Red light therapy speeds muscle recovery

In small randomized trials in healthy people, red or near-infrared light shone on a muscle shortly before hard exercise was followed by somewhat better recovery in the following days. A 2024 pooled analysis of 34 randomized trials found that strength came back a little faster (a standardized difference of 0.24, which the authors described as moderate) and that creatine kinase, a blood marker of muscle damage, was lower. A 2025 pooled analysis found lower soreness scores when light was applied before exercise, and graded that evidence as low certainty. A second 2025 pooled analysis, of 21 trials on leg muscles, also found less loss of strength and lower creatine kinase, and reported that 19 of its 21 trials were run in Brazil.

The picture is less clear for light applied after exercise, and studies of whole-body devices have not found a benefit. After exercise, small trials disagree. In a 2016 trial of 50 men, light given minutes after hard exercise and again on each of the next three days was followed by better strength, less soreness and lower creatine kinase than a sham device; one of its authors worked for the company that made the device. A 2019 trial of 12 men found no difference between light and a sham after sprint training, and a 2022 trial that applied light in the three days after exercise found no change in soreness, strength or jumping compared with no treatment. An older pooled analysis of single sessions, before or after exercise, found no difference from placebo in strength, swelling or range of movement, with creatine kinase lower only when a laser was used before exercise. A 2025 review of five whole-body panel and bed studies found no benefit for recovery or performance. In the 2024 analysis, people classed as physically active, neither sedentary nor athletes, showed no benefit. None of these sources measured safety with repeated home use, and none studied muscle injuries such as strains.

The trials used lasers or clusters of LEDs placed directly on the working muscle at set wavelengths and doses, around a lab exercise protocol built to cause muscle damage, such as the eccentric (lowering) exercise in the 2016 and 2022 trials. Most trials were small: the 15 studies in the 2016 pooled analysis averaged about 21 people each. The 2024 analysis found benefits in untrained people and in athletes but not in the physically active group between them, and its authors suggested a possible explanation involving muscle fiber type.

The proposed mechanism is that red and near-infrared light is absorbed by an enzyme in the mitochondria, raising energy production and damping oxidative stress and inflammation in the muscle. That account rests mainly on cell and animal work. In the one direct human test among these sources, a 2026 study of 12 adults found that a single session did not change mitochondrial respiration in thigh muscle compared with the other leg, while the skin on the treated leg warmed by about 8 degrees C.

In the United States, several devices sold as red light or LED systems, including an LED bed and an LED belt marketed for pain, were cleared between 2005 and 2023 under the FDA device category for infrared therapeutic heating lamps. That listing records how the devices were classified, not whether they aid recovery.

Soreness after unaccustomed exercise is different from a strained or torn muscle. These trials studied healthy people after a planned exercise test and do not show what light does for an injury, which is a question for a clinician.