Red Light Therapy for Athletic Performance: Scientific Evidence

12 male CrossFit athletes averaging 27 years of age took part in a 2022 randomized triple-blind placebo-controlled crossover trial of photobiomodulation combined with a static magnetic field for athletic performance and muscle recovery. Each received the treatment before a workout, after a workout, at both times, or as a placebo, with 633, 850, and 905 nm light applied in contact with the muscles at the front and back of the thigh and hip and the calves, at 1.25 to 40 mW and 60.76 to 270.72 J, in sessions of 115 seconds to 2.15 minutes given 4 times per week across 28 days. Performance on a 1-minute squat test improved with the active treatment, and the markers of muscle damage, inflammation, and cell damage moved in its favor. How hard the effort felt was tracked alongside them by an assessor kept blind to the allocation.

Among 10 para-athletes averaging 20 years of age, a 2022 case series of athletic performance found faster swimming times after photobiomodulation than after a sham treatment. Each completed 3 maximal 50 m freestyle swims separated by 5-minute intervals, once after light and once after sham a week later, with 660 and 850 nm light delivered to the biceps, the shoulder muscle, and the muscle across the upper back and neck at 5 mW and 108 J, in 10-minute sessions given once per week across 21 days. Swimming time, heart and lung endurance, and muscle activity all appeared better after the light session. The authors noted that earlier work on this therapy had looked at healthy individuals rather than para-athletes.

This 2022 randomized double-blind placebo-controlled crossover study tested red light photobiomodulation for short-burst power in an all-out 30-second cycling test. 16 healthy, physically active men averaging 21.7 years of age completed 3 test sessions 48 hours apart, receiving either 630 nm LED light at 4.6 J/cm² and 6 J per point across 16 points, or a placebo, in sessions given 3 times per week across 4 days. Peak power and mean power were both higher after the light session than after the placebo. Red light may therefore offer a small gain in short-burst capacity.

Across 797 participants, a 2021 narrative review examined photobiomodulation for sports performance and recovery after exercise. The included studies applied light in the 640 to 950 nm range in contact with the muscle at 10 to 200 mW, 20 to 300 J, and pulse frequencies up to 1500 Hz, in 30-second sessions. Light given before exercise, most consistently at a 30 J dose, appeared to raise performance, reduce muscle soreness, and improve the blood markers tied to muscle damage. Light therapy appeared adaptable to different sports and levels of effort.

Endurance athletes finished a 3000 m test 7 seconds faster after photobiomodulation therapy (PBMT) than placebo in a 2021 randomized double-blinded placebo-controlled trial of athletic performance and running efficiency, with 15 of 20 improving. The athletes, averaging 34 years of age with 7.6 years of training behind them, received 780 to 1400 nm light on the front and back of the thigh, the buttock muscle, and the calves at 5.01 W, 244 mW/cm², and 1500 J, in 30-second sessions given 4 times per week across 3 days, before and after each run. Individual gains ranged from 3 to 40 seconds, while 5 athletes ran slower. This was the first trial to test the therapy on a 3000 m athletics track.

Comparing 6 different timing windows against a placebo, a 2020 randomized triple-blinded placebo-controlled trial examined photobiomodulation combined with a static magnetic field for athletic performance and recovery. 60 healthy untrained men were distributed across the groups and received 633, 850, and 905 nm light in contact with the front of the thigh at 1.25 mW to 50 W, 0.14 to 180 J and pulse frequencies of 2 and 250 Hz, in 115-second sessions applied once. Every active group improved against placebo, and the benefit held whether the light came 5 minutes or 6 hours beforehand. The effects appeared to last up to 54 hours after treatment and began to fade once the window stretched to a full day.

According to a 2019 review, researchers drew together recent systematic reviews and randomized trials to produce clinical recommendations for photobiomodulation therapy (PBMT) in athletic performance and recovery after exercise. The recommendations cover light in the 640 to 950 nm range applied in contact with the muscle groups used in the activity, at 10 to 200 mW, and 20 to 300 J, in 30-second sessions. Doses between 120 and 300 J for large muscle groups appeared to produce the most consistent results. Future guidelines should be built on the same evidence base, the review argued.

