Graying of hair has recently been shown to be caused by massive accumulation of hydrogen peroxide. Such huge accumulation of hydrogen peroxide builds up overtime from tiny amounts produced due to wear and tear of the hair follicles. The free oxygen radicals liberated from this chemical, gradually block the production of melanin.
It may be of interest to know that production of hydrogen peroxide is a normal process, but the tiny amounts which are produced are broken down by an enzyme known as catalase. The researchers made this discovery by examining cell cultures of human hair follicles. It is the deficiency of this catalase which lies at the root of this accumulation.
Source:- http://www.antivitiligo.com/vitiligo/research/why-turn-white.html
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