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.
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?
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?
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.
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).
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.