A method and composition for permanent hair shaping with time-dependent reduction of the waving performance

Process for the permanent shaping of hair, in which is added with a content of a keratin-reducing active ingredient and an initial pH of 7.5 to 10 an alkali-hydrolysable compound immediately before use an alkaline permanent shaping agent, the hair before and / or after holds it in the desired shape, treated with the ready to use agent, rinsed after the contact time the hair with water, oxidatively after-treated, rinsed again with water, optionally arranged in a water wave, and then dried, characterized in that the alkaline-hydrolysable compound is chosen that the initial pH without the addition of a esterspaltenden enzyme is lowered within 5 to 30 minutes by at least 0.5 units, and the alkaline-hydrolysable compound is chosen from the groups: Lactone of aldonic acid or uronic acid, Acylsalicylsaure having 1 to 5 carbon atoms in the acyl group, dialkyl esters of oxalic acid each having 1 to 4 carbon atoms in the alkyl group, and polymeric anhydride.