To best understand how IPL works for hair removal, you need to understand a bit about hair growth  

The growth of hair on the human body is not as simple as it may first seem. Each hair grows from a structure in the skin called a hair follicle.

At the very bottom of the follicle is a group of germination cells from which the growth of all hair begins.  Each individual hair follicle has its own cycle of growing(ANAGEN), falling out (CATAGEN) and resting (TELOGEN). The cycle’s length varies on different parts of the body, e.g upper lip cycle is completed in around 5 months while the leg hair cycle takes 1 year ! 

There can be as many as 500 hair follicles or more, per square centimetre of skin, but only 10% (or 50) may actually be growing at any one time. For this reason you may actually have more hair in the area you wish to be treated than you ever realized, particularly if you have been plucking on a regular basis. If you pluck your hair today it will take 6 to 12 weeks for it to appear on the surface again. It is physically impossible for it to appear sooner. So you will see, that hair that you might have thought was growing back two weeks after treatment with waxing or with other methods, was in fact a hair from another follicle.

Intense pulse light ( IPL) works by using light energy to heat up the hair follicles in the skin during the growth phase and when enough heat is produced, the follicle is destroyed preventing re-growth of the hair. It is a very safe and effective process, with many people seeing between 80-90% less hair growth after a course.