Red Light Therapy - Skin, hair & pain
Red light for pain and exercise recovery
Last updated 30 September 2026. How we write this .
Trials suggest low-level light can modestly ease some joint and muscle pain, such as neck and knee pain, and may help muscles recover after exercise. Results vary widely and many of the trials are small.
Start here Trials suggest low-level light can modestly ease some joint and muscle pain, such as neck and knee pain, and may help muscles recover after exercise. Results vary widely and many of the trials are small.
By the end, you will understand Does red light help neck pain? What about knee arthritis and low back pain? Does it help tendon pain? Key words used in this lesson Analogue A molecule deliberately modified from a natural one, usually to make it last longer in the body or bind more selectively. An analogue is not the same substance as the peptide it was derived from and can behave differently. Placebo An inactive comparison given so that the effect of expectation can be separated from the effect of the intervention itself. Without one, improvement over time cannot be attributed to the treatment. Near-infrared Light just beyond the visible red part of the spectrum, commonly around 800 to 850 nanometres. It penetrates tissue further than visible red light, which is why devices often combine the two. Full plain-English glossary
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Red and near-infrared light, given at low power so that it does not heat the tissue, has some trial evidence for easing certain kinds of musculoskeletal pain and for helping muscles recover after hard exercise. The best results come from neck pain and knee arthritis, where reviews found pain scores falling by roughly 15 to 20 points on a 100-point scale. For back pain, tendon pain and getting injured athletes back on the field, the picture is weaker or mixed. Most of the pain trials used lasers aimed at the painful area, which is not the same thing as the panels and masks sold for home use.
Does red light help neck pain?
This is where the best-known evidence sits. In 2009 The Lancet published a review by Chow, Johnson, Lopes-Martins and Bjordal that pooled 16 randomised trials with 820 patients. Pain was measured on a visual analogue scale, a 100 mm line where people mark how bad their pain is.
In chronic neck pain, five trials reporting improved or not improved found that people given laser treatment were about four times as likely to report improvement as those given a placebo. Across 11 trials, pain fell by about 20 mm more on the 100 mm line than with placebo or comparison treatment. In seven trials that followed people up for between one and 22 weeks after treatment, the benefit was still there, at about 22 mm. In acute neck pain, only two trials were available, with a smaller benefit. Side effects were mild and no different from placebo. A 20 mm fall is a real reduction, not an end to pain. The trials were small, and they used many different lasers and settings.
What about knee arthritis and low back pain?
For knee osteoarthritis, a 2019 review in BMJ Open by Stausholm and colleagues in Bergen, Norway, pooled 22 placebo-controlled trials with 1,063 people. Pain was about 14 mm lower than with placebo at the end of treatment and about 16 mm lower one to 12 weeks later. Trials that used doses in line with the World Association for Laser Therapy's recommendations did better than those that did not. No adverse events were reported. The review notes that light therapy is still not recommended in major knee osteoarthritis guidelines, and two of its authors are former board members of that association, which they disclosed.
Back pain is less encouraging. A Cochrane review of laser therapy for non-specific low back pain, last updated in 2008, found seven trials of reasonable quality. Three small studies with 168 people showed pain relief that was statistically significant but too small to matter clinically. In three studies with 102 people, adding laser to exercise did no better than exercise alone. The reviewers concluded there was not enough data to draw firm conclusions.
Does it help tendon pain?
Here a careful trial is worth more than a pile of small ones. In 2012 Steve Tumilty and colleagues in New Zealand randomised 40 people with Achilles tendon pain. Everyone did the same three-month programme of eccentric exercises, which load the tendon while the calf muscle lengthens. Half also received laser treatment and half a placebo. At 12 weeks there was no difference in tendon function scores between the groups, and at four weeks the placebo group was actually doing better. The authors concluded that adding laser to exercise had not been shown to help with the settings they used.
Can it speed up recovery after exercise?
Two of the main reviews here come from one laboratory in São Paulo, led by Ernesto Leal-Junior. His team's 2015 review found 13 trials of acceptable quality, nearly all of which applied light before exercise. Ten reported better performance. Pooled together, time to exhaustion rose by about four seconds compared with placebo. Light given before exercise gave the most consistent results.
The same group's larger 2018 review, led by Vanin, included 39 trials with 861 people. It again found effects in favour of light therapy for measures such as repetitions and time to exhaustion, but rated the quality of evidence as very low to moderate. The reviewers pointed to small samples and to wide variation in exercise tests and light settings.
An independent 2024 review from China, led by Li, pooled 34 randomised trials in healthy people. Light before exercise improved muscle endurance and helped strength recover, with lower levels of creatine kinase, a blood marker of muscle damage. The authors called these effects moderate, though the endurance figure is on the small side by the usual statistical rules of thumb. The benefit showed up in athletes and inactive people, but not in people who were already physically active.
Will it get an injured athlete back sooner?
The evidence says probably not, at least so far. A 2024 review by Morgan and colleagues in the United States found six randomised trials with 205 injured athletes. Light therapy reduced pain compared with control treatments. But the two trials that measured time to return to play found no benefit.
Why are the results so mixed?
Three things make this area hard to read. First, light therapy seems to have a dose window, so trials using too little or too much light can fail even if the treatment works at other settings. Second, the trials are small and use many different devices, wavelengths and schedules, which makes pooling them shaky. Third, in the exercise field the same laboratory both runs trials and writes major reviews of them. None of this means the positive findings are wrong. It does mean the size of any benefit is uncertain, and a result from a clinic laser on a specific joint may not carry over to a consumer device.
Pain that is severe, follows an injury, or comes with swelling, numbness, weakness or fever should be properly assessed by a GP or physiotherapist. If you are unsure where to go, NHS 111 can advise.
This lesson is for education only and is not medical advice. Talk to a GP or physiotherapist before trying any treatment for ongoing pain.
Related in this classroom Related in other classrooms The studies behind this page Efficacy of low-level laser therapy in the management of neck pain: a systematic review and meta-analysis of randomised placebo or active-treatment controlled trials - The Lancet, 2009Efficacy of low-level laser therapy on pain and disability in knee osteoarthritis: systematic review and meta-analysis of randomised placebo-controlled trials - BMJ Open, 2019Low level laser therapy for nonspecific low-back pain - Cochrane Database of Systematic Reviews, 2008Clinical effectiveness of low-level laser therapy as an adjunct to eccentric exercise for the treatment of Achilles' tendinopathy: a randomized controlled trial - Archives of Physical Medicine and Rehabilitation, 2012Effect of phototherapy (low-level laser therapy and light-emitting diode therapy) on exercise performance and markers of exercise recovery: a systematic review with meta-analysis - Lasers in Medical Science, 2015Photobiomodulation therapy for the improvement of muscular performance and reduction of muscular fatigue associated with exercise in healthy people: a systematic review and meta-analysis - Lasers in Medical Science, 2018Can pre-exercise photobiomodulation improve muscle endurance and promote recovery from muscle strength and injuries in people with different activity levels? A meta-analysis of randomized controlled trials - Lasers in Medical Science, 2024Effects of photobiomodulation on pain and return to play of injured athletes: a systematic review and meta-analysis - Journal of Strength and Conditioning Research, 2024Sources for this classroom
Educational content only. Not medical advice, diagnosis or treatment. Always consult a qualified healthcare professional before changing your health regimen.