forms of vitamin c in skincare

Did you know that not all Vitamin C is the same?

Like, there are a gazillion different forms that do pretty much all the same thing. Except…

Some work best at kicking free radicals in the butt while others excel at fading dark spots.

Some have the lifespan of a moth while others will keep your skin company for a few months.

Some sting your skin badly while others will barely make it tingle.

There’s enough to make your head spin, isn’t there? How are you supposed to choose the right type of Vitamin C for you?

Fret not, I’ve done the work for you. Here’s a quick guide to the most common types of vitamin C used in skincare products:

FYI: All types of Vitamin C should help fade dark spots to some extent. Here, I’ve only highlighted those that have been scientifically proven to do this better than the others. All types of Vitamin C could also irritate sensitive skin (what doesn’t irritate sensitive skin?). Here, I’ve only highlighted the more irritating forms. You get the gist.

best vitamin C serum: drunk elephant c-firma day serum

L-Ascorbic Acid

What it is: L-Ascorbic Acid is the pure form of vitamin C. The original. It’s water-soluble.

What it does: It’s a powerful antioxidant that fights free radicals, boosts the production of collagen and reduces dark spots. It’s the most effective form of Vitamin C out there.

Side effects: Super unstable. That means it easily oxidizes (ie, becomes ineffective) when exposed to heat, light and air. This isn’t something you can stock up in the sale and expect it to be effective 6 months later. Buy it only if you’re gonna use it straight away. High concentrations of L-Ascorbic Acid often irritate skin, too – especially when formulated at the low pH it needs to work. One more thing: L-Ascorbic Acid can sometimes cause mini pimples in oily and acne-prone skin types.

Should you use it?: If you’re serious about anti-aging, and your skin isn’t sensitive or oily, this is the best form of Vitamin C out there.

Best Picks:

Related: Skinceuticals CE Ferulic VS Paula’s Choice C15 Booster: Which One Is Better?


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Ascorbic Acid Polypeptide

What it is: A water-soluble derivative of Vitamin C.

What it does: It’s very stable and easily converts to L-Ascorbic Acid when applied to the skin. It provides its same benefits (brightening, collagen-boosting, and wrinkle prevention) with less irritation.

Side effects: It could irritate very sensitive skin.

Should you use it?: There’s not much research on it at the moment. If you’re curious, pick a serum that uses both Ascorbic Acid Polypeptide and other forms of Vitamin C (like the one below).

Best Pick:

  • Be Plain Vitamin Brightening Ampoule ($16.90): Available at Yes Style

Ascorbyl Glucosamine

What it is: Vitamin C + glucosamine (an amino sugar).

What it does: It fights free radicals and reduces dark spots.

Side effects: There’s only little research supporting its effectiveness.

Should you use it?: There’s not much research on it at the moment. If you’re curious, pick a serum that uses both Ascorbic Acid Polypeptide and other forms of Vitamin C.

Best Picks: I currently don’t know any good products that use it.

paula's choice 10% niacinamide booster 01

Ascorbyl Glucoside

What it is: Vitamin C + glucose (a monosaccharide sugar). In-vitro (non on real people) studies show it can penetrate skin.

What it does: It fights free radicals, boosts collagen, and reduces dark discolourations.

Side effects: There are only few studies that support the skin-lightening claim.

Should you use it?: If you have sensitive skin that can’t tolerate L-Ascorbic Acid and are looking for a brightening form of Vitamin C to treat your dark spots, this is worth a try.

Best Picks:

Related: My Full Review Of Paula’s Choice 10% Niacinamide Booster

Ascorbyl Palmitate

What it is: L-ascorbic acid + palmitic acid (a fatty acid). Unlike most other forms, it’s non-acidic.

What it does: It has antioxidant properties, but there’s no evidence it can brighten skin or boost collagen yet.

Side effects: It’s not very stable and goes bad almost as quickly as L-Ascorbic Acid. Plus, we don’t know yet, if it converts into L-Ascorbic Acid once it penetrates skin (if it can’t, it won’t work).

Should you use it?: I don’t recommend it, unless it comes in a product with other, more effective, forms of Vitamin C.

Best Picks:

Magnesium Ascorbyl Phosphate

What it is: A water-soluble derivative of Vitamin C.

What it does: It fights free radicals and increases collagen production. It’s stable, less irritating and effective at lower concentrations than L-Ascorbic Acid

Side effects: Like all other forms of vitamin C, it degrades (but more slowly!) when exposed to light and air.

Should you use it?: If you have sensitive skin that can’t tolerate L-Ascorbic Acid, this is a good alternative to consider.

Best Picks:

Mad Hippie Vitamin C Serum

Sodium Ascorbyl Phosphate

What it is: A L-ascorbic acid monophosphate, consisting of a stabilized (phosphorylated) sodium salt of L-ascorbic acid (thanks to my reader Eva for this info!).

What it does: It’s a powerful antioxidant that fights free radicals, brightens skintone and boosts collagen. Plus, it helps fight acne. Studies show SAP reduces sebum oxidation (a main cause of acne and inflammation) by up to 40%! It’s also more effective than 5% benzoyl peroxide and 0.1% differin.

Side effects: Like all other forms of vitamin C, it degrades (but more slowly!) when exposed to light and air.

Should you use it?: If you have oily or acne-prone skin, this is the best form of Vitamin C for you (better even than L-Ascorbic Acid).

Best Picks:

  • Facetheory Regena C20 20% Stabilized Vitamin C (£18.99): Available at Facetheory
  • Insta Natural Vitamin C Serum ($23.66): Available at Beauty Bay and Yes Style
  • Mad Hippie Vitamin C Serum ($33.99): Available at Ulta

Related: My Full Review Of Mad Hippie Vitamin C Serum

Tetrahexyldecyl Ascorbate

What it is: The newest form of vitamin C on the market. It penetrates skin deeper and faster than any other form of Vitamin C.

What it does: It fights free radicals, boosts collagen production, and brightens skin. Keep in mind that most of the research is done in-vitro, non on human skin. Still, the results are very promising.

Side effects: It may be irritating for sensitive skin.

Should you use it?: If you can’t tolerate L-Ascorbic Acid, this is the next best thing.

Best Picks:

Related: Skinceuticals CE Ferulic VS Paula’s Choice Resist Super Antioxidant Serum: Which One Is Better?

How To Choose The Best Vitamin C Products

Have decided which type of Vitamin C to go for? Great! Here are a few more things to keep in mind when you go looking for it at Sephora (or wherever else you get your skincare fix from):

  1. High concentrations: The higher the concentration, the more effective it is. If your type of vitamin C isn’t at the beginning of the ingredient list, don’t bother.
  2. No jars allowed: Vitamin C loses a bit of its effectiveness when exposed to light and air. Go for an opaque, air-tight tube or bottle.
  3. Better with friends: Vitamin C is more effective when used with Vitamin E and ferulic acid. They also boost the protection of your sunscreen.

What’s your favourite type of Vitamin C? Leave a comment below and let me know.