Erythrulose Good Colouring Agent/Pigment Hydration Erythrulose description Substance chemically similar to the self-tanning agent dihydroxyacetone. Depending on your skin colour, there can be a difference in the colour with erythrulose. Erythrulose needs about two to three days for the skin to show a colour change, while dihydroxyacetone completely changes the colour of skin within two to six hours. For this reason, most products that contain erythrulose also contain dihydroxyacetone. Related ingredients: Dihydroxyacetone DHA