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Which kind of vitamin C is best for skin? The Beauty Brains Show episode 31

Posted May 20 2014 1:05am

What’s the best kind of vitamin C for skin? Plus: Randy and I talk about the experimental MINK makeup printer.

Click below to play Episode 31 or click “download” to save the MP3 file to your computer.

3D printing comes to cosmetics! This week we discuss the pros and cons of the new MINK makeup printer.

Illdiko (from Hungary) asks..I really love vitamin C serums, but I would like to use them properly. Do vitamin C products really need a special low pH? And what about their derivates, like Magnesium Ascorbyl Phosphate and others? Which vitamin C ingredient is the best?”

Vitamin C is a chemical called ascorbic acid that is naturally occurring in skin. It is known to play a role in collagen production. In addition, when topically applied it is thought to help heal acne, increase the barrier function of skin to decrease moisture loss, protect from UV radiation, and prevent age spots.

Sounds too good to be true, huh? Well there is a downside – it’s difficult to deliver VC to skin in a form that is stable, effective and non-irritating.

There are something like 7 or 8 different forms of VC that are used in cosmetics and there’s a LOT of noise out there about how the different versions work, how much to use, what kind of formula is required to deliver the ingredient, and so forth.

So, today, we’re going to try to get to the bottom of that mess by reviewing the best scientific data available on each ingredient. And we’ll do that using the three Kligman questions format that we’ve used before. Randy, want to describe that again for our readers?

1. Based on the chemistry of the ingredient, is there any scientific mechanism that could explain why it would work?
2. Does it penetrate to the part of the skin where it needs to be in order to work?
3. Are there peer reviewed, double blind, placebo controlled studies demonstrating the ingredient really works when applied to real people?

Our assessment is based primarily on a paper which reviews the technical literature on Vitamin C through 2012: “Stability, transdermal penetration and cutaneous effects of ascorbic acid and its derivatives” from the Journal of Cosmetic Dermatology, 2012.

Let’s start by discussion the mechanism. Remember the active form is ascorbic acid so all the derivatives must be converted to ascorbic acid on the skin.

Remember that unlike many other anti aging ingredients, Vitamin C is naturally found in skin (mostly in the epidermis, some in the dermis) and it’s role in skin biology is well documented. For example…

Protecting from UV damage
Although VC is NOT a sunscreen but it protects skin from the free radicals that are caused by UV exposure. It’s been shown to reduce lipid peroxidation, limit the release of pro-inflammatory cytokines, protect against apoptosis (or cell death) and to reduce redox-sensitive cell signaling. All this means that VC reduces many of the nasty effects of sun exposure.

Increasing collagen to reduce wrinkles
As you know collagen collapse is a major cause of wrinkles. Vitamin C regulates the synthesis of collagen and it does this by hydroxylating collagen which makes it more stable and improves the way it supports the epidermis.

Reducing skin pigmentation
VC not only reduces melanin production but it also reduces oxidation of the melanin that is produced. It’s also thought to reverse the conversion of DOPA to o-DOPA quinone (which is a skin pigment).

So, as you can see, the effects of VC in the skin are well understood. Now let’s look at the other properties of each ingredient and what kind of data is available to prove that they work.

Is it Stable? Stable at pH less than 3.5 in aqueous solution and it’s stable in anhydrous systems

Does it penetrate? Ex vivo testing proves it penetrates as a solution or micro particles

Does it convert to Ascorbic Acid? No conversion required.

Protects from UV damage: Yes, human in vivo testing.

Increases collagen synthesis: Yes, human in vivo testing.

Reduces skin pigmentation: Yes, human in vivo testing.

So this ingredient is the gold standard for Vitamin C. However because it’s often used at very low pH it can be harsh to skin which has lead to the development of other versions of AA. For example….

Is it Stable? Stable at pH 7

Does it penetrate? There is limited ex vivo animal testing which shows it penetrates.

Does it convert to Ascorbic Acid? There is no data showing it converts to AA.

