Senile Hair Graying: H2O2-Mediated Oxidative Stress Affects Human Hair Color by Blunting Methionine Sulfoxide Repair

The study demonstrated that senile hair graying was associated with the accumulation of hydrogen peroxide (H2O2) in gray/white hair shafts, leading to oxidative stress. This oxidative stress resulted in the almost complete absence of catalase and methionine sulfoxide reductase A and B proteins, impairing the repair of methionine sulfoxide (Met-S=O) in the hair follicle. The oxidation of methionine residues, including Met 374 in tyrosinase, reduced the enzyme's functionality, contributing to the loss of hair color. The research suggested that H2O2-induced oxidative damage affected the entire hair follicle, not just melanocytes, and proposed that preventing Met oxidation with L-methionine could offer new strategies for reversing hair graying.