What Is Red Light Therapy?

Red & Near‑Infrared Light

Red light (≈600–700 nm) is visible and tends to act on the skin and more superficial tissues—often discussed for complexion, barrier support, and scalp care.

Near‑infrared (≈700–1200 nm) is invisible and penetrates deeper, interacting with muscles, joints, and some deeper structures—often discussed for post‑exercise comfort and mobility support.

They are complementary rather than mutually exclusive—using both tends to provide broader, more comprehensive coverage from surface to depth.

Why It Works: Mitochondria & ATP

Mitochondria power our cells by running the electron transport chain to produce ATP—the cell’s “energy currency.” Specific bands of red/NIR light are thought to be absorbed by light‑sensitive targets in mitochondria (e.g., cytochrome c oxidase), supporting a more efficient electron transport chain and greater ATP availability. With more available energy, cellular repair and metabolic processes can run more smoothly.

The Optical Window

Biological tissues absorb light differently: hemoglobin absorbs strongly below ~600 nm while water absorption rises above ~900 nm. The 600–900 nm band is often called the “optical (therapeutic) window,” where penetration and biocompatibility are favorable. Selecting multiple wavelengths inside this window helps address both superficial and deeper tissues.

Modern Humans are "Mal‑Illuminated"

The human body requires light to function, with light playing important roles in many biological processes. The solar spectrum includes UV, visible and infrared light, each with distinct biological effects. For example, UVB helps synthesize vitamin D, while blue light helps regulate circadian rhythm.

Yet modern people spend less time in sunlight. Housing, transport, and workplaces are often indoors, reducing exposure to the beneficial aspects of natural sunlight.

Modern Humans are Red & NIR Light Deficient

Modern LED and CFL lighting often lacks beneficial red and near infrared wavelengths, and indoor illuminance is far lower than natural daylight—even on cloudy days. Energy‑efficient windows in buildings and vehicles further reduce these wavelengths.

Together with indoor lifestyles, exposure to red/NIR wavelengths has dropped dramatically over the last century. From this perspective, supplementing with high‑quality, well‑designed LED red/NIR light devices for wellness use can make practical sense.