What You Need to Know About Vitamin C in Skincare—And Why It’s a Must for Every Skin Type

Here’s how to use vitamin C in your skincare routine to get the best results.

Citrus fruit essential oil bottle with dropper or vitamin c organic cosmetic on citrus background top view.

Photo, iStock.

Vitamin C is one of the ingredient darlings of the skincare world. It’s frequently recommended by dermatologists, it harnesses multiple skincare benefits, is safe to use on all skin types and doesn’t have the same potentially skin-irritating effects as other active ingredients like retinol. But just like introducing any new ingredient into your beauty routine, you want to ensure you’re using the right product and using it correctly. We chatted with 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 get the breakdown on everything you need to know about using vitamin C—plus any other pointers about the anti-aging superhero.

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 hyper-pigmentation) and 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 also says pairing dietary vitamin C with topical applications will give you the best results.

What are the skincare benefits of vitamin C?

Vitamin C has long been considered 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 pigmentation (goodbye, dark spots!) and 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 is able to help minimize sun damage and inhibits melanogenesis, which is the process of pigment formation in the skin. “[It] detoxifies, 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?

We get it, there are umpteen vitamin C formulas to choose from in beauty aisles and frankly, it’s overwhelming. For starters, both DuPéré and Humphrey say that using a vitamin C serum formula is the most effective. “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 there are so many percentages of vitamin C on the market in different formulas, it’s worth seeking advice from a physician or skincare expert. But to get you started, DuPéré says you should look for stable 10% to 20% L-ascorbic acid (a specific form of the vitamin) mixed with vitamin E for better absorption. 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.

When do I use vitamin C?

While some active ingredients can only be used at night, vitamin C can be used in the day, too. 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 washed skin every morning, followed by moisturizer and broad spectrum sunscreen. “Because vitamin C has a reservoir effect, using it once a day is sufficient as it will have an affect on your skin for up to 24 hours,” says Humphrey.

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

While some more potentially irritating skincare ingredients like retinol require a slow intro to your skin, vitamin C is a bit easier to navigate when it comes to application. But even though vitamin C isn’t a common irritant to most skin, DuPéré still advises starting with applying it a few times per week and working your way into daily application. Your skin will likely be completely fine with daily usage, but if you do have a slight tingly sensation, don’t panic. “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. “[People] 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 the best match for your skin.

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

That just means vitamin C is water-soluble and breaks down when exposed to oxygen. But, this makes formulating it into products—and keeping them active once opened—tricky. To keep your products as effective as possible, Humphrey recommends storing any vitamin C skincare at room temperature and out of direct sunlight. She also advises looking for formulas that are packaged in dark glass containers or opaque packaging, which will help improve stability and reduce oxidation. If you’re unsure of how long your vitamin C will last once it’s open, ask an expert. “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. Remember: fresh vitamin C serums 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 time and money to perform studies and research that ensure 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 higher] price point,” says Humphrey.

But a higher price alone isn’t enough. “When looking at formulas, it’s not about money, it’s about evidence,” says Humphrey. “You want to have clear scientific evidence that the product is stable so that 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.”

That can be difficult to tell just by skimming boxes, so seek out recommendations from a dermatologist or a beauty expert, or at the very least do as much online research as you can to ensure you’re getting a quality product. Look for brands that post before and after photos of their research along with study results. Also keep in mind that typically, it takes two to four weeks of using vitamin C serums for results to appear, so keep a close watch on your skin. If it starts looking brighter and sun spots are lighter, that’s a sure sign your serum is doing its job.