Enzymatic Method for Assessing Hair Damage with Reduction and Subsequent Oxidation

The study assessed the impact of permanent wave treatment on hair using an enzymatic method, finding negligible morphological differences between untreated and permed hair initially. However, after protease treatment, permed hair showed accelerated degradation and significant morphological differences compared to untreated hair. The extent of degradation correlated with hair damage, advancing from the surface to the inner hair fiber, and was associated with a structural change from Alpha-helix to random coil. The degradation of damaged hair with protease was closely related to the denaturation of the Alpha-helical region.