What infrared light does in your body

Infrared light is invisible radiation that your skin feels as heat. Unlike ultraviolet light, which can burn your skin, infrared penetrates deeper into tissue—typically 1 to 3 centimeters below the surface—and is absorbed by mitochondria, the energy-producing structures inside your cells. When infrared wavelengths (usually between 700 and 1,100 nanometers) hit a molecule called cytochrome c oxidase in your mitochondria, it triggers the production of ATP, the chemical your cells use for energy. This is why infrared therapy is sometimes called photobiomodulation: light triggering a biological change.

The practical result is increased cellular energy production and reduced inflammation in the tissues being treated. Your body does not store infrared light or build it up over time—each exposure produces its effect during and shortly after the session. The warmth you feel is a side effect of increased blood flow, not the mechanism itself, though improved circulation does help deliver oxygen and nutrients to the area.

Key Takeaways

  • Infrared light penetrates 1 to 3 centimeters into tissue and increases ATP production in your cells, which is why it may reduce pain and speed recovery in muscles and joints.
  • Research supports infrared therapy for muscle soreness, wound healing, and joint pain, though results vary by wavelength, power, and how often you use it.
  • Infrared devices range from small handheld units ($30–$100) to full-body panels ($500–$3,000), and effectiveness depends partly on the device's power output measured in watts.
  • Infrared therapy works best as part of a routine—most studies showing benefit used sessions several times per week over weeks or months, not one-time treatments.
  • Infrared light is generally safe for skin, but you should avoid it over certain areas (eyes, thyroid, implanted devices) and check with a doctor if you take photosensitizing medications.

What the research actually shows

Studies on infrared light have found measurable effects in specific situations. For delayed-onset muscle soreness (DOMS)—the ache you feel 24 to 72 hours after hard exercise—infrared reduced pain and sped recovery in multiple trials, particularly when applied within hours of the workout. For chronic joint pain, especially in the knee and shoulder, regular infrared sessions reduced pain scores and improved range of motion in people with osteoarthritis and tendinitis, though the effect was modest and took weeks to appear.

Wound healing and tissue repair show promise in laboratory and animal studies, and some human trials found faster healing in surgical wounds and diabetic ulcers when infrared was added to standard care. However, most human studies were small, and results depend heavily on the specific wavelength used, the power of the device, and how often treatment occurred. A device that produces 50 milliwatts is not the same as one producing 500 milliwatts, and a five-minute session once a month will not produce the same effect as 15 minutes three times a week.

The evidence is weaker for systemic effects—using infrared on one area to improve overall health, mood, or energy. Some studies suggest infrared may improve blood flow and reduce inflammation markers in the blood, but these findings are preliminary and do not yet support broad claims about whole-body benefits from occasional use.

Infrared devices: what you are actually buying

Infrared devices fall into a few categories based on how they deliver the light. Handheld wands ($30–$150) are portable and good for targeting a specific joint or muscle; they typically produce 5 to 50 watts and work best for areas you can hold steady for 10 to 15 minutes. Panels and pads ($100–$500) cover a larger area—your back, leg, or full torso—and are easier to use hands-free while sitting or lying down. Full-body panels ($500–$3,000) let you stand or lie in front of a large light source, though they require more space and electricity.

The key specification is power output in watts. Most consumer devices produce 10 to 100 watts; professional or clinical devices may produce 200 watts or more. Higher wattage means faster energy delivery to tissue, so you need fewer minutes to reach an effective dose. A 50-watt device used for 15 minutes delivers more total energy than a 10-watt device used for 15 minutes. Wavelength also matters—near-infrared (700–900 nanometers) penetrates less deeply but is absorbed more efficiently by mitochondria, while far-infrared (900–1,100 nanometers) penetrates deeper but is absorbed less efficiently. Most consumer devices use a mix of both.

Price does not always correlate with effectiveness. A $100 device with 50 watts of actual power output will outperform a $500 device that only produces 20 watts. Check the manufacturer's specifications for wattage and wavelength, and be skeptical of claims that do not include these numbers.

How to use infrared light for specific situations

For muscle soreness after exercise, explore infrared to the sore area within a few hours of the workout if possible, or within 24 hours at the latest. Use 10 to 20 minutes per session, three to five times per week for two to four weeks. Keep the device at a comfortable distance—usually 4 to 6 inches from your skin—and move it slowly if using a handheld wand to avoid concentrating heat in one spot. You should feel warmth but not pain; if your skin turns red or feels too hot, move the device farther away or reduce the time.