A 2018 randomized controlled trial evaluated photobiomodulation therapy (PBMT) at 3 different doses for athletic performance during submaximal running. 18 male recreational runners received 670, 850, 880, and 950 nm light in contact with the front and back of the thigh and the calves at 15, 30, and 60 J per site, in 64-second sessions given 5 times per week, with each of the 5 conditions tested on a single day. Sensor readings of muscle activity fell at the 15 J dose compared with placebo, pointing to more efficient muscle work during running. Effect sizes were small across all the measures, and the authors described this as the first study to compare energy doses for running efficiency.

Published in 2016, this review pooled 46 clinical trials covering 1045 participants to examine light therapy for sports performance and muscle recovery. The included studies applied single lasers, diode clusters, LEDs, and flexible arrays to the biceps, the front of the thigh, the front of the shin, and the muscles that bend the elbow and straighten the knee, at wavelengths spanning 590 to 981 nm, 1.1 mW to 5 W, 1 to 1273.4 J and pulse frequencies of 2 to 73 Hz, in sessions of 7.5 seconds to 5 minutes given 3 to 7 times per week. Light delivered before or after exercise appeared to benefit sports performance across the body of work reviewed. The authors noted that irradiance and dose varied so widely between studies that direct comparison was difficult.

Doses of 10, 30, and 50 J were tested against a placebo in a 2016 randomized double-blind placebo-controlled clinical trial of low-level laser therapy (LLLT) for athletic performance and recovery after exercise. 28 high-level soccer players received 810 nm light from a 5-diode cluster applied to 6 sites on the front of the thigh at 200 mW, in sessions of 60 seconds to 5 minutes on a single day, before exercise that lengthened the muscle under load. Maximum strength rose with the 50 J dose from immediately after exercise to 24 hours, and with the 10 J dose from 24 to 96 hours, while the blood markers of muscle damage and inflammation fell with both, most strongly at 50 J. Muscle soreness did not improve at any dose, and the 30 J dose changed nothing that the researchers measured.

Whether light works better before or after a workout was the question behind a 2016 randomized double-blinded placebo-controlled trial of athletic performance during strength training. 48 male volunteers aged 18 to 35 completed a 12-week program with laser and LED phototherapy cluster probes combining 640, 875, and 905 nm light applied in contact with the front of the thigh before each session, after each session, or both, at 0.31 to 17.5 mW, 0.0712 to 180 J and pulse frequencies of 2, 16, and 250 Hz, in 3.8-minute sessions given 24 times per week across 84 days. Maximum strength and the heaviest weight lifted once in the leg press and leg extension both improved significantly with light given before exercise. Thigh circumference did not differ between any of the groups at any point.

Comparing LED therapy against placebo in identical male twins, a 2016 case-control study tracked muscle growth, athletic performance, and recovery after strength training. Each twin received 830 to 870 nm light in contact with the front of both thighs immediately after every training session, at 100 mW and 5 W and 1.5 to 75 J, in 15-second sessions given 36 times per week across 84 days. The twin who received real LED therapy lifted a heavier maximum load, tired less, showed a lower blood marker of muscle damage, and reported less pain. Gene readings shifted in the same direction, with less activity in genes tied to inflammation and muscle wasting and more in genes tied to protein building and defense against cell damage, alongside greater thigh muscle growth.

Among 12 high-level male rugby athletes, a 2016 randomized crossover double-blind placebo-controlled study tested photobiomodulation therapy (PBMT) for performance and recovery during a sprint test on the field. Players received either active PBMT or a placebo across 2 test weeks, with light at 640, 875, and 905 nm delivered to 17 sites on each leg at 30 J per site, applied on a single day before a repeated sprint test. Sprint performance improved, and recovery came faster after the active treatment than after the placebo. Earlier work on this therapy had been confined to the laboratory rather than the field.

A 2015 randomized controlled trial tested low-level laser therapy (LLLT) added to eccentric training for athletic performance, with muscle thickness rising 15.4% against 9.4% for training alone and peak force 32.2% against 20%. 30 healthy men were distributed into a control group, a training group, and a training-plus-laser group, with 810 nm light applied to the muscles that straighten the knee before each session at 200 mW and 1 W, and 6 to 240 J, in 30-second sessions across 56 days of training that lengthened the muscle under load. The control group showed no change in any measure across the study. It was also found that applying the laser before each session may improve both muscle growth and strength gain in healthy people.

