Is Ethyl Ascorbic Acid a Worthy Vitamin C Derivative?

3-o-ethyl ascorbic acid, or “ethylated ascorbic acid” is a vitamin C derivative that’s risen quickly in the popularity ranks in recent years. But just because it’s a structural cousin of hte famed ascorbic acid doesn’t automatically mean that it’s going to delivery all those vitamin C skin benefits you’re looking for. So let’s break down the science - chemist style - and get the the bottom of just whether or not ethyl ascorbic acid is the stable, gentle, age-prevention superstar worthy of replacing your ascorbic acid serum.

Why do we use vitamin C derivatives in Skincare?

Vitamin C is one of the most well-known actives in the skincare realm - and for good reason. It’s pretty much THE proven topical antioxidant with benefits ranging from age-prevention to skin brightening. But unfortunately, the form of vitamin C behind all these proven benefits (L-ascorbic acid) is a finicky, unstable ingredient that’s very difficult to work with in formula. This means that many formulas lose their potency before you even finish the bottle. 

This is where vitamin C derivatives come in. Vitamin C derivatives are molecular “cousins” of L-ascorbic acid that touts similar skin benefits but with enhanced stability. 

That said, not all derivatives perform equally, and each one should be judged on its own merits. Just like the retinoid family (tretinoin, retinol, retinaldehyde, adapalene, etc.), the efficacy, optimal formulation type, and efficacy can vary. 

3-o-ethyl ascorbic acid skin benefits (according to clinical data)

So just how does 3-o-ethyl ascorbic acid (EAA) clinical data stack up? How believable is the marketing data? Let’s break it down one by one.

Stability

This is the most straightforward part of the research. Research shows that 3-o-ethyl ascorbic acid is significantly more stable than l-ascorbic acid, maintaining integrity over the course of a week in controlled tests in elevated temperatures. Though this was only a short test, the fact that ethyl ascorbic acid was tested directly against L-AA is a promising sign.

This however, doesn’t mean that your EAA serums are automatically ultra-stable. In another study, the stability of EAA was tested in a range of common cosmetic solvents such as propylene glycol, glycerin, hexanediol, etc. and showed that the solvent can directly impact EAA stability over time. This means that the formulation still plays a big part in stabilizing EAA.

Antioxidant Potential

Of course, we can’t talk about vitamin C without touching on antioxidant potential. Sadly… this is where things get a bit nuanced. While 3-o-ethyl does have demonstrated antioxidant activity, it’s also proven to be less efficient as l-ascorbic acid at neutralizing free radicals. In fact, there are studies (in vitro) that show the same concentration of EAA can only quench half the free radicals that pure ascorbic acid can quench. Though in vitro concentration doesn’t always directly translate to topical use (ie. this doesn’t necessarily mean you need to scope out a 30% 3-o-ethyl product for it to work), it’s also not a great look for those arguing EAA is just as good an antioxidant as OG ascorbic acid.

Brightening and Collagen Support

Lastly, another cornerstone of vitamin C skin benefit are brightening and collagen boosting properties. 3-o-ethyl clinical data here is quite weak. We couldn’t find any clinicals that tests 3-o-ethyl products directly on human skin. There are in vitro studies on melanocytes (pigment-producing skin cells) that show 3-o-ethyl can inhibit melanin production. There are also in vitro studies that show collagen protection benefits. But ultimately, the lack of actual topical human studies doesn’t give us a lot of confidence.

Who should use 3-o-ethyl ascorbic acid?

Compared to L-ascorbic acid, sadly, 3-o-ethyl seems to show promise, but with sparse at best clinical evidence. That said, if L-AA serums that semll like hot dog water are just not for you, you can consider 3-o-ethyl in these scenario:

• Sensitive skin users: 3-o-ethyl is a fairly vanilla ingredient with less irritating potential than L-AA. They’re also typically formulated right around the same pH as your skin, compared to L-AA serums’ low pH of under 3.5. Moreover, you can find options on the market at low concentrations much easier than L-AA, making this a solid option for sensitive skin users.

• Those who struggle with oxidized hot dog waters: because of the enhanced stability, you’re less likely going to end up with brown, meaty-smelling juice after a month of use

That said, if your skin tolerates L-AA well and you are after more reliable efficacy, we’d say L-AA is still the way to go.

