Klimiuk PA. The influence of Multiwave Locked System (MLS) laser therapy on clinical features, microcirculatory abnormalities and selected modulators of angiogenesis in patients with Raynaud's phenomenon. Clin Rheumatol. 2015 Mar;34(3):489-96.
References / further reading on EZ Water and Water as a Chromophore:
Cells, gels, and the engines of life — Gerald Pollack
The fourth phase of water — Gerald Pollack
Water and the cell — Gerald Pollack
https://www.bodyworkmovementtherapies.com/article/S1360-8592(13)00068-5/fulltext
A revolution in the physiology of the living cell — Glibert Ling
https://www.westonaprice.org/podcast/build-the-4th-phase-of-water-in-the-body/#gsc.tab=0
Cancer and the new biology of water — Thomas Cowan
Human heart, cosmic heart — Thomas Cowan
Midwest Doctor Series **Excellent**
Part 1: https://www.midwesterndoctor.com/p/what-is-the-forgotten-side-of-water
Part 2: https://www.midwesterndoctor.com/p/what-actually-happens-with-water
Part 3: https://www.midwesterndoctor.com/p/what-causes-water-to-move-inside
Part 4: https://www.midwesterndoctor.com/p/what-is-the-relationship-between
Part 5: https://www.midwesterndoctor.com/p/how-to-improve-zeta-potential-and
Another Good article to read: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4782038/#B25
Cells, gels, and the engines of life — Gerald Pollack
The fourth phase of water — Gerald Pollack
Water and the cell — Gerald Pollack
https://www.bodyworkmovementtherapies.com/article/S1360-8592(13)00068-5/fulltext
A revolution in the physiology of the living cell — Glibert Ling
https://www.westonaprice.org/podcast/build-the-4th-phase-of-water-in-the-body/#gsc.tab=0
Cancer and the new biology of water — Thomas Cowan
Human heart, cosmic heart — Thomas Cowan
Midwest Doctor Series **Excellent**
Part 1: https://www.midwesterndoctor.com/p/what-is-the-forgotten-side-of-water
Part 2: https://www.midwesterndoctor.com/p/what-actually-happens-with-water
Part 3: https://www.midwesterndoctor.com/p/what-causes-water-to-move-inside
Part 4: https://www.midwesterndoctor.com/p/what-is-the-relationship-between
Part 5: https://www.midwesterndoctor.com/p/how-to-improve-zeta-potential-and
Another Good article to read: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4782038/#B25
The theory clearly points to the benefits of having multiple wavelengths, now let’s look at a few studies that actually compared multiple-wavelengths to single wavelengths. A 2016 review article on athletic performance summarizes why Red and NIR are often used in combination: “It is important highlight the scientific rationale for the use of red and NIR wavelengths at the same time. Our research group already reported previously that irradiations with red and NIR wavelengths at the same time possibly offer advantages based on the absorption bands of the chromophores in the cells that absorb light, in special cytochrome c oxidase in the mitochondrial electric transport chain, resulting in even more synthesis of ATP than either red or NIR used alone.” [2]
One study found that Nitric Oxide production was much greater for simultaneous usage of 635nm and 808nm than using them individually or even sequentially. [1] For brain health studies have found sequential or simultaneous 670nm and 810nm performed better than either wavelength alone. [3] For skincare a study found that simultaneous 633nm and 830nm wavelengths performed better than the individual wavelengths. [4] A study on diabetic wound healing found that the 660nm and 808nm combined wavelengths performed synergistically over the individual wavelengths. [5] A study on wound healing in rats found that combined 685nm and 830nm light provided additional benefits than single wavelength treatment. They specifically cited the theory that it was the differing penetration and absorption bands that likely enhanced the treatment. [6]
The study on skin health noted that 633nm alone reduced melanin and improved skin brightening. The 830nm alone offered improved skin elasticity increase. Overall, the 633nm and 830nm gave the best objective and subjective results. [4] Another interesting combination used often in studies is 808nm and 904nm. Where the 808nm is for the CCO absorption. and 904nm focuses more on water absorption. [7] The study notes this, similar to many of the multiple-wavelength studies:
“Two emissions are absorbed by different mitochondrial complexes and can affect cellular energy metabolism by acting on multiple sites in the cellular respiratory chain at the same time.” [2]
Overall, the studies we have reviewed imply that additional wavelengths are a welcomed synergistic benefit to red light therapy treatments, as long as they are in the effective ranges that have been identified.
