From Dr. Mercola:
One you reach the age of 30, you have a 10 percent to 20 percent chance of graying hair with each passing decade.1 It’s a fact of life that, eventually, virtually everyone will go gray.
Your hair color comes from pigment called melanin. Each hair may contain dark melanin (eumelanin) and light melanin (pheomelanin), which blend together to form the many shades of hair color among humans.
When you’re young, special pigment stem cells called melanocytes inject pigment into keratin-containing cells.
This keratin, a protein, makes up your hair and is responsible for giving it its color. As you age, melanin is reduced, which is why your hair turns gray and, ultimately, white (this means there’s no melanin left).2
Scientists Discover Gene Linked to Graying Hair
What exactly causes melanin to be reduced and hair to turn gray has remained a mystery, until now. An international team of researchers has discovered the first gene linked to gray hair.
The study involved a genome-wide association scan in more than 6,000 Latin Americans to look for genes related to features of scalp hair and facial hair, including graying, balding, beard thickness, monobrow, eyebrow thickness and more).3
A gene that has previously been linked to blonde hair in Europeans turned out to be connected to gray hair as well and accounted for about 30 percent of hair graying among the study participants.
The other 70 percent is likely due to factors such as age, environment, stress and more. The researchers plan to look for ways to manipulate this genetic pathway to prevent hair from turning gray (including drugs, which I would not recommend taking for the purpose of changing your hair color).
Kaustubh Adhikari, Ph.D, a postdoctoral researcher at University College London, told TIME:4
“We might have drugs that boost or stop the protein from acting and change the amount of melanin in hair follicles and change the hair internally So once the hair comes out like the way you want, you don’t have [to] go out and buy dyes.”
Does Your Hair Have Its Own ‘Biological Clock?’
According to Desmond Tobin, Ph.D., professor of Cell Biology from the University of Bradford in England, your hair follicles may be regulated by a “melanogentic clock” that eventually slows down the activity of melanocyte cells. Further, according to the Library of Congress:5
“ Tobin suggests that hair turns gray because of age and genetics, in that genes regulate the exhaustion of the pigmentary potential of each individual hair follicle.
This occurs at different rates in different hair follicles. For some people it occurs rapidly, while in others it occurs slowly over several decades.”
It’s known, for instance, that white people may start going gray in their mid-30s, while Asians typically go gray beginning in their late 30s. African Americans typically don’t go gray until their mid-40s.6
What Else Causes Gray Hair?
Other factors for why hair turns gray include:
Hydrogen peroxide: Hydrogen peroxide is a