Red light therapy: what does the research really say?

A lot is claimed about red light therapy, and very little of it is backed up. One product page says it rejuvenates your skin, another says it helps your muscles recover faster, and neither usually cites a source. This article does it the other way round. For each use, it sets out what the scientific research actually shows, with a link to every study we rely on, so you can read it for yourself.

We sell red light equipment. That is exactly why we want to write this piece as soberly as possible: a shop that only shows you the favourable half of the literature is no use to you. So you will also find the studies that found nothing, the guidelines that advise against laser therapy, and the criticism researchers have of their own field. If you want the basics first, start with the complete guide to red light therapy. If you want to know what the nanometres mean, read the guide to wavelengths in red light and infrared. This article is about the evidence.

How to read research on red light therapy

Almost every claim about red light therapy ends with the words "research shows". On its own that means almost nothing, because there is a huge difference between an experiment with cells in a culture dish and a guideline that doctors follow. Before you read the rest of this article, it helps to know that ladder.

One more thing to know: in this field a positive result often means "a small difference that is statistically significant". Statistically significant means the difference is probably not down to chance. It does not mean you will notice it. That distinction comes up again and again in this article.

What the field is really about: photobiomodulation

The scientific name for red light therapy is photobiomodulation, PBM for short. You will also come across the older term low level laser therapy, LLLT for short. In 2015 a group of leading researchers proposed dropping that old term, because "low" and "level" were never defined and the field has long since stopped working with lasers alone (Anders, Lanzafame and Arany, 2015). Since 2016, photobiomodulation has also been the official search term in medical databases.

The definition goes roughly like this: light that does not ionise and does not work by heating, but by being absorbed by substances in the body itself. That is straight away the clearest difference from an infrared sauna blanket or a heat lamp, which do work through heat. We explain that difference in the article on red light and infrared.

The mechanism: what is assumed and what has been shown

Whenever you read how red light therapy works, you almost always get the same story. It is a good story. It is just less certain than it sounds.

The standard story

It goes like this. Your cells contain mitochondria, the parts that supply energy. Inside them is an enzyme called cytochrome c oxidase, CCO for short. Red and near infrared light is said to be absorbed by that enzyme, releasing nitric oxide that was inhibiting it. Energy production then runs better again, and signalling substances are released that prompt the cell to repair itself. This model has been described in most detail by Michael Hamblin, the most cited researcher in this field (Hamblin, 2018, and de Freitas and Hamblin, 2016).

The same work also contains a detail you rarely see on a product page. According to this model, the light that works falls in two bands, roughly 600 to 700 nanometres and 780 to 1100 nanometres, with a dip in between where little happens. That explains why 660 and 850 nm appear on panels everywhere, and why nobody advertises 730 nm.

Why that story is shaky

This is where it gets interesting, and you will not read this in any advert. The mechanism is not an established fact but a hypothesis, and in recent years it has developed some serious cracks.

• In 2019 researchers exposed cells to 660 nm that had no working cytochrome c oxidase at all. Those cells responded anyway, with more cell division and more energy production. If the enzyme were the key, that could not have happened (Lima et al., 2019).
• In 2020 Quirk and Whelan concluded bluntly that there is no reliable demonstration of any light induced effect on that enzyme, and that the field needs more rigorous research instead of ever broader applications (Quirk and Whelan, 2020).
• In 2022 Hamblin himself, together with Liebert, wrote a paper titled to say that the mechanism goes beyond cytochrome c oxidase. In it they point to ion channels in the cell membrane and other pathways, and argue that the active mechanism depends on wavelength, intensity and tissue (Hamblin and Liebert, 2022).

That does not make red light therapy pointless. It means something else: the underlying story that sellers present as proven is itself a subject of debate within the field. Anyone who tells you that "the light switches on your mitochondria" is giving you a simplified version of an open question.

The evidence is strongest for the idea that the dose matters, and weakest for the explanation of why it would work.

Dosage: why more is not better

If there is one thing the research broadly agrees on, it is this. The relationship between the amount of light and the effect is not a straight line upwards. Too little does nothing, and too much also does nothing or even works against you. In the literature this is called the biphasic dose response, described in two widely cited reviews (Huang et al., 2009 and the 2011 update).