One study found that Nitric Oxide production was much greater for simultaneous usage of 635nm and 808nm than using them individually or even sequentially. [1] For brain health studies have found sequential or simultaneous 670nm and 810nm performed better than either wavelength alone. [3] For skincare a study found that simultaneous 633nm and 830nm wavelengths performed better than the individual wavelengths. [4] A study on diabetic wound healing found that the 660nm and 808nm combined wavelengths performed synergistically over the individual wavelengths. [5] A study on wound healing in rats found that combined 685nm and 830nm light provided additional benefits than single wavelength treatment. They specifically cited the theory that it was the differing penetration and absorption bands that likely enhanced the treatment. [6]
The study on skin health noted that 633nm alone reduced melanin and improved skin brightening. The 830nm alone offered improved skin elasticity increase. Overall, the 633nm and 830nm gave the best objective and subjective results. [4] Another interesting combination used often in studies is 808nm and 904nm. Where the 808nm is for the CCO absorption. and 904nm focuses more on water absorption. [7] The study notes this, similar to many of the multiple-wavelength studies:
“Two emissions are absorbed by different mitochondrial complexes and can affect cellular energy metabolism by acting on multiple sites in the cellular respiratory chain at the same time.” [2]
Overall, the studies we have reviewed imply that additional wavelengths are a welcomed synergistic benefit to red light therapy treatments, as long as they are in the effective ranges that have been identified.

Ultimate Red and Near-Infrared Photobiomodulation Penetration and Absorption Mechanisms Cheat-sheet
We summarize all of these mechanisms of penetration depths, CCO absorption bands, water, and heat and light channel wavelengths are put together in a single chart below:
The Theraputic Optical Window for the Skin is 600nm-1100nm [study] [2][6]
The official definition of Red light is 600nm-780nm. The scientific definition of Near-Infrared is referred to more precisely as Infrared-A (IR-A) range is 780nm to 1,400nm. [IR-A Reference]
https://www.icnirp.org/en/frequencies/infrared/index.html
The Most Bioactive Ranges are Red Range 600-700nm and NIR 780nm-950nm. With 700nm-780nm being insignificant. [1]
The 600-850nm range is for ideal CCO Absorption [3]
Above 810nm+ Increases Heat and Light Ion Channel Activation [6]
Wavelength absorption above 720nm+ increases EZ water production [3]
These wavelengths have been shown to be the ones:
1) that are optimally absorbed by Cytochrome C (600-680 and 800-880)
2) Optimally absorbed by water for light/heat Ion Channel functioning (904-1080)
3) Optimally absorbed by water for enhanced energy production via 4th phase of water -> TRP, ATP-ase activity (904-1080)
One 2020 review article on the mechanisms of red light therapy really highlights the importance of understanding the different wavelength absorption ranges and their mechanisms.
"The application of red light (600–810 nm) is absorbed by the enzyme cytochrome c oxidase, which is located in the unit IV respiratory chain of the mitochondria. Nitric oxide (NO) is then displaced and activates the enzyme and this leads to a proton gradient. Consequently, calcium ions (Ca2+), reactive oxygen species (ROS), and ATP production levels are increased. On the other hand, the application of near-infrared light (810–1064 nm) activates light-sensitive ion channels, and increases the levels of Ca2+. ROS and cyclic AMP (cAMP)then interact with the calcium ions." [5]
We can quickly visualize from this chart that if we have multiple wavelengths that intersect several of these key regions of penetration and absorption, then we would theoretically be better situated for giving us the best probability for results with photobiomodulation.
[1] Zein R, Selting W, Hamblin MR. Review of light parameters and photobiomodulation efficacy: dive into complexity. J Biomed Opt. 2018 Dec;23(12):1-17.
[2] Lima, Andrezza & Sergio, Luiz Philippe & Fonseca, Adenilson. (2020). Photobiomodulation via multiple-wavelength radiations. Lasers in Medical Science. 35. 10.1007/s10103-019-02879-1.
[3] Tsai SR, Hamblin MR. Biological effects and medical applications of infrared radiation. J Photochem Photobiol B. 2017 May;170:197-207.
[5] Austin E, Geisler AN, Nguyen J, Kohli I, Hamzavi I, Lim HW, Jagdeo J. Visible light. Part I: Properties and cutaneous effects of visible light. J Am Acad Dermatol. 2021 May;84(5):1219-1231.
