The present invention is directed to methods and formulations of treating keratin fibers, in order to provide long lasting curl reduction and styling results for keratin fibers from a single application. The present invention may include forming sufficient active sites on the keratin fibers followed with fixation and/or cross-linking of active compounds via covalent and strong ionic bond formation to the active sites on the keratin fibers. The active sites may be produced by breaking a sufficient number of disulfide bonds in the keratin fibers by using one or more reducing agents. The active compounds may then be fixed and/or cross-linked to the active sites. The fixation and/or cross-linking reactions of the active compounds onto the keratin fibers is facilitated by allowing the formulations containing the active compounds to react on the keratin fibers at ambient conditions for a sufficient time, followed with heating the keratin fibers to approximately 400° F.
