Number of sessions

Multiple treatments depending on the type of hair and skin color have been shown to provide long-term reduction of hair. Most patients need a minimum of seven treatments. Current parameters differ from device to device but manufacturers and clinicians generally recommend waiting from three to eight weeks depending on the area being treated. The number of sessions depends on various parameters, including the area of the body treated, skin color, coarseness of hair, reason for hirsutism, and gender. Coarse dark hair on light skin is easiest to treat. Hair on darker skin is harder to treat. Certain areas (notably men's faces) may require considerably more treatments to achieve desired results. The main reason multiple sessions are needed is that hair grows in several phases (anagen, telogen, catagen) and a laser can only affect the currently active growing hair follicles (anagen), so several sessions are needed to kill hair in all phases of growth. This problem is countered by spacing appointments sufficiently so that inactive follicles will start to grow again. Laser does not work well on light-colored hair, red hair, grey hair, white hair, as well as fine hair of any color, such as vellus. For darker skin patients with black hair, the long-pulsed Nd:YAG laser with a cooling tip can be safe and effective when used by an experienced practitioner.