Best Vitamin C Serums: Top 5 Picks Based on 25 Studies (Science Explained)
Hi, everyone! Apologies for missing last week’s blog post. Long story short I went on vacation to Central America, and got hit with a bad case of food poisoning. Was doing the double-dragon and all (google with caution). Hint: numbers 2 and 3 on urban dictionary.
Anyway…. enough about that. Today we will be continuing our ongoing “best of” series, by focusing on vitamin C serums. Specifically, ascorbic acid vitamin C serums since these are the most potent types available today.
If you’re tuning in for the first time, I started this series for two reasons:
- I’m always being asked for product recommendations — be it moisturizers, toners, chemical exfoliants, serums, sunscreens etc.
- I’m annoyed by gimmicky and inefficacious skincare after 7+ years of burning cash on lame products that only made my skin worse. You can read more about my story here.
For reference, here’s an old photo:
Note: not all of these were bad!
Okay, let’s dive right in!
Vitamin C (Ascorbic Acid) Benefits for Skin.
You may be asking yourself: what’s the point of a vitamin C serum? Why would I want to use one? Great questions!`
If there is any skincare ingredient that will more single-handedly give you “glowing skin,” well…. ascorbic acid would be it ladies and gents. In fact, research has noted it causes a noticeable lightening effect on the skin. (1, 2, 3) Translation: go get your glow on gurl! (Or boy….)
And that’s just the tip of the iceberg!
Multiple in vivo studies have shown it has strong anti-wrinkle effects. (4, 5, 6) This is probably due to its ability to directly increase collagen production. (7, 8, 9, 10, 11) Collagen being the main structural protein found in connective tissue throughout the body. It’s what makes your skin all nice and plump / bouncy!
Note: the collagen boosting benefits of ascorbic acid also make it a good adjunct for the treatment of atrophic acne scarring. That’s the main reason I use it, which is something I discuss in my dermarolling guide.
Unfortunately, collagen decreases with age (by about 1% every year after the age of 20, to be exact). (12) The result? Sag city…. Or aging.
Apart from increasing collagen production, ascorbic acid also leads to smoother skin, reduces skin roughness, enhances the moisture content of the stratum corneum, and is an effective treatment for hyperpigmentation, or uneven skin tone. (13, 14, 15, 16, 17, 18, 19)
Fun fact: vitamin C is the most abundant antioxidant in human skin!
With that said, there are a lot of vitamin C serums on the market today that will do diddly squat for skin for a variety of reasons — weak formulation, ineffective forms of vitamin C, and most importantly: WRONG pH.
If you want to get all the amazing benefits of ascorbic acid I just listed above, the solution must have a pH below 3.5 for effective penetration. If you have no idea what pH is, or why it’s important in the context of skincare, check out my guide: “Why the pH of Skin and Products Are Crucially Important.”
Without further ado, let’s take a look at the top 5 vitamin C serums. All of these have taken an evidenced based approach when it comes to formulation!
Full ingredient list:
Aqua / Water / Eau, Ethoxydiglycol, 15% Ascorbic Acid, Glycerin, Propylene Glycol, Laureth-23, Phenoxyethanol, Tocopherol, Triethanolamine, Ferulic acid, Panthenol, Sodium Hyaluronate
pH 2.5 – 3.
Coming in at the top of the list, a vitamin C serum so expensive it makes even Beyonce scoff (see price on Amazon). Don’t worry, I’ve made more affordable recommendations in this article for the ordinary mortals like you and me. :p
So why is this dang thing so expensive? A couple of reasons.
Firstly, SkinCeuticals has really done their homework when it comes to maximizing the effectiveness of vitamin C. Their formula includes what many skincare addicts refer to as “the holy trinity.”
In other words, it has 15% vitamin C (ascorbic acid), 1% vitamin E (tocopherol), and 0.5% ferulic acid. Research has shown that these 3 in combination create a super-jam-packed, ultra-kick-ass, crazy-awesome vitamin C serum. But don’t take my word for it, here’s a quote from a research paper:
“A combination of 0.5% ferulic acid (a potent antioxidant of plant origin) with 15% Vit. C and 1% Vit. E can increase the efficacy of Vit. C eight-fold.” (23)
Not sure if that needs reexplaining, but just in case: combining vitamin C (ascorbic acid) with ferulic acid and tocopherol, makes vitamin C eight times more effective! Say waaaaaaat? 😮 Crazy, huh?
Wanna know something even crazier? SkinCeuticals owns the patent on such a formulation! By law, this means that no other company is allowed to use “the holy trinity,” unless otherwise explicitly stated in some type of formal agreement (i.e. contract).
And that folks, is the tale of mob SkinCeuticals — the biggest drug lords in America! I’m teasing. But seriously, that’s how they’re able to put such a high price tag on their product.
Another thing that makes this vitamin C serum extraordinary is it’s lack of yeast-feeding ingredients. For those who don’t know, skin conditions like adult acne, eczema, seborrheic dermatitis, psoriasis, dandruff, tinea versicolor etc. are exacerbated by a commensal yeast that lives on the skin called malassezia.
