The Wavelength Equivalence Guide to Red/NIR Light Therapy

Do we need specific wavelengths of light to produce different benefits with Red and Near-Infrared (NIR) light therapy? If so, then if we want all the clinical benefits then we would need to buy devices with multiple wavelengths or have many devices for different applications. 

How close do wavelengths need to be on target? If a study used 810nm, could you not get the same result with 850nm? If a study used 670nm, could you not use 660nm? How far away from a wavelength can you be to have assurance that you would get the same result? +/- 1nm, +/- 5nm, +/- 10nm, +/- 20nm, +/- 50nm, or more?

This quandary is explained by the quote from a 2025 article below. There are many wavelengths available for Photobiomodulation, however the selection of wavelengths is limited by the current Laser and LED technology. Even as of 2025, there is a lack of direct comparisons of these wavelengths to decide which are optimal for different diseases. 

"PBM utilizes wavelengths distributed between 620-630 nm, 650 nm, 670 nm, 800-810 nm, 830 nm, 850 nm, 900-910 nm, 1064 nm, and 1267 nm. This limitation may be related to the current development of lasers that do not adequately cover the 620-1270 nm spectrum. Furthermore, there is a lack of sufficient research comparing the effectiveness of different wavelengths for specific diseases." [1]

Which would make us wary of any brands or influencers producing charts and lists of the best wavelengths for specific applications.

[Source]

Their job is to convince the consumer that every single nanometer has a different effect so they can maximize sales and give the illusion of customization for consumers. Otherwise there would be no differentiation between panels on the market, making them harder to sell. 

In contrast, the current science indicates that exact wavelengths are not required for all of the PBM benefits. The effects of individual wavelengths are very broad, and we can use dosing adjustments to get similar responses from different wavelengths.

Summary:

Leading researchers like Dr. Hamblin have often noted in interviews that most of the Red (600's) wavelengths and NIR (800's and 1000's) wavelengths have a similar benefit, with only a few exceptions in the 700's and 900's.

The molecular-level interactions with light have wide spectrum of active wavelengths, and they often are observed to lead to the same result regardless of the theoretical mechanism. 

The Einstein dosing theory adopted by leading researchers and the World Association for Laser Therapy (WALT) also acknowledges that all wavelengths can have the same benefit. They recommend adjusting the dose to account for the energy per photon (eV) to reach the same effect. 

Comparison studies between different wavelengths on humans often show similar results, with occasionally one wavelength with a marginally better result. But that does not mean the other wavelength is ineffective, and we know that adjusting the dose can often match the effectiveness of the other wavelength. 

Even Red or NIR light alone has been shown to be effective in fighting acne, which would make those treatments safer if they can be done without Blue light. 

The consumer can be confident that a simple device with 1-2 wavelengths of Red and/or NIR can cover a wide range of benefits and applications. It is only speculation that certain wavelengths or combinations of wavelengths are better for a particular application.

We would not want consumers to forsake the benefits of PBM entirely because they cannot obtain every possible wavelength being promoted as the "best". Especially when the best wavelengths are defined by influencers and brand owners capitalizing on trends, not based on rigorous scientific analysis. 

Different Mechanisms, Different Benefits:

To produce different effects, then we would need a different absorption molecule, action spectra, and mechanisms for each individual wavelength. However, according to the current science there are only a few known chromophores with broad absorption ranges.

Generally the 600nm-810nm range more directly affects Cytochrome C Oxidase (CCO). As the wavelengths increases then 810nm-1400nm will gradually have more of an effect on Ion Channels (TPRVs) and intracellular water structure (EZ Water). 

This is noted in a recent article, as well as many others: 

"In the case of 600-810 nm red laser, the chromophore that absorbs the photons is the CCO [9], which leads to upregulation of cellular respiration, a significant increase in reactive oxygen species (ROS), nitric oxide (NO), adenosine triphosphate (ATP) levels and cyclic adenosine monophosphate (cAMP) [10–12]. At the wavelengths of 800–1064 nm, the photosensitive channel TRPV absorbs most of the photons, resulting in the opening of Ca²⁺ channel on the cell membrane and an increment of intracellular Ca²⁺ [13]." [2]

Thus, the mechanisms are already established to cover broad ranges. For example, the mechanism for 630nm, 660nm, 670nm, and even 810nm have similar effects and may even be redundant to each other. Similarly wavelengths around 810nm, 830nm, and 850nm are also redundant as the are close to each other on the spectrum share a similar mechanism and penetration depth. 810nm seems to straddle both mechanisms, which may explain why it is one of the best wavelengths used in PBM. 

