“The voice of the intellect is a soft one, but it does not rest until it has gained a hearing.” Sigmund Freud

A beautiful, healthy tan. A nice dark Victoria Secret-like tan requires no sun at all anymore but a can of spray tan. There are various different ingredients serving as tanning agents but there is one that finds its way on most products’ INCI labels: DHA or Dihydroxyacetone, a simple, non-toxic three-carbon ‘sugar’. So how does it work on the skin? The very basic principles are the same as a cut apple staying a little too long in the air. Amino acids interact with sugars to create brown or golden brown compounds, we call this kind of reaction Maillard reaction. Currently it is defined as the reaction of the amino group of amino acids, peptides, or proteins with the glycosidic hydroxyl group of sugars, forming brown products referred to as melanoidins. And there we have the dark tint on our skin. There is only one common ‘skepticism’ that i hear so often: “But doesn’t it turn your skin orange?” Yes and no, and that is where we have to be a little smart.

Only the monomeric form of DHA undergoes the Maillard reaction that leads to tanning and biproducts like Glyceraldehyde (an orange light oily six-membered H-bonded conformation of DHA) and the other dimeric forms of DHA want to be avoided. So there are a few tricks that can ensure your tan develops its best: Don’t use your product in combination with very alkaline or let’s say ‘soapy’ products, DHA requires a slightly acidy surrounding to develop its best and your skin -not fresh from the shower- is a great base for it, so put at least 4 hours before and 4 hours after your application of the self tanner and a shower and happily use the skins own buffer to achieve the optimal pH of 5-6. Another tip: Don’t carry your self tanner or DHA product in your beach bag that might get hot in the sun and store it in a cool, dark place. DHA is not stable over 40°C, temperature-dependent spectra have indicated that increasing the temerpature favored the formation of glyceraldehyde (see here). One last thing you: never forget your SPF. There are studies that have shown that DHA-treated is especially sensitive for a day after self-tanner application and excessive sun exposure should be avoided and sunscreen should be worn outdoors. An antioxidant cream could also minimize free radical production. Another study though showed a 3% DHA solution overnight provides SPF of at least 3 in the UVB region and SPF of 10 in UVA region on skin treated with a 15% solution of DHA (read more here). But most of self tanners only have 3-5% DHA formulations, so it isn’t a compeating fact to the sun-sensitivity. Save your skin, Ea Birkkam.

today: the white bikini and colourful hues