What Is Vitamin C Serum, and How Does It Help Your Skin?

You might reach for vitamin C when you feel a cold coming on, but did you know it can also help you achieve a glowing complexion? In recent years, vitamin C has become a holy grail product for anyone looking to maximize their skin health.

“Vitamin C is a hot topic, and it is buzzworthy, because it has so many preventive and maintenance benefits,” says Nazanin Saedi, MD, a board-certified dermatologist and a clinical associate professor at Thomas Jefferson University in Philadelphia.

Here, we dive into everything you need to know about vitamin C serums, including why to use one, how to apply it, and what to watch out for.

A vitamin C serum is a skin-care product packed with vitamin C. It has the consistency of a liquid or gel, which you can apply directly to your skin. You’ll find these serums wherever you normally purchase skin-care products — at department stores, beauty stores, some drugstores, and in your dermatologist’s or aesthetician’s office too. On the packaging, you’ll likely see words touting skin benefits like “firming,” “brightening,” and “collagen boosting.” These skin benefits are the reason so many people have started adding vitamin C serum to their daily routines.

“The benefit of vitamin C is it’s an antioxidant, so it helps prevent the forming of free radicals, which go on to break down collagen and elastin,” Dr. Saedi says. She explains that the result of incorporating vitamin C serum into your skin-care routine is glowing, youthful skin.

However, you can apply vitamin C directly to your skin, and that’s where serums come in handy. “Vitamin C is best known for its ability to neutralize free radicals and improve aging skin,” says Joel Schlessinger, MD, a dermatologic surgeon in Omaha, Nebraska. “It can also improve collagen and elastin synthesis — which can improve the appearance of fine lines and wrinkles, help reduce inflammation, provide natural, mild exfoliation, and brighten skin.”

Saedi recommends vitamin C serums for people of all ages because virtually everyone is at risk of sun damage. With vitamin C serums, “we are minimizing the amount of sun damage that our skin’s getting from sunlight,” she says. She explains that vitamin C serum does double duty, both protecting the skin and helping problem areas recover. “It’s preventive in that it’s protecting you from sun damage and signs of aging like wrinkles,” Saedi says. “It also helps promote collagen and boost your natural collagen formation.”

The price of these serums can vary greatly, from about $10 to $250 per ounce. Pay attention to the vitamin C concentration levels, usually referred to as L-ascorbic acid or ascorbic acid on the label. Schlessinger explains that some of these serums may have 10 percent, while others may have 15 or 20 percent.

Look for one with a concentration higher than 8 percent, which is the minimum amount considered biologically significant. The higher the concentration, the stronger the serum, though the benefits taper off after 20 percent. “Twenty percent is where it maxes out — you’re not going to get anything more powerful than that,” Saedi adds.

Saedi says to apply a few drops of serum to your face after you wash and dry it. “A little bit goes a really long way,” she says. She recommends putting it on every morning, all year round. “It has some benefits with sun exposure, so it helps to apply it in the morning as the first layer of protection,” she says. She says to then layer on your moisturizer and sunscreen. Serums are better than drops of vitamin C “boosters” added to your moisturizer, Saedi says. Vitamin C drops may not be as potent as serums, and mixing them with moisturizer may dilute the effects.

Store your bottle in an area away from extreme heat, such as a bathroom cabinet. “Storing a vitamin C serum correctly is integral to its success,” Schlessinger says. “A good rule of thumb is to toss the serum six months after it’s been opened and to keep the serum in a cool, dark place.” If you’re using it according to the instructions, it’ll likely be gone before the six months are up. If not, you’ll want to throw it out. “When vitamin C is used past its shelf life, it can actually have negative effects,” Schlessinger says.

Vitamin C is a safe and generally well-tolerated ingredient. “The only risk is that some of these serums have so many different ingredients in them,” Saedi says, adding that these extra ingredients may result in an allergic reaction in some people.

SkinCeuticals C E Ferulic With 15 Percent L-Ascorbic Acid ($166, Skinceuticals.com) is “tried and true,” says Saedi, who notes it has a cultlike following.

Drunk Elephant C-Firma Day Serum ($79, Sephora.com) contains 15 percent L-ascorbic acid, plus ferulic acid for a powerful yet lightweight day serum.

Paula’s Choice C15 Super Booster ($55, Dermstore.com) is another high-potency pick with 15 percent vitamin C, along with vitamin E and ferulic acid, plus hyaluronic acid to attract moisture for supple skin.

Vichy 16 Percent Pure Vitamin C Brightening Serum ($35, Ulta.com) boasts minimal ingredients to keep things simple. With ascorbic acid, vitamin E, and hyaluronic acid, this serum may boost skin smoothness and radiance.

The Takeaway

• Many people have started using vitamin C serums due to their ability to boost skin health, minimize fine lines, and protect from sun damage.
• Vitamin C can help improve collagen production, brighten your skin, and reduce dark spots or hyperpigmentation.
• While vitamin C is generally very safe for everyone, if you have sensitive skin, consider using a lower concentration when you’re first starting out with a serum.

Additional reporting by Jessica Migala.