Ketoses

class=skin-invert-image|thumb|right|250px|Fructose, an example of a ketose. The ketone group is the double-bonded oxygen.

D-Erythrulose (also known as erythrulose) is a tetrose carbohydrate with the chemical formula C4H8O4. It has one ketone group and so is part of the ketose family. It is used in some self-tanning cosmetics, in general, combined with dihydroxyacetone (DHA).