Take note how most summaries of the Red/NIR light therapy mechanisms does not delineate by specific wavelengths. They usually explain the mechanisms shared by the entire range of Red-NIR around 600nm to 1100nm.

Regardless of the mechanism, the end results seem to be the same. Increased ATP production, increased Nitric Oxide, modulating intracellular Calcium, modulating ROS, and then the downstream benefits of increased cellular proliferation, protection, and reduced inflammation. 

Diagrams like this one and this one from peer reviewed articles also show multiple wavelengths can lead to the same effects through different pathways. [3] [4]

Even a recent article makes this comment about the mechanisms of PBM:

"Although the exact mechanism of PBM is not fully understood, it could depend on the target and type of cell being modulated." [5]

We may not even know true mechanism(s) on a direct molecular level, we can only observe the outcome of cellular metabolism, inflammation, cell proliferation, etc. 

Dr. Hamblin on Wavelengths:

This causes leading researchers like Dr. Michael Hamblin to state that he observes similar benefits from the Red and Near-Infrared wavelengths, with no significant difference between them. 

In one interview Dr. Hamblin says:

"We have done a lot of studies over the years and we cannot really detect a difference between red light like 660 and near-infrared at let us say 810, 830, 850nm. So first of all, all the 800's seem to be the same and also so far as we can tell something in the mid-600's like 660 is the same as the near-infrared. Now, a few other folks have claimed to find some differences, but there is not much difference. "

Dr. Mercola was even surprised by this and asked a follow-up question to confirm:

"Really, so the red at 660nm will still provide the same mitochondrial benefits?"

To which Dr. Hamblin quickly replied:

"Yup, absolutely."

Dr. Mercola notes that he thought that Red and Near-Infrared were completely different. But he quickly covers his ignorance by noting that those wavelengths are not very far apart on the spectrum, making sense of the similar effects. [Link]

Normally we exaggerate the distance between waves for charts so you can understand the concepts and terminology. But now look at how similar all of these waves are, remember we are on the entire Electromagnetic Scale and this range is only a small portion of it. 

But what about longer wavelengths like the 1000-1100nm that have gotten so trendy and popular lately? Perhaps those are the exception with some unique benefit? 

Dr. Hamblin mentions that in a recent interview:

"And the other [ion channel mechanism] is the water. The nanostructured water, which you can hit with 980 or with longer infrared wavelengths. And these ion channels. The thing that is confusing is that the ion channels are actually in the mitochondria. So when you measure it in the cells. It is difficult to distinguish what you get activating Ion Channels and what you get activating Cytochrome C Oxidase in mitochondria. Because the results are kind of similar." [Link]

According to Dr. Hamblin wavelengths in the 800's, mid-600's, and even >980nm are all biologically similar. From a cellular perspective, we can only notice the upregulation of markers like ATP, ROS, and NO - but we are not able to discern which molecular mechanism it came from. 

Of course, we don't want to accept hearsay and speculations from the worlds leading researcher. Especially when he is contradicting a very profitable sales narrative. We only accept what Dr. Hamblin says when he is confirming our biases. 

Thus, we need to see the studies that definitively proves that all of these wavelengths are so similar as he claims. 

Cellular Response to Different Wavelengths:

Peer reviewed articles do mention how these wavelength ranges have similar effects. Like below:

"The effect of NIR irradiation is analogous to that of red light improving the bioavailability of NO through several mechanisms of action (Pchelin et al., 2023), increasing signal transduction accompanied by a temporary rise in ROS, cellular energy availability and calcium (Ca2+) levels (Migliario et al., 2018)." [6]

They report that NIR is analogous to Red, meaning the effects are similar for both.

Another article makes a similar statement:

"While wavelengths from 780 - 980 nm may yield similar outcomes, their mechanisms of action differ." [7]

It bears repeating. Even with different molecular-level mechanisms, the overall benefits and outcomes are observed to be similar.

Indeed, this has been demonstrated in many studies observing the cellular effects of different wavelengths. Studies on isolated cells with different wavelengths show varying levels of elevated ATP, Nitric Oxide, and ROS as markers of the effect. [8][9][10][11][12][13]

These responses are both wavelength and dose-dependent. Which will be important for the next section. 

