HIGH ABSORPTION in (Eu)melanin:
By absorption of the laser light the hair is heated and the cells in the surrounding, which are responsible for hair regrowth are damaged. (Cooling of Epidermis necessary, especially for dark skin, which also contains melanin!!)
LOWER ABSORPTION in blood and water:
The blood and the skin (which contains water) absorb only a little bit of light and are therefore not much heated. That‘s why the risk of side effects is low.