Alkylamino-mercaptoalkylamides have the formula ##STR1## wherein A represents the divalent radical --(CH.sub.2).sub.n --, wherein n is a whole number ranging from 2 to 5, or the divalent radical --(CH.sub.2).sub.2 --O--(CH.sub.2).sub.2 --,m is 0, 1 or 2,R.sub.1 represents hydrogen or linear or branched lower alkyl having 1-5 carbon atoms,R.sub.2 and R.sub.3, each independently, represent hydrogen or a linear or branched lower alkyl having 1-4 carbon atoms with the proviso that R.sub.2 and R.sub.3 are not hydrogen simultaneously and the salts of the compound of formula I as well as the corresponding disulfides with the exclusion of the disulfide in which A=--(CH.sub.2).sub.2 --, m=0, R.sub.1 and R.sub.2 =H and R.sub.3 =--C.sub.2 H.sub.5. The compound of formula I is used as a reducing agent in a cosmetic composition for the permanent deformation of hair.