What Causes Gray Hair?

Instructor: Sarah Friedl

Sarah has two Master's, one in Zoology and one in GIS, a Bachelor's in Biology, and has taught college level Physical Science and Biology.

Though it might be a touchy subject, we're still going to tackle it in this lesson. Gray hair: what causes it, its links to genetics and environmental factors, and shock theory.

Going Gray

I don't want to alarm you, but at some point it's very likely that you're going to get gray hairs. I'm sorry, it's just a fact of life and it happens to most people. And the bad news is, there's not much you can do about it!

This is because the color of your hair comes from two types of melanin, which is the same pigment in your skin that gives you a tan when you sit out in the sun. There's dark melanin and light melanin, and together they give us the multitude of hair colors we see on different people.

Gray hair occurs when there is a loss in melanin pigments.
gray hair

Here's how it works. Melanocytes, which are melanin-forming cells inject melanin pigments into keratin producing cells called keratinocytes (keratin is a protein in your hair). As you get older less melanin is injected into the keratin, so there is less pigment and voila! Gray hair.

What's in a Gene?

You probably already know that the color of your hair is determined by your genetics, but did you know that your genetics are also quite responsible for when you will go gray? The good news is that the rate at which you go gray over the years may be under your control. There are known environmental factors that can contribute to hair going gray faster. These include things like stress, emotions, cigarette smoking, obesity, and even a vitamin B12 deficiency.

The link between genetics and gray hair is a recent one. Scientists performed a genetic analysis that showed a gene variant, called IRF4, was responsible for about 30 percent of their gray-haired participants. The rest were likely due to environmental factors such as the ones mentioned above.

Gray hair is somewhat linked to genetics, so if your parents have gray hair you likely will too.
picture of a family

But genetic studies have also led scientists to understand that Europeans go gray more often than people of Asian and African descent. The genetic variant linked to gray hair is also associated with light-colored hair (such as blonde). We also know that you will likely inherit your gray hair from your parents because of its genetic linkage. Even though gray hair stands out more on people with dark hair they aren't necessarily more likely to go gray than anyone else.

Shock Theory

You may have heard that Marie Antoinette's hair turned gray when she was led to the guillotine to be executed and that Annie Oakley's hair did the same thing after a train accident. However, these two stories are just urban legends.

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