Chromelin Complexion Blender is a non-toxic stain thatdyes the skin to darken light or unpigmented areas of skin affected by vitiligo, scars and other causes. Chromelin contains dihydroxyacetone (DHA). The exact mechanism of DHA is not known, however researchers believe it reacts with a component in the outermost layer of skin to produce a brownish coloration. It is a safe, FDA approved ingredient that has been used to dye skin for over 30 years. The color produced by Chromelin is WATERPROOF. The covering cosmetics tend to rub off on clothing or anything coming in contact with covered areas. People often use Chromelin on their hands and other areas where they need waterproof color that will not rub off. Even when Chromelin is not a perfect match, most people prefer some color to the stark, conspicuous white color of skin lacking pigment. Great alternative to Dy-O-Derm Vitiligo Stain!