Hair turns gray because the pigment cells stop making pigment, or color. Melanocytes are cells responsible for skin and hair color and are found everywhere in your skin and in the base of each hair follicle. In everyone, these hair-based melanocytes eventually peter out. For most people this begins around the age of thirty-five. By the time most hit age 50, 50 percent of people are 50 percent gray.
The root of every strand of hair is surrounded by a tube of tissue under the skin that is called the hair follicle. Each hair follicle contains a certain number of pigment cells. These pigment cells continuously produce a chemical called melanin that gives the growing shaft of hair its color of brown, blonde, red, and anything in between.
Melanin is the same stuff that makes our skin’s color fair or darker. It also helps determine whether a person will burn or tan in the sun. The dark or light color of someone’s hair depends on how much melanin each hair contains.
As we get older, the pigment cells in our hair follicles gradually die. When there are fewer pigment cells in a hair follicle, that strand of hair will no longer contain as much melanin and will become a more transparent color — like gray, silver, or white — as it grows. As people continue to get older, fewer pigment cells will be around to produce melanin. Eventually, the hair will look completely gray.
People can get gray hair at any age. Some people go gray at a young age — as early as when they are in high school or college — whereas others may be in their 30’s or 40’s before they see that first gray hair. How early we get gray hair is determined by our genes. This means that most of us will start having gray hairs around the same age that our parents or grandparents first did.