PTF ( Photo Therapy Flash ) are often referred to as photo rejuvenation. It is a non-invasive, completely safe procedure,effective for both males and females. PTF can use photothermolysis to remove unwanted hair. This procedure works on the growing hairs and not an dormant hairs. Therapy flash works by emitting targeted pulses of energy into the hair follicles, to remove it at the root. The procedure is virtually pain-free (with just a tingling/tenderness sensation) and completely safe, the surrounding tissue and skin is not affected and thanks to the cooling optical crystal head of the system. Complete destruction of all hair follicles from any one treatment is unlikely, and will require several treatments to obtain a significant,long-term reduction of hair growth. This can vary from one person to the next.