Sweet baby 24-year-old me thought I was helping my friend when I told her she hadn’t massaged in her dry shampoo all the way. She laughed. “That’s not dry shampoo; I’m going gray.” I was so confused. She was only 28. How can you get gray hair in your 20s? Well, now I’m 29, and I catch little gray hairs sprouting from my roots often, no matter what hair color I put over them. I’m still in the throes of situationships, not understanding taxes, and DoorDash dinner just after I’ve bought groceries. I’m just a baby! How can I have gray hair?!

Turns out, going gray in your 20s is not all that uncommon, and there really isn’t a “normal” time to go gray. Whether you find a few scattered across your head, have a streak around your face, or are fully heading into silver fox territory, getting gray hairs at any age is largely genetic. But could anything else be causing gray hair before turning 30? I tapped a dermatologist to break down exactly what causes gray hair in your 20s. And if you’re not ready to embrace the silver streaks just yet, don’t worry—I asked if you can prevent going gray, too.

Gray hair is an inevitable part of life, but when your hair actually begins to gray is determined by a few different factors. “Gray hair in your 20s can be influenced by genetics, meaning if your parents or grandparents grayed early, you’re more likely to as well,” board-certified dermatologist Mona Gohara, MD, says. Let’s break down the science of what it actually means when your hair turns gray.

Put simply, your hair color is determined by the amount and combination of melanin present, predetermined by your genetic code (aka your parents). “Melanin production in hair follicles decreases over time,” says Dr. Gohara. Less melanin translates to less pigment, which turns your hair gray—FYI, this means gray hair has less pigment and white hair has a total lack of pigment. While most people will start to see gray hair in their mid-30s, Dr. Gohara says, it’s definitely possible in your 20s and, in some cases, even in your late teens.

While aging is the reason for gray hair and genetics is the most influential in terms of the timing, Dr. Gohara says oxidative stress, lifestyle factors, and even certain health conditions (though less common) can also accelerate the graying process.

Genetics

As mentioned, melanin production will decrease as we age (among the other ~wonderful~ things that happen as we get older). “When it happens early, it’s often hereditary.” Just take a look at your parents and their parents—if someone from your family has a history of premature graying, it’s likely you may, too. The same is true for hair thinning—when and how quickly this happens is genetically predetermined. In fact, science says that by the age of 50, half of all men and women will have at least 50 percent gray hair.

Health conditions and nutrient deficiencies

“In some cases, vitamin B-12 deficiency, thyroid issues, or pituitary problems can lead to premature graying,” Dr. Gohara says. A study examining premature graying in people under 20 indicated lower copper levels appeared in those affected. Although more research will need to be done to fully explain why, if you believe or have been tested to have low copper, a diet rich in shellfish, seeds, nuts, and fish may help. However, don’t play doctor: If you feel you may have a medical problem, see a professional who can diagnose and treat you properly.

Stress

You’ve likely seen the photos of presidents before and after four (or eight) years in office. They go gray from all the stress. While the science verdict is out on if this is actually a proven phenomenon or not, “Stress has been shown to contribute to the depletion of stem cells responsible for hair color,” says Dr. Gohara. This, in turn, can potentially lead to graying. “No, it won’t make hair turn gray overnight, but chronic stress can speed up the process.”

Smoking

As we all know, smoking does no good for us. The obvious ones—i.e., cancer, heart disease, diabetes, wrinkles—also have some not-so-well-known companions. Smoking goes deep—it affects your organs and even how your DNA works, the Cleveland Clinic says. If you smoke, it’s been found that you’re 2.5 times more likely to have premature graying hair. Another reason to put down the nicotine, eh?

As we covered, when you develop gray hair is most often determined by your genetics, which, sorry, you can’t do anything about (thanks to your parents). That said, in some cases, if you’re dealing with a health issue or vitamin deficiency (hi, vitamin B-12, copper, thyroid, or pituitary problem), these may be reversible with proper treatment, says Dr. Gohara. This is why it’s always important to head to the doctor with any questions you have. Yup, even related to gray hair.

Another very important fact to be aware of? “Don’t believe the hype in terms of reversal,” says Dr. Gohara. “There are pills, lotions, and potions, none of which have science to support at this point.” (Ahem, the same can be said about hair growth vitamins, oils, and shampoos!)

First of all, you absolutely don’t need to hide them. But if you want to, you’ve got a lot of options. I love temporary root cover-up products, like L’Oréal Paris Magic Root Cover-Up Spray, because they are so easy and just wash out in the shower. If you want a more permanent option, though, try a demi-permanent hair color all over. Or, of course, skip the DIY and make an appointment with your hairstylist.

And hey, if you wanna embrace it, try a purple shampoo to help brighten up your silver strands.

Your genetics play a large role in the timing of when your hair will gray. While, yes, most people will start to see it begin in their mid-30s, Dr. Gohara says there is typically no cause for concern if you experience it in your 20s and even your late teens unless you fear it may be due to an underlying health issue. In these rarer instances of a vitamin deficiency or medical problem, by fixing the root of the issue, you may (emphasis on the may) be able to slow down the progression or reverse it. If you suspect the latter, don’t play doctor; see one instead—they’ll be able to properly diagnose and treat you.

• Mona Gohara, MD, is a board-certified dermatologist in Hamden, Connecticut. Dr. Gohara is an associate clinical professor at Yale School of Medicine and president of the Women’s Dermatologic Society. Her areas of expertise include medical and surgical dermatology and skin of color.

Beth Gillette is the beauty editor at Cosmopolitan with eight years of experience researching, writing, and editing stories on hair, makeup, and nails.

Siena Gagliano was the associate editor at Cosmopolitan, where she wrote about beauty, fashion, and lifestyle for four years.