Can Red Light Therapy Help Knee Osteoarthritis Pain? Here's What the Trials Show

Knee osteoarthritis is one of the most common reasons people look for a way to manage joint pain without surgery or long-term medication. Red light therapy — technically called photobiomodulation — has been studied specifically for this for years, and the evidence has been building.

What the research looked at

A 2024 systematic review and network meta-analysis pooled data from multiple randomized controlled trials to work out which wavelengths of low-level light therapy actually help with knee osteoarthritis symptoms, comparing red and near-infrared light across different doses against sham (placebo) treatment.

Separately, a randomized clinical trial looked at photobiomodulation therapy specifically around total knee arthroplasty (knee replacement surgery), measuring swelling and recovery outcomes against a control group.

What they found

Across the pooled trials, light therapy in the red-to-near-infrared range (roughly 630–904 nm) was consistently better than placebo at reducing pain, both at rest and during movement. Some trials reported pain reductions in the range of 30% or more on standard pain scales. The picture is more mixed on function and stiffness — several trials found clear benefits for pain, but less consistent improvement in day-to-day mobility scores.

In other words, the current evidence supports red light therapy as a legitimate option for pain relief in knee osteoarthritis — not as a cure for the underlying joint degeneration, but as a non-drug way to take the edge off pain that a lot of people live with daily.

What this means in practice

If you're using red light therapy for joint pain, consistency seems to matter more than a single session — the trials that showed benefit used repeated sessions over weeks, not a one-off treatment. If you have significant joint damage or are considering surgery, this is something to bring up with your doctor rather than a replacement for their advice.