Red Light Therapy for Pain and Inflammation: Knees, Joints and Tendons

Red and near-infrared light has the most evidence for pain in three places: knee osteoarthritis, neck pain and tendon pain around the elbow and shoulder. In placebo-controlled trials, light reduced pain scores by roughly 10 to 20 points on a 100-point scale, which is modest but real, and the effect lasted weeks after treatment stopped. It works best at the right dose, alongside exercise rather than instead of it, and nearly all of the trials used clinic lasers rather than home LED panels. For a stiff, aching joint it is a reasonable thing to add; for a hot, swollen or newly injured one, see a doctor first. This article goes through the evidence joint by joint, explains how light acts on inflammation, and sets out how to use a panel on a sore knee or shoulder.

Does red light therapy help with pain and inflammation?

For chronic joint and tendon pain, controlled trials say yes, modestly. Near-infrared, which reaches deeper, is the wavelength most of the joint research used.

The trials that count compared real light with a placebo device, and the light came out ahead for knee arthritis, neck pain and several kinds of tendon pain. The size of the effect varied with the dose: trials that followed the recommended doses did better than those that did not. The photobiomodulation researcher Praveen Arany, writing for The Conversation, makes two practical points: professional lasers may be more effective than home LED devices, and overdoing it can reduce the benefit. The Conversation.

How does red light reduce inflammation?

Light is absorbed in the mitochondria, the energy-producing parts of cells, and in cells that are already inflamed it tends to turn inflammatory signals down.

A 2017 review of the mechanism by Michael Hamblin sets out the chain. The main light-absorbing target is an enzyme in the mitochondria, cytochrome c oxidase; light is thought to release nitric oxide that was blocking it, so the cell makes more energy. In healthy cells this produces a brief burst of reactive oxygen species; in stressed or inflamed cells, the same light lowers them. Immune cells called macrophages shift from their inflammatory type towards their repair type, and in animal models of arthritis, light reduced joint swelling and inflammatory markers. Review. The same review stresses the dose rule that runs through the whole field: low doses stimulate and high doses inhibit.

Red light therapy for knee pain and osteoarthritis

This has the strongest evidence. At the recommended doses, pain fell more than with placebo and stayed lower for weeks afterwards.

A 2019 meta-analysis in BMJ Open pooled 22 placebo-controlled trials with 1,063 people with knee osteoarthritis. At the recommended doses, pain was 18.7 mm lower than with placebo at the end of treatment and 23.2 mm lower two to twelve weeks later, peaking at about 32 mm at two to four weeks. No side effects were reported. The effective trials used near-infrared at 785 to 860 nm or 904 nm. Full paper. A 2024 review in Physical Therapy of ten placebo-controlled trials found a moderate reduction in pain at rest and concluded that light should complement other treatment rather than stand alone. Review.

One older trial is closer to home use. In 1992, 50 older adults with knee osteoarthritis treated themselves with red, infrared or placebo light emitters for 15 minutes twice a day for ten days. Pain fell by more than half in the red and infrared groups and did not improve with placebo. Study summary. It is small and old, but it is one of the few trials where patients applied non-laser light themselves.

Verywell Health's July 2026 report makes the key point about wavelength: for a knee, the light needs to be near-infrared, around 780 to 860 nm, not only the 630 to 660 nm red used in face masks. Verywell Health. Exercise to strengthen the thigh muscles remains the backbone of knee arthritis care; light is an addition to it.

Red light therapy for neck pain

Chronic neck pain has good evidence: in a Lancet meta-analysis, people treated with light were about four times as likely to improve as those given placebo.

The 2009 review pooled 16 randomised trials with 820 people. For chronic neck pain, the relative risk of improvement against placebo was 4.05, and pain was 19.9 mm lower on a 100 mm scale; at follow-up one to 22 weeks later it was 22.1 mm lower. Side effects were mild and no different from placebo. The trials used wavelengths from 632.8 nm red to 904 nm near-infrared. Study summary. Neck pain after a fall or accident, or with numbness or weakness in the arms, needs a doctor before any home treatment.

Red light therapy for tendonitis: elbow, shoulder, Achilles and heel

Positive at the right dose. Too little light and tendon trials found nothing; enough, and pain fell by 10 to 20 mm against placebo.

