Abstract: The hair shaping composition for permanent shaping of hair contains a cysteine ester of the formula (I):HS--CH.sub.2 --CH(NH.sub.2)--COO--CH.sub.2 --CH.sub.2 --R (I)as a keratin-reducing material, wherein R is a hydroxy group, alkoxy groups, a poly(alkoxy) group or a hydroxypoly(alkoxy) group, or one of its acid additional salts. Cysteine ester compounds and their methods of preparation are also described. Preferred embodiments of the hair shaping composition have a pH of from 4.5 to 9.0 and contain from 4 to 30% by weight of the cysteine ester or its acid addition salt and provide a safe and uniform shaping of hair without allergic or sensitizing reactions.