Shaving simply cuts the hair shaft up to the skin surface. The hair shaft and the cells producing the hair are intact & doing their job. Waxing pulls hair out from its root, however, the surrounding cells in the hair follicle keep working, and a new hair will peek out in a couple of weeks. Laser light is converted to heat energy, and permanently destroys the cells responsible for producing the hair, but not damage to the top of the skin or any other tissues.