[6] Dompe C, Moncrieff L, Matys J, Grzech-Leśniak K, Kocherova I, Bryja A, Bruska M, Dominiak M, Mozdziak P, Skiba THI, Shibli JA, Angelova Volponi A, Kempisty B, Dyszkiewicz-Konwińska M. Photobiomodulation-Underlying Mechanism and Clinical Applications. J Clin Med. 2020 Jun 3;9(6)
We summarize all of these mechanisms of penetration depths, CCO absorption bands, water, and heat and light channel wavelengths are put together in a single chart below:
The Theraputic Optical Window for the Skin is 600nm-1100nm [study] [2][6]
The official definition of Red light is 600nm-780nm. The scientific definition of Near-Infrared is referred to more precisely as Infrared-A (IR-A) range is 780nm to 1,400nm. [IR-A Reference]
https://www.icnirp.org/en/frequencies/infrared/index.html
The Most Bioactive Ranges are Red Range 600-700nm and NIR 780nm-950nm. With 700nm-780nm being insignificant. [1]
The 600-850nm range is for ideal CCO Absorption [3]
Above 810nm+ Increases Heat and Light Ion Channel Activation [6]
Wavelength absorption above 720nm+ increases EZ water production [3]
These wavelengths have been shown to be the ones:
1) that are optimally absorbed by Cytochrome C (600-680 and 800-880)
2) Optimally absorbed by water for light/heat Ion Channel functioning (904-1080)
3) Optimally absorbed by water for enhanced energy production via 4th phase of water -> TRP, ATP-ase activity (904-1080)
One 2020 review article on the mechanisms of red light therapy really highlights the importance of understanding the different wavelength absorption ranges and their mechanisms.
"The application of red light (600–810 nm) is absorbed by the enzyme cytochrome c oxidase, which is located in the unit IV respiratory chain of the mitochondria. Nitric oxide (NO) is then displaced and activates the enzyme and this leads to a proton gradient. Consequently, calcium ions (Ca2+), reactive oxygen species (ROS), and ATP production levels are increased. On the other hand, the application of near-infrared light (810–1064 nm) activates light-sensitive ion channels, and increases the levels of Ca2+. ROS and cyclic AMP (cAMP)then interact with the calcium ions." [5]
We can quickly visualize from this chart that if we have multiple wavelengths that intersect several of these key regions of penetration and absorption, then we would theoretically be better situated for giving us the best probability for results with photobiomodulation.
[1] Zein R, Selting W, Hamblin MR. Review of light parameters and photobiomodulation efficacy: dive into complexity. J Biomed Opt. 2018 Dec;23(12):1-17.
[2] Lima, Andrezza & Sergio, Luiz Philippe & Fonseca, Adenilson. (2020). Photobiomodulation via multiple-wavelength radiations. Lasers in Medical Science. 35. 10.1007/s10103-019-02879-1.
[3] Tsai SR, Hamblin MR. Biological effects and medical applications of infrared radiation. J Photochem Photobiol B. 2017 May;170:197-207.
[5] Austin E, Geisler AN, Nguyen J, Kohli I, Hamzavi I, Lim HW, Jagdeo J. Visible light. Part I: Properties and cutaneous effects of visible light. J Am Acad Dermatol. 2021 May;84(5):1219-1231.
[6] Dompe C, Moncrieff L, Matys J, Grzech-Leśniak K, Kocherova I, Bryja A, Bruska M, Dominiak M, Mozdziak P, Skiba THI, Shibli JA, Angelova Volponi A, Kempisty B, Dyszkiewicz-Konwińska M. Photobiomodulation-Underlying Mechanism and Clinical Applications. J Clin Med. 2020 Jun 3;9(6)
Always Include 830nm
You may wonder why some LED beds use only 660nm and 850nm? That is good but far from ideal. It seems to be a mistaken notion that 660 and 850 together is some kind of gold standard but this has no basis in research!
Lets look at some quotes from peer-reviewed published articles by real researchers and experts.
The following 2023 review article on using Photobiomodulation for muscle function reviewed 29 studies (narrowed down from thousands) to make this conclusion:
Maximum Penetration
"It is believed that optimal wavelengths are near 810 – 840 nm, since in these regions the surface chromophores have weak absorption, and therefore there is maximum penetration of light into the skin, generating an optimal window of penetration and absorption by organic molecules [38]." [2]
Eye Health
Another December 2022 review article on Photobiomodulation for eye health makes this statement as part of their literature analysis:
"Red to near-infrared light photons with long wavelengths can directly transfer energy to cytochrome C oxidase, leading to an increase in enzyme activity and energy metabolism, which may play a key role in further inducing PBM. Based on the literature summary above, light wavelengths at 635–680 nm and 810–830 nm are more suitable for inducing PBM to treat retinal diseases." [3]
Again, conspicuously excluding 850nm while highlighting the optimal range of 810-830nm for eye health.
