Dehydroascorbic acid and polymeric/monomeric derivatives and isomers thereof are useful for artificially coloring the skin and more particularly as a skin self-tanning agent; the dehydroascorbic acid may be formed “in situ” from ascorbic acid or a derivative or salt thereof via chemical oxidation and/or via enzymatic oxidation, and a two-component agent thereof includes a) a first component (B) containing, in a physiologically acceptable medium, at least ascorbic acid or a derivative or salt thereof; b) a second component (C) containing, in a physiologically acceptable medium, at least one chemical oxidizing agent and/or one enzymatic oxidizing agent; components (B) and (C) being stored separately.