An improved process and composition for straightening or waving hair is achieved combining ammonium bisulfite and ethanolamine sulfite in a single mixture which is maintained at a pH of between about 6.5 and 8.0. By employing the present invention, long lasting, waved or straightened hair is attained. Furthermore, using the hair waving/straightening composition and method of the present invention, the desired waving and/or straightening of hair fiber is achieved in a single step, without the need for a separate application of an oxidizing or neutralizing agent.

A leave-on oxidizing solution useful for permanent waving of hair containing water, an oxidant which is capable of being left on the hair and dried on the hair without damage to the hair, and an acidic agent to provide the solution with a pH value of less than about 7. The use of the leave-on oxidizing solution decreases the amount of time required for carrying out a permanent waving of hair process.

Compositions, optionally heat-activated, methods and kits for lanthionizing keratinous fibers to achieve relaxation of the keratinous fibers comprising applying to keratinous fibers a composition comprising at least one hydroxide compound and at least one oxidizing agent.

Compositions, optionally heat-activated, methods and kits for lanthionizing keratinous fibers to achieve relaxation of said keratinous fibers comprising applying to keratinous fibers a composition comprising at least one hydroxide compound and at least one reducing agent chosen from thiols, sulfites, and derivatives thereof, and heating the keratinous fibers.

A composition for lanthionizing keratin fibers comprising at least one hydroxide compound, with the proviso that said at least one hydroxide compound is not sodium hydroxide, lithium hydroxide or potassium hydroxide; and at least one activating agent chosen from cysteine-based compounds; and methods and kits for use thereof.