Hydrogen peroxide in hair
Hydrogen peroxide inhibits pigment synthesis
Hydrogen peroxide (also known as "H2O2") is a well known bleaching agent and disinfectant. It is a household item for many people.
Hydrogen peroxide is also found in hair - and in fact accumulates in white and gray hair. It inhibits the synthesis of pigment known as melanin.
Reference
Schallreuter KU, et al. The redox--biochemistry of human hair pigmentation. Pigment Cell Melanoma Res. 2011
This article was written by Dr. Jeff Donovan, a Canadian and US board certified dermatologist specializing exclusively in hair loss.