Wound Healing
A 2016 study on wound healing makes this comment about the ideal wavelengths for penetration and mechanisms:
"Both scattering and absorption of light by tissue are highly wavelength-dependent and NIR light around 810–830 nm have been found to have the deepest penetration and homogeneous illumination of the full dermis and part of the hypodermis [12,15]." [4]
Brain Health
One 2019 review article on transcranial Photobiomodulation (red light therapy on the brain) for depression made this conclusion about the ideal parameters to optimize penetration and effectiveness for brain health.
"Based on the data presented above, using wavelengths in the range of 808–835nm, laser devices, higher power densities, and pulsed parameters will likely increase efficacy." [5]
Heart and NO
A 2018 review article on using Photobiomodulation for Cardiovascular Health and Nitric Oxide production made this statement about the most researched wavelengths from their review:
"The most extensively studied spectrum for PB includes light
in the spectrum of 630–830 nm." [6]
PAIN
A 2020 review of LLLT for pain management had this to say in their conclusions of the best wavelengths for pain:
"Wavelengths of 820 to 830 nm and mean doses of 0.8 to 9 J for 15 to 180 seconds are reported as optimal.
...
Bjordal et al find that wavelengths of 632 to 660 nm, or infrared lasers with wavelengths of 810 to 830 nm, show anti-inflammatory effects" [7]
They don't directly mention 850nm in the article quoted above, but they note the average wavelength of 846nm was associated with negative outcomes compared to wavelengths closer to 810nm were associated with positive outcomes.
A 2016 study had this to say about the typical wavelengths used to treat pain:
"For clinical pain relief, the usual wavelengths are in the red range (λ=632.8 and 670 nm) and in the NIR (λ=780; 810 to 830; 904 nm)." [8]
Now this quote purposely skips over 850nm in their list of wavelengths to include 810-830nm and then jumps to 904nm. At this point it is rather laughable that these ranges are specifically excluding 850nm.
This list of quotes above would lead us to question if these researchers even consider 850nm as a viable wavelength at all, not even bothering to debate if 850nm is the best.
What would cause these researchers to forget about 850nm, the supposedly "best" wavelength acclaimed by many brands?
Did these researchers miss the memo about how great 850nm is? Or are they just following the actual evidence?
[2] Cubas IH, Eckert JA, Canalli LV, Carvalho AR D, Bertolini GR F. Photobiomodulation in aspects of muscle function – a scoping review. J Pre Clin Clin Res. 2023;17(1):32-36.
[3] Zhang, Chun-Xia et al. “Considerations for the Use of Photobiomodulation in the Treatment of Retinal Diseases.” Biomolecules vol. 12,12 1811. 3 Dec. 2022,
[4] Keshri, Gaurav K et al. “Photobiomodulation with Pulsed and Continuous Wave Near-Infrared Laser (810 nm, Al-Ga-As) Augments Dermal Wound Healing in Immunosuppressed Rats.” PloS one vol. 11,11 e0166705. 18 Nov. 2016,
[5] Askalsky, Paula, and Dan V Iosifescu. “Transcranial Photobiomodulation For The Management Of Depression: Current Perspectives.” Neuropsychiatric disease and treatment vol. 15 3255-3272. 22 Nov. 2019, doi:10.2147/NDT.S188906
[6] Bath, A.S., Gupta, V. Cardio-light: nitric oxide uncaged. Lasers Med Sci 34, 405–409 (2019).
[7] Taylor, David N et al. “Low-Level Laser Light Therapy Dosage Variables vs Treatment Efficacy of Neuromusculoskeletal Conditions: A Scoping Review.” Journal of chiropractic medicine vol. 19,2 (2020): 119-127.
[8] Pires de Sousa, Marcelo Victor et al. “Transcranial low-level laser therapy (810 nm) temporarily inhibits peripheral nociception: photoneuromodulation of glutamate receptors, prostatic acid phophatase, and adenosine triphosphate.” Neurophotonics vol. 3,1 (2016): 015003. doi:10.1117/1.NPh.3.1.015003
You may wonder why some LED beds use only 660nm and 850nm? That is good but far from ideal. It seems to be a mistaken notion that 660 and 850 together is some kind of gold standard but this has no basis in research!
