What turns many presidents gray? Or transforms a Michael Scott-playing Steve Carell into what Huffpost called its "New Favorite Silver Fox"?
Quick hair 101: The hair we see is called the shaft. The bottom portion is called the root, which sticks into a follicle — or a tiny little sac on our head. Follicles are surrounded by melanocyte cells, which produce melanin. More melanin means darker hair. Less melanin means lighter hair. As we age, the cells slow down.
"Those cells divide over time. And as cells divide and divide and divide over the decades of our life, sometimes they get less efficient or less able at doing the job they initially were set out to do," said Dr. Jenna Lester, assistant professor of dermatology at the University of California San Francisco.
Experts say this is one theory on why our hair goes gray or white. Eventually, the melanin produces a lighter pigmented shaft which grows out. While there's no one thing that can cause graying, there are a few factors that may contribute.
Dr. Loretta Ciraldo is a board-certified dermatologist with over 40 years of experience.
"Smoking, psychological stress, physical stress, an unhealthy diet. And to me, one of the biggest is the sun," Ciraldo said.
She says genes can also play a role.
"There is some degree of heredity. So, if your dad turned gray in his 40s, then you're a little more likely," she said.
There’s an entire industry of pills, creams and sprays to prevent graying, but Lester says it’s always smart to do your homework before making any purchases.
"I always recommend people check with their physician to make sure that something that they're about to use is not going to cause more harm than good," Lester said.
Because there’s no black and white fix to going gray.