Infrared light penetrates to the inner layers of the skin at about 2 to 7 centimeters deep. It reaches the muscles, nerves and even the bones. Many studies have shown that a frequency of infrared light, with wavelengths from 700 to 1,000 nanometers, is best used for healing inflammatory conditions. Also, infrared therapy is safe and effective, without adverse side effects. As a matter of fact, infrared light is safe and is used even for infants in neonatal intensive care.