The mechanism of action behind laser hair removal is the selective photothermolysis (SPTL). Lasers can lead to the damage of hairs in a localized area by selectively heating the dark pigment melanin. It damages the area of hair growth (the follicle), and do not harm the rest of the skin. It is based on the principle that light is absorbed by dark objects, thus laser energy can be absorbed by the presence of dark material in the skin with speed and intensity. The dark target matter related to the hair growing region is known as chromophore and it can be either naturally-occurring or induced artificially.

Hair removal lasers are designed in such a fashion that they selectively target melanin. Melanin is regarded as the chief chromophore for all the hair removal lasers available today. Melanin occurs naturally in the skin and it is this pigment that provides colour to skin and hair. In hair, there are basically two types of melanin including eumelanin that is responsible for brown or black colour and pheomelanin that provides hair blonde or red colour. Due to the selective absorption of photons of laser light, it is possible to remove only black or brown hair. Laser hair removal functions best with dark coarse hair. The best results of the laser are observed with light skin and dark hair. There are also new lasers in the market that target dark black hair in person with dark skin.

Laser hair removal has become widely famous as it is fast and offers good efficacy. The efficacy of the treatment is also depends on the skill and experience of the laser operator. The choice and availability of different laser technology also determine the efficacy of treatment. Some treatment might require touch-up treatments on large areas after 3-8 sessions. Overall, it is one of the best treatment options for hair removal.