Lets look at some quotes from peer-reviewed published articles by real researchers and experts.
The following 2023 review article on using Photobiomodulation for muscle function reviewed 29 studies (narrowed down from thousands) to make this conclusion:
Maximum Penetration
"It is believed that optimal wavelengths are near 810 – 840 nm, since in these regions the surface chromophores have weak absorption, and therefore there is maximum penetration of light into the skin, generating an optimal window of penetration and absorption by organic molecules [38]." [2]
Eye Health
Another December 2022 review article on Photobiomodulation for eye health makes this statement as part of their literature analysis:
"Red to near-infrared light photons with long wavelengths can directly transfer energy to cytochrome C oxidase, leading to an increase in enzyme activity and energy metabolism, which may play a key role in further inducing PBM. Based on the literature summary above, light wavelengths at 635–680 nm and 810–830 nm are more suitable for inducing PBM to treat retinal diseases." [3]
Again, conspicuously excluding 850nm while highlighting the optimal range of 810-830nm for eye health.
Wound Healing
A 2016 study on wound healing makes this comment about the ideal wavelengths for penetration and mechanisms:
"Both scattering and absorption of light by tissue are highly wavelength-dependent and NIR light around 810–830 nm have been found to have the deepest penetration and homogeneous illumination of the full dermis and part of the hypodermis [12,15]." [4]
Brain Health
One 2019 review article on transcranial Photobiomodulation (red light therapy on the brain) for depression made this conclusion about the ideal parameters to optimize penetration and effectiveness for brain health.
"Based on the data presented above, using wavelengths in the range of 808–835nm, laser devices, higher power densities, and pulsed parameters will likely increase efficacy." [5]
Heart and NO
A 2018 review article on using Photobiomodulation for Cardiovascular Health and Nitric Oxide production made this statement about the most researched wavelengths from their review:
"The most extensively studied spectrum for PB includes light
in the spectrum of 630–830 nm." [6]
PAIN
A 2020 review of LLLT for pain management had this to say in their conclusions of the best wavelengths for pain:
"Wavelengths of 820 to 830 nm and mean doses of 0.8 to 9 J for 15 to 180 seconds are reported as optimal.
...
Bjordal et al find that wavelengths of 632 to 660 nm, or infrared lasers with wavelengths of 810 to 830 nm, show anti-inflammatory effects" [7]
They don't directly mention 850nm in the article quoted above, but they note the average wavelength of 846nm was associated with negative outcomes compared to wavelengths closer to 810nm were associated with positive outcomes.
A 2016 study had this to say about the typical wavelengths used to treat pain:
"For clinical pain relief, the usual wavelengths are in the red range (λ=632.8 and 670 nm) and in the NIR (λ=780; 810 to 830; 904 nm)." [8]
Now this quote purposely skips over 850nm in their list of wavelengths to include 810-830nm and then jumps to 904nm. At this point it is rather laughable that these ranges are specifically excluding 850nm.
This list of quotes above would lead us to question if these researchers even consider 850nm as a viable wavelength at all, not even bothering to debate if 850nm is the best.
What would cause these researchers to forget about 850nm, the supposedly "best" wavelength acclaimed by many brands?
Did these researchers miss the memo about how great 850nm is? Or are they just following the actual evidence?
[2] Cubas IH, Eckert JA, Canalli LV, Carvalho AR D, Bertolini GR F. Photobiomodulation in aspects of muscle function – a scoping review. J Pre Clin Clin Res. 2023;17(1):32-36.
[3] Zhang, Chun-Xia et al. “Considerations for the Use of Photobiomodulation in the Treatment of Retinal Diseases.” Biomolecules vol. 12,12 1811. 3 Dec. 2022,
[4] Keshri, Gaurav K et al. “Photobiomodulation with Pulsed and Continuous Wave Near-Infrared Laser (810 nm, Al-Ga-As) Augments Dermal Wound Healing in Immunosuppressed Rats.” PloS one vol. 11,11 e0166705. 18 Nov. 2016,
[5] Askalsky, Paula, and Dan V Iosifescu. “Transcranial Photobiomodulation For The Management Of Depression: Current Perspectives.” Neuropsychiatric disease and treatment vol. 15 3255-3272. 22 Nov. 2019, doi:10.2147/NDT.S188906
[6] Bath, A.S., Gupta, V. Cardio-light: nitric oxide uncaged. Lasers Med Sci 34, 405–409 (2019).