That update makes one more point that is directly practical. The same total amount of energy, delivered by a stronger device in a shorter time, does not give the same result as a weaker device over a longer time. So power and time are not freely interchangeable. A panel that is twice as strong does not simply replace half of your session time.

Why protocols vary so widely

A 2018 review set the settings used in the literature side by side and reached a sobering conclusion: after more than fifty years of research, there is still no agreement on parameters and protocols. Some groups recommend less than 100 mW per square centimetre and 4 to 10 joules per square centimetre, while others go up to 50 joules per square centimetre at the surface (Zein, Selting and Hamblin, 2018).

The same study noticed something striking. Tissues with lots of mitochondria, such as muscle and nerve tissue, seemed to respond to lower doses than tissues with few mitochondria, such as skin and tendons. And failed studies in tissue rich in mitochondria seemed more often to be the result of too much light than too little.

That last row comes from a methodological review of 27 skin studies using LEDs, and it is sharp. Not one of those 27 studies checked whether the device actually delivered the dose the researchers recorded (Grimes, 2025). If doses that differ by a factor of a thousand are used for the same condition, and nobody measures what actually comes out, then the question "how much do you need" simply has not been answered yet.

How much light actually gets in

A question that is rarely asked: of all the light a panel emits, how much actually reaches the spot where you want it? The answer is less than most people think. A review of penetration measurements found that at 630 to 810 nanometres, only 0.2 to 10 per cent of the incoming light passed through the human scalp and skull, while in some strains of mice it was 60 to 70 per cent (Salehpour et al., 2019).

That difference from lab animals is one of the reasons to be careful with results from animal studies. It is also why we do not state a penetration depth in millimetres on our product pages. Figures like that vary by tissue, by person and by measuring method, and they almost always appear in an advert and rarely in a source.

Use by use: what the research shows

Now for the real work. For each use, we set out what has been studied, what came out of it and where the weak spot is. The order runs roughly from the topic consumers search for most to the topic where the evidence is strongest. Those are not the same order, and that is exactly the point.

Skin, wrinkles and skin texture

This is what most people think of with red light therapy. And there really has been research on it.

In a lab study on cultured skin, pulsed light at 660 nm gave on average about 31 per cent more type I procollagen and 18 per cent less MMP-1, the enzyme that breaks collagen down (Barolet et al., 2009). That is a credible biological starting point. A double blind study in which participants received light on one half of the face and a sham treatment on the other, with 76 participants and wavelengths of 633 and 830 nm, found measurable improvement in wrinkles and elasticity after four weeks, with more collagen and elastic fibres in tissue samples (Lee et al., 2007). Note: the percentages most often quoted from that study are maximums, not averages.

The best known study is the one by Wunsch and Matuschka from 2014, with just over a hundred participants and thirty sessions over fifteen weeks. It found improvement in skin roughness, in collagen density measured by ultrasound and in the judgement of blinded assessors (Wunsch and Matuschka, 2014). Two caveats belong with it: the control group received no sham treatment but nothing at all, so the expectation effect was not ruled out, and the study was paid for by a manufacturer of the equipment used.

The best counter test is more recent. In 2025 a double blind study was published with 95 women aged 45 to 60, with a real sham treatment as the control and 660 nm light for four weeks. On the clinical wrinkle scale there were no differences between the groups. Only image analysis software measured a reduction. Satisfaction was higher in both light groups than in the sham group (Bragato et al., 2025).

For home devices the evidence is thinnest. A small pilot study with 24 participants and a home device using 637 and 854 nm found significantly better skin elasticity on the treated side after six and eight weeks, but without a sham treatment and without blinding the participants (Ng, Wanitphakdeedecha and Yan, 2020).

Honest summary: there is a plausible mechanism and there are measurable effects in controlled studies, but the effects are small, the studies are short, and the best blinded study saw the effect on the clinical scale disappear. If you expect visible rejuvenation within a few weeks, you will be disappointed.

Acne

The main source here is a Cochrane review, and it does not pull its punches. Based on 71 randomised studies with a total of 4,211 participants, the authors conclude that high quality evidence for light therapy in acne is lacking, with the certainty of the evidence ranging from very low to moderate (Barbaric et al., 2016). The median study had 31 participants.