The best ethyl ascorbic acid serum on the market

If you’re thinking of trying this ingredient out, but not sure how to choose, we tested some of the most popular ones so you don’t have to try them all. Here are our chemists notes on each of hte ones we’ve tried:

1. Beauty of Joseon Light on Serum

1. Formula notes: 10% 3-o-ethyl with centella asiatica water as the main base, which gives it a slightly soothing touch

2. Texture: lightweight  emulsion with a clean, soft finish. Not enough to be a standalone moisturizer, but adds a bit of hydration.

3. Chemists’ Verdict: Our favorite texture-wise - layers nicely with a medium concentration of 3-o-ethyl

2. Elf Bright Icon Serum

1. Formula notes: 15% vitamin C (blend of 3-o-ethyl and L-AA), 1% vitamin E, 0.5% ferulic acid

2. Texture: feels and smells like it’s trying to mimic the famed CE Ferulic - so sticky and melly

3. Chemists’ Verdict: might as well just use actual CE ferulic at this rate…

3. Olay Vitamin C + Peptides Brightening Serum

1. Formula notes: 3-o-ethyl (guestimated at 2% max), niacinamide, peptides, and low levels of lactic acid

2. Texture: lightweight emulsion - not as elegant as Beauty of Joseon’s, but still light and easy to layer

3. Chemists’ Verdict: niace supporting cast of ingredients at low concentrations. Good intro product

4. Innisfree Green Tea Enzyme Vitamin C Serum

1. Formula notes: 3-o-ethyl (concentration likely around the same as Olay’s), niacinamide, ferulic acid, glutathione (another antioxidant)

2. Clinical Data (gasp!): 45% reduction in dark spots after 4 weeks with 32 women

3. Texture: hydrating, comfortable texture feel

4. Chemists’ Verdict: solid pick for the clinical alone

5. Numbuz:n No. 5 Serum

1. Formula notes: big blend of actives with niacinamide, tranexamic acid, and glutahione. 3-o-ethyl only in here at 0.01% - only included here because this will come up when you search for 3-o-ethyl

2. Texture: it’s okay - slightly sticky but still pretty layerable

3. Chemists’ Verdict: Interesting combo of actives aimed to target hyperpigmentation. Would not consider this as a vitamin C serum, should actually pair well with classic CE Ferulic

Final Verdict: Is 3-o-ethyl ascorbic acid a worthy vitamin C derivative?

3-o-ethyl ascorbic acid is an intriguing derivative with stability advantages over old school pure vitamin C. But ultimately, testing and clinical evidence of efficacy remain at a very early stage. So if you're frustrated with unstable vitamin C serums, 3-o-ethyl might be worth exploring, but just set your expectations straight. There are interesting products in this category with good supporting ingredients, but 3-o-ethyl alone should not be considered a worthy one-to-one replacement for L-AA.

3-o-ethyl Ascorbic Acid on the Chemist Confessions Podcast

References

Golonka, I., Oleksy, M., Junka, A., Matera-Witkiewicz, A., Bartoszewicz, M., & Musiał, W. (2017). Selected physicochemical and biological properties of ethyl ascorbic acid compared to ascorbic acid. Biological and pharmaceutical bulletin, 40(8), 1199-1206.

Golonka, I., Oleksy, M., Junka, A., Matera-Witkiewicz, A., Bartoszewicz, M., & Musiał, W. (2017). Selected physicochemical and biological properties of ethyl ascorbic acid compared to ascorbic acid. Biological and pharmaceutical bulletin, 40(8), 1199-1206.

Liao, W. C., Huang, Y. T., Lu, L. P., & Huang, W. Y. (2018). Antioxidant Ability and Stability Studies of 3-O-Ethyl Ascorbic Acid, a Cosmetic Tyrosinase Inhibitor. Journal of Cosmetic Science, 69(4), 233-243.

Zerbinati, N., Sommatis, S., Maccario, C., Di Francesco, S., Capillo, M. C., Rauso, R., ... & Mocchi, R. (2021). The anti-ageing and whitening potential of a cosmetic serum containing 3-o-ethyl-l-ascorbic acid. Life, 11(5), 406.