by liz, founderEvery self tan on the market — mousse, drops, gradual lotion — is built on the same active ingredient: dihydroxyacetone, universally shortened to DHA. It is a simple sugar, and the way it works is genuinely elegant.
the browning reaction
When DHA meets the amino acids in the outermost layer of your skin, it reacts to form brown pigments called melanoidins. Chemists know the reaction family well — it is closely related to the Maillard reaction, the same chemistry that browns toast and sears steak. On skin, it happens gently over one to eight hours at body temperature, which is why every self tan has a development window.
what it is not
DHA tanning has nothing to do with UV, melanin or your skin's own tanning response. The colour sits in the dead outer layer of skin only — which is why it exfoliates away over about a week, and why prep (an even outer layer) matters so much to the finish.
why undertone differs between brands
The green-brown base in our formulas counteracts the warm-orange direction the raw reaction can drift toward — that is the difference between a tan that reads bronzed and one that reads, well, orange. Development time matters too: rushing a rinse mid-reaction is how patchy, brassy results happen.
quick answers
Is DHA the same as a UV tan?+
No. DHA creates colour through a surface chemical reaction with amino acids in dead skin cells. It doesn't involve UV exposure or melanin at all.
Why does self tan have a development time?+
The DHA reaction takes hours to complete at skin temperature. Rinsing is fine once the guide colour has done its job, but the colour keeps deepening for several hours afterwards.
