have finally identified a gene involved in the hair-graying process. What does this mean

and how does your hair actually go from colored to gray? Watch and weep.

Geneticists recently examined the DNA of more than 6,000 people and found specific genes

that influence things like baldness, beard thickness, hair curliness, and even unibrow...ness.

But the find that got the most attention was a particular variation in the IRF4 gene that

affects when your hair goes gray. Finding this specific graying variation in the gene

could help scientists develop products to slow the graying process. Or, speed it up,

I suppose, if you want to be a silver fox or avant garde hipster.

But we all actually start out gray, in a way. Before your hair pops out of your scalp, it’s

completely white. It gets its color from chemistry—specifically a group of pigment molecules called melanin,

which also determine your skintone and eye color. For hair, there’s eumelanin that

creates dark shades and pheomelanin that produces lighter hair colors. The proportion of these

two types determines your—and everyone else’s—hair color.

How that color gets into your initially colorless hair is up to your follicles. Every hair follicle

in your scalp contains cells called melanocytes, which produce melanin. As hair grows in the

follicle, melanocytes inject melanin pigments into your hair cells that contain keratin,

a protein that’s also in your skin and fingernails. So as your hair grows out of your head, it

gets dyed with its natural hue. Over time, our melanocytes produce less pigment, so our

hair starts to lighten as we age.

Scientists have recently found that as we get older, our hair follicles start accumulating

hydrogen peroxide—the same stuff people use to bleach their hair. Some hydrogen peroxide

is normal. We actually make our own H2O2 as melanocytes color our hair. Enzymes, especially

catalase, break down hydrogen peroxide and keep its concentration in check. But things

get out of whack when older follicles can’t generate enough catalase. Higher concentrations

of hydrogen peroxide attack tyrosinase , an important enzyme in melanin production.

No melanin, no color in your hair.

If you haven’t gone gray yet you probably will around the same age as your parents did.

But what about factors outside of age and genetics? A recent study suggests that smoking

can result in early onset graying. And people are always saying stress brings on the gray,

right? Just look at how gray presidents get while they’re in office. Some researchers

say emotional stress could accelerate what’s called oxidative stress, the damage caused

by reactive oxygen species like hydrogen peroxide. But others contend there isn’t solid scientific

evidence backing this up yet. I guess you could call all of these hypotheses a gray area.

At any rate, it’s probably not worth stressing about going gray, anyway. It’s completely

natural and you can totally rock the look. Share a pic of your favorite gray-haired celebrity

or your own cool silver ‘do in the comments. The Speaking of Chemistry gang needs ideas.

Special thanks to Jerry Weissmann, an emeritus professor at the New York University School

of Medicine for his help with this video. Now hit that share button and don’t forget

to subscribe on your way out.