Photobiomodulation in Human Muscle Tissue: An Advantage in Sports Performance?
Technology context Photobiomodulation on muscle using laser probes, laser diode clusters, LED clusters and mixed arrays
Finding: Across 46 human studies with 1,045 participants, photobiomodulation applied before or after exercise was reported to increase muscle mass gained after training and decrease inflammation and oxidative stress in muscle biopsies.
Main limitation: Device types varied enormously - single laser probes, laser diode clusters, LED clusters and mixed arrays - so results cannot be attributed to any one kind of equipment.
Executive summary
This review is where red light performance and recovery claims come from, and it is more equivocal than those claims suggest.
The authors searched MEDLINE up to 2016 for randomised controlled trials and case-control studies in healthy trained and untrained participants and elite athletes. Searches retrieved 533 studies, of which 46 were included, covering 1,045 participants.
Performance metrics included fatigue, number of repetitions, torque and hypertrophy, alongside measures of muscle damage and recovery such as creatine kinase and delayed-onset muscle soreness. Both preconditioning - light delivered to muscles before exercise - and photobiomodulation applied after exercise were examined.
The devices used were highly varied: single laser probes, clusters of laser diodes, LED clusters, mixed clusters combining lasers and LEDs, and flexible LED arrays, using red, near-infrared, and red/NIR mixtures.
The authors report that photobiomodulation can increase muscle mass gained after training and decrease inflammation and oxidative stress in muscle biopsies. They categorise parameters into those associated with positive effects and those with no effect on muscle performance and recovery - which is the practically important structure, because it implies the parameters, not the technology label, determine the result.
They close by raising whether photobiomodulation should be permitted in athletic competition by international regulatory authorities - a question that would not arise if they considered the effects trivial.
Why this research matters
This is the largest collection of human data on red light and muscle, and it is what a performance claim should be measured against.
Its most useful contribution is the parameter categorisation. If some parameter sets produce effects and others do not, then 'red light therapy' is not one intervention, and a panel cannot inherit results from a study that used different wavelengths, irradiance and dose.
Study design
- Study type
- Review of human clinical trials
- Database searched
- MEDLINE, to 2016
- Studies retrieved
- 533
- Studies included
- 46
- Total participants
- 1,045
- Populations
- Healthy trained participants, untrained participants, and elite athletes
- Eligible designs
- Randomised controlled trials and case-control studies
- Timing examined
- Preconditioning (before exercise) and application after exercise
- Device types
- Single laser probes; clusters of laser diodes; LED clusters; mixed laser and LED clusters; flexible LED arrays
- Wavelengths
- Red, near-infrared, and red/NIR mixtures
- Outcomes
- Fatigue, repetitions, torque, hypertrophy, creatine kinase, delayed-onset muscle soreness
- Meta-analysis
- Not performed
What the researchers found
From 533 retrieved studies, 46 were included covering 1,045 participants.
The authors report that both preconditioning and post-exercise application can increase sports performance in athletes, that photobiomodulation can increase muscle mass gained after training, and that it can decrease inflammation and oxidative stress in muscle biopsies.
Parameters used across the studies were categorised into those with positive effects and those with no effect on muscle performance and recovery.
The devices spanned single laser probes, clusters of laser diodes, LED clusters, mixed laser and LED clusters, and flexible LED arrays, using red, near-infrared and combined wavelengths.
No pooled effect sizes, confidence intervals or p-values are generated by this review and none are reproduced here.
What the results mean
There is a real body of human evidence here, which distinguishes photobiomodulation from several other technologies in this category where the human literature is thin.
But the review's own structure is the caution. Some parameter sets produced effects and some did not. That means a positive study is evidence for the wavelength, irradiance, dose, distance and timing that study used - not for red light in general, and not for a panel with different specifications.
The device heterogeneity compounds this. A single laser probe delivering concentrated coherent light to a small area is a materially different intervention from a flexible LED array, and both appear in this review.
What this study does not prove
- It does not establish that any consumer LED panel produces performance or recovery benefits.
- It does not identify a definitive optimal parameter set, only that some parameters were associated with effects and others were not.
- It does not pool results, so no effect size can be quoted from it.
- Findings from laser-based studies do not transfer automatically to LED devices.
- It does not establish long-term outcomes; the trials examined short-term performance and recovery measures.
- It does not support claims that red light treats, cures, prevents, or mitigates any disease.
- The muscle mass findings do not establish that photobiomodulation substitutes for or reduces the training required.
Evidence strength
Narrative review of human clinical trials
A review of human randomised controlled trials and case-control studies rather than cell or animal work, which makes it the most clinically relevant photobiomodulation entry for exercise applications.
It is a narrative review, not a meta-analysis, so no pooled effect estimate is produced. The authors categorise study parameters into those with positive effects and those with no effect, which is a useful structure but is not formal quality grading.
Strengths and limitations
Strengths
- Largest collection of human clinical data on photobiomodulation and muscle at the time of publication.
