I don’t know about you but trying to decipher the different (and many) forms of vitamin C out there just left me contemplating if I reeeeeally needed that ever sought after glow. But once the headache from reading passed, I decided that ‘Yes!’ I did want and need that glow haha! So let’s GLOW… (I couldn’t resist!).

Let’s start at the top of the chain, the absolute gold standard form of vitamin C for our skin…

Ascorbic Acid

Pure vitamin C, otherwise known as ascorbic acid or L-ascorbic acid (L-AA) is the most researched form of the vitamin when it comes to benefits for the skin.

You will see many ascorbic acid-containing products out there with high concentrations. This is because many studies that show efficacy used L-ascorbic acid with concentrations of 15% or higher. So, we know this is the minimum amount we want in our products in order to experience the benefits that ascorbic acid can offer (for a recap on the benefits, see here).

But in short, Vitamin C has three main benefits for the skin: it’s an antioxidant, can boost collagen and brighten the skin.

What About The Stability Of L-AA?

So, this great form of vitamin C is unstable. It can oxidise quickly when exposed to water, heat or air. This is because of L-ascorbic acid’s strong desire to bind to free radicals, like oxygen (this process is called oxidation). Which is great on our skin but not if it’s happening inside the bottle it’s contained in, before it even reaches our skin!

Once vitamin C is oxidised, it changes colour from clear to slightly orange and then dark orange. This colour change shows that the activity of ascorbic acid is disabled. Basically it’s not performing much of those great benefits mentioned above!

This is why you will see brands either employ the use of an airless and dark coloured container (if a water-based formula) or they will base the L-AA in a water-less solution. This is all to help the ascorbic acid from being negatively affected by heat, light or air and ultimately, last longer.

Another way of getting around the stability issue of ascorbic acid is by using…

Derivatives Of L-AA

So on to other forms of vitamin C, which are known as derivatives of ascorbic acid. These derivatives have been made to be stable because as we know, pure vitamin C tends to be very unstable and hard to formulate. Plus, pure vitamin C products, once opened, have to be used up very quickly before they oxidise. They are also generally expensive because of that difficulty to formulate and so both of these factors can be very off-putting to consumers like me and you!

Therefore, because of these issues the skincare industry came up with some derivatives that still have the same incredible anti-ageing properties of pure vitamin C (antioxidant protection, collagen boosting and fading hyperpigmentation) but without the disadvantages (unstability and difficulty to formulate). 

Some derivatives of ascorbic acid that exist are:

  • Ethyl Ascorbic Acid: consists of L-AA and an ethyl group. This form is soluble in both water and oil and appears to penetrate the skin well (better than ascorbyl glucoside which currently holds the title!). It acts directly like ascorbic acid and is closer in molecular weight to L-AA. This allows for faster visible results.
    This derivative also appears to have both an antioxidant and anti-inflammatory effect, and it’s claimed to be able to boost the skin’s collagen production and brighten the skin. Overall, Ethyl Ascorbic Acid is a very promising but not a fully proven Vitamin C derivative. 
  • Ascorbyl Glucoside: a form of L-ascorbic acid combined with glucose. This makes it much more stable in water compared to L-AA but much less potent. It’s a well-researched derivative that’s easy to formulate, has great brightening abilities but its ability to improve uneven skin tone or spots is relatively weak. We do know that it penetrates the skin well also. 
  • Tetrahexyldecyl Ascorbate (TDH): an analogue of L-ascorbic acid which is oil-soluble. This form of vitamin C can penetrate the epidermis (top layer of skin) and the dermis (second layer of skin) very well. As shown by many studies and unlike other forms of vitamin C. However, like most derivatives, it may be well absorbed by the skin but we’re unsure how much of it is actually converted into ascorbic acid for use by the skin.
  • Magnesium Ascorbyl Phosphate (MAP): a water-soluble, effective antioxidant for the skin but, less potent than L-AA. This form can increase skin’s hydration and is effective at skin brightening (more so than other derivatives). It’s usually found in a concentration of 10% or less due to how difficult it is to solubilise. We do know as well that this derivative is poorly absorbed by the skin so this leads us to question how much ascorbic acid you would actually get in the skin from this derivative. 
  • Sodium Ascorbyl Phosphate: A water-soluble form of L-ascorbic acid. It’s L-ascorbic acid combined with palmitic acid, a fatty acid, and sodium. It’s potentially effective for brightening an uneven skin tone and has been shown in research to positively influence factors linked to breakouts (at concentrations between 1% & 5%). This is because of its strong antimicrobial activity on acne causing P. acnes. However, sadly it has been shown to be poorly absorbed by the skin and therefore, its ability to convert into ascorbic acid for the skin to use appears limited!
  • Ascorbyl Palmitate: a non-acidic, oil-soluble form of L-ascorbic acid. Less stable than Sodium Ascorbyl Palmitate, Magnesium Ascorbyl Palmitate, or Ascorbyl Glucoside. Particularly good at minimising environmental damage to the skin but that’s about it!

There are lots of different derivatives out there but hopefully this list helps you to feel a bit clearer on what’s in your different vitamin C products! Screenshot the list if you would like, so that it’s handy for you to refer back to when shopping around for vitamin C products!

Ok so why don’t we just use the derivatives of vitamin C, what’s the fuss about pure vitamin C?!

They Have To Convert

Vitamin C derivatives are a great alternative to using L-ascorbic acid. However, they still need to be first absorbed by the skin (as we’ve discussed above) and then converted to pure vitamin C (L-ascorbic acid). This conversion occurs when the derivatives have penetrated the skin.

And so because of this, a direct comparison on their potency compared to L-ascorbic acid cannot be made. This is because the efficacy of the conversion is often unknown. So what that means is, all of the derivative may be absorbed by the skin but how much of that amount is then actually converted into pure vitamin C/ascorbic acid, we don’t know! 

However, some derivatives have been shown to have better brightening effects than L-ascorbic acid (e.g. MAP). And so some research into the product reviews of a derivative form of vitamin C that you are looking at, is definitely worth it. This is especially true if you are primarily looking for brightening results. If you are looking for the other general benefits that vitamin C can offer, then that is where L-AA wins hands down!

Well that’s it from me on vitamin C derivatives. If you’re wondering why I’m looking at these in depth, it’s because my next product review is on a vitamin C serum which contains Ethyl Ascorbic Acid and Ascorbyl Glucoside. So, I thought it would be helpful to look in-depth at the ingredients before we go into the product review!

Subscribe here to not miss that product review!

Love & Knowledge



Want to read more about ascorbic acid and the above derivatives? Incidecoder is a great place to go for help on decoding ingredients!

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