In plain terms: Photobiomodulation (musculoskeletal) has some human trial evidence supporting it, but the evidence is not yet strong enough for EBL to call it established. It is worth knowing about and worth discussing with your clinician.
Photobiomodulation (musculoskeletal)
The evidence as the record states it
Chow et al. (Lancet, 2009; PMID 19913903): 16 randomized trials, 820 patients, placebo or active controls; in chronic neck pain, pain fell by about 20 mm on a 100 mm scale, lasting up to 22 weeks. Yap and Lim (Journal of Back and Musculoskeletal Rehabilitation, 2025; PMID 40437920): 15 randomized trials, short-term pain relief in chronic tendinopathy. Tomazoni et al. (Journal of Physiotherapy, 2020; PMID 32680739): 12 randomized trials, 1,046 people with nonspecific low back pain, mostly low risk of bias; the effect against sham was too small to matter. Glazov et al. (Acupuncture in Medicine, 2016; PMID 27207675): benefit only in subgroups. Pereira et al. (Journal of Lasers in Medical Sciences, 2025; PMID 41789279): a systematic review of 8 trials of low-level and high-intensity laser for orthopedic pain, without pooling; it is not a deciding citation.
Evidence by specific use
Why Grade B and not Grade A
Grade B reflects moderate human evidence -- typically a single strong trial, multiple smaller trials, or surrogate endpoint data without hard clinical outcome replication. To reach Grade A, Photobiomodulation (musculoskeletal) would require at least one additional independent randomized trial demonstrating a hard clinical endpoint or objectively measured functional outcome in a comparable population.
What this grade covers and what it does not
What would move this grade
An independent randomized trial demonstrating a hard clinical endpoint -- mortality, major adverse event, or objectively confirmed functional improvement -- in an adequately powered sample, with results independently replicated, would support Grade A.