How Does a Self-Tanner Work? Ask Typology

In a self-tanner, DHA or dihydroxyacetone, which are very often combined with erythrulose, are the ingredients responsible for artificially coloring the skin.

These molecules belong to the family of sugars (oses) and produce the desired effect through the non-enzymatic tanning phenomenon known as the Maillard reaction. When these tanning agents are applied to the skin, they react with the amine functions of amino acids in the dead cells of the stratum corneum (corneocytes) to form pigments called melanoidins or brown chromophores.

The twenty amino acids react differently to DHA, producing different shades of color from yellow to brown. Lysine, glycine, and histidine have also been shown to react very rapidly with DHA. The resulting coloration is similar to that of melanin, the natural substance found in the deeper layers of the skin. Nevertheless, the mechanism of this artificial tanning is entirely different from natural tanning, which is based on increased melanin production as a result of UV radiation.

Thus, the effect of artificial tanning of the skin by using a self-tanning care results from this reaction on the surface. This takes place only in the stratum corneum and, unlike the UV rays of the sun, does not pose any danger to the skin or health in general.

Fun Fact: This reaction is similar to cooking, such as when a chicken is roasted in the oven and turns brown.

Pigmentation of the skin occurs within 2 to 6 hours after applying the self-tanner. However, this color gradually fades and completely disappears within 5 to 7 days. This is due to the frequent renewal of the horny layer (natural desquamation process).

It is very important to remember that self-tanner does not protect from the effects of the sun's UV rays, especially if it does not contain sunscreen filters. The fact that you have a sun-tanned complexion after using a self-tanner does not equate to sun protection. For this reason, it is essential to apply broad-spectrum sunscreen when sunbathing.

Self-tanning products may also contain other ingredients, such as antioxidants (vitamin E, etc.) that protect the skin from free radicals responsible for skin aging and cellular damage, or tan-promoting molecules that stimulate the skin's natural melanin production, such as carob extract, Buriti oil, etc., to ensure even distribution and a more natural tan.

Dihydroxyacetone (DHA) is a carbohydrate monomer with the molecular formula C3H6O3. This molecule can be of synthetic or plant origin. Naturally occurring dihydroxyacetone is usually obtained through a biotechnological process in which glycerol from plants such as canola, corn or beets is fermented and transformed by bacteria.

DHA is now the most important active ingredient in self-tanning products. In the 1960s, however, this compound was not popular because it left an unnatural orange tint and streaky lines on the skin. It wasn't until the 1980s that it became popular, since when combined with Erythrulose, it produced a much more even and naturally tanned complexion. Erythrulose is also a biotechnologically produced compound. This natural sugar is found in the cells of plants such as raspberries and beets.

The combination of these two compounds therefore promotes a natural tan. In addition, erythrulose has moisturizing properties that counteract the drying effect of DHA.

Note: Although these two molecules act on skin cells in the same way, they do not react at the same rate. For example, DHA tones the skin very quickly, while erythrulose acts slowly and gradually. This balance between the reaction times of the two compounds is also what promotes a natural tan.