[7] Taylor, David N et al. “Low-Level Laser Light Therapy Dosage Variables vs Treatment Efficacy of Neuromusculoskeletal Conditions: A Scoping Review.” Journal of chiropractic medicine vol. 19,2 (2020): 119-127.
[8] Pires de Sousa, Marcelo Victor et al. “Transcranial low-level laser therapy (810 nm) temporarily inhibits peripheral nociception: photoneuromodulation of glutamate receptors, prostatic acid phophatase, and adenosine triphosphate.” Neurophotonics vol. 3,1 (2016): 015003. doi:10.1117/1.NPh.3.1.015003

Here is a beautiful painting by Georges De La Tour, "Christ with St. Joseph in the Carpenter's Shop", in the Musee du Louvre in Paris. Notice that the artist knew that light penetrated through the hand, and that it was red light that was the most penetrating!! And there were no flashlights in the 1630's!

RATS
Reflection/Remittance - bounces off (only reason you can see red light on the skin is because light is bouncing off of the skin. A lot of reflection.
50-80% reflection red light.
Light Penetration -
Reflection/Remittance - bounces off (only reason you can see red light on the skin is because light is bouncing off of the skin. A lot of reflection.
50-80% reflection red light.
Light Penetration -

IV. Reflection issues
B. Minimizing Diffuse Reflection - Need panels close on skin!
Just as important as intensity, time, dose, and repetition - researchers understand there is a significant difference between skin contact treatment versus non-contact treatment. In fact, there is massive debate and inconclusive evidence about the “best” parameters in terms of wavelengths (nm), dose (J/cm^2), or intensity (mW/cm^2) for different conditions. Astonishingly, the only treatment parameter that is well-settled in the science – is that skin contact is the ideal way to administer red light therapy.
Bias Towards Non-Contact Treatment:
Unfortunately, the new generation of red light therapy “experts” have been biased by non-contact LED panels advertised to be used 6 inches away. They all conveniently overlooked the differences between skin contact and non-contact delivery while they wrote their original books and blogs with their affiliate promotions.
You might think that 6 inches is some magical clinically-studied treatment number since that is what everyone talks about. But you would be surprised that there are practically NO studies referencing 6 inches! In fact looking through pub med, I only found ONE STUDY and the results were basically NO EFFECT!! All positive studies with red light therapy and low level laser are ALL DIRECT CONTACT!!
There are multiple reasons for this the main one being reflection! So standing any significant distance away from a red light panel will result massive losses due to skin reflection alone!
The NIST database of skin reflectance spectrum measurements shows a skin reflectance on average of about 60% in white skin around 660nm to 850nm! This is very high! Other references which corroborate the high average reflection estimate of 60% include:
1. The evolution of human skin color measured reflectance at 685nm in Northern Latitudes at about 65%! [2]
2. Another reflectance measurements of human skin study showed a very similar spectrum as the NIST data. [3]
3. Researchers used a camera technique to measure reflection spectrum and found about 60% reflection (and increasing) in the Red range. [4]
4. Spectral Reflection study of facial skin of 241 participants showed an average reflectance of 60% in the red range and clearly increasing reflectance towards NIR. [5]
5. In one review the authors mention how 4-7% of most wavelengths pass through the first layer of skin, but through internal reflection and scattering, light will exit the body through what is called remittance. Their remittance spectrum shows similar to the NIST data, with Caucasion skin having over 60% remittance between 600nm to 900nm. [6]
So ALL 5 of these references match very well, no matter what year they were studied, including the NIST data makes 6 well studied skin reflection metrics. Despite what some authors might say otherwise.
60% reflection is a tremendous amount of intensity losses! Lets say you have a panel that you THINK emits 100mW/cm^2 at 6 inches. Well actually they lied about intensity and it is about 45mW/cm^2 at 6 inches. Then 60% of that gets reflected away so you are left with an effective intensity of 18 mW/cm^2. Is that what you paid for?
Most panel companies don’t tell you about skin reflection because they don't want their customers to realize they are using an inefficient and mostly unscientific dosing method by being 6+ inches away. And some delusional brands and self-proclaimed experts may not even be aware of this issue, so I do presume to blame them for their misinformation.
