The active ingredient in all spray tan solution is dihydroxyacetone (DHA), a colorless sugar that darkens the skin through staining. DHA reacts with the amino acids (keratin proteins) in the outermost layer of your skin. As these dead skin cells naturally wear off, the color gradually fades, just like a genuine sun tan. The solution I use also includes a bronzer which allows me to see where the solution has been placed and make sure that you are covered evenly. This bronzer will rinse off when you shower.