Photon Energy Dosing Equalizes Wavelength:

It was assumed that the activity of these wavelengths were mapped to action spectra of CytoChrome C Oxidase. With known peaks around 620nm, 680nm, 760nm, and 820nm. 

"The range 580–860 nm shows two doublet bands in the ranges 620–680 nm and 760–830 nm with well-defined maxima at 620 nm, 680 nm, 770 nm, and 820 nm." [14]

If these were the best wavelengths, then that would have been clearly demonstrated in human studies. However, we have not been able to map a clear action spectrum for human biological responses to light, even now decades after this theory was first proposed by Tiina Karu. 

This is likely due to the complexity of human biology on how we metabolize wavelengths of light, compared to plants that have a more predictable response to light. The CCO theory also was unable to explain the effectiveness of longer wavelength light >870nm. 

The lack of action spectrum on humans has created an entirely new dosing theory on how wavelengths affect our biology. It is the Einstein or Photonic Fluence dosing theory. 

This dosing theory follows that the Energy per Photon (eV) is the only consistent marker for the impact of a wavelength on human biology. In other words, the chart below may be the real action spectrum mapping activity of light spectrum on humans.

The chart above shows how shorter wavelengths have higher Energy per Photon, and longer wavelengths have lower Energy per Photon. Since Photonic Energy is inversely proportional to the Wavelength, there are simple charts and calculators to tell you the energy of a photon at a particular wavelength.

Basic photochemistry tells us that that photons with higher energy values will have a higher probability of facilitating a chemical reaction or dissociation. Photons with lower energy invoke less photochemical events. 

The Einstein dose theory clearly implies that all of the wavelengths have the same effects on cells as long as the dose is properly compensated for by the Photonic Energy. The intent is that this theory would harmonize dosing standards. 

For example, one recent review article on PBM for osteonecrosis of the jaw made this dosing recommendation:

"The authors established a proposed PBM laser dosimetry protocol for future RCTs, for the first time, which is as follows: 808 nm at 5 J/cm² is 7.5 p.J/cm², which is 1.7 Einstein; 1060 nm at 6.5 J/cm² is also 7.5 p.J/cm², which is 1.7 Einstein." [15]

They recommend 1.7 Einstein dose for this treatment. That equates to 5 J/cm^2 with 808nm wavelength or 7.5 J/cm^2 with 1060nm wavelength.

They recommend two very different wavelengths for the same clinical treatment at either 808nm or 1064nm. Whereas a brand or influencer would be more restrictive that only one of these wavelengths could be the best. The real experts know that a dosing adjustment with the Einstein dose theory can equilibrate the effects. 

Notice how the 1060nm needs 1.5 times more fluence (J/cm^2) to reach the same response. That is because the theory tells us that 1060nm is less photochemically active by having lower Energy Per Photon than 808nm. 

As people seem to enjoy "overdosing" red light therapy these days, it will make more sense to use longer wavelengths that are less photochemically active to avoid the biphasic dose response. 

This dosing method has been enacted in a World Association for Laser Therapy (WALT) position paper on using PBM to manage cancer radiation therapy induced side effects like oral mucositis. 

"For Prevention of oral mucositis with a transcutaneous device, WALT recommends a near-infrared wavelength (800-1100 nm) LED/Laser device with a power density (treatment surface irradiance) of 30-150 mW/cm² for a total dose 1 Einstein (photon fluence at 810nm = 4.5 p.J/cm²) per treatment field" [16]

As we can see, this dosing theory allows for a wide range of wavelengths (800-1100nm) for the same treatment as long as the photonic energy is accounted for. This is what the scientific consensus has agreed upon, that a wide range of wavelengths can treat the same condition as long as the dosing is properly adjusted. 

Photon Energy Conversion Calculator:

Thus, we can create a simple calculator to show the dosing correction factors to get equivalent benefits from different wavelengths. 

 

This is quite literally the intent behind the Einstein dose theory. Research groups across the world are working with different wavelengths depending on what their clinic has access to. If one clinic only has 810nm wavelengths and another has 1064nm, they would be able to treat the same condition by using the Einstein dose calculations. 

"A major advantage of this approach is its ability to enable harmonized dose interpretation and communication that can be universally implemented with accessible PBM wavelength devices that may otherwise be globally restrictive." [17]

Consider that when Photobiomodulation does gain mainstream approval to treat certain conditions, we would not want it to be restrictive as not every clinic will have access to the same wavelengths. So they needed to make the official dosing recommendations flexible for ranges of appropriate wavelengths to treat a condition. 

