dihydroxyacetone

Dihydroxyacetone (DHA) is a simple ketotriose with chemical formula C3H6O3 and IUPAC name 1,3-dihydroxy-2-propanone. Its structure is HO-CH2-CO-CH2-OH. It is the simplest member of the ketotriose family. In water, DHA exists in equilibrium with glyceraldehyde due to keto–enol tautomerism.

DHA occurs in trace amounts in nature but is produced commercially for cosmetic use. Industrially it is obtained by oxidation of glycerol or via fermentation-based processes, followed by purification.

The principal use of DHA is as the active ingredient in sunless tanning products. When applied topically, DHA reacts with amino groups in skin proteins and sugars to form brown pigments (Maillard-type reaction). Color development begins within hours and can last several days. DHA is not a sunscreen.

Safety and regulation: Regulatory agencies generally consider DHA safe for external cosmetic use when used as directed. Adverse effects are uncommon but may include local irritation or allergic reactions. Inhalation of DHA powders or aerosols can irritate the respiratory tract; avoid contact with eyes and mucous membranes, and do not apply to broken skin.

Chemistry notes: DHA is highly water-soluble and is hygroscopic. In solution, it can slowly interconvert with glyceraldehyde. It is a relatively stable but reactive compound that participates in Maillard-type browning reactions upon contact with skin proteins.