Red light therapy vs. infrared heat: Understand key differences, wavelengths & how each uniquely benefits your skin, pain relief & detoxification.
Each day we are bathed in light energy—sometimes visible, sometimes not. For centuries, scholars have pondered what light is, how it travels, and how it shapes life on Earth. Ancient cultures offered many ideas, but in the 1860s Scottish physicist James Clerk Maxwell proposed that light behaves as synchronized electric and magnetic waves, giving rise to the concept of electromagnetic radiation. This insight produced the electromagnetic spectrum, which arranges energies from low-frequency, generally safe bands such as radio, microwave, infrared, visible, and ultraviolet, to higher-frequency x-ray and gamma rays that require greater caution.
The human eye can see wavelengths from roughly 380–700 nanometers, yet the body can feel invisible bands such as the warmth of infrared.
Many wellness services now use light or heat; two common options are red-light therapy and infrared heat. Both are increasingly offered in spas and clinics, and although they are often confused, they differ in depth of penetration and proposed benefits.
Humans need regular light exposure for optimal health; sunlight-derived vitamin D is a familiar example. More than half of solar energy is infrared, while ultraviolet makes up only a small fraction. Within the visible range, violet light carries the highest energy and red light the lowest.
The spectrum classifies each band by wavelength in nanometers (nm) and its interaction with human tissue. Red light, at 630–700 nm, is visible and acts mainly on the skin surface. Infrared, adjacent to red at 800 nm–1 mm, is invisible and may reach about 1.5 inches beneath the skin, producing overlapping yet distinct effects.
Because infrared wavelengths are longer, they penetrate more deeply, which may explain why some reported benefits differ from those of red light. Interest in these effects is not new: in the late 1800s physician Niels Ryberg Finsen used light therapy against smallpox and received the 1903 Nobel Prize in Medicine and Physiology. In 1910 John Harvey Kellogg published “Light Therapeutics,” describing red and infrared applications. Later, NASA employed red LEDs to grow plants in space and noted favorable effects on crew mood and wound care; the agency also used infrared heat for cardiovascular conditioning. These observations helped popularize both modalities in contemporary wellness settings.
PubMed search: photobiomodulationPMC overview: low-level light therapy
Although infrared is classified as light energy, we don’t see it; we feel it as warmth. Because all humans produce infrared, it’s safe, natural, and readily absorbed by tissues. During and after exposure, users often report pain relief, increased circulation, weight-management support, a sense of detoxification, skin rejuvenation, relaxation, and better sleep. Historical practices across cultures have long used warmth to ease metabolism, inflammation, allergy discomfort, and heart function, though individual results vary. Infrared may encourage sweating, which some view as a complementary route to support the body’s natural detox processes.
Tissues with poor circulation due to injury may benefit because infrared warmth can promote cell-level activity. It appears to stimulate fibroblasts, increase DNA and protein synthesis, and improve local oxygen delivery, factors that may aid tissue repair and offer relief for chronic discomfort.
Red light sits next to near-infrared on the spectrum. Many devices combine low-level infrared with red LEDs; infrared reaches deeper layers while red light acts nearer the surface. Studies suggest red light may rejuvenate facial skin, even tone, build collagen, reduce wrinkles, and fade sun damage. It might also activate the lymphatic system, calm inflammation, diminish scars or stretch marks, and possibly support hair retention. These effects are thought to arise from red light’s ability to energize fibroblasts, keratinocytes, and other skin cells.
Red-light therapy is popular for collagen stimulation, which requires wavelengths around 700 nm. People with arthritis sometimes report joint relief after treatment. Salons, spas, and clinics now offer red-light facials or body sessions to improve skin appearance, ease minor aches, and encourage an overall sense of well-being.
PubMed search on photobiomodulation | Full-text articles at PMC
Infrared and red light share several features: both are natural, drug-free, non-invasive, and generally well tolerated, with users rarely reporting adverse short- or long-term effects. Many describe positive outcomes. The best option depends on your goal. Surface skin concerns may respond to red light alone, whereas deeper detoxification goals sometimes prompt the addition of infrared energy, which penetrates further. Infrared sessions may also support calorie expenditure, gentle detoxification, pain relief, and relaxation, offering a broader wellness experience while still providing skin-level benefits similar to red light.
