A handset is used to deliver microwave radiation into the skin. The idea being that the microwaves causes heat in the hair follicle, killing it, and giving rise to permanent hair removal. As this process doesn't target melanin, it can be used on all hair colours.
The disadvantages of this system are many, and even though it has been approved by use by the FDA, there are few studies done on long term effects. The microwave handset delivers radio frequencies, of a certain wavelength. This wavelength has been used for years in microwave ovens, to provide piping hot food at the touch of a button. The microwaves work by agitating the molecules in water, sugars and fats. The agitation causes the molecules to move faster, hence increasing the heat of the object.
When used on the skin, these microwaves target not just the hair follicle, but all the water, sugar, and fat in the skin. In order to raise the temperature of the hair follicle to a point that it will be damaged, the temperature in the rest of the skin cells have to be raised. This may cause extensive damage to the skins tissues at the least, and maybe even more serious damage long term. This non-selectivity has caused the system to be banned from use on the face. Caution is definitely advised before using this method.