For blue light around 415 nm there is a controlled study with 41 participants in which the number of inflamed spots fell by about half, while it rose slightly in the control group (Ash et al., 2015). And in a recent home study with 30 participants, the red and blue group did improve within itself, but there was no significant difference from the group that received blue light only (Friedmann et al., 2026). Improvement within a group without a difference between groups is weak evidence: you do not know whether the light did it.

Muscles, sport and recovery

This is one of the best studied uses, and at the same time a textbook example of how a mountain of publications can still rest on a thin foundation.

The largest summary pooled 39 randomised studies with 861 participants. It concluded that some effect in favour of photobiomodulation was found, but explicitly on the basis of evidence of very low to moderate quality, and the authors write that further research is needed before its use in sport can be justified (Vanin et al., 2018). An earlier meta analysis of 13 studies found that time to exhaustion increased by an average of 4.12 seconds and the number of repetitions by 5.47 (Leal-Junior et al., 2015). Four seconds. Statistically real, practically hard to notice.

Against that stands a series of null results, and they are at least as telling.

• A meta analysis of 15 studies with 317 participants found no effect on muscle soreness, swelling, range of motion or strength. Only the blood marker for muscle breakdown fell, and only when the light was applied before exercise (Nampo et al., 2016).
• A study with a sham device as the control, in which 39 trained men trained for six weeks with or without light therapy, found no difference whatsoever. All groups got equally stronger (Machado et al., 2022).
• A study with 48 participants and a full body panel found no effect on peak power, average power or lactate during maximal exercise (Forsey et al., 2023).
• And the most relevant detail if you are considering a panel at home: a meta analysis of 34 studies found the benefits only in people who barely exercised and in elite athletes, and not in the group that is recreationally active (Li et al., 2024).

There is something else going on here. A large share of the most influential meta analyses in this field have the same researcher among their authors, and his own publication states that he receives research support from a manufacturer of laser equipment (Leal-Junior, Lopes-Martins and Bjordal, 2019). That does not invalidate the research. But it is something you should know before you accept the conclusions.

Pain and joints

This is where it gets truly contradictory, and that in itself is the most honest answer we can give.

On the positive side is a 2009 meta analysis in The Lancet on neck pain, with 16 studies and 820 participants. For chronic neck pain it found a pain reduction of about 20 points on a scale of 100, in some studies lasting up to about 22 weeks after the course of treatment (Chow et al., 2009). For knee osteoarthritis, a meta analysis of 22 studies with 1,063 participants found a pain reduction of about 14 points on the same scale of 100, with a larger effect at the recommended doses (Stausholm et al., 2019).

On the other side is the following, and it concerns exactly the same conditions.

• A meta analysis of 9 studies with 518 patients with knee osteoarthritis found no significant difference at all from a sham treatment, neither straight after the course nor after twelve weeks. The literal conclusion is that the best available evidence does not support its effectiveness (Huang et al., 2015).
• A large, blinded study with 148 patients with chronic lower back pain found no clinically relevant difference from the sham treatment at any point of measurement. The title of that paper literally says that photobiomodulation is no better than a sham treatment (Guimarães et al., 2021).
• The Cochrane review on lower back pain, based on 7 studies with 384 participants, concludes that there is not enough data to draw firm conclusions (Yousefi-Nooraie et al., 2008).

What guidelines make of it is then the most revealing. The UK NICE guideline for osteoarthritis is explicit: do not offer laser therapy to people with osteoarthritis, because there is not enough evidence of benefit. There, laser sits in the same list as TENS and ultrasound (NICE guideline NG226, recommendation 1.3.9). And closer to home for us: the Dutch physiotherapy guideline for nonspecific neck pain also advises against low level laser and focuses on education and exercise therapy (Bier et al., KNGF guideline, 2018).

If you want warmth on a stiff back or neck, that is a different story and a different technique. That is what the article on the infrared lamp for back pain and neck complaints covers. Warmth is comfort, and that can simply be the reason too.

