A method, a kit and a first composition for treating hair are provided. The method for treating hair comprises applying to the hair a first composition comprising in a cosmetically acceptable carrier, one or more at least bi-functional carboxylic acids, or cosmetically acceptable salts thereof, or mixtures thereof, and applying to the hair a second composition comprising in a cosmetically acceptable carrier, one or more at least bi-functional carboxylic acids, or cosmetically acceptable salts thereof, or mixtures thereof, wherein the first composition has a pH from 7 to 13 and the second composition has a pH from 3 to 7.
