Vitamin C in Skin Care: How Does it Work?

vitamin c in antiaging skin care
Vitamin C.... doesn't it kind of sound like someone just decided to take their grandmother's advice for the common cold and extrapolate that to anti-aging skin care? Or maybe it was just an ingredient laying around that was easy to incorporate into more items?

Actually, it really does work.

So, what does it do?

First, go back to my how anti-oxidants work in skin care post to review oxygen free radicals and how anti-oxidants scavenge up those extra electrons. Remember that while those free radicals may have been taken care of, the damage that they've already done is still there.

So, Vitamin C, aka ascorbic acid, is one of those anti-oxidants that go around mopping up free radicals. But it also does so much more!

Read on to learn about all the different things that Vitamin C does, a little more about how it does them (I promised I've translated as much as possible into "regular" language, though this post is definitely of a higher level than most), and what to look for in a Vitamin C preparation.

Vitamin C as Anti-Oxidant
aka.... Problem: Vitamin C is Easily Inactivated
Yup, unfortunately this is true. It has to do with the chemical structure of the ring and things that can happen to it. Some of this chemistry is a little beyond me (I haven't taken a real chem class since I was a pre-med, though I did take a lot of them at that time!), so I'll ask my chemical engineering prof hubby if this is correct.

As I understand it, most of the Vitamin C in our bodies is in the Ascorbic Acid form (top right). If it accepts an electron (as part of being an anti-oxidant) it becomes the Ascorbate Ion. What's interesting about this ion is that while it is "transient", it is more stable than many other transient ions. It can do one of two things... either donate that electron somewhere else, or pick up a second electron (aka- be an anti-oxidant again!). So, really it doesn't stick around long as the Ascorbate Ion, it either goes back to Ascorbic Acid or it goes on to become Dehydroascorbic Acid (DHAA).

Now, here is where there is a problem. While DHAA could give off one, or even both of those electrons to go back to Ascorbate Ion or Ascorbic Acid, sometimes that doesn't happen. Sometimes that pentagon ring there opens instead. Once that ring opens, there is no going back. The whole thing is stuck and the Vitamin C is now inactivated.

Unfortunately, this can happen very quickly. Expose that Vitamin C to a high free radical situation, such as direct sunlight or air and the molecule can quickly progress back and forth between the 3 forms until that ring opens up and it is inactivated. So, Vitamin C quickly accepts those electrons, which can make it a potent anti-oxidant. But, that can lead to quick inactivation.

Cool Thing About Vitamin C: It Helps Collagen and Elastin Creation
Ascorbate is needed in the creation of collagen. Without it, there is no collagen production, or if any is made at all it is structurally not sound since it can't form properly. This is why Vitamin C deficiency results in Scurvy (oh yeah, remember that?). It also helps with elastin production, though the mechanism isn't quite clear.

Why do you care about collagen and elastin? If you head back to my dermis post you'll read about how important they are in the skin's structural integrity and elastic capabilities. They are key for anti-aging!

What does Vitamin C do to collagen and elastin? There is some evidence that fibroblast cells, in a petri dish, will increase their collagen production is response to extra ascorbic acid. However, it might be a bit of a balance since cell cultures with elevated ascorbic acid levels have less elastin. I know, it is all very confusing, especially since these findings seem to contradict each other. Remember that these studies are done in Petri dishes, which aren't exactly the same environment as your skin.

So, What Happens to Skin when you apply Vitamin C?

1) Aging
There have been studies finding improvement in wrinkles with application of Vitamin C over several months. These studies are not ideal as they aren't our "gold standard" of a randomized, double blinded trial, but they are positive results.

It isn't entirely clear how Vitamin C had this effect on wrinkles. Subjects in these studies tend to experience irritation from the Vitamin C application. Is the improvement in wrinkles due to increased collagen, or did the irritation and inflammation itself do something?

