I recently wrote an article about how beneficial vitamin C is for your skin, (in particular at fading hyperpigmentation). In this article, I talked about what factors you should consider when buying a vitamin C serum – one of those factors being what form of vitamin C the product contains (hint: it’s L-ascorbic acid).
It’s true, L-ascorbic acid (also known as L-AA) has the most amount of skincare research behind it and it’s therefore considered to be the best form of vitamin C for your skin. However, skincare products containing high concentrations of L-AA tend to be pricier than those containing other forms of vitamin C.
So, today I want to find out. What are the other forms (derivatives) of vitamin C used in skincare products, and how do they compare to L-AA? Are they just as good as L-AA in terms of fading hyperpigmentation and increasing collagen production?
How Is Vitamin C Beneficial For The Skin?
Vitamin C is an antioxidant – meaning it protects the cells in our body from free radical damage. When it comes to your skin, vitamin C protects against damage from ultraviolet light (AKA sun damage).
Vitamin C also has other big benefits – including it’s capability to increase collagen production (softening fine lines and wrinkles) and fading hyperpigmentation (including sun spots and post-acne marks).
I won’t go into the biochemical details of how vitamin C achieves this, but just perhaps trust me when I say that vitamin C is a powerful skin-brightening and anti-aging ingredient!
A Little Bit About L-Ascorbic Acid First
As I’ve already mentioned, L-AA is the preferred form of vitamin C used in skincare products.
This is because L-ascorbic acid is the active form of vitamin C (the form that the body can readily use) and is already naturally present in our skin and it’s role in skin biology has been well studied.
All the other forms of vitamin C are called derivatives, and must be converted into ascorbic acid first before having any effects on the skin.
So why don’t we just stick to L-AA? Why are other products being formulated with derivatives of vitamin C? The answer is that L-AA is a highly unstable ingredient that is difficult to formulate. It requires a pH below 3.5 (if in an aqueous solution) to prevent it from oxidizing very quickly – which can make it harsh to skin, causing skin irritation for some people or even exacerbating acne.
And I should mention, once the L-AA in your product has oxidized – it is no longer effective. This can be really frustrating and disappointing if your bottle still has so much product left in it and you don’t really can’t afford to buy another bottle.
Another downside of L-AA requiring such a low pH to remain stable is that applying it requires a wait time of 10-20 minutes before proceeding to the next step in your skincare routine. And we all know how precious our time is these days!
Vitamin C Derivatives Used In Skincare
The unfortunate downsides of L-ascorbic acid I mentioned above has led to the development of vitamin C derivatives, including:
- Sodium Ascorbyl Phosphate (SAP)
- Magnesium Ascorbyl Phosphate (MAP)
- Ascorbyl Palmitate (AA-PAL)
- Ascorbyl Tetra-Isopalmitate (VC-IP)
- Ascorbyl Glucoside (AA-2G)
- Ascorbyl 2-Phosphate 6-Palmitate (APPS)
- 3-O-Ethyl Ascorbate (EAC)
Now, let’s take a quick look at the properties of each of these L-AA derivatives. The first two derivatives (SAP and MAP) seem to be used in products the most and also appear to have the most research behind them (out of all the vitamin C derivatives).
While doing the research for this article, I noticed that vitamin C derivatives really aren’t being utilized as ingredients in Korean skincare products as much as they are in Western skincare products . Although there are Korean vitamin C serums available, most appear to contain L-AA.
So for now I’ve mostly recommended Western skincare products in this article (and it’s totally okay to have a mix of Korean and Western products in your skincare routine). However, hopefully this will change in the coming years and I’ll be able to add some more Korean skincare products containing vitamin C derivatives.
Sodium Ascorbyl Phosphate (SAP)
Sodium ascorbyl phosphate (SAP) is a water-soluble precursor of ascorbic acid. It may be a better option than L-AA for people with very sensitive skin, as it’s most stable at a pH of around 7. In other words, it’s much more gentle on the skin compared to L-AA.
Studies on human skin have shown that SAP does protect the skin from UV radiation, reduce skin pigmentation and increase collagen production. It has also been shown in many studies (such as here, here and here) that this form of vitamin C is effective against Propionibacterium acnes, the bacteria that causes acne.
