What colors of LEDs work the best?
Red has been used in light therapy for hundreds of years shining sunlight on the bare skin through stained glass. Probably more is known about treatment with red wavelengths than other colors. Research in Russia found biologic effects are most active with wavelengths around 440, 630 to 660, and 880 nanometers, corresponding to blue, red, and infrared (beyond what humans can see). Red seems to stimulate the system, blue to sedate. In recent studies blue light from LEDs has been effective in treating jaundice of the newborn, and a specific wavelength of blue light in treating acne. Other colors may have additional indications, especially when used on specific areas of the body.