"This novel dose system has been recently applied to the dosing recommendations by the World Association for Photobiomodulation Therapy (WALT) to increase practical implementation irrespective of individual wavelengths or devices that are available globally while preventing overdosing and enabling dose combination with various wavelengths [51]." [18]

Thus, the top PBM researchers understand that the same benefits can be gotten from a wide range of wavelengths, as long as the dosing is adjusted for the photonic energy.

Unfortunately this does not help the RLT Influencers and Brands sell products with exclusive wavelengths to treat specific needs. If the consumer knew that a single wavelength can support a wide range of benefits, then that would reduce sales. 

Wavelength Comparison Studies

The ultimate way to settle if certain wavelengths are best for specific conditions would be to have Randomized Controlled Trials (RCTs) that directly compare them. 

Unfortunately there are not many studies that directly compare different wavelengths on humans. This makes it suspicious how brands and influencers could confidently claim to know the best wavelengths for specific conditions. 

Take note that in most examples both wavelengths gain a benefit. Only in some cases does one wavelength perform better than another, but it is often marginal. 

Which may be the only basis of claims that a wavelength was shown to be "better" than another. The worst insult you can tell someone in the fitness or wellness industry is that their device or protocol is sub-optimal. Even if it is by a small margin. 

But remember that does not mean the other wavelength is entirely ineffective. We would not want to abstain from using Red/NIR Light Therapy just because a device lacks the best wavelength for a type of treatment. Because it would still be effective regardless of what is believed to be the best. 

We now know that with the right dosing adjustments they should both reach the same effect. Most of these studies attempt to deliver equivalent doses since they have not been using the new Einstein dose theory. 

What we would expect based on the marketing is that one wavelength would be entirely ineffective while the other is effective. Or at the very least, one wavelength should be dramatically better than another. This is rarely the case, if ever. 

So let us review the few human studies that do compare different wavelengths. 

Red vs NIR Wavelengths:

One important area is to consider is how Red compares to Near-Infrared light. The common marketing claim is that Near-Infrared is only for deep tissue treatments and Red is only for superficial treatments like skincare. 

This is generally true. Penetration depth may be the only significant factor of difference between Red and NIR wavelengths.  

The marketing implies that NIR is exclusive to deep tissue treatments and Red is exclusive to superficial treatments. But that is hardly the case as there are a lot of overlapping applications of these wavelength ranges. 

This Venn diagram illustrates the point better than most charts mapping specific wavelengths to specific conditions. There is much more overlapping benefits in the middle than there are differences. With only a marginal preference for NIR for deep tissue applications and Red for skincare applications. 

But we still need more studies directly comparing Red vs NIR for a wide range of conditions from deep tissue to skincare. It is possible that benefits come from systemic effects, and not from direct stimulation.

660nm vs 810nm for Dentin Hypersensitivity

One article treated 7 humans to see Red or NIR light's effect on pain signals and tooth hypersensitivity. 

"The results of the present study showed that both 660-nm and 810-nm diode lasers significantly improved dentin hypersensitivity." [19]

They noted the 810nm had a longer-lasting effect compared to 660nm, even though both showed an improvement. 

Red vs Near-Infrared for Muscle Fatigue:

One study used 660nm or 830nm on 10 students for bicep muscle exercise. They found that both wavelengths performed equally in improving muscle fatigue. 

"We conclude that both red than infrared LLLT are effective in delaying the development skeletal muscle fatigue and in enhancement of skeletal muscle performance. " [20]

Even the authors give comments about this unexpected result, as we would normally assume NIR would give the superiors response. 

Thus, there is no reason to exclude Red light for athletic performance or muscle benefits. Especially when it can be combined simultaneously with NIR in most commercial devices for a synergistic benefit. 

Red vs NIR for Knee Osteoarthritis:

One article compared 660nm versus 808nm versus placebo for knee osteoarthritis. Although both groups showed improvement, they found the 808nm did have an additional benefit for knee strength. 

"In conclusion, both intervention groups improved muscle strength and functional performance as compared to the control group. The 808 nm wavelength group showed better results in knee extensor strength." [21]

Another study used Red (633nm), Infrared (830nm), or Placebo to treat knee osteoarthritis. Both the Red and NIR groups received similar benefits above placebo. But there was no significant difference between Red or NIR. 

"No significant difference in pain relief was shown between the group treated with red light and the one treated with infrared light" [22]

So even for deep tissue treatments the Red light is proven to be effective, with either the same effectiveness or only slightly less effective than NIR.