Luxyor Lumi 110

• Compact panel for targeted use on a shoulder, knee or the face
• Seven wavelengths from 480 to 940 nm, with the emphasis on 660 and 850 nm
• Adjustable via touchscreen or remote control, with a timer
• 60 days to change your mind and 2 year warranty

View the Lumi 110

Hair growth

With hair loss the situation is unusual: there are relatively many double blind studies with home devices here, because laser combs and helmets are, after all, used at home.

A meta analysis of 11 double blind studies found a clear increase in hair density compared with a sham device (Liu et al., 2019). A second meta analysis, limited to seven studies with 607 participants and only devices cleared in the United States, came to a similar result, with real laser diodes doing better than combined LED setups (Lueangarun et al., 2021). The largest single study randomised 269 people over 26 weeks to a laser comb or an identical looking sham device and found a clear increase in the number of hairs per square centimetre (Jimenez et al., 2014). That study was funded by the manufacturer of the device.

Now the other side, and it matters. The Cochrane review on hair loss in women looked at two studies with 141 participants and noted something remarkable: the participants themselves did not find the laser comb more effective than the sham device, even though the researchers did count more hairs (van Zuuren, Fedorowicz and Schoones, 2016). And a 2025 meta analysis found that adding light therapy on top of minoxidil gave no demonstrable added value (Alosaimi et al., 2025). On top of that, hardly any study runs longer than 26 weeks, and very little is known about what happens when you stop.

For completeness: Luxyor does not sell laser combs or hair growth helmets. We include this section because it shows what a use looks like that has been studied relatively well and at the same time comes with serious caveats.

Wound healing

Here the picture is mixed and mostly disappointing. The Cochrane review on light therapy for diabetic foot ulcers, based on 8 studies with 316 participants, found that 64.5 per cent of wounds healed compared with 37.0 per cent in the control group, but rated that evidence as low quality because of small numbers and methodological shortcomings (Wang et al., 2017). On pressure ulcers Cochrane is even more cautious: based on 7 studies with 403 participants, the authors state that they are very uncertain about the effect (Chen et al., 2014). And for open leg ulcers caused by vein problems, a meta analysis of 11 studies with 615 patients found no significant effect on wound size (Rasul et al., 2026).

Inflamed mouth lining during cancer treatment

This is the use with the strongest evidence, and almost nobody knows about it. Chemotherapy and radiotherapy in the head and neck area often cause a painful inflammation of the lining of the mouth. Photobiomodulation is included for this in an international guideline drawn up by MASCC and ISOO, for prevention in three specific situations, with clearly defined protocols (Zadik et al., 2019, included in the MASCC/ISOO guideline by Elad et al., 2020).

The most recent summary pools 30 randomised studies with 1,748 patients and finds a relative risk reduction of about half for severe inflammation and for severe pain. At the same time, the authors rate the certainty of that evidence as very low to low, and no significant effect was found on dry mouth or quality of life (Pedroso et al., 2026).

Two things to take away. First: even for the best supported use, the quality of the evidence is low. Second, and this is the heart of this whole article: this is a treatment with laser equipment, inside the mouth, by healthcare professionals, following a precise protocol. That is fundamentally different from a panel in your living room.

The uses side by side

The biggest weakness of the whole field

If you had to remember one source from this article, it would be this one. In 2025 an umbrella review was published that summarised 15 meta analyses, together covering 204 randomised studies and more than nine thousand participants, spread across 35 outcome measures. The result is sobering (Son et al., 2025).

• Of the fifteen meta analyses, according to the standard quality measure, one was of high quality, two of moderate and twelve of low quality.
• Not one of the 35 outcomes reached high certainty of evidence. Over half fell into the low category and a quarter into very low.
• For about one in five outcomes, signs of publication bias were found: the pattern where studies with a positive result get published and studies without a result stay in the drawer.

Combine that with the review of skin studies mentioned earlier, in which about 37 per cent of the studies were funded by the device manufacturer and another 11 per cent were carried out by commercial clinics that offer the treatment themselves, and the picture is complete. This is not proof that red light therapy does not work. It is a reason to look at every confident claim with suspicion, including ours.

From study to your living room: four translation problems

Say a study shows a nice result. A lot still has to happen before that tells you anything about the device you buy. These are the four steps where it goes wrong.

