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This is the best vitamin C serum of 2024 — it's potent, innovative and long lasting

We tested more than a dozen brands. Here's why Drunk Elephant's C-Firma serum is a better anti-aging vitamin C product than all the rest.

Vitamin C serum on a bright background
Drunk Elephant's C-Firma Fresh Day Serum arrives in two parts — you get to mix the product fresh before use. (Amazon)

Though vitamin C itself was discovered early in the 20th century (and was the first chemically produced vitamin, starting in 1933), vitamin C face serums are relatively new in anti-aging skin care. In fact, for a long time, beginning in 2005, there was only one expert-trusted vitamin C serum — SkinCeuticals' cult-favorite C E Ferulic, which became famous enough for its skin-brightening qualities to be independently studied in labs worldwide. However, since the advent of TikTok, vitamin C products have exploded on the beauty scene. And it's not just social media noise: I interview dozens of dermatologists and aestheticians each year and, more and more, every expert I talk to recommends the same skin-care regimen: daily SPF, moisturizer, a high-quality retinol and regular use of vitamin C serums to bolster healthier, younger-looking skin.

Quick overview

"A vitamin C serum is nonnegotiable. You need it twice a day," explains facial plastic surgeon Dr. Kay Durairaj. "In the morning, it's an antioxidant to treat sun damage; in the evenings, it's going to help build collagen and skin repair."

"Vitamin C is an antioxidant. Antioxidants are substances that can protect, prevent or delay cellular damage by counteracting the free radicals and oxidative stress caused by environmental pollutants, UV rays, chemicals and other factors," says Beverly Hills cosmetic dermatologist Dr. Ava Shamban. "Vitamin C is perhaps our most important antioxidant, it can boost brightening, improve hydration, reduce the appearance of wrinkles and hyperpigmentation and fight inflammation."

Unlike with many popular beauty ingredients, vitamin C's skin-health benefits have been extensively researched. Studies show that consistent, daily use of a stable form of vitamin C improved skin texture and evened skin tone on both the face and neck (results were seen in as little as three months). In clinical trials, vitamin C serums were shown to reduce hyperpigmentation from sun damage, lighten dark spots and diminish redness, particularly if the formula had a concentration of 10% to 20% vitamin C and contained stabilizing ingredients like ferulic acid and vitamin E.

Vitamin C skin care is ultra trendy right now and, as with any hot commodity, a lot of snake oil is sold by bad actors trying to cash in. Luckily, choosing a quality product is relatively straightforward — at least once you understand a few basic facts. First thing to know: Vitamin C is an extremely unstable molecule that degrades rapidly when exposed to elements like sunlight or heat. This means you want packaging (like opaque plastic or dark-colored glass) that will hold up in transit and, later, storage. You also want to guarantee the product inside is "fresh" (more on this in my review below). Remember, vitamin C works best in tandem with ferulic acid and vitamin E, so before making any new purchase, study labels. Last, a serum with less than 10% concentration of vitamin C will not reap the skin-brightening, collagen-boosting benefits you want. On the flip side, more is not more: Over 20% concentration will irritate most skin types. The sweet spot here is somewhere in between.

Over the past year, I tried more than a dozen of the most popular vitamin C serums meeting the qualifications above. I stuck to those that implemented the vitamin C derivative L-ascorbic acid, since this has been clinically proven to yield the best results. Of these options, Drunk Elephant C-Firma serum remains my favorite, Here's why.

