Walk into any modern wellness space, and you’ll hear the terms red light, infrared, and near infrared used almost interchangeably. They’re related, but they are not the same thing. Each sits in a different part of the light spectrum, reaches a different depth in the body, and supports different outcomes.
Understanding the difference between infrared and red light therapy helps explain why the best systems use both, and why a session under a multi-wavelength device feels like more than a single-color light.
Where Red and Near Infrared Light Sit on the Spectrum
Light is measured in wavelengths, expressed in nanometers (nm). The longer the wavelength, the deeper it can travel into tissue.
Visible
Invisible
Heat
Shorter wavelength ← → Longer wavelength, deeper reach (not to scale)
- Red light falls in the visible range, roughly 600 to 700 nm. You can see it as a warm red glow.
- Near infrared light sits just beyond what the eye can detect, roughly 760 to 940 nm. During a session, this light is essentially invisible, even though it’s doing significant work.
- Far infrared extends much further along the spectrum and behaves very differently, which is where a lot of the confusion around red light therapy vs. infrared comes from. More on that below.
Both red and near-infrared wavelengths fall within what researchers call the therapeutic window: the range of light the body’s cells can absorb and use. According to research published in Frontiers in Neuroscience (2022), an enzyme in the mitochondria called cytochrome c oxidase is the primary acceptor of photons in these red and near-infrared ranges, which is why both trigger increased cellular energy production, improved circulation, and reduced inflammation.
So the mechanism is shared. The difference is where in the body it happens.
What Red Light Does Best
Because red wavelengths are shorter, they are absorbed closer to the surface, in the skin and the tissue just beneath it. That makes red light the workhorse for:
Supporting collagen production, skin tone, and texture
Improving blood flow in the skin and superficial tissue
Most surface-level repair happens exactly where red light is absorbed
The red glow itself signals to clients that something is happening
If the goal lives at the surface, red light is doing most of the lifting.
What Near Infrared Light Therapy Does Best
Near infrared light is where depth comes in. Measurements published by Stolik and colleagues in the Journal of Photochemistry and Photobiology (2000) found that longer wavelengths in this range penetrate progressively deeper into human tissue than visible red light. In practical terms, near infrared light therapy reaches past the skin into muscle, joints, and connective tissue.
That deeper reach makes near infrared light the driver behind:
Reaching the muscle belly where post-exercise soreness actually lives
Joint comfort and mobilitySupporting tissue around joints that red light simply cannot reach
Deep tissue inflammationResearch by Dr. Michael Hamblin, published in AIMS Biophysics (2017), documents anti-inflammatory effects of red and near infrared light across a wide range of tissue depths
Recovery and performanceThe outcomes most active clients are chasing happen below the surface
Red Light Therapy vs Infrared: Clearing Up the Confusion
Here’s where terminology trips people up. When most people say “infrared,” they’re thinking of infrared saunas, which use far infrared wavelengths. Far infrared works primarily by heating the body: it raises tissue temperature, induces sweating, and creates a heat-based experience.
Near infrared light therapy is fundamentally different. It is non-thermal. Rather than heating tissue, near infrared photons are absorbed directly by structures inside the cell, triggering biological effects through light, not heat. A session feels gentle and comfortable, with no sweating, no elevated core temperature, and no cool-down needed afterward.
So when comparing infrared vs. red light therapy, the honest answer is that near-infrared and red light belong in the same family (photobiomodulation), while far infrared saunas are a separate, heat-driven category altogether.
The Difference Between Infrared and Red Light Therapy at a Glance
Red light
600 to 700 nm · VisibleBest for skin and superficial tissue
Near infrared light
760 to 940 nm · InvisibleBest for muscle, joint, and recovery outcomes
Far infrared
Beyond 3,000 nm · Heat-basedUsed in saunas; works through warming rather than cellular light absorption
Why the Best Systems Use Both Red and Near Infrared
Framing this as red light vs near infrared misses the point: they are partners, not rivals. Red light covers the surface, near infrared covers the depths, and together they treat the body as a whole in a single session.
This is exactly why professional-grade systems are built around multiple wavelengths rather than one. The Excell Spectrum 7, for example, blends seven wavelengths across the red and near infrared spectrum, so every session delivers surface-level and deep-tissue benefits at the same time, in the same 10-minute window.
Frequently Asked Questions
Yes. Near infrared light therapy is non-invasive, produces no UV radiation, and does not heat or damage tissue. It is generally well tolerated. As always, individuals with specific medical conditions should consult their healthcare provider.
Not really, and that’s normal. Near infrared light is invisible and non-thermal, so clients typically feel little more than gentle warmth from the visible red wavelengths. The absence of sensation doesn’t mean an absence of effect.
Neither is “better”; they simply work at different depths. Red light excels at skin-level goals, while near infrared reaches muscle and joints. For most recovery and wellness goals, a system that combines both delivers the most complete result.
No. Near infrared light therapy uses specific light wavelengths that interact directly with cells without raising tissue temperature. They are complementary but distinct services.
Learn More About Red and Near Infrared Light
If you’d like to explore how red and near infrared light could work in your space, we’d love to talk. The Excell team can walk you through wavelengths, equipment options, room layout, and session design, all tailored to your goals. Reach out today to start the conversation at connect@excellredlight.com.