Example
In the first-ever study using a top name brand LED Panel [their most powerful] system had athletes use the panels at 12 inches away for 5 minutes. Based on their calculations with skin contact dosage in earlier studies, the authors thought 5 minutes would be plenty sufficient for a clinical benefit. But they found no significant improvement in the treatment group. [7]
The above studies show what happens when companies don’t educate the market about the skin reflection issue. It hurts the science and customers might not get the results that they expect then they stand 6+ inches away from a panel.
[1] NIST Skin Reflection Data
https://www.nist.gov/programs-projects/reflectance-measurements-human-skin
Raw Data: https://opendata.nist.gov/1832_Data_JResNIST_skinrefl%20v3.txt
[2] Evolution of Human Skin Coloration.
Nina G. Jablonski and George Chaplin
Department of Anthropology, California Academy of Sciences, Golden Gate Park,
San Francisco, CA
https://anth.la.psu.edu/research/research-labs/jablonski-lab/research/JablonskiLabskin.pdf
[3] Cooksey, Catherine & Allen, David. (2013). Reflectance measurements of human skin from the ultraviolet to the shortwave infrared (250 nm to 2500 nm). Proceedings of SPIE - The International Society for Optical Engineering. 8734. 87340N. 10.1117/12.2015821.
https://www.researchgate.net/publication/269325503_Reflectance_measurements_of_human_skin_from_the_ultraviolet_to_the_shortwave_infrared_250_nm_to_2500_nm
[4] Validation of a Method to Estimate Skin Spectral Reflectance Using a Digital Camera.
Christopher Thorstenson
Rochester Institute of Technology
RIT Scholar Works
5-9-2017
https://scholarworks.rit.edu/cgi/viewcontent.cgi?article=10602&context=theses
[5] Koran A, Powers JM, Raptis CN, Yu R. Reflection spectrophotometry of facial skin. J Dent Res. 1981 Jun;60(6):979-82. doi: 10.1177/00220345810600061301. PMID: 6939721.
https://pubmed.ncbi.nlm.nih.gov/6939721/
https://deepblue.lib.umich.edu/bitstream/handle/2027.42/67548/10.1177_00220345810600061301.pdf
[6] Anderson RR, Parrish JA. The optics of human skin. J Invest Dermatol. 1981 Jul;77(1):13-9. doi: 10.1111/1523-1747.ep12479191. PMID: 7252245.
[7} Zagatto, Alessandro & Dutra, Yago & Lira, Fabio & Antunes, Barbara & Bombini Faustini, Júlia & Malta, Elvis & Fialho Lopes, Vithor & de Poli, Rodrigo & Brisola, Gabriel & dos Santos, Giovanny Viegas & Rodrigues, Fabio & Ferraresi, Cleber. (2020). Full Body Photobiomodulation Therapy to Induce Faster Muscle Recovery in Water Polo Athletes: Preliminary Results. Photobiomodulation Photomedicine and Laser Surgery. 38. -. 10.1089/photob.2020.4803.
B. Minimizing Diffuse Reflection - Need panels close on skin!
Just as important as intensity, time, dose, and repetition - researchers understand there is a significant difference between skin contact treatment versus non-contact treatment. In fact, there is massive debate and inconclusive evidence about the “best” parameters in terms of wavelengths (nm), dose (J/cm^2), or intensity (mW/cm^2) for different conditions. Astonishingly, the only treatment parameter that is well-settled in the science – is that skin contact is the ideal way to administer red light therapy.
Bias Towards Non-Contact Treatment:
Unfortunately, the new generation of red light therapy “experts” have been biased by non-contact LED panels advertised to be used 6 inches away. They all conveniently overlooked the differences between skin contact and non-contact delivery while they wrote their original books and blogs with their affiliate promotions.
You might think that 6 inches is some magical clinically-studied treatment number since that is what everyone talks about. But you would be surprised that there are practically NO studies referencing 6 inches! In fact looking through pub med, I only found ONE STUDY and the results were basically NO EFFECT!! All positive studies with red light therapy and low level laser are ALL DIRECT CONTACT!!
There are multiple reasons for this the main one being reflection! So standing any significant distance away from a red light panel will result massive losses due to skin reflection alone!
