The number of treatments required for long-term benefits varies on the area being treated, along with your hair density, depth of color and the hair's natural growth cycle. Age, diet, medications, and hormones can also be important factors in how the laser works on hair.
There are three phases of hair growth — Anagen (active), Catagen (regression) and Telogen (resting). Lasers are designed to treat hair in the first phase, the Anagen phase of growth.
Each client is unique however, it is recommended that you do an average of 6-8 treatments spaced every 3-4 weeks apart.