Everything You Need To Know About Vitamin C In Skincare

A firm favourite in the beauty industry, vitamin C is a brightening powerhouse backed by a ton of scientific research. The ingredient is frequently recommended by dermatologists as it harnesses multiple skincare benefits, is safe for all skin types and doesn't have the same potentially skin-irritating side effects as other active ingredients like retinol and exfoliating skincare acids.

Want to learn more about what vitamin C can do for you? We asked Dr. Marc DuPéré, aesthetic plastic surgeon and founder of Visage Clinic in Toronto, and Dr. Shannon Humphrey, cosmetic dermatologist and medical director at Carruthers & Humphrey in Vancouver, to share everything you need to know about using vitamin C skincare.

What is vitamin C?

Vitamin C (also known as ascorbic acid) is a water-soluble vitamin that has antioxidant benefits for the skin when applied topically (think: fading hyperpigmentation). It also has immune-boosting benefits when ingested.

"It's important to get adequate vitamin C in your diet and vitamin C levels are correlated to eating fresh fruit and vegetables," says Humphrey. She suggests pairing dietary vitamin C with topical applications to yield the best results.

What are the skincare benefits of vitamin C?

Consider vitamin C a skincare staple because it's not just a one-trick pony—it has multiple skin benefits when used properly. "Vitamin C protects the skin from UV damage, it suppresses hyperpigmentation (goodbye, dark spots!). It also preserves the integrity of collagen and elastic fibres and even promotes synthesis of collagen," says Humphrey.

Because it is such a powerful antioxidant, vitamin C helps minimize sun damage and inhibits melanogenesis, which is the process of pigment formation in the skin. "[It] brightens and evens out the complexion and strengthens the skin’s vascular wall providing an anti-inflammatory effect," says DuPéré.

How do I pick the right formula for my skin?

For starters, both DuPéré and Humphrey say that using a vitamin C serum is the most effective way to make the most of the ingredient's benefits. "An aqueous base formula such as a serum is preferred for home use as it provides better absorption and is an easier application," says DuPéré.

Since different skincare products contain different percentages of vitamin C, it's worth seeking advice from a physician or skincare expert. Get started with a stable 10 to 20 percent L-ascorbic acid (a specific form of the vitamin) mixed with vitamin E for better absorption, according to DuPéré.

For first-timers, look for products formulated with tetrahexyldecyl ascorbate, which is a stable form of Vitamin C—DuPéré says this form is less irritating to the skin and is generally tolerated by all skin types. It layers well with sunscreen, too.

Other options include magnesium ascorbyl phosphate and sodium ascorbyl phosphate.

When do I use vitamin C?

While some active ingredients can only be used at night, vitamin C can be used during the day. In fact, it's usually recommended for daytime use because of its free radical protection, something your skin generally needs more of during the day due to pollution and UV rays.

Humphrey says the best way to use it is to apply a few drops of vitamin C serum on freshly cleansed skin every morning, followed by moisturizer and broad spectrum sunscreen.

"Because vitamin C has a reservoir effect, using it once a day is sufficient to have an impact on your skin for up to 24 hours," says Humphrey.

It can be paired with ingredients like hyaluronic acid and niacinamide, which you'll often find in vitamin C serums, and ceramides, which is great in moisturizers to help calm down any sensitivity and increase collagen production.

Do I need to introduce it into my skincare routine slowly?

While some more potentially irritating skincare ingredients, like retinol, require a slow introduction to your skincare routine, vitamin C doesn't require quite as much caution. Though vitamin C isn't a common irritant for most skin types, DuPéré still advises using products infused with the ingredients just a few times a week to start with and working up to a daily routine.

If you feel a slight tingling sensation upon application, it's completely normal. "Vitamin C can be used on all skin types but because the pH of the product is low. Sometimes it can have a slight stinging sensation," says Humphrey.

"Those with sensitive skin may feel that more than others, but all patients can benefit from adding a vitamin C into their regime." It just comes down to finding the formulation that's best for your skin.

I've read that vitamin C is unstable. What does that mean?

Vitamin C is water-soluble and breaks down when exposed to oxygen. It's really that simple.

This property makes products containing vitamin C tricky to formulate, and their potency more difficult to maintain once the bottle has been cracked open. To keep your products as effective as possible, Humphrey recommends storing any vitamin C skincare at room temperature and out of direct sunlight.

Look for formulas that are packaged in dark glass containers or opaque packaging. This helps improve stability and reduce oxidation.

If you're unsure of how long your vitamin C will last once open, look for the information on the packaging. "There are formulations that will last just a month and there are others that will last up to three months, but it's generally not a product that can stay on your shelf for six, nine, twelve months," she says.

Keep in mind that fresh vitamin C products work better.

When shopping for skincare, does a more expensive vitamin C formula equal better results?

Not necessarily. Another consequence of vitamin C's instability is that brands have to spend more time and money on research to ensure that their products are shelf-stable and will be properly absorbed into the skin—and that cost is often passed along to consumers.

"The formulations I've seen with reasonable scientific evidence behind them have a [slightly] price point," says Humphrey of these skin care products.

But a higher price alone isn't enough. "When looking at formulas, it's not about money, it's about evidence," says Humphrey. "Have clear scientific evidence that the product is stable so when you open it and put it on your skin, there's actually still vitamin C in it and that it's also penetrating the skin."

Skimming packaging won't get you far when it comes to finding a quality product. Seek out recommendations from experts and do your research. Look for brands that post before and after photos of their research and study results. Remember, it can take two to four weeks of daily usage to see results.

If skin starts looking brighter, that's a sure sign your vitamin C products are working.

The best vitamin C skincare to shop for 2024

Garnier Green Labs Brightening Serum Mask, $4

For a quick fix, try this five-minute sheet mask infused with a serum made of vitamin C and pineapple extract.

SkinCeuticals CE Ferulic with 15% L-Ascorbic Acid, $208

There’s no vitamin C serum as beloved as this SkinCeuticals staple, and for good reason. From fine lines to laxity to dark spots, this powerhouse tackles it all.

Ilia C-Beyond Triple Serum SPF 40, $83

Canadian brand Ilia’s latest launch is an innovative waterless serum packed with SPF, vitamin C and niacinamide. The sheer tint balances out the dreaded white cast mineral filters often create.

Paula's Choice C15 Vitamin C Super Booster, $76

This serum contains ferulic acid, an effective brightening ingredient that also works to stabilize vitamin C and vitamin E.

OleHenriksen Barrier Booster Orange Ferment Essence, $65

Rated 5 stars on Sephora, this brightening essence contains vitamin C and niacinamide. Swipe or tap all over the face to get glowing.

Vichy Liftactiv Supreme Vitamin C Serum, $64

Mineral-rich volcanic water, hyaluronic and a 15 percent concentration of vitamin C strengthen skin while smoothing it out and improving its tone. Reviewers say it improves the look of fine lines and wrinkles with ease and is a quick addition to any skincare routine.

Originally published in 2019; updated in 2024.