The NIST database of skin reflectance spectrum measurements shows a skin reflectance on average of about 60% in white skin around 660nm to 850nm! This is very high! Other references which corroborate the high average reflection estimate of 60% include:
1. The evolution of human skin color measured reflectance at 685nm in Northern Latitudes at about 65%! [2]
2. Another reflectance measurements of human skin study showed a very similar spectrum as the NIST data. [3]
3. Researchers used a camera technique to measure reflection spectrum and found about 60% reflection (and increasing) in the Red range. [4]
4. Spectral Reflection study of facial skin of 241 participants showed an average reflectance of 60% in the red range and clearly increasing reflectance towards NIR. [5]
5. In one review the authors mention how 4-7% of most wavelengths pass through the first layer of skin, but through internal reflection and scattering, light will exit the body through what is called remittance. Their remittance spectrum shows similar to the NIST data, with Caucasion skin having over 60% remittance between 600nm to 900nm. [6]
So ALL 5 of these references match very well, no matter what year they were studied, including the NIST data makes 6 well studied skin reflection metrics. Despite what some authors might say otherwise.
60% reflection is a tremendous amount of intensity losses! Lets say you have a panel that you THINK emits 100mW/cm^2 at 6 inches. Well actually they lied about intensity and it is about 45mW/cm^2 at 6 inches. Then 60% of that gets reflected away so you are left with an effective intensity of 18 mW/cm^2. Is that what you paid for?
Most panel companies don’t tell you about skin reflection because they don't want their customers to realize they are using an inefficient and mostly unscientific dosing method by being 6+ inches away. And some delusional brands and self-proclaimed experts may not even be aware of this issue, so I do presume to blame them for their misinformation.
Example
In the first-ever study using a top name brand LED Panel [their most powerful] system had athletes use the panels at 12 inches away for 5 minutes. Based on their calculations with skin contact dosage in earlier studies, the authors thought 5 minutes would be plenty sufficient for a clinical benefit. But they found no significant improvement in the treatment group. [7]
The above studies show what happens when companies don’t educate the market about the skin reflection issue. It hurts the science and customers might not get the results that they expect then they stand 6+ inches away from a panel.
[1] NIST Skin Reflection Data
https://www.nist.gov/programs-projects/reflectance-measurements-human-skin
Raw Data: https://opendata.nist.gov/1832_Data_JResNIST_skinrefl%20v3.txt
[2] Evolution of Human Skin Coloration.
Nina G. Jablonski and George Chaplin
Department of Anthropology, California Academy of Sciences, Golden Gate Park,
San Francisco, CA
https://anth.la.psu.edu/research/research-labs/jablonski-lab/research/JablonskiLabskin.pdf
[3] Cooksey, Catherine & Allen, David. (2013). Reflectance measurements of human skin from the ultraviolet to the shortwave infrared (250 nm to 2500 nm). Proceedings of SPIE - The International Society for Optical Engineering. 8734. 87340N. 10.1117/12.2015821.
https://www.researchgate.net/publication/269325503_Reflectance_measurements_of_human_skin_from_the_ultraviolet_to_the_shortwave_infrared_250_nm_to_2500_nm
[4] Validation of a Method to Estimate Skin Spectral Reflectance Using a Digital Camera.
Christopher Thorstenson
Rochester Institute of Technology
RIT Scholar Works
5-9-2017
https://scholarworks.rit.edu/cgi/viewcontent.cgi?article=10602&context=theses
[5] Koran A, Powers JM, Raptis CN, Yu R. Reflection spectrophotometry of facial skin. J Dent Res. 1981 Jun;60(6):979-82. doi: 10.1177/00220345810600061301. PMID: 6939721.
https://pubmed.ncbi.nlm.nih.gov/6939721/
https://deepblue.lib.umich.edu/bitstream/handle/2027.42/67548/10.1177_00220345810600061301.pdf
[6] Anderson RR, Parrish JA. The optics of human skin. J Invest Dermatol. 1981 Jul;77(1):13-9. doi: 10.1111/1523-1747.ep12479191. PMID: 7252245.
[7} Zagatto, Alessandro & Dutra, Yago & Lira, Fabio & Antunes, Barbara & Bombini Faustini, Júlia & Malta, Elvis & Fialho Lopes, Vithor & de Poli, Rodrigo & Brisola, Gabriel & dos Santos, Giovanny Viegas & Rodrigues, Fabio & Ferraresi, Cleber. (2020). Full Body Photobiomodulation Therapy to Induce Faster Muscle Recovery in Water Polo Athletes: Preliminary Results. Photobiomodulation Photomedicine and Laser Surgery. 38. -. 10.1089/photob.2020.4803.
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