Across 13 randomized controlled trials, a 2015 systematic review and meta-analysis assessed light therapy for exercise performance and recovery. The included studies treated the biceps, the front of the thigh, the jaw muscle, and scar tissue at wavelengths of 640, 655, 660, 808, 810, 830, and 850 nm, 1 to 200 mW, 0.3 to 41.7 J and pulse frequencies of 10 and 830 Hz, in 3-minute sessions given 3 to 20 times per week, most often before exercise. 10 of the 16 assessed studies reported positive effects on performance, and 3 reported no effect. The benefit across the pooled trials appeared modest.

Muscle force increased significantly in the early stages of a resistance test after treatment in a 2014 double-blind clinical trial of light therapy and athletic performance. 12 physically active women aged 18 to 30, with an average of 6 years of training behind them, received 780 nm low-level laser therapy in contact with the front of the shin at 30 mW and 23.49 J, in 27-second sessions applied once on a single day. The gain appeared in the second of 4 measurement windows and did not persist across all of them, and researchers attributed it to changes in how the muscle cells produce energy.

36 healthy young men averaging 20.8 years of age took part in a 2011 randomized controlled trial testing whether low-level laser therapy (LLLT) added to strength training could improve athletic performance. Participants were distributed to training plus LLLT, training alone, or a control group, with 808 nm light applied in contact with the front of both thighs immediately after each leg-press session at 60 mW and 0.6 to 50.4 J, in 2.33-minute sessions given 24 times per week across 84 days of training at 80% of the heaviest weight they could lift once. The heaviest load lifted in the leg press rose above baseline in both training groups after 12 weeks. The group that also received light appeared to gain more than the group that trained alone.

18 rugby players received 850 nm LED photobiomodulation at 4 timing points, from before exercise to not at all, in a 2024 randomized crossover clinical trial of athletic performance. Male and female players received the light at 8 J/cm², with performance measured on balance, hop, sprint, and repeated shuttle-running tests. Light given before exercise improved performance on the first shuttle-running test, and light given during the interval improved the second test and the sprint test. The researchers reported that the blood markers of muscle damage did not shift under any condition, so the authors framed the benefit as a performance boost rather than protection against damage.

36 young volleyball athletes were distributed across photobiomodulation therapy (PBMT), electrical stimulation, and control groups in a 2020 randomized controlled trial of muscle strength and jumping. Continuous 850 nm light was applied in contact with the front of the thigh at 150 and 290 mW and 2 to 36 J, in 40-second sessions given 18 times per week across 42 days of training. Both the light therapy group and the electrical stimulation group improved significantly against the control group after training. Only the electrical stimulation group held that improvement at the 8-week follow-up.

Among 45 healthy young men, a 2019 randomized controlled clinical trial LED therapy added to strength training for athletic performance in the biceps. 45 healthy young men averaging 21 years of age were randomized into 3 groups of 15, covering training plus LEDT, training plus a sham device, and a non-training control, with 850 nm light applied in contact with the biceps of the dominant arm after each session at 100 mW and 4 to 28 J, in 40-second sessions given 2 times per week across 56 days. Training loads were reassessed every 2 weeks throughout the program. The added light therapy appeared to offer only a partial benefit for muscle performance over training with a sham device.

Comparing light applied to the exercising leg against light applied to the opposite leg, a 2018 randomized controlled trial examined athletic performance during leg-press exercise. 12 physically active men completed 4 randomized sessions of 4 sets at 80% of the heaviest weight they could lift once, receiving either active or placebo LED irradiation at 660 and 850 nm on the front and back of the thigh, at 10 and 30 mW and 41.7 to 834 J, in 60-second sessions given 4 times per week across 5 days. Maximum repetitions ran 11.3% higher when the treated leg was the leg doing the work, a statistically significant difference, and the muscle tired more slowly. The opposite leg showed no such advantage, and the substance that builds up in working muscles did not differ under any condition.

Across 105 physically active participants pooled from 5 studies, a 2025 systematic review examined whole-body photobiomodulation for exercise performance and recovery. The included studies applied light in the 620 to 1400 nm range across the whole body, before or after exercise, in participants of both sexes across a range of exercise types. None of the 5 studies reported any benefit for performance or recovery. 2 did report better sleep quality alongside a higher sleep hormone level and a lower overnight heart rate, and the authors called for work to resolve why whole-body treatment behaves differently from light aimed at specific muscles.

