What This Review Looked At
Researchers from Kyung Hee University Medical Center in Seoul, South Korea, published an umbrella review in the journal Systematic Reviews examining the effects of photobiomodulation across a wide range of health conditions. Rather than conducting new trials, the review synthesised findings from 15 existing meta-analyses of randomised controlled trials — the highest tier of clinical evidence — covering 204 individual studies and more than 9,000 participants across 32 countries. The review evaluated 35 distinct health endpoints across 15 disease conditions, applying a unified GRADE framework to assess the certainty of evidence for each outcome.
Photobiomodulation uses non-thermal red or near-infrared light in the 600 to 1,100 nanometre wavelength range to stimulate biological processes at the cellular level. The same wavelengths used in the devices we carry at Health4me fall within this therapeutic spectrum.
What They Found
Of the 35 health endpoints assessed, photobiomodulation showed statistically significant effects for 12. Five of these were supported by moderate certainty of evidence — the strongest level found in the review — and represent the outcomes where the researchers expressed the most confidence in the findings.
Fibromyalgia showed the strongest results overall. Patients receiving photobiomodulation reported large reductions in fatigue severity, overall symptom burden as measured by the Fibromyalgia Impact Questionnaire, and stiffness — all with effect sizes classified as large and supported by moderate certainty of evidence.
Knee osteoarthritis showed significant improvement in physical disability with moderate certainty, though the effect on pain alone was smaller and rated at low certainty. Burning mouth syndrome — a chronic condition involving persistent oral pain — showed significant pain reduction with moderate certainty. Androgenetic alopecia showed increased hair density with moderate certainty and a strong effect size. Age-related cognitive impairment showed meaningful improvement in cognitive function scores with moderate certainty of evidence.
Additional conditions showing significant effects at low certainty included temporomandibular disorders, tendinopathy, myofascial neck pain, and fibromyalgia-related pain and anxiety. Effects on rheumatoid arthritis, plantar fasciitis, Achilles tendinopathy, fractures, carpal tunnel syndrome, and tinnitus did not reach statistical significance in the re-analysis.
The mechanism driving these effects is well established. Photobiomodulation activates cytochrome c oxidase in the mitochondrial respiratory chain, increasing ATP production — the cellular energy currency that drives tissue repair, cell proliferation, and survival. It also reduces pro-inflammatory cytokines, decreases oxidative stress through antioxidant enzyme activation, and modulates pain signalling by reducing substance P and bradykinin while promoting endorphin release.
What This Means in Context
This is an umbrella review — a review of meta-analyses rather than individual studies — which gives it significant methodological weight. However, the authors are clear that no outcome was supported by high-certainty evidence, and that the overall certainty for most endpoints ranged from low to moderate. The variability in treatment protocols across the underlying studies — different wavelengths, session durations, and device types — is the primary source of uncertainty and makes direct comparison between studies difficult.
The authors conclude that photobiomodulation may serve as a promising non-invasive adjunctive therapy for several conditions, and that larger standardised trials are needed to establish definitive clinical protocols. The therapy was consistently described as safe across all reviewed conditions — no serious adverse effects were reported in any of the included meta-analyses.
What It Means for You
If you are dealing with chronic pain, joint problems, fatigue, or cognitive changes associated with aging, this review adds meaningful scientific weight to the case for exploring photobiomodulation as a supportive measure. The breadth of conditions covered — from musculoskeletal to neurological to dermatological — reflects how fundamental the underlying mechanism is. Light at the right wavelength stimulates cellular energy production, and the downstream effects are felt across many body systems.
As with all complementary approaches, we encourage open dialogue with your treating physician. Photobiomodulation works best as part of a considered, integrated approach to health — not in isolation.
Citation
Son, Y., Lee, H., Yu, S., Kim, H.J., Park, J., Woo, S., Lee, H., Fond, G., Boyer, L., Rahmati, M., Smith, L., López Sánchez, G.F., Dragioti, E., Kang, J., Kim, T., & Yon, D.K. (2025). Effects of photobiomodulation on multiple health outcomes: an umbrella review of randomized clinical trials. Systematic Reviews, 14, 160. https://doi.org/10.1186/s13643-025-02902-3
