During laser hair removal, a laser emits a light absorbed by the pigment (melanin) in the hair. The light energy is converted to heat, which damages the tube-shaped sacs within the skin (hair follicles) that produce hairs. This damage inhibits or delays future hair growth. Although laser hair removal effectively slows hair growth for long periods, it usually doesn’t result in permanent hair removal. Multiple laser hair removal treatments are needed for initial hair removal, and maintenance treatments might also be required. Laser hair removal is most effective for light skin and dark hair, but it can be successfully used on all skin types. Hair color and skin type influence the success of laser hair removal. The basic principle is that the pigment of the hair, but not the skin’s pigment, should absorb the light. The laser should damage only the hair follicle while avoiding damage to the skin. Therefore, a contrast between hair and skin color — dark hair and light skin — results in the best outcomes.
Laser hair removal usually requires two to six treatments. The interval between treatments will vary depending on the location. The treatment might be repeated in four to eight weeks on areas where hair proliferates, such as the upper lip. In areas of slow hair growth, such as the back, the treatment might be every 12 to 16 weeks. Hairs do not fall out immediately, but you will shed them over days to weeks. This may look like continued hair growth. The repeated treatments are usually necessary because hair growth and a loss naturally occur in a cycle, and laser treatment works best with hair follicles in the new-growth stage. Results vary significantly and are difficult to predict. Most people experience hair removal that lasts several months, and it might last for years. But laser hair removal doesn’t guarantee permanent hair removal. When hair regrows, it’s usually finer and lighter in color.