Once the hair root is destroyed, it can no longer produce and grow hair. Thus, you benefit permanently from the treatment.  However, we cannot guarantee 100% removal of all hair in the treated area. For one thing, the laser can only treat the hair or hair follicles that you have today and not the hair that may grow later. And on the other hand, there may still be hair roots in the skin area that have not formed any hair at the time of the treatment, but will form a hair later.