Does underarm hair removal affect perspiration? Laser hair removal is based on the principle of selective photothermolysis. The wavelength chosen acts only on melanin and not on sweat gland tissue, so it does not cause damage to sweat glands. Why does laser hair removal work? The pulse width selected for laser hair removal will act on the melanin in the hair follicle and destroy the hair follicle to achieve hair removal. Can lasers remove hair permanently? The concept of permanent hair removal is actually translated from Permanent Hair Removal, which may be more scientifically translated as long-lasting hair removal. The current international standard is that a hair removal treatment is considered Permanent Hair Removal if there is no visible hair growth for a significant period of time (e.g. 1-2 years) after the treatment is completed. How many times does laser hair removal take? The effectiveness of laser hair removal treatment is determined by the number of treatments, the time between treatments, the energy used during treatment, and the individual differences in the body. Generally speaking, the more the number of treatments, the more likely it is that permanent hair removal will be achieved; if the number of treatments is too few, the results will be temporary.