I never would have expected this from the tech gurus over at Wired , but the magazine has deciphered the ingredient list of L'Oréal Sublime Bronze  self-tanner ($7.81). It's interesting stuff, if only to see what all of those tongue-twisting chemical names really do. For instance:
Dihydroxy Acetone: The star of the show. This carbohydrate reacts with the skin's amino acids, like arginine, in what chefs call the Maillard reaction (it's what makes cooked foods turn brown). Heat this stuff to body temperature and it produces brown polymers known as melanoidins that bind to the outer layer of the skin (and no deeper).
So that's how it works. And did you know that the same silicone compound that goes into Silly Putty goes into this lotion? I'm oddly fascinated by this parsing of the label. Are you?