Hair follicles produce small amounts of hydrogen peroxide, a chemical that has been used for decades as an inexpensive way to lighten or bleach hair. However, if a hydrogen peroxide buildup occurs, your hair color may start to fade. As this 2013 study published in the Federation of American Societies for Experimental Biology journal reports:
In a new research report ... people who are going gray develop massive oxidative stress via accumulation of hydrogen peroxide in the hair follicle, which causes our hair to bleach itself from the inside out. Most importantly, the report shows that this massive accumulation of hydrogen peroxide can be remedied with a proprietary treatment ... described as a topical, UVB-activated compound called PC-KUS (a modified pseudocatalase). What's more, the study also shows that the same treatment works for the skin condition, vitility.