Light-based hair treatment is founded on the principle of phototherapy (also known as Low-Level Light Therapy, LLLT). In this process a specific wavelength of light is directed on the scalp and a series of complex chemical reactions produce a result that increases terminal hair growth and thickness.
A prerequisite for effective phototherapy of the scalp is that the light sources should cover all of the areas on the scalp that are commonly affected by androgenetic hair loss. Laser light produces a narrow light beam, while LEDs have a more diffused beam. Considering these unique light characteristics, the most effective and efficient method for full scalp coverage is through the use of LEDs, or a combination of lasers and LEDs.