2) Hyperpigmentation
Vitamin C is frequently overlooked as an ingredient to help fight hyperpigmentation. It will inhibit the enzyme tyrosinase, so it helps prevent melanin production. There have been studies that found significant lightening of hyperpigmentation with vitamin C. What is really cool about Vitamin C as a pigmentation fighter though, is that one researcher found that Vitamin C didn't lighten the skin of normal people. Which means that it seems to target the problem pigmentation areas, but leaves everything else alone.

So, use Vitamin C without worrying that it will lighten your skin. Or use it to target those areas of hyperpigemention, but don't worry that it will lighten everything around the problem area, making it stick out even more.

3) Anti-Inflammatory
Vitamin C has been found to work as an anti-inflammatory. Cells in culture have been found to have decreased levels of inflammatory markers. This has lead some to theorize that Vitamin C can help post-inflammatory hyperpigmentation.

So, How Should You Use Vitamin C?
The interesting thing to know is that oral supplementation of Vitamin C does not seem to affect levels in the skin beyond normal. Meaning, you can drink all the OJ you want, just because there is more Vitamin C in your system doesn't mean that your body will transport it to your skin or that your skin will even work to take up more of the available Vitamin C from the blood. More of that "you can lead a horse to water" theory, similar to whether increasing oxygen levels will help your skin. So, you'll need to supplement topically.

Vitamin C can be formulated many different ways for skin application. The bad news is that many of these forms aren't able to penetrate beyond the most superficial layers of the skin, which makes them essentially useless. While there are some manufacturers that claim to have altered formulations to target specific areas of the skin, no one has actually compared absorption rates and depths in human subjects.

What to Look for in a Vitamin C Product
As well, remember all of those instability issues above? You spent the money on that Vitamin C, make sure it doesn't become inactivated before it even leaves the package!

You should look for Vitamin C products that come in airtight and UV Protected packages. Other strategies have been employed to improve stability, such as encapsulating the Vitamin C, excluding oxygen during the formulation process and using a low pH (in other words, making the formula acidic).

Side Effects
I mentioned it a little above, but you'll likely have some irritation from Vitamin C use. Usually just a little stinging and mild irritation. My main dermatology text book recommends telling patients to include it in their diet not for the effects on the skin (again, remember you can't increase the levels in the skin with oral supplementation), but to extend the anti-oxidant benefits to other organs in the body.

My book specifically mentioned the brands Skinceuticals, Murad, La Roche-Posay as the best for effective Vitamin C products.


  1. I love these scientific posts. Cant wait to read more.

  2. Thank you for such an informative article - so helpful to find this when there is so much misinformation around!

  3. Love the technical stuff! I'm a dentist and I've forgotten most of my regular chem classes as well, except for organic chem for some reason.

  4. Great post that put in understandable terms confusing chemistry that's really important. When the vitamin C in a product is inactivated it's caramel colored, that's one way to see if the product still has some active. I've tried lots of vitamin C products over the years in my practice and CRS is the one that I think is tops. The Topix chemists used a dimethicone base and the airtight, light impenetrable container that we want to see. It would be nice to get great studies but they just don't happen without a big pharma budget. Hmmm

  5. Great job breaking down the information! I love learning about how anti-oixidants work to help the skin.

  6. Great post! I used to use Skinceutials C&E Ferulic serum but it just got too expensive. That was also before I became a beauty blogger and had to try eleventy billion different skin care brands. I think I will try to find a cheaper Vitamin C serum and incorporate it back into my routine.

  7. Great post. For someone like me who knows nothing I'm thrilled to have an expert opinion.

  8. Thanks for the great comments everyone! I worked on this post for MANY hours. :D

    Cindy, I've used that same serum and really liked it, though I agree that it is expensive! I need to write it up still, I had been waiting on this post to be complete before I did. Hopefully in the next month or so.

  9. Great post Christine!! I have been reading and hearing so much about Vitamin C lately...The Kiehl's New Year's live chat that just happened kept bringing it up. I just looked up some of the brands you recommended and most of the Murad Essential C products, such as the Active Radiance Serum which claims to have a Vitamin C complex, don't have Absorbic Acid listed as their ingredients, but they have Absorcate or Orange Oil..are these just as good? Sorry I am still confused about the chemistry and what ingredients to look for!!

