What is it that makes hair go gray in the first place and could it possibly be caused by stress? For a long time, scientists believed that melanin was the culprit behind graying hair. Each hair follicle has its own supply of individualized melanin, made up of two shades—eumelanin (dark brown or black) and pheomelanin (yellow or red) that combine in different proportions to create your specific hair color. As we age, something causes us to stop producing this melanin and the result is gray, and then eventually white hair.
More recently though, scientists have discovered that the real reason we go gray is because of an excess of hydrogen peroxide. In 2009, a study was published in the FASEB Journal (Federation of American Societies for Experimental Biology) that found that as we age, we build up hydrogen peroxide in our hair follicles because of the reduction of the enzyme catalase. You see, hydrogen peroxide is produced by our hair cells all throughout our lives. When we are younger, the enzyme catalase simply breaks the hydrogen peroxide down into water and oxygen. As we age, though, we lose some of this enzyme and the buildup of hydrogen peroxide results. In essence, this buildup of hydrogen peroxide bleaches our hair from within. The study could lead to targeted drugs or products for people who want to prevent the graying process from within as opposed to simply dying their hair.
It seems, though, that while some say that stress may move this process along a bit faster, when you go gray is generally a genetic predisposition. So instead of blaming your crazy kids for that latest crop of gray hairs, better ask your mom when she saw her first gray hairs and mentally prepare yourself.