SAP is a very soothing ingredient and appears in some very hydrating serums, such as the DERMA-E Vitamin C Concentrated Serum. This serum also contains a bunch of other beneficial antioxidant ingredients such as green tea, vitamin E and vitamin A (in the form of rosehip oil). It also contains aloe vera gel extract and hyaluronic acid for extra hydration.
One of the only Korean products I found to contain a vitamin C derivative is the Seoul Ceuticals Day Glow Serum, which contains a whopping 20% SAP, as well as vitamin E, ferulic acid, and hyaluronic acid. This powerful little bottle of vitamin C serum is actually often considered a dupe of the popular (but much more pricey) Skinceuticals Vitamin C + Vitamin E + Ferulic Acid Serum (which contains 15% L-ascorbic acid)!
Another great SAP-containing skincare product I would highly recommend is the Mad Hippie Vitamin C Serum! It also contains vitamin E, ferulic acid, hyaluronic acid, konjac root powder, grapefruit, chamomile extract, and clary sage, and really not much else – so you know it’s good for your skin.
However, SAP is still a fairly new derivative and so there is not a great deal of research comparing it’s effects to the effects of L-ascorbic acid. This means that although it has been shown to provide many benefits to the skin, we just don’t know yet how much of the derivative converts to ascorbic acid on the skin.
Magnesium Ascorbyl Phosphate (MAP)
Magnesium ascorbyl phosphate (MAP) is very similar to SAP, in that it is also a water-soluble derivative of ascorbic acid – AND, it’s also stable at a neutral pH of 7, therefore having a gentle effect on the skin. However, studies have shown that although it is a more stable form of vitamin C, it is less effective (or potent) as L-ascorbic acid.
This in vitro (test tube) study compared the skin effects of some vitamin C derivates to ascorbic acid. They found that L-ascorbic acid had the best antioxidant potential, however MAP showed another significant affect – that it is able to improve hydration deeper within the skin than ascorbic acid and other derivatives.
If your skin is too sensitive for L-AA, and you would like to use vitamin C as a preventative ingredient in your routine, then MAP may be a good alternative.
I highly recommend the NuFountain CelSignal MAP and B3 Hydrating C15 Serum. This serum contains 15% MAP, as well as hyaluronic acid and 5% niacinamide (yes, you CAN use vitamin C and niacinamide together) – AND it’s got a pH of about 5.5 (the pH of healthy skin). It’s also made fresh (in the USA) when you order!
Ascorbyl Palmitate (AA-PAL)
Ascorbyl palmitate (AA-PAL or sometimes AP) is a vitamin C ester (formed from ascorbic acid and palmitic acid). It is fat-soluble as opposed to water-soluble (like ascorbic acid, sodium ascorbyl phosphate and magnesium ascorbyl phosphate).
Just as with ascorbic acid, this vitamin C derivative also requires a low pH to remain stable. Animal studies have shown that it does penetrate the skin, although this is highly dependent on the formula.
There is also currently no data to show that it converts to ascorbic acid in the skin, although studies have shown that it does protect against UV radiation damage. Sadly no studies have been conducted to determine whether it is effective at reducing skin pigmentation and only in vitro (test tube) testing has shown that it increases the production of collagen.
A great vitamin C product that contains ascorbyl palmitate (as well as 4 other vitamin C derivatives) is the Drunk Elephant C-Tango Multivitamin Eye Cream. Since it doesn’t contain L-AA, it’s gentle enough for the eye area but still has anti-aging and skin-brightening benefits!
Ascorbyl Tetra-Isopalmitate (VC-IP)
Ascorbyl tetra-isopalmitate is more commonly known as tetrahexyldecyl ascorbate. Like ascorbyl plamitate, it’s also oil-soluble, however, it’s derived from ascorbic acid and isopalmitic acid.
It is stable at a pH below 5 making it easier to formulate than ascorbic acid. It’s been shown to remain stable in air and water for up to 18 months!
Studies have shown that it penetrates both the epidermis (the uppermost layer of the skin) and the dermis (the deepest layer of the skin). It has also been shown to have a higher rate of conversion to ascorbic acid within the skin when compared to other vitamin C derivatives (although studies have only been in vitro so far).