Red vs NIR for Rheumatoid Arthritis:

A meta-analysis looked at several human studies with various wavelengths on Rheumatoid Arthritis. They found a wide range of wavelengths from 632nm to 1064nm were used, and in the analysis between wavelengths the found no statistically significant differences. 

"There were no statistical difference between wavelengths. However, there was a trend for improved outcome with the 632 nm compared to 820 nm for pain although the confidence limits overlap [SMD 632 nm: ‐0.7 (95% CI: ‐1.2, ‐0.3) vs SMD 820 nm: ‐0.4 (95% CI: ‐0.8, 0.1)]." [23]

Ironically, they did find that the 632nm seemed to have a slightly better outcome, even though this is feared as a poorly penetrating wavelength. However, the statistical differences were not compelling to determine if one was superior over the other. 

Red vs Near-Infrared for Oral mucositis 

Another Meta-Analysis of studies using PBM for Oral Mucositis found similar effects when comparing Red and Near-Infrared ranges. 

"RR was similar between the red (630-670 nm) and infrared (780-830 nm) LLLT." [24]

As we established earlier, the WALT also gave wide wavelength ranges for their recommendations. 

Red vs NIR for Skin Rejuvenation:

An excellent skincare study split 76 patients into different groups to treat with 633nm, 830nm, or 633nm+830nm. [26]

All 3 treatments groups showed benefits. They noted that 633nm was better for skin brightening, and 830nm was better for skin elasticity. The combination of Red+NIR was found to be the superior. [26]

A 2025 review article on Photobiomodulation for skin rejuvenation investigated the best wavelengths to use for skincare. 

"Determining optimal wavelengths: Studies suggest that red (630 - 670 nm) and near-infrared (810 - 850 nm) light are most effective for stimulating collagen synthesis and reducing fine lines." [7]

Notice how they recommend both Red ranges of 630-670nm and Near-Infrared ranges of 810nm-850nm for the skin.  Both ranges promote collagen and reduce fine lines and wrinkles. 

Red vs NIR for Diabetic Foot Ulcers 

A human study with 53 patients received 650nm, 940nm or 650nm+940nm treatments for diabetic foot ulcers. They found that both Red and NIR were effective, with the Near-Infrared groups having a better effect. 

"The use of photobiomodulation with red and infrared LED, individually applied, clinically tended to be more effective in the DFU healing process, promoting reduction in the
wound area. However, infrared LED showed to be more effective than red LED. " [27]

A 2021 review article on diabetic foot ulcers also recommends the ranges of Red or Near-Infrared for treatment. 

"For DFU healing, the most successful PBM wavelengths are 630 nm-660 nm or infrared wavelengths of 850 nm or 890 nm." [28]

Again showing the flexibility offered by scientific researchers on ranges of either Red or NIR to treat the same condition. 

Red or NIR for Brain Health

A 2025 review article of Photobiomodulation used for human brain diseases summarized the wavelengths used as:

"Applied wavelengths ranged from 630 to 1080 nm, with 6 studies involving NIR light (around 810 nm and/or around 1070 nm), 1 involving red light (650 nm) and 2 involving both NIR and red light (630 and 810 nm)." [28]

Showing that a range of wavelengths from Red (630nm) to Near-Infrared (1080nm) has been used for human brain diseases. 

Another 2024 review article summarized the wavelengths used for aging brains in both animal and human studies. They found that 70% of the studies used NIR light of either 808nm, 810nm, 830nm, 1070nm, 1072nm or 1267nm. That leaves 26% of studies having used Red of 610nm, 630nm, 635nm, 660nm, or 670nm. And the remainder study used a combination of Red and NIR. [29]

Neither article makes any determination of the "best" wavelengths to use for brain health, just reporting what happened to be used up to this point. Although there is a preference for Near-Infrared wavelengths for brain health, there is good evidence for Red light to be effective also. 

Red or NIR for Eye Health 

A 2022 review article of using Photobiomodulation for retinal (eye) diseases summarized the recommended wavelength ranges as:

"Red to near-infrared light wavelengths in the range of 635–680 nm and 810–830 nm are suitable for inducing PBM to treat retinal diseases, while a 670 nm red laser or LED light wavelength is the most reported light source wavelength in the literature for inducing PBM to treat retinal diseases." [31]

Again showing that both Red (635-680nm) and NIR (810-830nm) can be appropriate for supporting eye health, although the majority of studies have used 670nm. 

