Use of a peptide containing an oxidized methionine residue to ameliorate theeffects of oxidative stress in humanskin. A short polypeptide containing an oxidized methionine at its C-terminusis shown to inhibit the production of Sunburn Cellsin living skin models and to upregulate methionine sulfoxide reductase.Cosmetically acceptable compositions and methods of usingthe polypeptide are disclosed. The oxidized peptide may repair oxidized alpha1-antitrypsin, which, in turn, inhibits breakdownof connective tissue by elastase. This effect may have wide rangingramifications, including, for example, repair of sun damagedskin and treatment of emphysema.
