Can hair be protected from oxidative damage during and after bleaching?

The purpose of bleaching human hair is to oxidise the naturally occurring pigment, melanin, in order to lighten the hair in preparation for further colour changes. Hydrogen peroxide (H2O2) is the principal oxidizing agent commonly used in conjunction with alkaliser(s) in order to boost the speed of the oxidative reaction.

In addition to the desirable oxidation of melanin, a host of undesirable reactions take place: Cell Membrane Complex degradation, disulphide bond oxidation and peptide bond hydrolysis [1,2,3,4]. Developing bleaching systems that cause minimal undesirable alterations to the hair fibre remains an important challenge to the industry .

The aim of this study was to assess ex vivo three different materials for their capacity to mitigate some of the above undesirable effects. The investigated actives were: L-arginine, hydrolysed keratin and cystine-silanol copolymer. They were selected on the basis of their affinity to hair proteins and their stability at high pH (pH≤10.