By properly adjusting laser wave length and pulse width, the laser can penetrate the top layer of skin and then reach the hair follicle. Then the light energy will be adsorbed and converted into thermal energy which can destroy the hair follicle. Thus the laser will make the hair lose its ability to regenerate while not destroying surrounding tissue. After the client receives the treatment, the hair grows less and less, grows slower, grows thinner, and the hair color becomes lighter and lighter. The growth of hair is stable after 6 months–no longer grows at 9 and 12 months, 90% of patients get permanent hair removal, and the regenerated hair becomes thinner in diameter, lighter in color and natural.