The essence of the laser's action on the hair follicle is the phenomenon of selective photothermolysis. Laser light is selectively absorbed by the melanin-containing structures of the hair follicle and is converted into heat, which in turn destroys the elements of the hair responsible for its growth, thus causing permanent hair loss and follicle destruction. As research has shown, this phenomenon works most effectively on hair in the active growth phase (anagen). The other growth periods of our hair - the atrophic (catagen) and resting (telogen) phases - are "silent" to the laser.