Abstract: A composition for permanent hair shaping comprising: (i) About 0.5% by weight to about 35% by weight of a N-alkyl-2-mercaptoacetamide of formula wherein R1 is a straight chain alkyl residue with about 3 to about 6 carbon atoms or a straight chain hydroxyalkyl with about 3 to about 6 carbon atoms, R2 and R3 are hydrogen or straight chain alkyl residues with about 1 to about 3 carbon atoms, or the salt thereof, (ii) about 0.1% by weight to about 15% by weight of at least one cationic polymer; and (iii) about 5% by weight to about 95% by weight of water; and a method of permanently shaping hair using said composition.