The present invention relates to a cosmetic or pharmaceutical, and in particular dermatological, composition comprising, in a physiologically suitable medium, peptides derived from the trans-prenyl transferase enzyme, as active agent, alone or in combination with at least one other active agent. The invention also relates to the use of a composition capable of protecting the skin against oxidative damage and of preventing or treating the signs of skin ageing. The invention also relates to a cosmetic treatment process for protecting the skin and the appendages against external attacks and for combating skin ageing.