This 2023 double-blind sham-controlled randomized clinical trial examined photobiomodulation and physical performance in women during the first half of the menstrual cycle. 27 physically active healthy women averaging 25.7 years of age received either 630 and 850 nm light at 3.9 and 6.5 W and 200 J, or a sham, applied to the front and back of the thigh and the calves 10 minutes before testing. Performance on an all-out effort test, how hard that effort felt, and the substance that builds up in working muscles showed no advantage for the light condition. The trial found no benefit for physical performance at this point in the cycle.

According to a 2023 randomized double-blinded placebo-controlled crossover trial, researchers tested photobiomodulation for short-burst athletic performance in well-trained cyclists. 15 healthy male road and mountain bike cyclists received either 630 nm light at 4.6 J/cm² and 6 J, or a placebo, given 2 times per week across 2 days, before testing for a performance boost during all-out effort. Therne was No improvement in short-burst capacity following the light treatment. The authors reported the therapy as ineffective for this outcome in cyclists at this level.

A 2023 randomized double-blind placebo-controlled crossover study tested photobiomodulation as a preconditioning step for repeated-sprint athletic performance. 10 professional basketball players received either 660 and 850 nm LED light at 12 J/cm² and 83.4 J per point across 10 points, or a placebo, given 2 times per week after a warm-up, before running 10 sprints of 30 m with a change of direction and 30 seconds of rest between each. At the end of the study, sprint times showed no advantage for the light condition over the placebo. The trial found no preconditioning benefit for repeated-sprint ability in these players.

No additional gain followed treatment in a 2022 randomized placebo-controlled trial of photobiomodulation added to a training program for men who were already trained. 39 healthy men aged 18 to 30 were randomized to active light at 30 J per site, a placebo, or no extra treatment, with 640, 875, and 905 nm light applied in contact with the front of the thigh at 0.0312 mW to 12.5 W, 0.07 to 19.44 mW/cm², 0.0712 to 180 J, and pulse frequencies of 16, 20, and 250 Hz, in 3.8-minute sessions given 12 times per week across 42 days. Maximum strength and standing jump height both improved over the 6 weeks, but they improved equally in every group. The authors concluded that adding light to combined training brought no benefit over placebo in people who already train.

13 amateur female futsal players averaging 24.1 years of age took part in a 2020 randomized counterbalanced crossover trial of photobiomodulation therapy (PBMT) for high-intensity and intermittent athletic performance. Each completed a battery of tests covering a standing jump, an agility course, and a repeated shuttle-running test after either 15 minutes of PBMT or a sham treatment, with 660 and 850 nm light applied in contact with the front and back of the thigh and the calves at 200 J, in 90-second sessions given 2 times per week across 7 days. Neither agility nor intermittent running performance differed between the light and sham conditions. Perceived recovery and muscle soreness scores came out much the same under both.

2020 brought a randomized crossover double-blind placebo-controlled study asking whether different energy doses of light change peak running speed and the body's response to a treadmill test. 15 participants received photobiomodulation at 660 and 850 nm in contact with the front and back of the thigh and the calves at 10 and 30 mW, 30 to 1800 J and pulse frequencies up to 1500 Hz, in sessions of 15 to 90 seconds given 5 times per week on a single day. Peak running speed came out at roughly 13.4 km/h under every condition, including control and placebo. The substance that builds up in working muscles, heart rate, and how hard the effort felt were all likewise unchanged.

No significant difference appeared in any measure in a 2020 clinical trial of LED therapy applied on consecutive days to cycling athletes. 48 male cyclists averaging 33.8 years of age received red light at 610 to 630 nm, infrared at 930 to 950 nm, both combined, or a sham, applied to the front of both thighs at 1.6 to 1.76 W, 33.7 and 52.86 mW/cm², and 180 to 360 J, in sessions of 102 seconds to 2.55 minutes given 3 times per week across 3 days. Peak force, average power, and how long the cyclists could keep going all showed moderate to large effect sizes in the combined red and infrared group 24 hours after the last treatment, but none reached statistical significance. This was the first study to test light applied in sequence as a preconditioning step.