The interactions between skin and light
Light as in Sun is partially reflected by the skin. This means that the original energy contained in the beam of light is partially lost, which therefore causes the surface of the skin to heat up. The amount of light reflected varies depending on the angle at which the inital light beam arrived on the skin and on the distance it travelled through the air beforehand. At Hairfree we use a ultrasound or cooling gel to avoid any possibility of surface burns. The cooling gel works as a conductive agent to assist the light on its journey towards the hair follicle. The light from the IPL is looking for the melanin in the hair follicle, this orginates deep in the dermis approximately 6 or 7mm from the surface.
Body hair grows according to a well-defined cycle. This cycle has been divided into three phases.
- The first phase is called the anagen, or the growth phase. During this phase the hair grows until it reaches the surface of the skin. The hair will then continue to lengthen. The duration of this phase is variable depending on the ethnic origin of the individual, the persons lifestyle and surrounding environment as well as where the hair is found on the body.
- The second phase is called the catagen phase, during which the hair stops growing, this phase is very short. It lasts one to two weeks. During this phase the bulbous part at the bottom of the hair comes away from the hair follicle. The hair is therefore progressively shed from its sheath.
- The final phase is called the telogen phase. During this phase the hair follicle is at rest and dead hair starts to fall out. Hair loss is often finalized when a new hair starts to grow underneath, as the the next anagen phase begins.
It is due to the cyclical nature of hair growth that multiple sessions are always required.