For more information about this yeast, check out my massive guide on malassezia, which goes into detail about how to treat the aforementioned skin conditions.
I won’t go into much detail here, but SkinCeuticals is free of oils, fatty acids, esters, and polysorbates, meaning that if you have a history of any of the skin conditions I listed above, you can use this serum without having to worry about worsening your symptoms. Hooray!
UPDATE 3/22/19: a couple people have pointed out in the comments that Dr. Brenner’s Vitamin C Serum is an extremely affordable dupe for Skinceuticals! It even includes holy trifecta (vitamin C, E, and ferulic acid) and is equally safe for malassezia! :O This now takes the number one spot on the list!
Full ingredient list:
Purified Water, 20% L-Ascorbic Acid, Ethoxydiglycol, DL- Panthenol, Glycerin, Magnesium Sulfate, Ferulic Acid, Sodium Hyaluronate, Sodium PCA, Phenoxyethanol, Caprylyl Glycol, Sorbic Acid.
pH of 2.5 – 3.
Next on our list is a far more budget-friendly option, and what I use personally: the Nufountain C20 Ferulic. As you can see from the photo above, I’ve gone through two bottles of this stuff in the past.
In english that means it will protect your skin from sun damage to a greater degree, than ascorbic acid would by itself. Considering 80% of skin aging is attributed to UV rays, that’s excellent news if your primary concern is anti-aging!
Pro-Tip #1: apply your vitamin C serum before sunscreen! This boosts the sunscreen’s effectiveness.
What’s particularly awesome about Nufountain is that they make their serums fresh with every order. This ensures you won’t be receiving any oxidized vitamin C.
Ascorbic acid is a terribly finicky ingredient to formulate. It degrades quickly when it comes into contact with light (usually within 1 to 3 months). You will know it’s gone bad when the liquid starts to turn color like you see in the picture below.
Notice how it’s slightly yellow? (I promise I didn’t pipette urine from a toilet bowl.) This is the color of vitamin C that is just starting to go bad. Fresh vitamin C (ascorbic acid) should always be crystal clear.
Pro-Tip #2: extend the shelf-life of your vitamin C serum by wrapping it up in foil! This makes the bottle lightproof, and is a simple way to protect light-sensitive substances.
Depending on the manufacture, fresh ascorbic acid isn’t always a guarantee. Take a look at reviews online and you’ll quickly find this is a common complaint of many buyers.
Luckily for us, Nufountain makes this is a non-issue, so we can happily stroll along applying our glow-inducing face serums! 😀 Woohoo!
Full ingredient list:
Water, Ethoxydiglycol, 20% L-Ascorbic Acid, Propylene Glycol, Alpha Tocopherol, Polysorbate 80, Panthenol, Ferulic Acid, Sodium Hyaluronate, Benzylalcohol, Dehydroacetic Acid, Fragrance.
Many consider the Timeless Vitamin C serum a cheaper dupe to the expensive SkinCeuticals. You may have noticed that, it too, contains the holy trinity (i.e. ascorbic acid, ferulic acid, and vitamin E).
“But wait, can they do that? I thought it was illegal because SkinCeuticals has the patent and whatnot?”
Not exactly. The patent specifies a vitamin C serum with 5% to 20% L-ascorbic acid, 0.5% to 5.0% ferulic acid, and 0.5% to 2.0% vitamin E with a pH range between 2.5 -3.5. Timeless has a pH of 2.4. (26)
However, it’s not without its share of caveats.
For one, this serum isn’t for everyone. It contains polysorbate 80, which feeds malassezia. This is potentially bad news for those with adult acne, eczema, pityrosporum folliculitis, seborrheic dermatitis etc.
Secondly, there’s no way of guaranteeing we’ll receive a fresh batch.
UPDATE 7/9/17: I’ve gotten a couple messages and comments from people saying this has never been an issue, and that Timeless arrives fresh every time!
Full ingredient list:
Water, Ascorbic Acid (vitamin C/antioxidant), Ethoxydiglycol (hydration), PPG-26 Buteth-26 (texture-enhancing), PEG-40 Hydrogenated Castor Oil (texture-enhancing), Tocopherol (vitamin E/antioxidant), Ferulic Acid (antioxidant), Sodium Hyaluronate (hydration/skin replenishing), Acetyl Octapeptide-3 (skin-restoring), Glycerin (hydration/skin replenishing), Panthenol (skin replenishing), Sodium Metabisulfite (stabilizer/antioxidant), Triethanolamine (pH adjuster), Phenoxyethanol (preservative).
Another vitamin C, vitamin E, and ferulic acid combo serum. I’m not entirely sure how Paula’s Choice was able to use this formula. Considering they’re a massive skincare company, they probably negotiated the use of the patent with some dolla’ bills. $$$
This is another great option for those who AREN’T sensitive to malassezia, or especially acne-prone, since it contains hydrogenated castor oil. An ingredient that can be pore-clogging to some.
