Human World

What causes hair to turn gray?

As you age, your hair turns hair gray. Why?

Some people blame their teenage children for their gray hairs. But it would be more scientifically accurate to blame their parents and grandparents. In other words, how much gray hair you have is an inherited characteristic.

Here’s how it works. Our hair gets its color because of natural pigments in the hair shaft. These chemicals – called melanins – are made by special cells at the root of each hair on your head. As these cells age, they lose their ability to make the pigments, so you get colorless – or white (gray) – hair.

It’s your genes that tell your body how much melanin to make in the first place. That’s why most people will start having gray hairs around the same age that their parents or grandparents first did. Your genes also tell your body what type of melanin to make. The exact chemical structure of the melanin in hair varies from person to person. Black hair contains a large amount of one kind of melanin. Auburn hair also contains a type of melanin that has a reddish color. And natural blondes don’t have much melanin at all.

People can go gray hair at practically any age. Some people spot their first gray hairs as early as high school or college, while others may be in their 30s or 40s. From the time a person notices a few gray hairs, it may take more than 10 years for all of that person’s hair to turn gray.

December 5, 2010
Human World

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