What it can do for your skin, why you should be using it, and how to get the best results.

By By Melanie Rud Chadwick
July 17, 2018
Photo: Stefan Cioata/Getty Images

You may think of it as the standout vitamin in your morning glass of OJ, but vitamin C also delivers a whole host of benefits when used topically-and chances are you've seen it popping up in your skin-care products more and more. Even though the ingredient is hardly the new kid on the block, it's certainly one of the most popular ones at the moment. Ted Lain, M.D., a dermatologist in Austin, TX, attributes this to a growing understanding of what's damaging our skin...and how vitamin C can help. "There's a resurgence in popularity of vitamin C products because of the increased awareness of the effects sun and pollution have on the skin, and the ingredient's protective benefits," he says. (More on that in a minute.)

So what's all the hype about? Well, skin docs love it for its multitude of anti-aging qualities, making it a smart solution for all kinds of complexion concerns. Here, the expert lowdown on this VIP vitamin.

It's an anti-aging triple threat.

First and foremost, vitamin C is a powerful antioxidant. "Exposure to UV rays and pollution creates reactive oxygen species-or ROS-in the skin, which can damage your cells' DNA and lead to both signs of aging and skin cancer," explains Dr. Lain. "Vitamin C works to neutralize those damaging ROS, protecting your skin cells." (FYI, this happens even if you're super diligent about sunscreen application, which is why anyone and everyone can benefit from using topical antioxidants.)

Then, there are its brightening abilities. Vitamin C-aka ascorbic acid-is a mild exfoliant that can help dissolve hyperpigmented or discolored skin cells, explains New York City dermatologist Ellen Marmur, M.D. Even more so, it also works to help inhibit tyrosinase, an enzyme critical for the production of new pigment; less tyrosinase equals fewer dark marks. Translation: Vitamin C both helps fade existing spots and prevents the formation of new ones, ensuring your skin stays spot-free. (As long as you're using sunscreen regularly, of course.)

And finally, let's talk about collagen production. By working as an antioxidant, it keeps those pesky ROS from breaking down both collagen and elastin (which keep the skin firm). Some studies have also shown that vitamin C stimulates fibroblasts, cells that produce collagen, notes Emily Arch, M.D., a dermatologist at Dermatology + Aesthetics in Chicago. (And FYI, it's never too early to start protecting the collagen in your skin.)

For these collagen-building purposes, your diet is also important. According to a study published in the American Journal of Clinical Nutrition, higher vitamin C intake was associated with less wrinkled skin. Ingestible vitamin C helps a bit more with collagen production than topical versions, says Dr. Arch, since it's able to reach the deeper layers of skin in the dermis. Consider this yet another reason to load up on vitamin C–rich fruits and veggies such as red peppers, Brussels sprouts, and strawberries. (More on that here: 8 Surprising Sources of Nutrients)

Just keep in mind that it's notoriously unstable.

The major drawback here is that vitamin C is just about as unstable as it is powerful. Exposure to air and sunlight can quickly render the ingredient inactive, cautions New York City dermatologist Gervaise Gerstner, M.D. Look for products that are housed in opaque bottles and store them in a cool, dry place, she adds.

You can also seek out a formula that combines the vitamin with ferulic acid, another potent antioxidant: "Ferulic acid works not only to stabilize the vitamin C but also boosts and enhances its effects," explains Dr. Lain. SkinCeuticals C E Ferulic ($166; skinceuticals.com) is a long-time derm favorite. (Related: Skin-Care Products Dermatologists Love)

There's also a whole new category of vitamin C powders, meant to be mixed in with any moisturizer, serum, or even sunscreen; in theory, these are more stable because they're less likely to come in contact with light.

You only need to use it once a day.

There's certainly no shortage of new vitamin C–based products out there; we're talking everything from serums to sticks to masks to mists...and everything in between. Still, to get the most bang for your buck, your best bet is a serum. Not only do these formulas typically contain the highest concentrations of the active ingredient, they're also easily layered under other products, points out Dr. Gerstner.

One to try: Image Skincare Vital C Hydrating Anti-Aging Serum ($64; imageskincare.com). Apply a few drops across your entire face-post-cleansing, pre-sunscreen-every morning. And if you're trying to save some cash (because let's face it, vitamin C products are generally pretty pricey), Dr. Arch notes that you can actually get away with using your vitamin C product every other day. "If you're using it for brightening it's best to use daily, but for the antioxidant effect, you could use it every other day since once it's on the skin, it's shown to be active for up to 72 hours," she explains.

As with any powerful skin-care ingredient, it does have the potential to cause some irritation, especially if your skin is sensitive to begin with. First-timers should start by using it only a few times per week, then gradually increasing the frequency if your skin can tolerate it.