How does laser hair removal work?

A short burst of light is fired at the skin's surface. If the hair is in the growth stage (anagen), the heat is transmitted down the hair shaft to the base of the follicle and to the germ cells lining the follicle shaft, causing their destruction. 

Hair caught in the growth stage will not grow again. Other follicles, which are not actively growing may produce new hair. These follicles will need to be targeted in the growth stage to effect follicle damage.