Red vs NIR on Facial Muscle Fatigue

This study compared 660nm versus 808nm on the orbicularis oris. They found no change or improvement with either wavelength. [31] So even when studies fail, both wavelengths fail together. 

More importantly, the researchers comment that they believe that Photobiomodulation can be effective for this condition, so they specifically write it was at these particular dosing parameters that failed, not the wavelengths. 

"Photobiomodulation with the parameters investigated in this study had no immediate effect on orbicular oris fatigue." [31]

Which reminds us that wavelengths alone do not deliver benefits. It is the combination of wavelengths and proper dosing application to receive the benefits. 

Influencers need consumers to think that wavelengths alone control the benefits, to hide the fact that the type of products they sell are not clinically studied. And their dosing recommendations do not follow the science. So if they connect all of their medical claims to wavelength, then they can circumvent those marketing problems. 

NIR vs NIR Wavelengths:

Which Near-Infrared (NIR) wavelength is best for deep tissue treatments? Inconclusive, they all seem to work similarly. 

Long COVID Brain Fog:

One study use either a Full Body LED bed (660nm+850nm) or LED Helmet (1070nm) for Long COVID brain fog. Both groups received a similar result with insignificant differences. [17]

905nm vs 808nm for Low Back Pain

A human study on low back pain found that both 905nm and 808nm were effective. They recommended the 905nm as having a better response. 

"The findings show that, after 15 treatment sessions, Laser therapy with 905 nm & 808 nm
are effective for chronic low back pain. But 905 nm LLLT had a better clinical implication than 808nm LLLT." [32]

904nm+605nm vs. 1064nm Trigeminal Neuralgia

One study compared a combined 904nm+605nm Laser versus a 1064nm laser for Trigeminal Neuralgia. They found both treatments were effective, with a better effect from the 904+605nm laser. 

Red Light Therapy vs Broad Spectrum Lamps

We see many internet doctors reporting on the beneficial research of Red and NIR light therapy from Lasers and LEDs. However, they often pivot towards claiming the same benefits can be gotten from sunlight. 

This would also affirm that many of these internet experts also believe that the benefits of wavelengths are non-specific. They claim that broad-spectrum sunlight can deliver the same benefits of a narrowband LED study. 

"My thoughts are now that it is not about a specific wavelength range, we have got to recreate a broad spectrum, and that spectrum is a sunlight spectrum." [Podcast]

In the quote above, famous researcher Glen Jeffrey seems to plan to eschew LED studies and start using more broad spectrum incandescent-type lights in future research. 

According to Dr. Roger Seheult in a recent interview:

"But the question is, and I think actually is being answered by work from Glen Jeffrey, is that when he does Red lights vs Incandescent bulbs, which is a way of saying 'broad spectrum', there are actually more robust endpoints being met with the broad spectrum of the incandescent bulb than with the monochromatic single wavelength red light therapy"

[Link]

LED Panel manufacturers are adding more wavelengths and colors than ever before, which would make them more of a broad spectrum emitter. Since the additional wavelengths often represent a small percentage of their output, sometimes only <10% or 5%, this would indicate that they do not believe in the research needing specific isolated wavelengths to produce the effects as shown in most studies are still only monochromatic.

There are incandescent bulb companies claiming to promote the same benefits as Photobiomodulation even though they have wide spectrums. All of these claims also seem to imply that they believe the benefits of wavelengths are more generalized and non-specific. 

However, we would need to see more studies comparing the differences between quasi-monochromatic LEDs versus broad spectrum sources to make sure that the benefits would be equivalent. Until then, the research on LEDs and Lasers are often misrepresented by most internet doctors when they pivot the topic towards sunlight.

660nm vs Broad Spectrum for Wrinkles 

One study compared a 660nm red light vs a white light emitting 411nm to 777nm. There were 52 females treated with the same dose of either Red or White broad-spectrum light. 

"The red LED group showed slightly better improvement, but there were no statistical differences. In assessments by blinded dermatologists, no significant differences were observed in both groups. " [34]

They found no statistically differences between the Red light or White light for wrinkles.

On average one group will always be better than the other as they note the Red was slightly better. But without statistical significance it could just be from random variation and they would need larger trials to see if there was a meaningful difference. 

Broad Spectrum Lights for Skin Rejuvenation

One study had 128 patients and used 4 different broad-spectrum ranges of Red and/or Near-Infrared from 570nm to 850nm. They found the different treatment groups with different spectrums received similar results.