    Essential-C Daily Renewal Complex® has Absorbic acid listed in the ingredients and it is their most expensive products of the Essential C so I am thinking maybe that is the most authentic?

  10. The orange oil shouldn't be as good (think of it like you would Orange Juice, there's Vitamin C in there but it's just one component), but the Absorcate is probably the vitamin C.

    I wouldn't worry as much about which form of Vitamin C (other than orange oil, I probably wouldn't count that as Vitamin C), I'd look for anything that says Ascorb... or Vitamin C and pretty much count that.

    The Essential C Daily Renewal has it as the #2 ingredient, the Active Radiance Serum has Sodium Ascorbyl Phosphate, which is also Vitamin C (it's about 25% down), the Essential-C Day Moisture SPF 30 has Tetrahexyldecyl Ascorbate...

    They all seem to have Vitamin C, though when you look the Ascorb bit is just buried in there a little. Quite a few of those forms, like that Tetrahexyldecyl Ascorbate have been chemically altered to be more easily absorbed and more stable, which is great!

  11. So I've started using vitamin C, but I've heard that not only is unstable or oxidized vitamin C useless, but that oxidized vitamin C can actually have the opposite effect on skin health if used because of radical formation. What do you think of this? And, do the benefits of using Vitamic C serum outweigh costs of possibly using a bad batch? is there a good way to test vitamin C presence at home? maybe with a litmus strip or a simple titration?

  12. Hi Shruti,
    Because the vitamin C will have that ring break pretty quickly once it becomes fully oxidized, its chemical structure is changed enough that it can't give off any radicals/assist in radical formation. Theoretically, it could do this prior to the ring breaking, but it goes back and forth readily and then the ring breaks, effectively trapping those free radicals in the vitamin C that's now broken. So, I wouldn't worry about radical formation, there's a reason so many derms love Vitamin C :D

    I don't know of a way to check for activity at home. Dr. Bailey does say in her comment above that "When the vitamin C in a product is inactivated it's caramel colored, that's one way to see if the product still has some active" So, that seems like a pretty easy way to me!

  13. Great post! Thanks(:
    Rawrs, Evey

  14. I would love to hear your take on post-call skincare!

  15. Thanks for the article dear. It was so helpful.

  16. This is a very long post that really says you just don't know. So just say that!

  17. I'm pretty sure it didn't say that at all....

  18. Are you mental? I am a professional with a science background and I can tell you that the talk about free radicals and electrons is pure gibberish. I don't care what terminology you use to promote beauty products, but please don't misuse actual science terms!

  19. Umm... I guess anyone feels free to be rude in the internet, huh?

    I'm board certified in 2 specialities, and I'm married to a chemical engineer. While I've simplified things and converted over to lay terms to explain scientific ideas (something any physician should be able to do when talking to their patient), and I've tried to make things entertaining, I find it interesting that you think free radicals are pure gibberish.

    In fact, free radicals (and reactive oxygen species) were first proposed in the 1950s and are a VERY widely accepted theory for aging of the skin, something I've made up for fun.


  20. Do you know about any vitamin c product you can buy at a health food store or pharmacy that can be used on my skin? I have hyperpigmentation all over my face. And thank you for your post, very informative!

  21. Not that I know of from a health food store. I'd look at products like the Kiehl's Clearly Corrective.

  22. Hi... I love your article even though I can only understand some of it..LOL.. Right now I am using Vitamin C powder
    ( L- ascorbic acid). I make a small amount everyday just before using it and use it with Hyaluronic acid powder also .
    I have a few scar that have some pigmentation so I am hoping it helps. So far they look a bit better ! To make it absorb a bit better I have been using a derma roller with short needles and go over my fave only lightly a few times. It gets red but disappears after an hour so I do this at night. I have seen results and honestly I think my skin is looking a bit more even skin toned and smooth. I use alot less makeup now and love that ! I am going to do this always as skin care ! Love it !