1. Laser is not LEDBy far most of the positive studies were done with lasers. A laser delivers a focused beam of a single wavelength, an LED a broader beam. A laser study is not evidence for an LED panel, not even at the same nanometre value.
2. Clinical is not homeIn studies, a precisely defined spot is treated, at a fixed distance, for a fixed number of seconds, by someone who does it every day. At home the panel stands where it fits and you sit at whatever distance happens to be comfortable.
3. The dose is usually unknownA product page rarely states the intensity at a given distance. Without that figure you cannot know whether you come anywhere near the dose at which the effect was found in the study. And as we said: more is not automatically better.
4. The outcome measure is often not what you want to knowA study measures a blood marker for muscle breakdown or collagen density on an ultrasound scan. You want to know whether you feel better or look better. That is not the same thing, and marketing routinely glosses over the difference.

Safety: what is and is not known

The good news first. In the published studies, red and near infrared light on the skin is remarkably well tolerated. In a systematic review of 14 randomised studies on photobiomodulation for chronic pain, thirteen studies reported no side effects at all, and the fourteenth only a slight feeling of warmth and mild discomfort (Ferreira et al., 2026). In 2025 an international panel of dermatologists concluded that photobiomodulation with red light does not cause DNA damage in adults (Maghfour et al., 2025).

That reassurance has its limits. The studies are small and short, so little is known about rare or long term effects. And "no side effects reported in twenty participants over four weeks" is a weak basis for saying that something is safe.

The eye is the point of attention, not the skin

For lamps and LEDs there is an international standard for photobiological safety, IEC 62471, which sorts devices into risk groups. That classification partly relies on your own defence reflex: you blink and look away from bright light. That is exactly where the problem lies with near infrared. It is invisible, so you do not blink, while the energy is still there. The international commission for nonionising radiation, ICNIRP, also sets exposure limits for visible and infrared light on the cornea, lens and retina (ICNIRP, guidelines on visible and infrared).

How real that is becomes clear from a very different corner. With devices in China that shine 650 nm red light straight into children's eyes to slow down short sightedness, independent researchers measured that with some laser based devices the safety limit was reached after just 1.4 to 2.8 seconds, while the recommended treatment time is 180 seconds. The only LED device in that comparison stayed well below it (Ostrin and Schill, 2026, adding to their earlier measurement from 2024). There is also a documented case of a twelve year old girl who developed retinal damage and loss of vision after five months of use, which recovered after she stopped (Tian and Xiao, 2022).

That is a different use from a panel on your skin, and it is no reason to be afraid of a red light panel. But it is the best proof that "red light" as a category guarantees nothing. So do not look into a panel, wear red light glasses or keep your eyes closed, and stick to the times and distances in the manual.

When it is better to check first

There are a few situations in which it is better to check first or leave the device alone: photosensitive epilepsy, pregnancy and open wounds. Manufacturers list these points in their manuals, and it pays to read that list before you start. A draft US guidance document for photobiomodulation devices also states explicitly that the long term effects are unknown and that treatment over suspicious patches of skin should be avoided (FDA, draft guidance on PBM devices, 2023).

A nuance on medication: many warnings concern medication that makes you sensitive to light, but those reactions mainly occur in the ultraviolet range, not in red or near infrared. That makes the warning a precaution rather than a proven risk. Even so, checking with your doctor or pharmacist remains the wisest choice if you take such medication.

What we do and do not conclude from this

We sell red light panels. Based on everything above, this is what we say about them, and it is deliberately less than what you read elsewhere.

What we do not say: that red light therapy cures, treats or prevents a condition. The research cannot support a promise like that, and anyone who makes it anyway is selling certainty that does not exist.

What we do say: there is serious research on photobiomodulation, the safety profile on the skin looks good in that research, and measurable effects have been found for some uses. Those effects are mostly small, they usually come from clinical research with laser equipment, and they do not automatically say anything about your result with a panel at home. If you buy a panel, you are currently buying a reasonable bet based on an unfinished body of evidence, not a certainty.

And if you are mainly looking for warmth and relaxation, a red light panel is not the logical answer anyway. Then you end up with far infrared, and that is exactly what an infrared sauna blanket does. We make no medical claims about that either: it is warmth, it feels good, and that can be enough.

