Key takeaways
Meta-analyses find small benefits of red and near-infrared light applied to muscles before exercise for muscular endurance and cycling time to exhaustion, with low-quality evidence
There is no good evidence that red light therapy raises VO2max, and whole-body panels have shown no benefit for performance or recovery so far
Home devices rarely match the doses used in studies, so treat them as optional and protect your eyes
Red light panels, masks and beds are everywhere, from gyms to wellness clinics and bedroom walls. Claims range from faster recovery and better performance to more energy and more mitochondria. Some of this has a real research base. Much of it is extrapolation from a different kind of treatment than most people are buying.
What is red light therapy?
The scientific term is photobiomodulation (PBM): shining red or near-infrared light, from lasers or LEDs, onto tissue at doses too low to heat it significantly. The proposed mechanism involves light absorption in mitochondria, which may alter cell energy production and signalling. Sports studies typically test it on a single muscle group, such as the quadriceps or biceps, rather than the whole body. The biology is plausible and studied in labs, but a plausible mechanism doesn't guarantee a useful effect in people.
The sports evidence
Vanin et al., 2018 — Lasers in Medical Science
This systematic review and meta-analysis included 39 randomised trials with 861 participants, testing light on muscle performance and fatigue in healthy people. Pooled analyses of time to exhaustion, repetitions, peak torque and blood lactate showed "some effect in favour" of PBM, but the quality of evidence ranged from very low to moderate. The authors flagged small samples, poor methods and wildly varying protocols. Positive results mostly used wavelengths of 655 to 950 nm, with doses of about 20 to 60 J for small muscle groups and 60 to 300 J for large ones.
Dutra et al., 2022 — Sports Medicine
A meta-analysis of 37 double-blind, placebo-controlled crossover studies (586 participants) looked at PBM before exercise by exercise type:
| Outcome | Result |
|---|---|
| Single-joint muscular endurance | Small improvement (SMD 0.27) |
| Single-joint strength | No effect |
| Cycling time to exhaustion | Small improvement (SMD 0.35) |
| Cycling all-out sprint | No effect |
| Running time to exhaustion, time trial, repeated sprints | No effect |
| Swimming time trial | No effect |
So the benefits that do appear are small and specific, and they largely vanish in the outcomes runners and swimmers care about most.
Whole-body beds — Álvarez-Martínez and Borden, 2025
The beds and full-body panels sold for recovery have barely been studied. A 2025 systematic review found just five studies with 105 active participants. Two reported better sleep measures, but none found benefits for fatigue markers or exercise performance. The authors concluded whole-body PBM "shows no evidence of benefits for exercise recovery or performance".
Does it affect VO2max?
Not in any convincing way, and none of these reviews reported VO2max gains. The studies above measure local muscle endurance and time to exhaustion, which can improve without any change in aerobic capacity. VO2max is mostly limited by how much oxygen your heart can pump, as explained in what limits VO2max. Raising it takes training like 4×4 intervals; see how to improve VO2max and check progress with the VO2max calculator.
Devices vs studies
Most positive trials used lasers or clusters of LEDs placed on specific muscles, with measured energy per site and timing just before exercise. Home products differ:
- Dose is often unclear. Marketing lists wavelengths and "power", but the energy reaching your muscle depends on distance, area and time, which are rarely tested independently.
- Whole-body exposure isn't the same treatment as targeted application, and so far it hasn't shown performance benefits.
- Placebo effects are strong for recovery, which is subjective. That's why only double-blind trials count.
- Skin and hair claims are a separate area of research and don't transfer to sport.
Eye safety
Red and near-infrared light can be bright, and near-infrared is partly invisible, so your blink reflex offers less protection. A 2023 case report in JAMA Ophthalmology described retinal damage after repeated low-level red-light laser exposure used to treat myopia. Practical rules:
- Never look directly into the light, and wear the goggles supplied.
- Follow the manufacturer's distance and time limits.
- Don't use devices on children's eyes without an eye specialist's supervision.
- Ask a doctor first if you have a light-sensitive condition, take photosensitising medication, or have skin cancer or suspicious moles in the treated area.
Where it fits
If you enjoy a red light session and can afford it, it's low risk when used sensibly, but don't expect measurable fitness gains. The same caution applies to other recovery trends: cold plunges can blunt adaptation, while sauna has more supportive data. The most reliable recovery tools are free: sleep, food and sensible training load, tracked with HRV and resting heart rate. Ordinary daylight at the right time of day has far better evidence for sleep than any panel. Spending on your home environment? A water quality check, a certified filter such as reverse osmosis if needed, or fixing damp and mould are more defensible priorities.
Frequently asked questions
Does red light therapy improve recovery?
Some small trials of targeted light applied to muscles report less fatigue and faster recovery, but the evidence is low quality and inconsistent. A 2025 review of whole-body red light beds found no benefit for exercise recovery or performance.
Does red light therapy increase VO2max?
There is no good evidence that it does. The most consistent effects in studies are on local muscle endurance, not aerobic capacity, and they are small.
Is red light therapy at home safe?
Generally low risk for skin when used as directed, but do not look into the light and use the goggles supplied. A case report has described retinal damage after repeated red laser exposure used for myopia.
How long until red light therapy works?
Studies usually applied light minutes before exercise or right after, with measured doses per muscle. Home panels rarely specify comparable doses, so there is no reliable timeline for them.
Sources
- Vanin AA, Verhagen E, Barboza SD, Costa LOP, Leal-Junior ECP. Photobiomodulation 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 Med Sci, 2018.
- Dutra YM, Malta ES, Elias AS, Broatch JR, Zagatto AM. Deconstructing the ergogenic effects of photobiomodulation: a systematic review and meta-analysis of its efficacy in improving mode-specific exercise performance in humans. Sports Med, 2022.
- Álvarez-Martínez M, Borden G. A systematic review on whole-body photobiomodulation for exercise performance and recovery. Lasers Med Sci, 2025.
- Liu H, Yang Y, Guo J, Peng J, Zhao P. Retinal damage after repeated low-level red-light laser exposure. JAMA Ophthalmol, 2023.