The present disclosure relates to hair care compositions such as hair restructuring compositions and composition for chemically treating hair comprising restructuring components. The disclosure also relates to methods for using the compositions to treat hair. The compositions and methods are unique because they dramatically improve the quality and durability of chemically treated hair. Typically, the compositions include at least: (a) one or more non-polymeric, mono-, di-, and/or tri-carboxylic acids； (b) one or more amines； and (c) one or more polymeric acid compounds and/or polymeric acid anhydride compounds.
