Laser hair removal works by having light energy absorbed by the melanin (pigment) in the hair follicle, where it is converted into heat. This selectively targets the hair follicle, causing the hair to fall out and reducing future growth. Since the treatment reacts to pigment, it is less effective on light-colored hair and works best on dark hair; however, caution is required for people with darker skin tones, as there is a risk of depigmentation spots caused by damage to pigment cells. Since hair grows in cycles and not all hair follicles can be treated at once, the procedure is typically repeated 3 to 6 times or more at intervals of 3 to 8 weeks. It is reported that the skin remains smooth for approximately 6 to 8 weeks after treatment. Temporary redness, swelling, and itching are common; in rare cases, bruising, pigmentation changes (hyperpigmentation or hypopigmentation), blisters, or infection may occur. The number of sessions required and the treatment response vary depending on skin and hair color, the treatment area, and hormonal factors, so a consultation is necessary to determine the appropriate course of action. This information is for informational purposes only and does not constitute a diagnosis. Please consult a specialist before undergoing the actual procedure.
[Source] https://dermnetnz.org/topics/alexandrite-laser-treatment