Dihydroxyacetone (DHA) is a simple carbohydrate that is primarily used as an ingredient in sunless tanning products. It is often derived from plant sources such as sugar beets and sugar cane.
When applied to skin, a chemical reaction occurs between amino acids and the outermost skin layer to produce a brown color, or tan appearance. It is approved by the US Food and Drug Administration (FDA) for sunless tanning.