Infrared light does reduce inflammation, and the evidence spans both lab studies and clinical settings. It works primarily by calming the body’s inflammatory signaling molecules while simultaneously boosting cellular energy production and blood flow. The effects have been documented in joint conditions, muscle recovery, wound healing, and even systemic inflammation, though results vary depending on wavelength, dose, and the specific condition being treated.
How Infrared Light Reduces Inflammation
The core mechanism starts inside your cells’ mitochondria, the structures responsible for producing energy. Infrared light is absorbed by an enzyme in the mitochondrial energy chain, which accelerates electron transport and increases the cell’s energy output. This energy boost gives cells the resources they need to repair damage and activate antioxidant defenses.
But the anti-inflammatory effect goes beyond just energy production. When infrared light hits that mitochondrial enzyme, it also releases nitric oxide that was previously bound to it. Nitric oxide is a powerful vasodilator: it relaxes the smooth muscle lining your blood vessels and lymphatic vessels, increasing blood flow to the treated area. Better circulation means more oxygen delivery, faster removal of inflammatory waste products, and reduced swelling.
At the molecular level, infrared light directly suppresses the inflammatory signals your body produces. In a controlled study published in SAGE Open Medicine, far infrared radiation kept levels of two key inflammatory molecules nearly flat during an acute inflammatory response. The control group saw one of these molecules spike to 8.5 times its baseline level within two hours, while the infrared-treated group peaked at only 2.5 times baseline and returned to normal. The other major inflammatory molecule stayed at baseline in the treated group while climbing steadily in the untreated group. This ability to dampen pro-inflammatory signals while stabilizing protective ones is central to how infrared light manages inflammation.
Near Infrared vs. Far Infrared
Infrared light spans a wide range of wavelengths, and different portions of that range behave differently in your body. Near infrared (roughly 800 to 1,500 nanometers) penetrates deeper into tissue and is the type most studied for joint, muscle, and wound applications. Far infrared (5,600 nanometers and above) doesn’t penetrate as deeply but transfers energy into subcutaneous tissue about 2 to 3 centimeters below the skin without overheating it. Far infrared primarily works by accelerating blood flow and increasing nitric oxide production in blood vessel walls.
Red light, often grouped with near infrared in therapy devices, uses wavelengths in the 600 to 700 nanometer range and is better suited for surface-level conditions like skin inflammation and wound healing. For deeper tissues like joints and muscles, near infrared wavelengths around 800 to 850 nanometers are more commonly used in clinical research because they penetrate further.
Joint Pain and Arthritis
Infrared light therapy has been used for osteoarthritis for years, though it remains somewhat controversial in mainstream medicine. A Cochrane review initially reported mixed results, but a subsequent reanalysis of the data found the original conclusions were neither robust nor valid. When the researchers included trials that had been improperly excluded and ran additional analyses, the results were consistently and significantly in favor of infrared light therapy for osteoarthritis.
Animal studies help explain why. In a model of osteoarthritis where cartilage damage and inflammation were induced in rat knee joints, a single infrared light application significantly reduced inflammatory cells in the joint fluid. The treatment also lowered the genetic expression of multiple inflammatory signaling molecules. Beyond reducing inflammation directly, infrared light appears to act on nerves by reducing pain transmission and activating the body’s own opioid receptors, which provides an additional analgesic effect separate from the anti-inflammatory one.
Muscle Recovery After Exercise
When you push muscles hard, the resulting soreness and stiffness over the next 24 to 72 hours come from microscopic damage and the inflammatory response that follows. Near infrared light applied after strenuous exercise has been studied as a way to shorten this recovery window. In a study published in the Journal of Athletic Training, researchers measured strength loss, range of motion, and muscle tenderness after intense resistance exercise, tracking recovery at 48 hours. While the treatment showed trends toward faster strength recovery, the researchers noted that more thorough investigation of recovery biomarkers at 48 hours and beyond is still needed.
The theoretical basis is solid: if infrared light reduces inflammatory signaling and increases cellular energy production, it should help muscle cells repair faster. Many professional sports teams and physical therapy clinics now use near infrared devices as part of recovery protocols, though optimal timing (before, immediately after, or hours after exercise) is still being refined.
Wound Healing and Skin Inflammation
Wound healing is where the anti-inflammatory effects of infrared light become especially practical. Healing happens in phases: first inflammation clears debris, then cells called fibroblasts rebuild tissue by producing collagen and forming new blood vessels. Infrared light accelerates this entire cascade. It stimulates fibroblast and skin cell proliferation, promotes collagen deposition, and modulates the acute inflammatory phase so wounds close faster with better scar quality.
The effects are particularly notable in chronic wounds like diabetic ulcers, where healing has stalled. In these cases, infrared light improves mitochondrial function, rebalances the chemical signaling environment, and shifts immune cells from a pro-inflammatory state to a repair-oriented state. Specifically, it suppresses inflammatory molecules while boosting anti-inflammatory and growth-promoting ones. A systematic review and meta-analysis in the International Wound Journal confirmed that near infrared light improves microcirculation at wound edges, reduces inflammatory markers, and stimulates the cell types needed for tissue repair.
For acute skin inflammation like sunburn, clinical studies have used daily or twice-daily treatments over about three days. For second-degree burns, protocols typically involve once-daily sessions for a week.
Systemic Effects Beyond the Treatment Site
One of the more intriguing findings is that infrared light delivered to one part of the body can positively affect distant tissues and organs. Both local and systemic anti-inflammatory mechanisms appear to be at work, though the exact cellular pathways behind the systemic response aren’t fully mapped yet. A six-year follow-up study on patients with thyroiditis (thyroid inflammation) who received infrared light therapy found that the treatment was safe over the long term and showed lasting benefits years after the treatment period ended.
This systemic reach is important because it suggests infrared therapy could influence conditions driven by widespread, low-grade inflammation, not just localized pain or swelling.
Typical Treatment Parameters
Infrared therapy doses are measured in energy density, expressed as joules per square centimeter of skin. The therapeutic range used across clinical studies spans from 0.04 to 50 joules per square centimeter, with power densities kept below 100 milliwatts per square centimeter. Within that broad range, the appropriate dose depends heavily on what’s being treated.
For inflammatory skin conditions like acne, studies have used doses ranging from about 4 to 12 joules per square centimeter delivered twice weekly over several weeks. For deeper tissue inflammation in joints or muscles, near infrared wavelengths around 808 nanometers delivering about 4 joules per treatment point have shown results. Treatment sessions typically last anywhere from a few minutes to 20 minutes per area, depending on the device’s power output and the target depth.
More is not necessarily better. In the osteoarthritis research, a lower power level (50 milliwatts) actually produced better anti-inflammatory results for some markers than double that power. This follows a well-documented pattern in light therapy where there’s a therapeutic sweet spot: too little energy does nothing, but too much can reduce or reverse the benefits.
Safety Considerations
Infrared light therapy is generally well tolerated, with most people experiencing no side effects beyond mild, temporary warmth at the treatment site. However, certain groups should avoid it. People with retinal diseases, including diabetic retinopathy, are at risk because infrared light can damage the retina. Those taking photosensitizing medications, including lithium, melatonin, certain antipsychotics, and some antibiotics, may have exaggerated reactions. People with a history of skin cancer or systemic lupus erythematosus should also avoid infrared light therapy, as it could worsen these conditions.
Eye protection is recommended during any infrared treatment, especially with near infrared wavelengths that are invisible but can still reach and damage retinal tissue. Home devices generally operate at lower power levels than clinical equipment, which reduces risk but also means longer treatment times to deliver the same energy dose.