Dihydroxyacetone (; DHA), also known as glycerone, is a simple saccharide (a triose) with formula .

DHA is primarily used as an ingredient in sunless tanning products. It is often derived from plant sources such as sugar beets and sugar cane, and by the fermentation of glycerin.

Chemistry

DHA is a hygroscopic white crystalline powder. It has a sweet cooling taste and a characteristic odor. It is the simplest of all ketoses and has no chiral center. The normal form is a dimer (2,5-bis(hydroxymethyl)-1,4-dioxane-2,5-diol). The dimer slowly dissolves in water, whereupon it converts to the monomer. These solutions are stable at pH's between 4 and 6. In more basic solution, it degrades into brown product.

:250px|Conversion of dihydroxyacetone dimer to monomer

Topical application of DHA causes a skin browning effect attributed to a Maillard reaction. DHA condenses with the amino acid residues in the protein keratin, the major component of the skin surface. When injected, no pigmentation occurs, consistent with a role for oxygen in color development. Glyceraldehyde is a structural isomer of dihydroxyacetone.

DHA can be derived from plants.

Sunless tanning

DHA is the main active ingredient in many sunless tanning skincare preparations, which may be classified as topical sunless tanner or temporary bronzers.

As opposed to bronzers containing pigment to coat the skin, DHA bronzers cause a coloration of the surface layer of the skin and do not wash off easily.

Current sunless tanners are formulated into sprays, lotions, gels, mousses, and cosmetic wipes. Her studies involved using DHA as an oral drug for assisting children with glycogen storage disease. The children received large doses of DHA by mouth, and sometimes spat or spilled the substance onto their skin. Healthcare workers noticed that the skin turned brown after a few hours of DHA exposure. Wittgenstein continued to experiment with DHA, painting liquid solutions of it onto her own skin. She was able to consistently reproduce the pigmentation effect, and noted that DHA did not appear to penetrate beyond the stratum corneum, or dead skin surface layer (the FDA eventually concluded this is not entirely true). Research then continued on DHA's skin coloring effect in relation to treatment for patients with vitiligo.

Coppertone introduced the first consumer sunless tanning lotion into the marketplace in the 1960s. This product was called "Quick Tan" or "QT". It was sold as an overnight tanning agent, and other companies followed suit with similar products. Consumers soon tired of this product due to unattractive results such as orange palms, streaking and poor coloration. Because of the QT experience, many people still associate sunless tanning with fake-looking orange tans.

In the 1970s the United States Food and Drug Administration (FDA) added DHA permanently to their list of approved cosmetic ingredients.

By the 1980s, new sunless tanning formulations appeared on the market and refinements in the DHA manufacturing process created products that produced a more natural looking color and better fading. Consumer concerns surrounding damage associated with UV tanning options (sunbathing, indoor tanning) spurred popularity of sunless tanning products as an alternative to UV tanning. Dozens of brands appeared on drugstore shelves, in numerous formulations.

Winemaking

Both acetic acid bacteria Acetobacter aceti and Gluconobacter oxydans use glycerol as a carbon source to form dihydroxyacetone. DHA is formed by ketogenesis of glycerol. It can affect the sensory quality of the wine with sweet/etherish properties. DHA can also react with proline to produce a "crust-like" aroma. Dihydroxyacetone can affect the anti-microbial activity in wine, as it has the ability to bind SO<sub>2</sub>.

References

  • How Stuff Works
  • US FDA/CFSAN – Tanning Pills
  • American Academy of Dermatology on Self Tanners
  • DHA and Vitiligo
  • New Zealand Dermatological Society recommends sunless tanners