Compositions, kits, and methods for repairing bonds, for example, disulfide bonds, in hair or on the skin are disclosed. The compositions provide improved conditioning benefit for dry hair or moisturize the skin. The compositions also provide a long lasting moisturized feel and smooth feel to the skin or hair, without feeling greasy. The compositions contain one or more compounds that covalently bind at least two thiol groups in the hair or on the skin. Use of the binding compositions prevents reversion of the repaired bonds to their free thiol state, for at least one week or one month, or more, after a single application of the composition. Improved methods of styling hair, for example permanent hair waving, hair curling, hair coloring or highlighting, and hair straightening, are also provided.