They specifically comment that their study would debunk the notion that specific wavelengths are needed for specific results. Both in being broad spectrum and having different wavelength distributions. 

"Some authors emphasize the importance of distinct wavelengths for optimal results.^{16–18,26–28} In our study, the differences between the RLT and ELT treatments in clinical outcome and patient satisfaction were not significant, indicating that despite spectral differences, both light sources were commensurably effective regarding study objectives." [35]

It would truly be interesting to see more studies particularly comparing LEDs to broad-spectrum sources like incandescent heat lamps. Especially now that we are seeing more patterns of equivalent results from different wavelengths. 

Yellow (570nm) vs Yellow (590nm) for Skin:

One study compared 570nm versus 590nm to treat skin photoaging. They were also combined with Red and Near-Infrared Light. So the two groups were actually:

• 570nm + 620nm + 850nm
• 590nm + 620nm + 850nm

"Both 570 nm and 590 nm yellow light, combined with red light and infrared LED therapy, effectively reduce pores, wrinkles, texture, and brown spots, improving skin photoaging. The 570 nm yellow composite LED treatment showed more significant effects on both facial wrinkles and brown spots." [36]

Both groups demonstrated a significant improvement, with the 570nm wavelength showing a better result. 

Red and Near-Infrared Light for Acne vs Blue

Blue light has been advertised heavily for treating acne, especially after one major brand added 2% blue to their panels and their affiliate influencer changed their criteria to accommodate them.

Then Blue light has became an essential part of "Red" Light Therapy, especially for the acne-blasting qualities. The effectiveness of Red and NIR have for acne has been conveniently omitted to sell more products.

However, blue light can run the risk of creating inflammation in the skin and increasing pigmentation or exacerbating melasma. 

One article notes these risks of Blue light for the skin:

"These potentially undesired effects span erythema (sunburn), photoaging, decreased skin hydration, elevated melanin production and subsequent hyperpigmentation" [37]

We cannot ignore the risks to the eyes from blue light exposure either.

"Skin photobiomodulation using blue LED may be a proven method; however, given the risk for retinal damage, it is better to use red or infrared light with longer wavelength for retinal safety." [38]

And it is no coincidence that the top RLT Influencers are now normalizing hyperpigmentation adverse reactions with "red" light therapy, which they can hardly even call Red Light Therapy anymore. 

Indeed, Red and Near-Infrared wavelengths have been successfully studied to treat acne on their own. 

One study compared Red (633nm) to Blue (415nm) light therapy for acne and found similar results.  [39]

"Red light and BL therapies have similar efficacy in mild-to-moderate acne vulgaris, especially for inflammatory lesions. RL had advantages with fewer adverse reactions compared with BL." [39]

Since the Red light has less risk of adverse reactions, any responsible person would recommend the safer option. Which was the conclusion made by the researchers.

One article compared Red (630nm) versus Near-Infrared (890nm) for acne. They found the Red wavelength to be very effective, with hardly any effect from the 890nm. [40]

Another article successfully used 785nm wavelength Near-Infrared light to treat acne.[41]

Several studies have compared Red (635nm) light alone to conventional chemical treatments and found a comparable improvement in Acne control. [42][43][44]

As always, we want consumers to get the best possible benefits with the least amount of risk or adverse reactions.

When dealing with acne, it is prudent to try Red or Red+NIR first without any Blue light to see if that makes any improvement. In many cases, it should be effective on Acne without the risks of blue light. Unfortunately the marketing objectives have taken priority over safety in this industry. 

Conclusions:

Wavelengths of Red and Near-Infrared light have very broad, generalized benefits on the body. The established mechanisms have wide spectral activation and the net results often appear to be the same. 

We learned in a previous blog that dosing red light therapy is like a switch. There are a broad range of interconnected dosing parameters of Intensity (mW/cm^2), fluence (J/cm^2), and Time (seconds or minutes).

It is likely that the wavelengths also play a role in this switch effect. The wavelengths may not have more or less effect, they all reach the same plateau of effectiveness. This has been demonstrated in many human studies comparing wavelengths and review articles summarizing wide ranges of wavelengths used to treat the same condition. 

Top researchers and consensus articles agree that these wavelengths can have the same benefits especially when equilibrated by dosing. They allow wavelength selection to be flexible so that when Photobiomodulation gains mainstream approval for specific conditions, clinics around the world will be able to implement it with various wavelengths.

