Red light therapy may help reduce pain and inflammation in some localized conditions, but it is not a proven general treatment for inflammation. The strongest human evidence concerns short-term improvements in pain and physical function, particularly in conditions such as knee osteoarthritis. Evidence that red light therapy reduces inflammation throughout the body or treats autoimmune and inflammatory diseases remains limited.
Red light therapy is also called photobiomodulation, low-level light therapy and low-level laser therapy. It uses non-heating red or near-infrared light to stimulate activity in cells.
Red Light Therapy for Inflammation at a Glance
| Question | Evidence-based answer |
|---|---|
| Can it reduce inflammatory pain? | Possibly, especially in some musculoskeletal conditions |
| Does it treat the cause of inflammation? | This has not been reliably established |
| Is it proven for systemic inflammation? | No |
| Is it suitable as a standalone treatment? | Usually not. It is better considered an add-on |
| Is it generally safe? | Short-term use appears low risk when used as directed, but precautions are important |
What Does the Research Show?
Human research suggests that photobiomodulation can improve pain and physical function in some cases. Results vary by condition, wavelength, dose and treatment schedule.
A 2023 literature review of 11 randomized controlled trials found mixed results. Some studies reported improvements in chronic pain and inflammation, while others found no clear benefit. The evidence is not consistent enough to treat red light therapy as a dependable anti-inflammatory treatment.
Knee osteoarthritis has some of the better clinical evidence. A 2024 systematic review included 10 placebo-controlled studies involving 542 people. Photobiomodulation reduced pain at rest compared with placebo, but the researchers rated the certainty of evidence as very low. They also said it should not replace established treatments.
A 2025 umbrella review assessed 15 meta-analyzes covering more than 200 randomized trials and over 9,000 participants. It found benefits for some outcomes, including disability related to osteoarthritis. However, most outcomes had low or very low certainty because of small studies, different treatment protocols and variations between devices.
How Might Red Light Therapy Affect Inflammation?
Red and near-infrared light may change cellular activity without heating tissue. Proposed effects include changes in mitochondrial function, oxidative signaling, blood flow, tissue repair and inflammatory cytokine activity. The U.S. Food and Drug Administration describes photobiomodulation devices as using a low, non-heating dose of light to produce biological effects.
Animal studies often report lower levels of inflammatory markers such as interleukin-1 beta, interleukin-6 and tumor necrosis factor-alpha. Results in animals do not prove that a red light device will reduce inflammation or improve symptoms in humans.
When Red Light Therapy May Be Worth Considering
Red light therapy may be reasonable as a complementary treatment when the inflammation is localized and a healthcare professional has assessed the underlying condition. Possible uses include:
- Knee osteoarthritis-related pain and stiffness
- Some tendon or soft-tissue injuries
- Certain rehabilitation settings
- Some dermatology treatments, when a dermatologist uses light therapy with standard care
The practical goal is usually to reduce pain, improve movement or support tissue recovery. Red light therapy should not be described as a cure for arthritis, autoimmune disease or unexplained inflammation.
The American Academy of Dermatology recommends treating red light as a complementary option for many skin concerns rather than assuming it can replace established treatment.
When It Should Not Replace Medical Treatment
Red light therapy is not a substitute for diagnosis or treatment of:
- Rheumatoid arthritis or another autoimmune disease
- A suspected infection
- A new or unexplained swollen joint
- Persistent or worsening inflammation
- Inflammatory bowel disease
- Cancer or a suspicious lesion
- A significant injury that requires medical assessment
The concern is not only that the device may fail to help. Using it instead of appropriate care can delay diagnosis of the condition causing the inflammation. The FDA has warned that marketing low-level light devices for inflammation without adequate evidence may create safety concerns if people postpone medical treatment.
Is Red Light Therapy Safe?
Short-term red light therapy appears to carry a low risk of serious side effects when used according to the device instructions. Possible problems include temporary irritation, discomfort, skin sensitivity, pigmentation changes or eye injury if the light is used incorrectly. Long-term safety data for many home devices are limited.
Speak with a healthcare professional before using red light therapy if you:
- Take medication that increases sensitivity to light
- Have lupus or another photosensitivity disorder
- Have a history of skin cancer or cancer at the treatment site
- Are pregnant or planning pregnancy
- Have an active infection, open wound or untreated skin lesion
- Have an implanted electronic device
- Are treating the face or eyes
Use the eye protection specified by the manufacturer. Sunglasses are not necessarily an adequate substitute for protective goggles.
What to Look for in a Red Light Therapy Device
Choose a home device based on the problem you want to treat. A red light mask cleared for wrinkles is not evidence that the same device treats knee inflammation or arthritis.
Look for:
- Clearly stated wavelengths and treatment instructions
- A device intended for the body area and condition in question
- Appropriate eye protection
- FDA clearance for its stated use, where applicable
- A manufacturer that provides irradiance, treatment distance and session duration
FDA clearance mainly addresses a device's regulatory status and intended use. It does not prove that the device works for every condition mentioned in online marketing.
Bottom Line
For diagnosed, localized inflammatory pain, red light therapy may be worth discussing as an add-on to standard care. It is not a proven general treatment for inflammation and should not replace medical assessment.
If inflammation is new, severe, widespread or unexplained, identify the cause first.