Humans are hairy! On average there are 300-500 hair follicles per square inch of skin on the body. Fortunately, not all of your hairs are active. With laser, you’ll need multiple sessions to get the most effective results as the hairs need to be in active hair growth phase (anagen phase) to be targeted, which varies hair to hair. Since not all of your hairs will be in the anagen phase at the same time (even if you see an actual hair) it is important to receive multiple treatments for the same area.