research Polyphenolization:Hair Browning by Phenolic Adhesion,Ambient Oxygen, and Transition Metals
This study found that a synthetic polyphenol, dimeric 1,2,4-benzenetriol (diBTO), can coat gray hair and gradually oxidize, creating a resistant brown layer similar to apple browning, which offers a practical hair dyeing solution that withstands washing and reduces the need for long dyeing sessions.
