I recently came across my first gray hair, thanks to a fellow Truth In Aging writer. As I leaned across his desk, skimming an article, he said quite candidly, “Hey. You have a gray hair. Want me to pull it out?” I stared at him. Then I began to sputter something barely coherent about the fact that a gray hair was impossible, given the fact that I am still in my early twenties, and that he had just ruined my day if what he said was, in fact, true.

Turns out, it was true. A single white strand lay buried under a layer of dark tresses. My first thought was hair dye, but I don’t use hair products of any kind (the last time I even blow dried my hair was for my high school prom) and anyway I would definitely be jumping the gun if I highlighted or colored my hair because of one measly strand. Still, I had to do something – so I decided to put all my nervous energy into researching gray hair; what it is, what it’s not and the truth behind some gray hair myths.

Graying of the hair, also called canities, is caused by a lack of pigmentation and melanin. Initially, all people have white hair. Your natural hair color comes about from the distribution, type (either dark pigment called eumelanin or light pigment called phaeomelanin) and amount of melanin in the hair shaft. Because follicles contain a finite number of pigment cells, eventually melanin will stop being produced in the root of the hairs and new strands will lose pigment (perceived as gray) and then lose pigment altogether (perceived as white).

Interestingly, your ethnicity may give you some clues about when exactly you will gray, if you haven’t yet hit that landmark. White people tend to gray first, starting in their mid-thirties. Asians are next, first reporting gray hairs in their late thirties, and Black people tend to keep the grays at bay until their forties. By age fifty, most people are about fifty percent gray.

This is one of many indicators that graying is more genetic than anything else. Still, we’ve all heard that there are plenty of other pigment-robbing catalysts. Take smoking, for example – will puffing on a cigarette cause you to go gray? Maybe, and it may actually cause premature graying. Recently, a study found that 13 of 23 underage smokers tested had gray hair, while 32 non-smokers had no gray hair. Supposedly, the chemicals in smoke may damage hair follicles, causing them to not only go gray, but also to fall out. A more comprehensive study found a strong, consistent link (though not a proven causal relationship) between gray hair and smoking for all age groups and sexes. According to this study, smokers are four times more likely to begin graying prematurely than non-smokers are.

What about the oldest age-related myth: pluck one gray hair and five more will appear in its place! Luckily for me, as I did indeed pluck out that pesky white strand, only one hair can grow out of one follicle. So while my white hair will surely grow back, I don’t have to worry about the surrounding hairs turning gray overnight.

And speaking of going gray overnight, is it true that you can go to bed with naturally blonde, brunette or red hair and wake up the next morning with grays? Say, from being frightened or shocked suddenly the night before? Supposedly, Marie Antoinette’s auburn hair turned white the night before her execution. And creator of the Taj Mahal, Shah Jahan, apparently awoke with a head of white hair after being racked with grief over the passing of his beloved wife.

The phenomenon is even documented in medical journals; a 1902 British Medical Journal describes a woman who witnessed a gruesome murder waking up the next morning with half of her pubic hair lacking any sort of pigment.

While no one can say for certain, it is likely that Marie Antoinette was denied her hair dye or wigs as she awaited her execution. But the cases cited in medical journals may very well be a result of alopecia areata, a disease that attacks the hair follicle and results in hair loss. A more severe form of the condition can cause only pigmented strands to fall out very quickly, perhaps in a matter of days, leaving the sufferer with a head of gray hair.

While alopecia areata is genetically linked, it may very well be brought on by high levels of stress. Another type of stress called genotoxic stress may also be implicated in turning hair gray. Genotoxic stress, like radiation, chemicals, UV rays, environmental pollutants and such, seems to be linked to premature graying. So there actually is some truth to that old wives’ tales regarding stress and going gray.

But there is one myth that is just that – a myth. Gray hair has been a symbol of aging for as long as people have existed. But the two really shouldn’t be associated, for two distinct reasons; first, graying is first and foremost, genetic. Yes, other factors can influence the process, but your predisposition to gray hair was determined way back when you were only a fetus. There’s a good chance that you’ll start to gray at the same time and at the same rate that your parents did. People may start to spot gray hair as early as childhood or as late as their seventies. While white hair often accompanies old age, it is not solely linked to it.

Second, gray hair is not indicative of other signs of aging. A study of 20,000 men and women examined links between physical signs of aging (like gray hair) and heart disease and other signs of longevity; they found no link at all. So while you may feel that you got the short end of the stick by prematurely graying, you don’t have to worry that you’re prematurely aging.

At the end of the day, though science has come a long way in its examination of gray hair, there are still more theories than hard facts. And there is no cure for gray hair, natural or artificial. So, we’ve all got one of two choices: pick up the hair dye and get to work, or learn to love your silver tresses.