Vitamin C for Skin: The Complete Guide

*Reaches for a vitamin C serum*

blonde girl in a pink sweater with natural light streaming in over a white background


Nowadays, vitamin C is a very well-known skincare ingredient. Ask any beauty buff or skincare enthusiast, and it's likely they'll be able to recite the following...Vitamin C, when applied topically, brightens dull and sun-damaged skin and stimulates collagen production to ward off fine lines and wrinkles. It's also a powerful antioxidant, meaning it fights free radicals that could cause future signs of aging (which is why it's often a core ingredient in anti-pollution skincare regimens). But let's take a step back. What exactly are free radicals? It’s a term that’s thrown around a lot in the beauty industry, yet for many of us it's unclear how they affect our skin or why they're so feared.

Type of ingredient: Antioxidant

Main benefits: Brightening, alleviates hyperpigmentation, neutralizes free radicals

Who should use it: In general, anyone with

How often can you use it? We recommend using vitamin C once daily, but everybody's skin is different.

Works well with: Ferulic acid and vitamin E.

Don’t use with: Retinols, because combined they can be incredibly irritating.

What is Vitamin C?

According to celebrity esthetician and skincare expert Renée Rouleau, free radicals are unstable electrons that attack our healthy cells, causing signs of aging to appear. "It is widely believed by scientists around the world that one of the main reasons we age is because unstable electrons in molecules (called free radicals) attack healthy cells and change their composition, which causes them to no longer function the way normal, younger cells do," she explains. So in order to stave off aging, we need to stave off those villainous free radicals. That's where vitamin C comes in. Its effect is near-immediate and visible, at least according to a viral photo and video, respectively, that are currently circulating the Internet. 

Meet the Expert

Renée Rouleau is a skincare expert and celebrity esthetician with more than 30 years of experience in the industry. Her eponymous skin care line caters to nine different skin types.

Vitamin C

First, we must understand exactly how free radicals work to damage the skin: There are three types of free radicals, but Rouleau is mainly concerned with the reactive oxygen species (ROS). "We are exposed to ROS from the air we breathe (oxygen), cigarette smoke, UV sunlight, stress, and smog," she says. The effects of ROS are no joke: They damage the dermis of the skin and alter DNA, the moisture barrier, skin texture, color, and cell functioning.

How to Use It

To demonstrate the effects of ROS and oxidative stress to the naked eye—and to prove how vitamin C works to combat them—Rouleau devised a simple experiment involving an apple. She cut out a single slice and coated one end with a thin layer of vitamin C serum. The other she left completely untouched. Then she waited three hours. This is what happened…

How Does Vitamin C Work
Renée Rouleau

As you can plainly see, the side of the apple that was coated with the vitamin C serum didn't oxidize at all. "This shows how topical vitamin C can prevent oxidation and therefore slow down the visible appearance of aging," Rouleau says. She notes that lemon juice would have the same effects, as lemon (like most other fruits) contain high levels of antioxidants. However, putting lemon on your face is never a good idea. It might provide your skin with antioxidant benefits, but it will do so at the expense of insanely irritated, dry skin (seriously, please don't put pure lemon juice on your face). 

Rouleau's photo is enough to make us want to slather our faces in a safe and effective vitamin C serum. That urge is only exacerbated by this next experiment, which is based on the very same principle as Rouleau's. Just like hers, it involves a vitamin C serum and an apple—only this time you get to see it work in real time. Keep scrolling to see it for yourself. 

The video was posted by @gothamista, a popular skincare enthusiast and beauty vlogger, for the purpose of an Instagram giveaway. In it, she used SkinCeuticals C E Ferulic ($166), which just so happens to be one of team Byrdie's all-time favorite serums (seriously, make sure you check out our full review of the skin-saving product). She starts out the experiment by applying a couple of drops to one half of an apple. After time goes by, we see that the other side of the apple is brown while the serum side is bright and fresh-looking. The serum had effectively protected the apple from oxidizing. 