Luxyor Lumi 700

• Panel 91 cm tall with 300 LEDs, freestanding or wall mounted
• Seven wavelengths from 480 to 940 nm, with the emphasis on 660 and 850 nm
• Adjustable intensity and timer via touchscreen or remote control
• 60 days to change your mind and 2 year warranty

View the Lumi 700

What to look out for in claims about red light

With the knowledge above, you can spot most nonsense within thirty seconds. These are the patterns you will come across most often.

• "Scientifically proven" without a source. Ask which study, with how many people, with laser or LED, and whether there was a sham treatment. If a seller cannot tell you, it is a slogan.
• A cell study presented as a result in humans. "Increases energy production in cells" almost always comes from a culture dish.
• Laser studies used to sell an LED panel. This is the most common translation error in the entire industry.
• Only the favourable half of the literature. For almost every topic above there is a counterpart that found nothing. Anyone who never mentions it is cherry picking.
• Penetration depths in millimetres. Figures like that vary by tissue and measuring method and rarely appear in a source you can check.
• More wavelengths or more watts as proof of quality. The dose response relationship is not linear, so more powerful is not automatically better.
• No figure at all for intensity at a distance. Without mW/cm² at a stated distance, you do not know what you are buying.
• "No side effects" or "100 per cent safe". That cannot be maintained, and keeping quiet about risks is misleading in itself.
• Medical promises on a product that is not medical. Cures, treats or prevents does not belong on the page of a wellness device.

This page is about light. The heat side, meaning infrared cabins, sauna blankets and lamps, has its own evidence page with the same layout: what the research says about infrared and heat.

Finally

Red light therapy is not a miracle cure, and it is not quackery either. It is a field that is genuinely being researched, where one use is included in an international guideline, where small but measurable effects have been found for a handful of other uses, and where the quality of evidence is low across the board. That is a dull answer, but it is the honest one.

What you can do with it in practice: do not expect a quick or big result, look at the stated wavelength and intensity rather than at superlatives, and treat every confident health promise as a reason to read on rather than to order. If you want to take it further from here, have a look at the red light therapy panels or read the guide on which red light device suits you. And if you come across a claim somewhere that sounds too good to be true, the list of sources below lets you check it for yourself.

Sources

All the sources below are peer reviewed publications, official guidelines or international safety standards. The links go straight to the original. Where a summary sits behind a paywall, you can still verify where it was published.

