Methods of permanent shaping and volumizing hair that are gentle and prevent overcurling are described. In one method using curlers to curl the hair, an alkaline permanent shaping composition having a pH of 7.6 to 11 and including a hair keratin-reducing substance is applied to the hair and allowed to act on the hair for 5 to 30 minutes at room temperature or for 2 to 20 minutes at an elevated temperature. Then the hair is optionally rinsed with water and subsequently with an acidic aqueous intermediate rinse, which has a pH of 2 to 6.5 and includes an aliphatic organic acid. Next the hair is wound onto curlers, after which the hair is allowed to rest for 30 minutes at room temperature or 20 minutes at an elevated temperature. After the resting period the hair is treated with an oxidant-based fixative, which can be a solution of hydrogen peroxide, and the curlers are removed. The hair is subsequently rinsed with water or washed with a shampoo to remove the fixative and combed into a hair style. For methods of uncurling hair the method is similar, but the step of winding on curlers is replaced by a step of combing the hair out and the acidic aqueous intermediate treating agent is in the form of a gel, cream or paste.
A two step method to increase the thickness of human hair in which in Step I, a high pH priming lotion is applied to pre-treat the hair to increase its pH, create an anionic charge and therefore loosen and lift the cuticle layers of the hair. In Step II, an acidic thickening composition is applied on top of the Step I composition to deliver polymers and conditioning ingredients to the hair's polypeptide molecule sites. The Step II components have cationic sites that chemically bond to anionic groups in the hair, making them substantive to the hair wherein they deposit under and around the crevices of the cuticles. The low pH of Step II tightly closes the cuticles, sealing the substantive ingredients to the surface of the hair, providing the hair with increased diameter and long lasting thickness.
