When does hair get old?
There is no benchmark age for hair to turn white. Hair color is drastically affected by bodily health status, ethnic heritage, diseased conditions, hormones and stress. On average, though, white people get white hair in their mid-30s as opposed to Asians whose hair lose its pigment in the late 30s.
Black people get white hair in mid-40s generally. Any hair turning grey way earlier is termed as ‘prematurely grey’ with some background pathology in action or plainly genetics.
Why hair changes its color to white?
Hair is originally white. It gets pigment, melanin, through specialized cells called melanocytes. These cells pump this pigment into the hair follicles that gives hair a characteristic color. Melanin is of two predominant types: Eomelanin (dark pigment) and Pheomelanin (light pigment).
These combine in various proportions and produce a huge range of hair textures. The amount and combination of various melanin types are determined mainly by our genes.
Melanocytes start their secretion even before our birth and their function regresses with our age. Generally, melanocyte function decreases 10-20% every 10 years after age 30. How melanocyte function lessens with age is a mystery.
Scientists believe that our hair follicles have a ‘melanogenic clock’ that regulates hair pigmentation with age and hence, minimizes it with aging. Grey hair is a precursor of white hair, and contains less or no melanin at all due to inactive melanocytes.
Must Read:- What Type of Differences We Can Find Between White Hair and Gray Hair?
The early scientific belief
Before scientific advancement, scientists thought that hair turned grey merely due to less or no production of melanin. Each hair has a separate melanin supply in the body.
With time and age, this supply lessens, producing grey hair, which culminates in complete inability to supply the pigment to the hair, thus causing white hair permanent.
The new scientific belief
Scientists have recently discovered a breakthrough in the aging process of hair. It is now believed that hair lose their pigment not due to decreased production of melanin, but increased production of hydrogen peroxide.
With old age, hydrogen peroxide collects in the hair follicles and cannot be degraded as the enzyme catalase loses its ability to do so. Hydrogen peroxide acts as a bleaching agent and whitens hair from inside out. Hence, the main culprit is the failure of the enzyme catalase to work in old age.
What actually causes white hair in humans?