As for the freshness factor. According to Paula’s Choice, oxidation is less of concern with their vitamin C because it comes in a UV protected bottle with an air-tight dropper system.
Additionally, there are 2 other skin-repairing ingredients (i.e. sodium hyaluronate, panthenol), and a synthetic peptide (acetyl Octapeptide-3) that may help the appearance of wrinkles.
The bottomline: Paula’s Choice C15 is slightly more expensive than Timeless, includes the holy trinity of SkinCeuticals (vitamins C, E, and ferulic acid), somewhat ensures the freshness of Nufountain, but may not be the safest pick for sensitive or especially acne-prone skin types.
5. OST C20 or OST C21.5.
These are two different serums from the same brand. Here are their respective ingredients.
OST C20 (full ingredient list):
Water, Ascorbic Acid, Ethanol, Sodium Lactate, Butylene Glycol, Glucose, Camellia Sinensis Leaf Extract, Rosa Davurica Bud Extract, Carthamus Tinctorius Flower Extract, PEG-60 Hydrogenated Castor Oil, Sodium Hyaluronate, Bis-PEG-18, Methyl Ether Dimethyl Silane, Diethoxyethyl Succinate, Ammonium Acryloyldimethyltaurate/VP Copolymer, Xanthan, PEG-180, Gluconolactone, Beta-Glucan, Citrus Aurantium Dulcis Oil, Zinc PCA, Panthenol, Niacinamide, Glycerin, Tocopherol Acetate, Lecithin, Caprylic/Capric Triglyceride, Ubiquinone, Diisopropyl Adipate, Phenoxyethanol, Methylparaben
pH 2.5 – 3.
OST C21.5 (full ingredient list):
Hippophae Rhamnoides Water, Ascorbic Acid, Sodium Lactate, 1,2-Hexanediol, Sodium Hyaluronate, Panthenol, Cassia Obtusifolia Seed Extract, Allantoin, Xanthan Gum, Ethyl Hexanediol
pH 2.5 – 3
Both of these are formulated with proper pH to work but have their fair share of weaknesses, which is why they come dead last on this top 5 list. Let’s start with the OST C20.
Right off the bat we see that alcohol (ethanol) is pretty high up on the ingredient list. Denatured alcohol isn’t the best ingredient to use on skin. Yes, it helps create a more cosmetically elegant finish, and acts as degreasing agent, but that comes at the cost of drying out the skin.
Ascorbic acid can already be a little irritating on its own because of the inherently low pH required for it to work. The last thing we want to do is further complicate matters by throwing in other suspect ingredients.
Secondly, it has hydrogenated castor oil like the Paula’s Choice C15. Again, you’ll want to avoid this ingredient if you’re especially acne-prone or have malassezia sensitivities. There’s also sweet orange oil in the formula. Just…. why? Citrus oil can be skin sensitizing.
And then we have the fact that they used tocopherol acetate instead of tocopherol as their vitamin E source. Why is this bad? Because there is evidence that tocopherol acetate may actually accelerate photocarcinogenesis! (25) This is the exact opposite thing we want it to do! That is, protect against skin cancer!
Yes, there are good things about this serum too. For example, it comes with ubiquinone, panthenol, sodium hyaluronate, gluconolactone, niacinamide, beta-glucan etc. which are all very EXCELLENT ingredients for skin health. But I feel that they lose their appeal for the reasons I stated above.
As for the OST C21.5 — this is great serum for sensitive skin. There’s nothing in there that’s sensitizing or will cause break outs. Like the Nufountain C20 + Ferulic, it is also 100% safe for adult acne, malassezia, and particularly sensitive skin.
It also comes with 3 amazing skin repairing ingredients (i.e. sodium hyaluronate, panthenol, and allantoin). The downside being there’s no vitamin E or ferulic acid in the formula. That means it has less photo-protective abilities than Nufountain, and a considerably shorter shelf-life.
Are you rich? Got lots of money? Or REALLY care about skincare? :p Go with SkinCeuticals. It comes with vitamin E and ferulic acid to increase the effectiveness of vitamin C eightfold, and is great for everyone and all skin types.
UPDATE 9/20/18: or get Dr. Brenner’s Vitamin C Serum! It’s an extremely affordable dupe for Skinceuticals that includes the holy trifecta (vitamin C, E, and ferulic acid)! In my opinion, this is the best option on the list given its affordability and safe ingredient profile.
Another cheap option without vitamin E that’s slightly less effective, but guaranteed fresh upon order is Nufountain! This too is great for all skin types.
The Timeless Vitamin C Serum is another dupe for SkinCeuticals and Dr. Brenner, however its pH is rather low which can be irritating. Additionally, there are some inactive ingredients in there that aren’t safe for folks with sensitivities to malassezia.
Welp, that does it for this blog post folks. I hope it was helpful and you’ve learned something new today.
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