Does red light or laser therapy work for knee arthritis?
Short answerNobody can say yet. Two reviews of the same kind of trial reached opposite answers, and major guidelines do not recommend it.
Evidence grade
Does not helpNot enough evidenceHelps a littleGood evidence
Not enough evidence yet
What it is
Low level laser therapy, also called photobiomodulation, shines red or near infrared light on the skin over the knee. It does not heat the tissue much. The idea is that the light calms inflammation and eases pain. A course is usually several sessions over a few weeks.
What the research shows
pooled randomised trials that compared laser with a sham laser, where the device looked real but gave no light. It found no clear difference in pain right after treatment or 12 weeks later, and concluded that the evidence did not support laser for knee arthritis.
pooled 22 placebo controlled trials with 1,063 people. It found that laser eased pain by about 14 points on a 100 point scale compared with placebo, and that results were best when the dose followed an international recommendation.
The two reviews disagree because they counted different trials and judged the doses differently. Until a large trial with the right dose is done, the question stays open. Major arthritis guidelines do not recommend laser for the knee.
Risks and effort
No serious side effects were reported in the trials. Eye protection is needed with some devices. The main drawback is time spent on a treatment with uncertain benefit.
They are close relatives. Both deliver light of specific wavelengths. Home red light panels and clinic lasers differ in power, so results from one may not apply to the other.
Does the dose matter?
The positive review suggests it does, but this idea has not been proven in a large trial.
Can I use it with exercise?
Yes. Laser has not been shown to replace exercise, so any use should sit alongside it.
Is it safe?
In the trials it was safe. Avoid shining it into the eyes.
Sources
Select a source to read what the study or guideline found, in plain words, with a link to the original.
Last reviewed 24 October 2026. Next review due October 2027.
