Age, genetics, and lifestyle choices are the main causes of going gray. Gray hair is caused by the slowed production of melanin within our hair follicles. We get our hair color from melanin, a type of pigment in the hair shaft. There are two types of pigments. Eumelanin is dark (such as black or dark brown), while phaeomelanin is light (such as yellow or red). The combination of these two pigments make up a wide array of different hair colors. As hair is being formed, special cells called melanocytes inject the pigment (melanin) into our hair’s keratin. This is what gives us our hair color.
What Happens as We Age?
We all know aging is the main cause of graying hair. But why? You might be aware that stylists use hydrogen peroxide as a bleaching agent in salons, but did you know our hair cells naturally produce it as well? As we age, more hydrogen peroxide is produced, which blocks melanin production. Therefore, the level of melanin produced decreases with age. Remember, melanin is what give our hair pigment. This is why hair begins to turn gray, and eventually white. Furthermore, we shed each individual hair about every 3 years, then the growth cycle begins again. Every time we grow a new hair, it wears out the pigment forming cells. Hair color doesn’t actually change, but new hairs begin to grow with lower levels of melanin. Our hair turns white when melanin production stops altogether.
Other Factors That Cause Gray Hair
The gene IRF4 is tied to lighter hair color in people of European descent. Researchers have found it can be linked to gray hair color as well. How much melanin the body produces is up to our genetics. IRF4 is partly responsible for our melanin regulation and production. As we age, this gene produces even lower levels of melanin, which may be why Caucasians lose pigment more quickly than other races.
Smoking has been linked to premature graying by multiple studies. In one study, smokers were over 2 times more likely to experience premature graying before hitting age 30 than nonsmokers. Smoke can cause free radical damage, which in turn destroys the pigment cells in hair follicles.
Race and Gender
Caucasians tend to go gray earlier than people of Asian and African descent. Men are typically more affected by gray hair than women. One study found that grays tend to appear first in the front of the head for women, and on the temples of men. Premature graying was found to occur on the side or back of the head, while later graying appears more at the front.
There is a long standing belief that stress will make you go gray earlier. The reasoning behind this is that stress can bring on hair loss, which targets pigmented hairs. This would leave behind white and gray hairs that are already present, creating the illusion that you have more gray hair than you do. You use pigment every time you grow a new hair, so premature shedding will cause loss of pigment in the follicles at a faster rate. Furthermore, if a person is predisposed to gray hair (once again, genetics), stress can make it appear sooner rather than later.