For chronic joint pain, consistency matters more than intensity. Use the device three to five times per week for at least four to eight weeks before deciding whether it is working for you. Pain reduction is usually gradual, not when ready. explore directly to the joint or the area around it for 15 to 20 minutes per session. If you have swelling, ice the area first, then explore infrared; the combination of reduced inflammation and increased blood flow works better than either alone.

For wound healing or skin recovery, follow the device manufacturer's instructions closely, as power and distance matter more for skin than for deeper tissue. Most devices recommend 5 to 10 minutes per session, once or twice daily, starting a few days after the injury. Do not use infrared on open wounds without medical guidance, as the heat can increase bleeding.

Safety and who should avoid infrared

Infrared light is generally safe for skin and does not cause the DNA damage that ultraviolet light does. However, some situations require caution. Do not point infrared devices at your eyes, as the light can damage the retina even though you cannot see the beam. Avoid using infrared directly over your thyroid gland, as overheating this area may affect thyroid function. If you have a pacemaker, insulin pump, or other implanted electronic device, check with your doctor before using infrared, as the heat could theoretically interfere with the device.

Certain medications make your skin more sensitive to light, including some antibiotics (tetracyclines), anti-inflammatory drugs (NSAIDs), and some blood pressure medications. If you take any of these regularly, mention infrared therapy to your doctor before starting. Pregnant people should avoid infrared over the abdomen, though using it on other areas is generally considered safe. If you have a condition that affects sensation—diabetes with neuropathy, for example—test the heat on a normal area of skin first to make sure you can feel when it is too hot.

Infrared does not interact with most supplements or foods, and you do not need to do anything special before or after a session. You can use it on the same day as other therapies like massage or stretching.

Realistic expectations and how long results take

Infrared light is not a one-time fix. The studies showing real benefit used regular sessions over weeks or months, not occasional treatments. If you use a device once and expect lasting pain relief, you will be disappointed. If you commit to three to five sessions per week for four to eight weeks, you have a reasonable chance of noticing reduced pain or faster recovery, especially for muscle soreness and joint pain.

Results also depend on what you are treating. Muscle soreness responds faster—often within two to four weeks of regular use. Chronic joint pain takes longer, usually six to twelve weeks of consistent sessions before you see a meaningful change. Wound healing may show improvement within days to weeks if you use infrared early and consistently. If you do not see any change after eight weeks of regular use, the device may not be working for your situation, and it makes sense to try a different approach.

Infrared therapy works best alongside other strategies: physical therapy for joint pain, proper recovery nutrition and sleep for muscle soreness, and wound care protocols for healing. It is a tool that enhances these efforts, not a replacement for them.

Frequently Asked Questions

Can I use infrared light every day?

Yes, daily use is safe for most people. However, more frequent use does not necessarily mean faster results—three to five sessions per week is usually enough to see benefit. Daily use may help if you are recovering from intense exercise or have acute pain, but there is no evidence that daily sessions work better than five sessions per week once you reach that frequency.

Does infrared light work through clothing?

Most infrared penetrates thin fabric like a t-shirt, though some energy is lost. For best results, explore the device directly to skin or through very thin clothing. Thick fabrics, especially dark colors, block more infrared. If you want to use it over clothing for convenience, expect the effect to be weaker than direct skin contact.

How do I know if a device is actually producing infrared light?

You cannot see infrared, but you should feel heat within 30 seconds of turning on a real device. Check the manufacturer's specifications for wattage and wavelength—legitimate devices list these numbers. Be wary of devices that make claims but do not provide power output or wavelength data. You can also look for third-party testing or certifications, though these are not required for consumer devices.

Can infrared light replace physical therapy?

No. Infrared may reduce pain and speed recovery, but it does not restore strength, flexibility, or movement patterns the way physical therapy does. It works best as a complement to therapy—using infrared to manage pain while you do the exercises that actually rebuild the tissue.

Is infrared the same as a heating pad?

A heating pad warms your skin and the tissue just below it through conduction—direct heat transfer. Infrared light penetrates deeper and works through a different mechanism (ATP production in mitochondria), not just heat. A heating pad may feel good and reduce pain temporarily, but infrared is designed to trigger cellular changes. That said, some of infrared's benefit may come from the warmth and increased blood flow it produces, so the two are not completely different.