  23. i recently read an article on making your own vitamin c serum. I think it contained absorbic acid distilled water and vegetable glycerine. What would be your advice about this.

  24. I love the idea of making your own serums like that, but I just don't know how stable the vitamin C would be in such a formulation. There are a lot of tricks that the skin care companies have to keep it stable (and therefore active) for a long time.

  25. I am a huge fan of murad and was so funny to come across this, whilst looking at why vitamin c is good for the skin. Murad daily renewal complex contains a patented formula so that is why you may not see all ingredients as they are top secret! But what I do kbiw is the vitamin c is the purest form you can get an is encapsulated so can be in a tub safely without becoming inactive, the vitamin c is water and oil soluble Is purest and this product does what it says on the tin, pigmentation is reduced massively, this combined with the radiance serum really is the best I have ever used!

  26. Hi Christine! I loved your article! I want to know your thoughts about the Philosophy Turbo Booster C Powder. Is it trustable, is the vitamin C activated in it? And also is it best to apply vitamin C in the morning or at night?
    Best regards,
    Edgar Fabila.

  27. Hi Edgar!
    I don't know a lot about the specifics of the Vitamin C in that product. It is Ascorbic Acid according to the ingredients (good), comes in a dark bottle to protect against light inactivation (also good), though it's all in 1 bottle and that could contribute to easy inactivation. I don't think there's anything in the formulation to specifically stabilize the Vitamin C, so that is a little bit of a concern.

    Usually it's recommended to use Vitamin C in the morning, it helps to prevent any oxidative damage from sun exposure augmenting your sunscreen.
    Hope that helps!

  28. Hi all and a well written great post.I am a doctor and a beauty fanatic in my mid thirtees and I always try to find ways to hold back the speed of aging process.In this journey,I started formulating all my own lotions and potions by myself after an extensive research and as a result I can use optimum concentration of all active ingredients,I can include the actives that are proven to work by the research,they are always fresh and not to mention that my skin is youthing instead of aging.Honestly the beauty market is full of hype and most products do not work.That is what drived me to DIY route.
    I can talk a lot about that but at the moment I wanted to share some important points regarding topical use of vitamin C in a hope to help someone.With apologies as I do not intend to hijack the post:)
    Effectiveness of vitamin C in a skin care product is dependent on pH of the formulation and it should be in its reduced form,not oxidized.Here are some ways to counter these challenges.
    Vitamin C can get oxidized even before any color change visible to the eyes.Another way to know if it is oxidized or not is to check its PH.The effective pH for vitamin C to work is between 2.8 and 3.5(3.2 to be more precise) If you have pH strips or a pH meter,check the pH of your C serum.If it is more than 3.5,then it has got oxidized and is no more effective.
    2)Somebody mentioned using powder form.YES it is almost 100% stable as long as it is in powder form and unless the powder has changed color(turned brown).But the problem is when you mix it with water to apply,you do not know what pH it ends up with and what concentration you are using.Optimum concentration for a vitamin C serum to work is more than 10%.
    3)There was a question regarding making C serum with water,Ascorbic acid and glycerin.I would say go for it.DIY is the best way.The only thing to consider is final pH(adjust between 2.8 and 3.2),put it in an opaque packaging(airless pumps are an option)and add some oil and an emulsifier.What an emulsion does is that oil helps the product better penetrate the lipid bilayer of skin calls.And most important is to keep it in fridge and not to mention,make small batches so that it is always fresh.A big stability problem with commercial C serums is that they keep sitting on shelves for months before they reach the consumer.
    4)Regarding Dehydroascorbic Acid (DHAA),it can be converted back to ascorbate by glutathione and other thiols SO take home point is:LOOK FOR C SERUMS THAT HAVE GLUTATHIONE AS WELL.
    Vitamin E,ferulic acid,kinetin also stabilize C serums.Even hydroquinone has been shown to help stabilize vitamin C although I am not advocating its use.
    Hope that helps someone.


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