Has photobiomodulation effect on backpain

The short version: for ordinary low back pain, the best evidence says light therapy doesn't work well enough to bother with.

A 2020 systematic review of 12 randomized trials found that photobiomodulation (laser or LED light therapy) did not produce a worthwhile reduction in pain or disability for people with chronic nonspecific low back pain, compared with a fake (sham) treatment [1]. The pain difference was too small to matter, and the evidence quality was rated low [1]. For acute or subacute back pain, adding light therapy to hot packs was unlikely to help either [1]. When compared head-to-head with exercise, there was no clinically important difference [1]. One small subgroup hinted that a proper dose of light therapy added to exercise might reduce pain, but the authors themselves said it was unclear whether that effect was real or trivial [1].

The mechanism story is real but doesn't rescue the clinical result. In mice, 810 nm light aimed at the lower-back nerve roots raised pain thresholds in a dose-dependent way, with no tolerance over 7 days [2]. That's a plausible biological signal, not proof it helps a human with back pain. Lab studies on spinal disc cells suggest light might influence tissue-repair enzymes, but that's a dish, not a person [3]. The dose-response is also tricky: too little light does nothing and too much can backfire, which is one reason trials disagree [4].

This retrieval is thin on long-term outcomes and on who funded the back-pain trials. It cannot tell you whether any trial showed a benefit that a later, larger one failed to replicate.

My call: for nonspecific low back pain, don't pay for photobiomodulation expecting relief; the best available synthesis says the effect is too small to be worthwhile. It appears low-risk, but low-risk and ineffective is still not worth your money. Confidence: moderate.