Ever wonder why hair begins to go gray with old age? Well there are a few different theories to why it happens, but how it happens can be explained more thoroughly with some basic biology.
The Process of Hair Pigmentation
Process of Hair Pigmentation
Like our skin, hair get’s its natural pigment from the formation of melanin. Melanin consists of cells known at melanocytes that position themselves at the openings of hair follicles on the skin’s surface in order to inject themselves into the keratin that our hair is composed of. Now hair has two types of melanin pigments, a darker brownish pigment known as eumelanin and phaeomelanin, a lighter yellow pigment. The combination of these two results in the wide array of hair colors.
Throughout the growth of your hair melanocytes continue to pass pigment to keratinocytes, the primary protein substance in hair and nails. The combination and continual injection of melanocytes leads to different pigments in hair.
So, Why does it Gray?
Pigment production is a complex process and varies depending on genetic factors, one being the Mc1R gene. The gene is known to have some control associated with the red pigment in human hair and a few other species. So now what does that have to do with gray hair?
Many families studied have had members with graying hair at early ages, some even as early as their 20’s, clearly proving that genetics plays an important role in determining your hair’s health. Researchers believe that ethnicity and stress can also be key factors in the production of melonacytes. Stress harmones may impact the activity and growth of melanocytes, however, a clear link has not yet been found between stress and graying hair.
“Graying could be a result of chronic free radical damage,” says Ralf Paus, professor of dermatology at the University Hospital Schleswig-Holstein in Lübeck, Germany. Stress hormones produced either systemically or …could produce inflammation that drives the production of free radicals—unstable molecules that damage cells—and “it is possible that these free radicals could influence melanin production or induce bleaching of melanin,” Paus says. “There is evidence that local expression of stress hormones mediate the signals instructing melanocytes to deliver melanin to keratinocytes,” notes Jennifer Lin, a dermatologist who conducts molecular biology research at the Dana-Farber / Harvard Cancer Center in Boston.
Another research group suggests that the graying of hair occurs due to a chemical chain reaction caused by a drop in the levels of catalase. Less catalase means that the hydrogen peroxide in our hair cannot be broken down leading to an eventual build up that bleachers our hair from inside out. The study hopes to aid in the development of new “anti-graying” products.
Hopefully that answers some of your questions, but a ‘true’ link to the graying of hair has not been clearly defined yet.
Great stuff…