Even the acne-fighting benefits can be gotten with Red or Near-Infrared light, so consumers do not need to face the risks of Blue light being pushed by influencers.  

This is to the detriment of manufacturers needing to sell more products with different wavelengths. They emphasize the Fear-Of-Missing-Out of specific benefits if your device lacks certain wavelengths. The influencer reviewers need a way to differentiate different products benefits by wavelength to create the illusion that you need to shop for specific wavelengths tailored to your condition. 

It is an interesting pattern that the top RLT Influencers are happy to extrapolate almost every other Photobiomodulation parameter like promoting high intensities, overdosing, excessive heat, oversized devices, and usage at a distance vs skin contact method. Yet the one thing they are overly strict about is the wavelength.

It seems most of the medical claims are anchored to wavelength so they can ignore the importance of optimal dosing and evidence-based treatment methods. As long as the consumer "has" a wavelength, even if it is a small percentage of the output (<5%), then the consumer is promised that they would get that medical benefit. 

Remember that the "standard" wavelengths of 660nm and 850nm had originally claimed to cover all the potential benefits that Red Light Therapy had to offer. The 660nm covered all of the superficial benefits, and the 850nm covered all of the deep tissue benefits.

All the original LED panel brands started out exclusively with just these 2 wavelengths, and the RLT Influencers had no problem with the lack of benefits offered by only 2 wavelengths. As usual, the standards only change when new wavelengths become commercially available in the influencer's favorite affiliate brands. Their standards shift based on commercial interests, not based on science. 

But perhaps the marketing around 660nm and 850nm was correct all along, as many influencers and consumers were perfectly happy with it. As usual, the human experimentation conducted by brands and influencers have already proven that most benefits can be gotten from limited and even sub-optimal wavelengths.

So in reality the majority of benefits of PBM can be gotten with a single wavelength in the 600nm-1100nm range. For good measure, at least 1 Red and 1 Near-Infrared wavelength can have synergistic effects and cover different penetration depths. Which is already provided by most commercial devices. 

Bonus Rant:

Wavelength: the Active Ingredient or Essential Nutrient?

We think of wavelengths for therapy similar to the Active Ingredient of a drug. The wavelength affects specific molecules to produce the photochemical effects. Different active ingredients have different effects, so we would want to choose the correct one for our desired application.

"PBM is a technology that utilizes specific wavelengths of light, typically red or NIR, to enhance biological processes within living organisms. This mechanism is distinct from photopharmacology, as PBM does not rely on engineered photosensitive proteins but instead exerts direct effects on various biomolecules, including mitochondrial oxidoreductases and ion channels [177,178] " [1]

We are programmed by the drug industry that they can only be marketed and approved for one condition at a time. Using a drug for "off-label" usage is highly scrutinized, even when there are clinical studies to support it. 

Consider the popular Semaglutide GLP1 peptide. When it is marketed to treat Diabetes then it is called Ozyempic. When marketed for weight loss it is called Wegovy. The same chemical approved separately depending on the marketing label. Why not have just one drug that is marketed for both? Because that is not how the system works, and not how to optimize marketing. 

But for more natural treatments like nutritional supplements, the benefits are much more generalized. Vitamins and essential nutrients are often marketed for a singular claim, but of course they play many roles in the body. 

For example, we know that Vitamin C plays a powerful role in many bodily functions. However, the marketing on the bottle only makes a single claim for what it supports. 

Why? Because generalized claims are too vague to motivate people to buy a product. We may intuitively believe that broad claims are better. But it is often the opposite.

Our psychology actually prefers that products make specialized claims to assure us that it will treat our specific needs. For example having different "forms" of Magnesium that treat specific health needs. Then the marketing got so out of hand that you need supplements with 5 different forms of magnesium to pray that you get all the marketed benefits of Magnesium.

The same thing has happened to wavelengths of light. Our minds want to believe that individual wavelengths have exclusive benefits. And the top RLT influencers are happy to tell the consumer what they want to hear to close the sale. 

Additionally, claims that are too broad may give us red flags that the product is snake-oil, a cure-all, or panacea.

If we claim that 810nm can give us practically all the benefits from PBM in a single wavelength, our mind needs to reject that as being oversimplified. We want PBM to be more complicated than it is to satisfy our societal programming.

However, we are dealing with natural wavelengths from Sunlight, an essential factor that has existed throughout all of evolution. It would be too oversimplified to assume specific wavelengths only play one role on the body, the same way we cannot reduce essential nutrients down to one marketing claim. 

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