- Restricted to randomised controlled and case-control designs.
- Covers both trained and untrained participants and elite athletes.
- Examines both pre-exercise and post-exercise application.
- Categorises parameters by effect rather than treating all devices as equivalent.
- Includes objective outcomes such as torque and muscle biopsy markers alongside subjective ones.
Limitations
- Narrative review without meta-analysis or formal bias assessment.
- Very wide device heterogeneity, from single laser probes to LED arrays.
- Wavelength, irradiance, dose and treatment distance varied across studies.
- Single database searched.
- Published in 2016; the field has continued to expand.
- Blinding is difficult for light-based interventions.
- Sample sizes of individual included studies not reported in the source abstract.
Does this apply to the equipment IMPERVITA sells?
This review covers many device types, and several of the studies used lasers or research-grade clusters rather than the LED panels sold for home use. Results should not be assumed to transfer to a consumer panel.
What transfers is the framework. Because the authors found that some parameter sets worked and others did not, the practical question for any panel is whether its wavelengths, irradiance at your treatment distance, and resulting session dose fall within the ranges that produced effects.
That is answerable only if the manufacturer publishes those figures - which brings this entry back to the same specification questions raised throughout the red light group.
Evidence in context
The mechanistic literature supports plausibility, and the 2021 critical review cautions specifically that much preclinical evidence used lasers rather than the diodes typically used at home - directly relevant to the heterogeneity documented here.
On the safety side, a 2023 systematic review found no clinical trial data linking photobiomodulation with significant adverse events in skin applications.
The field has not produced a large, well-powered randomised trial in a consumer-device configuration that would settle the performance question. Evidence volume has grown; parameter standardisation has not.
Related research
- Mechanisms and applications of the anti-inflammatory effects of photobiomodulation The mechanistic basis, including the biphasic dose response that explains why parameters decide outcomes.
- Photobiomodulation: a review of the molecular evidence for low level light therapy Critical review highlighting the laser-versus-diode gap this review's device list illustrates.
- Photobiomodulation: a systematic review of the oncologic safety of low-level light therapy for aesthetic skin rejuvenation Systematic review of oncologic safety.
- An evidence-based approach for choosing post-exercise recovery techniques to reduce markers of muscle damage, soreness, fatigue, and inflammation Places recovery methods on a common scale, useful for comparing red light against massage and immersion.
- Low-level light/laser therapy versus photobiomodulation therapy The terminology consensus underlying how these devices are described.
Practical buyer relevance
The parameter categorisation is the buying lesson. Two panels both described as 'red light therapy' can deliver completely different doses, and this review shows that difference determines whether anything happens.
Practically: ask for wavelengths in nanometres, irradiance at a stated treatment distance, and the session dose in J/cm² that results. Then ask what parameters the studies the seller cites actually used. If those two sets do not overlap, the citation is decorative.
It is also worth noting what this review does not claim: nothing here suggests light therapy reduces the training needed to gain muscle. The reported effect was on gains achieved after training, not instead of it.
Safety context
Follow the eye-safety guidance supplied with the specific device. High-output red and near-infrared sources warrant eye protection, and manufacturer instructions should be treated as requirements rather than suggestions.
People with a photosensitising condition, taking photosensitising medication, with a history of skin cancer, or who are pregnant may require guidance from a qualified healthcare professional before use. A device with no stated contraindication list is less carefully documented, not safer.
Full source record
- Title
- Photobiomodulation in Human Muscle Tissue: An Advantage in Sports Performance?
- Authors
- Ferraresi C, Huang YY, Hamblin MR
- Organization
- Wellman Center for Photomedicine, Harvard Medical School
- Publication
- Journal of Biophotonics
- Year
- 2016
- Volume / issue / pages
- Volume 9, issue 11-12, pages 1273-1299
- PMID
- 27874264
- PMCID
- PMC5167494
- Study type
- Review of clinical trials in human muscle tissue
- Sample size
- 46 studies, 1,045 participants
- Population
- Healthy trained and untrained participants and elite athletes
- Topic
- Performance, Recovery, Red Light
- Document type
- Narrative review
- Technology context
- Photobiomodulation on muscle using laser probes, laser diode clusters, LED clusters and mixed arrays
- Related equipment context
- Red Light Therapy
- Source last verified
- 19 August 2026
References
- Photobiomodulation in human muscle tissue: an advantage in sports performance?
- Mechanisms and applications of the anti-inflammatory effects of photobiomodulation
- Photobiomodulation: a review of the molecular evidence for low level light therapy
- Photobiomodulation: a systematic review of the oncologic safety of low-level light therapy for aesthetic skin rejuvenation
- An evidence-based approach for choosing post-exercise recovery techniques to reduce markers of muscle damage, soreness, fatigue, and inflammation
- Low-level light/laser therapy versus photobiomodulation therapy
Information provided by IMPERVITA is for educational and general wellness purposes and is not intended to replace professional medical advice, diagnosis, or treatment.
