As far as ingredients go, vitamin C is a superstar member of the skin-care hall of fame, right up there next to retinol and hyaluronic acid. It has myriad uses, from brightening uneven skin tones to preventing premature aging. It comes from a variety of sources in an array of potencies and in pretty much any type of product. You'll find it on ingredient labels listed as ascorbic acid, L-ascorbic acid, tetrahexyldecyl ascorbate, and ascorbyl palmitate.
Vitamin C is also a notoriously finicky active ingredient as it can oxidize quickly and become less effective if not stored properly or used in the correct order in your routine. It might sound like more of a hassle than it's worth, but trust us when we say if used correctly, it can be transformational to the skin.
So, how do you know if you're using vitamin C right? Well, that's what we're here for. Below, you'll find the five things everyone should know about adding vitamin C to their skin-care regimen, plus our picks for the best serums and treatments featuring this classic ingredient.
Use It In The Morning
Vitamin C is an antioxidant, meaning it works to protect your skin from the free radical damage that bombards it all day, like pollution and UV rays. That's why you'll get the most benefit from using it in the a.m. — your skin needs to be protected during the day, repaired at night. There are a few exceptions to that rule, like peels that combine acids and pore-refining botanicals with vitamin C for brightening and retexturizing effects, but more on those later.
Our go-to morning pick is the cult-classic Skinceuticals C E Ferulic serum. This revolutionary formula has been a dermatologist favorite since it first hit the scene back in 2005 and for good reason: It combines L-ascorbic acid (proven in research to be the purest, best-for-skin form of vitamin C) with vitamin E and ferulic acid to neutralize free radicals from UV rays. Combined with an SPF 30, it provides more complete protection from hyperpigmentation and fine lines and wrinkles caused by the sun. It also stays on the skin to remain effective for up to 72 hours of antioxidant protection, as well as increasing skin's firmness and replenishing lost moisture.
Store It Safely
Because it is such a hard ingredient to stabilize, it's imperative to keep your vitamin C serums in a cool, dry place. Too much light or heat will degrade it. That's why you'll see most products with vitamin C are housed in opaque, dark glass bottles with droppers or pumps — with jars you run the risk of it oxidizing because the product is more exposed to air, while clear bottles let in too much sunlight. So pay attention to packaging and keep your vitamin C in your bedroom (not the steamy bathroom) and out of direct sunlight.
Know Your Skin Goals
Vitamin C has so many uses and is an extremely effective ingredient when combined with other actives like alpha-hydroxy acids and hydrators — it can help boost the brightening results and antioxidant benefits in a formula. A fabulous example of this is the Bynacht Illuminating Super C Serum, a skin-tone evening and pore-refining treatment serum that works while you sleep to revitalize and restore skin. It uses a blend of vitamin C, hyaluronic acid, vitamin E, and rosemary extract to regenerate and create younger-looking, clearer, firmer skin overnight.
Mix With Caution
While it does work in tandem with many other ingredients, there are some that you should avoid mixing it directly with. Blemish-fighting beta-hydroxy acids (like salicylic acid) for instance, actually causes vitamin C to oxidize and become less effective. You can still use BHAs in your routine, but better to apply them at different times during the day — vitamin C products in the a.m., salicylic acid at night.
Retinol is another no-no, although not all experts agree on that. The prevailing thought is that because the two essentially have the same effect on the skin, using them together may make both less effective. Plus, those with sensitive skin may find their skin can't handle them at the same time.
As for other exfoliating ingredients like glycolic acid, those are usually well-tolerated when used alongside vitamin C, although again, those with sensitive skin may find using them together makes their skin sting a bit. Do a test patch first to see how your skin reacts, then ease into it by alternating days you use them, gradually building up to daily use.
You may notice that some products call out the percentage of vitamin C they contain, usually somewhere between five percent and 20 percent. And, while you might think a higher concentration is the better option, that's not always the case. It actually depends on your skin type — the higher the percentage of vitamin C, the more likely it can be to cause sensitivity. Those with dry, easily irritated skin should stick to lower doses, while those with oily, blemish-prone skin — or who need a lot of pigmentation help — should opt for higher percentages.
If skin-brightening is your ultimate goal, you need to check out the Goop Glow Vitamin C + Hyaluronic Acid Glow Serum. There are so many things we love about this innovative system, one of which is the fact that it is both extremely potent and gentle on the skin. The unique two-part design maximizes potency and freshness, delivering a serum that stays active all the way through its use. The L-ascorbic acid actually comes as a powder, which you pour in to the liquid hyaluronic acid base. Vitamin C in powder form doesn't need any stabilizers to keep it fresh, so you get that pure antioxidant goodness without any fillers. The ingredients work synergistically to help brighten the appearance of the skin, significantly improving its firmness, tone, texture, and hydration.
So, what have we learned today? That vitamin C is an essential skin-care ingredient that, when used properly, can make your complexion look radiant, luminous, and healthy. If you don't have it in your regimen already, now's the time to stock up!