Benefits: Brightens skin and dark spots, reduces appearance of sagginess and fine lines, gives skin a "glow" | Vitamin C potency: 15% | Skin Type: Any, but may be too harsh for the most sensitive skin | Dosage: A few drops in the morning | Size: Just over 1 ounce in combination of serum and powder | Cruelty Free: Yes

Ringing in at less than half the cost of Skinceuticals C E Ferulic, Drunk Elephant's C-Firma Fresh Day Serum is a high-quality, highly effective alternative. I love it for all sorts of reasons — including the fact that after six weeks of twice-daily use, it both lightened dark spots on my cheeks, noticeably tightened my skin and consistently gave my complexion a pretty, brighter glow. But what makes C-Firma superior to nearly any competitor is the unique way it's packaged: The formula arrives in two parts — a liquid serum along with an accompanying vial of pristine vitamin C powder. You mix the two just before your first use, maximizing the stability of the vitamin C molecules and thus ensuring freshness. Once mixed, the product remains potent for three to six months, depending how you store it (i.e., preferably in a cool, dark place, like a cabinet). 

And there's more to love: C-Firma contains ferulic acid and vitamin E, which boost its efficacy. It comes in an easy-to-use/easy-to-travel bottle with a convertible pump. It has a pleasant, mild, citrusy scent. It's lightweight and absorbs quickly, though the texture may feel a bit a sticky for some. Finally, it's potent — it may even sting your skin a bit.  

As compared to Skinceuticals C E Ferulic, Drunk Elephant's C-Firma gains points for being both cruelty-free and free from a foul odor (C E Ferulic has a deeply unpleasant scent). While many beauty editors will tell you that C E Ferulic is the only vitamin C game in town, keep in mind that it's also $182 to $285 for just one ounce, making it inaccessible for most bank-account-having humans, at least for long-term use. (I don't care if it's made of gold, I am not spending that kind of money on something to dab on my face — and I don't think you should have to either!)

At $74, C-Firma is not exactly a steal, but the formula (plus the effect on your skin) is top-notch. My first bottle lasted four months with twice-daily use, so a little goes a long way.  

Pros
  • Highest-quality ingredients
  • Innovative packaging means the product stays fresher longer
  • Brightens skin
  • Improves texture of aging skin
  • Lightweight
  • Absorbs quickly
Cons
  • Some may find the texture sticky
  • May be too harsh for the most sensitive skin
$74 at Amazon
Explore more purchase options
$79 at Ulta Beauty$79 at Kohl's

There's an entire worldwide web of vitamin C-serum-heads debating individual products' pH levels and the inferiority of C-derivatives like sodium ascorbyl phosphate over the gold-standard L-ascorbic acid. However, once you get DEEP in wonky skin-care Reddit, you find the consensus: For an affordable, high-quality vitamin C serum, the closest to Skinceuticals is this one by Timeless. It's lightweight, absorbs quickly, is less sticky than C-Firma and contains the right percentage of the main ingredient, combined with vitamin E and ferulic acid. Timeless's version boasts more than 6,000 exuberant 5-star reviews on Amazon, all repeating something along the lines of this one: "OMG!! Someone finally did Vitamin C RIGHT, and they’re NOT charging 100’s of $$ per ounce!!"

$33 at Amazon

This is a product I did not expect to like and wound up loving — it's formulated with just enough vitamin C to be effective (over 10%), but not at what the brand deems "extremely harsh levels that can strip, irritate, sensitize and otherwise compromise the skin barrier." The result is a solution that's gentle enough to use every day, no matter what your skin type, with potent results. This is a highly luxurious serum that feels like a treat for your skin — it's hydrating and silky (but not tacky under makeup). Not as important, but a bonus: The packaging is gorgeous — among the most beautiful I've seen. It's a bit steep, price-wise but would also make an excellent and impressive gift.

$84 at YSE

Experts are mixed on whether the antioxidant product is best used when you first wake up or before bed, but according to Durairaj, either — or both, to maximize efficacy.

Vitamin C is among the most potent and beneficial ingredients for maintaining healthy skin — if your skin can tolerate it, apply every day, at least once. If you find the ingredient irritating, try every other day to start and then build up over time.

Whether you choose morning or evening application, for the greatest benefit, vitamin C should be the first step in your skin-care routine after cleansing. Pat on a few (two to three) drops or pumps on a freshly washed face.

This is a resounding NO! If you're going to be outside during the day, always apply a high-quality, broad-spectrum sunscreen with SPF 30 or higher,