Light and photobiomodulation
Blue light (therapeutic)
Therapeutic blue light is visible light of roughly 400–500 nanometres. It is absorbed close to the skin surface. The Red Light sauna's range starts in the blue, at 460 nm.
Also called 400-500 nm, blue LED
Absorbed near the surface. Haemoglobin and melanin absorb strongly at these wavelengths, so blue light is absorbed at the skin surface.
Eye safety. Short-wavelength visible light is assessed for the retinal blue light hazard. See Eye safety and light.
Why it matters here
Blue is one of the colours in the Red Light sauna. It is absorbed close to the skin surface.