Pre-treatment composition for protecting hair during oxidative coloring

Abstract

The present disclosure provides a pre-treatment composition for protecting hair during oxidative coloring. The composition comprises a transglutaminase enzyme, a thiol donor selected from N-acetyl cysteine ethyl ester (NAC-EE), DL-homocysteine thiolactone (HCTL), and/or (R)-2-oxothiazolidine-4-carboxylic acid (OTC); and a cosmetically acceptable carrier. The pre-treatment composition may further include one or more of a penetration enhancer and a conditioning agent. Upon application to hair before oxidative coloring, the transglutaminase enzyme catalyzes the formation of internal isopeptide bonds within keratin fibers, reinforcing hair structure. During the oxidative coloring process, the thiol donor releases thiol groups under alkaline conditions to repair disulfide bonds in real time, thereby minimizing chemical damage. A method for protecting hair is also disclosed, comprising applying the pre-treatment composition to hair, leaving it in place, and subsequently subjecting the hair to oxidative coloring without rinsing off the composition.

Dependencies are inferred from the claim text.