1. Anders JJ, Lanzafame RJ, Arany PR (2015). Low-Level Light/Laser Therapy Versus Photobiomodulation Therapy. Photomedicine and Laser Surgery 33(4):183-184. doi:10.1089/pho.2015.9848
2. Hamblin MR (2018). Mechanisms and Mitochondrial Redox Signaling in Photobiomodulation. Photochemistry and Photobiology 94(2):199-212. PMID 29164625
3. de Freitas LF, Hamblin MR (2016). Proposed Mechanisms of Photobiomodulation or Low-Level Light Therapy. IEEE Journal of Selected Topics in Quantum Electronics 22(3). doi:10.1109/JSTQE.2016.2561201
4. Chung H, Dai T, Sharma SK, et al. (2012). The Nuts and Bolts of Low-level Laser (Light) Therapy. Annals of Biomedical Engineering 40(2):516-533. doi:10.1007/s10439-011-0454-7
5. Lima PLV, Pereira CV, Nissanka N, et al. (2019). Photobiomodulation enhancement of cell proliferation at 660 nm does not require cytochrome c oxidase. Journal of Photochemistry and Photobiology B 194:71-75. PMID 30927704
6. Quirk BJ, Whelan HT (2020). What Lies at the Heart of Photobiomodulation: Light, Cytochrome C Oxidase, and Nitric Oxide. Photobiomodulation, Photomedicine, and Laser Surgery 38(9):527-530. doi:10.1089/photob.2020.4905
7. Hamblin MR, Liebert A (2022). Photobiomodulation Therapy Mechanisms Beyond Cytochrome c Oxidase. Photobiomodulation, Photomedicine, and Laser Surgery 40(2):75-77. doi:10.1089/photob.2021.0119
8. Huang YY, Chen ACH, Carroll JD, Hamblin MR (2009). Biphasic dose response in low level light therapy. Dose-Response 7(4):358-383. PMID 20011653
9. Huang YY, Sharma SK, Carroll JD, Hamblin MR (2011). Biphasic Dose Response in Low Level Light Therapy, an Update. Dose-Response 9(4):602-618. doi:10.2203/dose-response.11-009.Hamblin
10. Zein R, Selting W, Hamblin MR (2018). Review of light parameters and photobiomodulation efficacy: dive into complexity. Journal of Biomedical Optics 23(12):120901. doi:10.1117/1.JBO.23.12.120901
11. Salehpour F, Cassano P, Rouhi N, et al. (2019). Penetration Profiles of Visible and Near-Infrared Lasers and Light-Emitting Diode Light Through the Head Tissues. Photobiomodulation, Photomedicine, and Laser Surgery 37(10):581-595. doi:10.1089/photob.2019.4676
12. Grimes DR (2025). Methodological issues in visible LED therapy dermatological research and reporting. PLOS ONE 20(9):e0332995. doi:10.1371/journal.pone.0332995
13. Barolet D, Roberge CJ, Auger FA, et al. (2009). Regulation of skin collagen metabolism in vitro using a pulsed 660 nm LED light source. Journal of Investigative Dermatology 129(12):2751-2759. doi:10.1038/jid.2009.186
14. Lee SY, Park KH, Choi JW, et al. (2007). A prospective, randomized, placebo-controlled, double-blinded, and split-face clinical study on LED phototherapy for skin rejuvenation. Journal of Photochemistry and Photobiology B 88(1):51-67. doi:10.1016/j.jphotobiol.2007.04.008
15. Wunsch A, Matuschka K (2014). A controlled trial to determine the efficacy of red and near-infrared light treatment. Photomedicine and Laser Surgery 32(2):93-100. doi:10.1089/pho.2013.3616
16. Bragato EF, Paisano AF, Pavani C, et al. (2025). Role of photobiomodulation application frequency in facial rejuvenation. Lasers in Medical Science 40. doi:10.1007/s10103-025-04383-1
17. Ng JNC, Wanitphakdeedecha R, Yan C (2020). Efficacy of home-use light-emitting diode device at 637 and 854 nm for facial rejuvenation. Journal of Cosmetic Dermatology. doi:10.1111/jocd.13613
18. Barbaric J, Abbott R, Posadzki P, et al. (2016). Light therapies for acne. Cochrane Database of Systematic Reviews 9:CD007917. doi:10.1002/14651858.CD007917.pub2
19. Ash C, Harrison A, Drew S, Whittall R (2015). A randomized controlled study for the treatment of acne vulgaris using high-intensity 414 nm solid state diode arrays. Journal of Cosmetic and Laser Therapy 17(4):170-176. doi:10.3109/14764172.2015.1007064
20. Friedmann DP, Verma KK, Gidwani K, et al. (2026). Comparing a red and blue light-emitting diode light device with an existing blue light device for at-home treatment of inflammatory acne. Dermatologic Surgery 52(7):687-691. doi:10.1097/DSS.0000000000005061
21. Vanin AA, Verhagen E, Barboza SD, et al. (2018). Photobiomodulation therapy for the improvement of muscular performance and reduction of muscular fatigue. Lasers in Medical Science. PMID 29090398
22. Leal-Junior EC, Vanin AA, Miranda EF, et al. (2015). Effect of phototherapy on exercise performance and markers of exercise recovery. Lasers in Medical Science. PMID 24249354
23. Nampo FK, Cavalheri V, Ramos SP, Camargo EA (2016). Effect of low-level phototherapy on delayed onset muscle soreness. Lasers in Medical Science. PMID 26563953
24. Machado AF, Leal-Junior ECP, Batista NP, et al. (2022). Photobiomodulation therapy applied during an exercise-training program does not promote additional effects in trained individuals. Brazilian Journal of Physical Therapy 26(1). doi:10.1016/j.bjpt.2021.100388
25. Forsey JD, Merrigan JJ, Stone JD, et al. (2023). Whole-body photobiomodulation improves post-exercise recovery but does not affect performance. Lasers in Medical Science. doi:10.1007/s10103-023-03759-5
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