Use of ascorbic acid derivatives of the formula I ##STR1## where the variables independently of one another have the following meanings: R.sup.1 is hydrogen, C.sub.1 -C.sub.20 -acyl, C.sub.1 -Cl.sub.2 -alkoxycarbonyl, C.sub.1 -C.sub.12 -alkyl, R.sup.2 is hydrogen, C.sub.1 -C.sub.20 -acyl, C.sub.1 -Cl.sub.2 -alkoxycarbonyl, C.sub.1 -C.sub.12 -alkyl, where R.sup.1 and R.sup.2, together with the oxygen atoms to which they are bonded and the carbon atoms bonded to the oxygen atoms, can form an unsubstituted or substituted heterocycle, R.sup.3 is hydrogen or a cation selected from the group consisting of NH.sub.4.sup.+, alkali metal and alkaline earth metal cations, R.sup.4 is C.sub.1 -C.sub.12 -alkoxycarbonyl, for cosmetic and pharmaceutical preparations is described.