Just like the other vitamin C derivatives mentioned here, once tetrahexyldecyl ascorbate has been converted to ascorbic acid within the skin, it acts as an antioxidant (preventing free radical damage), reduces the production of melanin, and boosts the production of collagen.
Although all results of studies on tetrahexyldecyl ascorbate have only been in vitro so far, I was really interested to learn about the benefits of this derivative and I think it’s a great option for people who’s skin is too sensitive to ascorbic acid (or who’s wallets can’t afford a new bottle every 3 months due to oxidation).
Here are a couple of great skincare products that you can find tetrahexyldecyl ascorbate in:
- Dr Dennis Gross C + Collagen Serum – A brightening and firming vitamin C serum containing 3 forms of vitamin C, niacinamide, and superoxide dismutase.
- Paula’s Choice Resist Super Antioxidant Serum – A hydrating and antioxidant enriched serum, containing two forms of vitamin C (tetrahexyldecyl ascorbate and magnesium ascorbyl phosphate), as well as vitamin E and ferulic acid. It also contains bearberry extract, which is a natural skin-lightening ingredient.
I did manage to find a Korean brightening serum that contains tetrahexyldecyl ascorbate: It’s Skin Power 10 Formula VC Effector. It comes in a beautiful yellow dropper bottle, has so many positive reviews, AND it’s super-affordable.
Ascorbyl Glucoside (AA-2G)
What do you get when you combine a glucose molecule with ascorbic acid? You get ascorbyl glucoside – a stable and water-soluble vitamin C derivative. Although it is water-soluble (which allows for a more pleasant serum texture), it is not as potent as ascorbic acid.
Research into the effectiveness of this vitamin C derivative is really lacking, and currently most studies including ascorbyl glucoside are company affiliated and in vitro only.
However, the upside of ascorbyl glucoside is that it has a much longer shelf life compared to ascorbic acid, and it’s not irritating on the skin. If you’d like to include ascorbyl glucoside in your routine, you should try Paula’s Choice BOOST 10% Niacinamide (Vitamin B3) Booster. As the name suggests, this serum also contains 10% niacinamide, as well as licorice root extract – making this serum perfect if you’d like to reduce the size of your pores, even out fine lines and wrinkles, as well as brightening and evening your skin tone.
Other Vitamin C Derivatives
There are a few more vitamin C derivatives that I haven’t mentioned (such as Ascorbyl 2-Phosphate 6-Palmitate and 3-O-Ethyl Ascorbate), however I won’t go into these as the research becomes really scarce and you’d be hard-pressed trying to find skincare products containing them.
It’ll be interesting to see how skincare products continue to incorporate vitamin C derivatives over the next few years, and I wonder if we’ll be seeing more Korean skincare products containing vitamin C derivatives too. I definitely see a lot of potential for at least some of the derivatives I’ve mentioned here.
Vitamin C has many known benefits, especially when it comes to protecting the skin from UV damage, reducing hyperpigmentation and boosting collagen production.
Ascorbic acid is the preferred form of vitamin C (by skincare brands and skincare enthusiasts), however it is a highly unstable ingredient that requires a very low pH – making it not only one of the most expensive products in your routine (since it has a very short shelf life), but also potentially irritating to use for some people.
That’s where vitamin C derivatives such as sodium ascorbyl phosphate, magnesium ascorbyl phosphate, and tetrahexyldecyl ascorbate come in. These ingredients are much more stable and easier to formulate than ascorbic acid – which means they are less irritating on the skin and have a much longer shelf life.
Although there are many awesome skincare products available with vitamin C derivatives, and we know from research that these ingredients do convert to ascorbic acid in the skin – we still require quantitative studies on actual human skin to determine if they are as effective as ascorbic acid.
As you will have noticed, I have mainly recommended Western skincare products in this post. That’s because I just couldn’t find many Korean skincare products with vitamin C derivatives in them. Since skin brightening is such a common skincare concern, I really thought it was useful to include these products (even if they aren’t Korean). Hopefully we will start to see some Korean skincare brands utiziling some of these vitamin C derivatives in their products soon.