Here's where it gets really interesting. She then applies a few drops of the C E Ferulic Serum to the browned half of the apple. After enough time goes by, it visibly reverses the oxidation damage of the apple, taking it from brown and over-ripe to fresh and bright. That, our friends, is the perfect demonstration for the brightening, preventative, and rejuvenating effects of vitamin C. Not only does it protect our skin from the oxidizing effects of free radicals, but it can also reverse some damage that's already there. 

Renee Rouleau Vitamin C & E Treatment
Renee Rouleau Vitamin C & E Treatment $68

"If you’re not using one, it’s definitely time to step up your anti-aging game and give your skin some serious protection," says Rouleau. "Applying a vitamin C serum topically to the skin can essentially keep your skin from turning brown, as well as make your skin look brighter, fresher, with a youthful glow." She recommends reaching for the vitamin C serum from her eponymous skincare line. The Vitamin C & E Treatment ($66) contains a safe and stable form of the ingredient, along with ultra-nourishing vitamin E to give you smooth, youthful, glowy skin. 

Side Effects of Vitamin C

Vitamin C, although not known to be particularly irritating, is also not known for its complete lack of side effects. It won't give you a rash most likely, but it could be a cause for redness or a slight increase in redness, at least at first.

Use a barrier booster or hydrating serum to help protect your skin against redness when you start your Vitamin C regimen.

If you experience severe itching or hives, however, wash your face and make a doctor's appointment—you might have an allergy.

The Best Products with Vitamin C

SkinCeuticals C E Ferulic
SkinCeuticals C E Ferulic $166

We could never forget the Skinceuticals serum. Although its star ingredient is the vitamin C, it's also formulated with vitamin E and ferulic acid. The former smoothes the skin, while the latter enhances the protective powers of the vitamin C. Ferulic acid also addresses dullness and loss of firmness, so you can be fighting aging both preemptively and retroactively.

Violet-C Brightening Serum 20% Vitamin C + 10% AHA
Tatcha Violet-C Brightening Serum 20% Vitamin C + 10% AHA $88

Tatcha's packaging is beautiful, and what's inside it is near-guaranteed to make you feel beautiful as well. In this case, it's a mix of vitamin C and fruit-based AHAs, which are supplemented by antioxidants from the Japanese beautyberry. It resurfaces, battles free radicals, and gives your skin a more even tone.

truth serum vitamin c serum in an orange bottle with a white pump
Ole Henriksen Truth Serum $49

Ole Henriksen's Truth Serum is one of those products you've seen so many times, it's probably what you picture when you read the words "Vitamin C serum". Henriksen's orange frosted-glass bottle with the white pump is nearly synonymous with the rise of skincare as a self-care practice. Not only is it that popular, it just works that well.

C-Firma Day Serum
Drunk Elephant C-Firma Vitamin C Day Serum $80

Another vitamin C serum whose popularity is so great it's near-synonymous with the category is this one from clean beauty brand Drunk Elephant. The founders of the brand authentically believe that their line can be used by anyone, and complaints about this serum are fewer and further between than they are for most vitamin Cs. If you have super sensitive skin, start out with this one.

CEO vitamin C rich hydration cream in a tub
Sunday Riley C.E.O Vitamin C Rich Hydration Cream $65

Just like we loved the oil and serum that preceded it, we absolutely love Sunday Riley's C.E.O cream. It's rich and hydrating, which is perfect for the time of year when you need the biggest brightening kick: winter. But this is a year-round moisturizer; the Vitamin C helps get rid of and stave off any hyperpigmentation issues the sun brings in summer, too.

lucent facial concentrate
Aesop Aesop Lucent Facial Concentrate $115

Vitamins C and B3 (niacinamide) work together in this hyper-conditioning serum from cult brand Aesop. Unlike many vitamin c products it doesn't have that distinct vitamin c smell, and the flower oils it contains are far enough down in the ingredients list that it shouldn't pill when used under a silicone moisturizer or face product.

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