Carboxymethylcysteine and pharmaceutically acceptable salts thereof improve the appearance and the structure of skin affected by stretch marks due to either pregnancy, weight training, weight gain or adolescent growth. Carboxymethylcysteine is preferably formulated in an appropriate topical composition and may be applied directly on the stretch marks； the composition may have a content in carboxymethylcysteine or a pharmaceutically acceptable salt from 0.1 to 25 % by weight.
