Anyone on a diet high in beta-carotene will need to change eating habits if they want best results. Beta-carotene, found in vitamin A, carrots, squash and other vegetables produces a yellow or orange color in the skin which absorbs the laser energy and interferes with it reaching the hair follicle. As beta-carotene can remain in the body for months, an adjustment in diet may be needed well in advance for optimum results. Persons with light skin are the easiest to treat, requiring less sessions as the results are faster. Persons with dark skin or sun tanned skin take longer to get results because melanin, the dark pigment in hair, is also present in skin.
Melanin absorbs some of the laser light.
There is the danger of dark skin being burned in these instances so a laser beam with a lower energy level is used. For this reason also a higher level of expertise is required on the part of the clinic. Here are some estimates which can give an approximate guide. At least 2 or 3 treatments are necessary, and hair that has been waxed or removed with tweezers could need from 5 to 8 treatments. Hair goes through cycles.