The primary principle behind laser hair removal is selective photothermolysis (SPTL), the matching of a specific wavelength of light and pulse duration to obtain optimal effect on a targeted tissue with minimal effect on surrounding tissue. Lasers can cause localized damage by selectively heating dark target matter, melanin, thereby heating up the basal stem cells in the follicle which causes hair growth, the follicle, while not heating the rest of the skin.
Laser removal hair has become popular because of its speed and efficacy, although some of the efficacy is dependent upon the skill and experience of the laser operator, and the choice and availability of different laser technologies used for the procedure. Some will need touch-up treatments, especially on large areas, after the initial set of 3-8 treatments. And laser treatment is the most effective, at the same time, is the relatively safe one.