Choosing the right target

Laser light, just like sunlight, penetrates into the skin up to several millimetres and turns into heat once it is absorbed by tissue pigments.

The trick consists in choosing the appropriate target, that is the target which will absorb the more light. The best target ever found is the melanin, present in the hair and in the bulb. It absorbs the laser hair removal light and turns it into heat, which leads to the irreversible necrosis of the deep structures of the hair.

Main rule in laser hair removal: use the appropriate device

Threes types of lasers are used to obtain permanent hair removal: the Ruby lasers (this gemstone produces a dark red laser light at a wavelength of 694 nanometers), the Alexandrite lasers (this semi-precious stone produces a very dark red laser light at a wavelength of 755 nanometers), and the laser diodes (semiconductors producing 790 to 810 nanometers infrared lights).

The whole treatment depends on the choice of the target and of the wavelength: all hair removal lasers target melanin. The figure opposite gives a relative idea of the absorption according to different types of lasers. (Source: Boulnois JL, photophysical processes in recent medical laser development. Published in Lasers in Medical Science Vol. I, 1986).