Monday, July 2, 2012Ingredient of the month

Dihydroxyacetone: a risk-free tanned complexion?

©Thinkstock/L'Observatoire des Cosmétiques

A beautiful tanned complexion is still associated with good health and prosperity, at least in our Western countries. However, thanks also to our way of life that keeps us indoors, winter is synonymous with pale complexion, and summer, or exposure under the tropical sun, is synonymous with dangers due to repeated exposure to the UV radiation from sun. Is self-tanning the answer? Its flagship molecule is dihydroxyacetone (DHA, as it is known). Is this "magic bullet molecule" risk-free?

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People interested in chemistry may understand that Dihydroxyacetone comes as acetone in which two hydrogen atoms have been replaced (substituted) by two hydroxyle groups; it is then a cetotriose. It is generally maunfactured by bioconversion of Glycerin , taken from corn, sugar cane, wheat, rape, beet or palm oil … This is why a "natural origin" is often referred to on labels for DHA, as it is à la mode.

Dihydroxyacetone is by far the main active ingredient in self-tanning products (often along with Erythrulose for more aesthetic results). In a cosmetics galenic form of gel or lotion, it allows for the getting, within 4 to 6 hours, of a "tanned effect", more or less deep, depending on its concentration in the product: after application, skin is gradually coloured until it seems to have a natural tan, without any exposure to sunrays.

It is also used in spray cans, especially in beauty salons, for a more uniform application and a more even aspect.

How does it do?

DHA reacts with the cutaneous keratine, or precisely with the aminoacids of the skin's proteins, by a Maillard reaction. This reaction produces brown pigments, called melanoidines, which give the skin its brown complexion.

Due to the steady and permanent renewal of the stratum corneum, this tan fades bit by bit, and disappears within 5 to 7 days, except if the self-tanning product is regularly applied.

Is it dangerous?

DHA has sometimes a bad press, is even said to be toxic, on the grounds that it modifies the structure of the skin cells. The modification of the proteins of the epidermis is suspected to be able to induce melanomes.

Wrong, some experts say. Dihydroxyacetone reacts only with the dead cells of the outer stratum corneum and is quickly cleared through the natural desquamation process, without entering the body. Further, with the passage of twenty years of use, it is possible to be firm when stating it is well tolerated.

Other experts do not concur, especially in the USA, who are concerned by the damages that DHA could induce (genetic alterations, modifications of the AND), particularly used as spray. In this case, it may be inhaled, goes more easily to the lungs, and may have a systemic effect (on the entire body, through the bloodstream). They think of a risk of cancer.

As per now, DHA has been declared as sure and adapted to use as a cosmetic ingredient by the American Food and Drug Administration (FDA); it has been recently evaluated by the European SCCS (Scientific Committee for Consumers Safety). In its opinion issued on 14 December 2010 , this Committee of experts states that using DHA, up to a rate of 10%, is safe for the human health, dispelling any carcinogen, mutagenic or toxic for the reproduction effect.
However, these two opinions apply only to DHA when applied on skin, and not for an application as spray.

Tan does not mean protection

Self-tanning safely seems possible … at least when using creams and gels to apply on skin, while avoiding breathing them …
Nevertheless, keep in mind that Dihydroxyacetone is not at all involved in the protective process of melanine producing, as does a real tanning due to sunrays. There is no protection at all against UV radiation. If exposed to sun, sunscreen is not optional!

To apply a product based containing Dihydroxyacetone and get fine results, also see
Sunless tanning: all you need to know , in Ising cosmetics the right way Section.

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