For tennis elbow, a 2008 meta-analysis of 13 trials, 730 people, found pain 10.2 mm lower overall, 17.2 mm lower with 904 nm and 14.0 mm lower with 632 nm, with the light aimed at the point where the tendon joins the bone. Full paper. For the shoulder, a 2015 review of 17 trials found pain 20.4 mm lower with light alone and 16 mm lower when light was added to exercise, and noted that trials using too low a dose showed no effect on anything. Study summary. For the lower limb, a 2022 meta-analysis in BMJ Open covering Achilles and knee tendon pain and plantar fasciitis found pain 15 mm lower than placebo at recommended doses, and 18 mm lower when light was added to exercise, with no side effects. Study summary.

Red light therapy for rheumatoid arthritis

A Cochrane review found short-term relief of hand pain and morning stiffness. It is a supplement to rheumatology care, not part of controlling the disease.

The review pooled five placebo-controlled trials with 222 people, mostly treating the hands. Pain was about 1.1 points lower on a 10-point scale, morning stiffness was 27.5 minutes shorter, and hand flexibility improved; function, range of motion and swelling did not change. The authors concluded light could be considered for short-term relief. Cochrane review. Rheumatoid arthritis needs disease-modifying treatment from a specialist; a flare with hot, swollen joints is a reason to call them, not to reach for a light.

Lasers in the trials, LEDs at home: what changes?

The wavelengths are the same; the delivery is different. Lasers put a concentrated dose on a few points, and a panel spreads light over a wide area.

Most of the trials above used low-level lasers applied to marked points. The dosing guidance from the World Association for Photobiomodulation Therapy, for example, gives a knee at least 4 joules per point at 780 to 860 nm over several points, with sessions daily for two weeks or every other day for three to four weeks. WALT dose table. A panel works differently: it covers the whole joint at once, and what matters is the distance, which sets how much light arrives, and the time. That is why we say a panel follows the research on wavelength and on consistency, rather than claiming the trial results carry over one for one. Arany's advice for home use, quoted by Verywell Health, is sessions of 10 to 20 minutes, no more than five times a week, on a device that combines red and near-infrared and has a timer.

How to use a red light panel on a sore joint

Bare skin, 6 inches away, 10 to 15 minutes, three to five times a week, for at least three to four weeks. Keep doing your exercises.

1. Bare the joint. Clothing blocks much of the light. Roll trousers above the knee or sit in shorts.
2. Get close. About 6 inches from a knee, elbow or ankle; 12 inches for a broad area such as the upper back.
3. Near-infrared up. Run the 810, 830, 850 and 1060 nm channels high; the visible red can be lower, and blue off.
4. Treat from more than one side. For a knee, the front and then the inside of the joint, where knee arthritis pain often sits.
5. Protect your eyes. Goggles on, even when the panel is at knee height.
6. Keep a simple log. Pain out of ten each morning, and how far you walked. Judge it at three to four weeks, not after one session.

How to set up a red light panel at home covers mounting heights, and light and muscle recovery covers use after training.

When should you see a doctor instead?

For any joint that is hot, red and swollen, pain after an injury, pain with fever, or pain that wakes you at night. Those need a diagnosis first.

Do not use light over a known or suspected tumour, or if you are pregnant, have epilepsy, have a thyroid condition or take thyroid medication, or take medication that makes your skin sensitive to light, and ask your doctor first if you have lupus. Is red light therapy safe explains each of these. Skin should feel warm during a session, never hot; stop if it does.

Using the Kivorla panel for joints and tendons

The panel carries the near-infrared wavelengths the joint trials used, each dimmable on its own, with its output at 6 inches printed on the page.

The 9-Spectrum Red Light Therapy Panel runs 810, 830, 850 and 1060 nm near-infrared alongside 630, 660 and 670 nm red, plus 480 nm blue and 590 nm amber, and each dims from 1 to 100 percent. At 6 inches it delivers at least 1567 W/m² across the spectrum, of which at least 1200 W/m² is near-infrared. The timer runs from 1 to 30 minutes and stops after 5 if you never set it, the front stays at or below 40°C, and goggles come in the box. The face mask is built for skin, not joints, so for knees, shoulders and tendons the panel is the one to use; mask vs panel compares them.

Read the precautions before ordering, since returns are accepted within 30 days, less a 10% restocking fee if the panel is unopened with its seals intact, or 20% if it is opened but undamaged and complete. Standard shipping to the US, UK and Germany is free.

Kivorla devices are general wellness devices, not medical devices, and do not diagnose or treat any condition. If you have ongoing joint pain, arthritis or an injury, speak to a doctor or physiotherapist before using a light therapy device.