Protects from UV damage: Yes, human in vivo testing shows is protects but less effective than AA.

Increases collagen synthesis: Yes, in vitro testing only and it’s less effective than MAP.

Reduces skin pigmentation: Yes, human in vivo testing (but from trade journal only so the data may be less robust.)

Is it Stable?  Stable at pH 7

Does it penetrate? Yes it penetrates, but data is limited to ex vivo animal testing.

Does it convert to Ascorbic Acid? In vitro testing indicates it converts to AA.

Protects from UV damage: No data.

Increases collagen synthesis: Yes but only in vitro testing. Apparently equally as effective as AA.

Reduces skin pigmentation: Yes, human in vivo testing.

Is it Stable? Same stability issues as AA (requires low pH or anhydrous system.)

Does it penetrate? In vivo animal testing shows it penetrates but it’s very dependent upon the formula.

Does it converts to Ascorbic Acid?  No data showing that it converts.

Protects from UV damage: Yes, animal in vivo testing shows it protects from UV.

Increases collagen synthesis: Yes, but in vitro testing only.

Reduces skin pigmentation: No data showing that it works.

Is it Stable? It’s stable at pH less than 5.

Does it penetrate? According to a trade publication, human ex vivo testing shows it penetrates better than MAP.

Does it converts to Ascorbic Acid? In vitro testing shows it converts to AA.

Protects from UV damage: Yes but in vitro data only.

Increases collagen synthesis: Yes but in vitro data only.

Reduces skin pigmentation: Yes, human in vivo testing (according to trade journal.)

Is it Stable? Yes, stable at a range of pH.

Does it penetrate? In vitro testing shows it penetrates.

Does it converts to Ascorbic Acid? In vitro testing shows it converts to AA.

Protects from UV damage: Yes, human in vivo testing shows it protects but it’s less effective than SAP.

Increases collagen synthesis: Yes but in vitro data only.

Reduces skin pigmentation: In vitro testing shows it diminishes dark spots. 

Is it Stable? Stable at pH 7

Does it penetrate? In vivo animal data shows it penetrates.

Does it converts to Ascorbic Acid? In vitro data shows it converts to AA.

Protects from UV damage: No data.

Increases collagen synthesis: No data.

Reduces skin pigmentation: Yes, human in vivo data shows it diminishes dark spots.

Is it Stable? No published data on stability.

Does it penetrate? Ex vivo animal testing shows it penetrates better than AA-2G.

Does it converts to Ascorbic Acid? No published data showing it converts to AA.

Protects from UV damage: No data.

Increases collagen synthesis: No data.  

Reduces skin pigmentation: Human in vivo data shows it works against dark spots.

This much is clear: of all the Vitamin C derivatives, Ascorbic Acid has the best data to prove that it really works for all three main functions. So, if possible, why wouldn’t you use AA?

That doesn’t mean that ANY product with AA on the label will be best. There are other factors at play…Which brings us to tip #2…

So how much AA should a product contain?

According to the Pauling Inst. the maximum skin absorption occurs at 20%. Higher concentrations actually have less absorption. Which is good since high concentrations are also more irritating.

Should you go lower? Paula Begon says that a proven range for vitamin C effectiveness is generally between 0.3% and 10%. 0.3 is a LONG way from the maximum absorption of 20% so that seems low.

If you can stand the irritation, 10% or even 15% should give better absorption.

AA can begin to oxide (which causes it to be used up) as soon as it’s dissolved in water. Look for products where water is NOT one of the first ingredients. That gives you a better chance of finding a product that will really work. That means looks for serums instead of cream based products.

Also, if water is present, look for products that use stabilizing agents – Paula’s Choice is good for this.

As we noted, AA is unstable above 3.5 or so. Look for low pH products. Of course pH is only meaningful if water is present so it’s less of an issue in the kinds of water free formulas we just discussed.

Any Vitamin C ingredient must be properly packaged to protect it from excess light and air.

Look for pump packaging (or individually sealed single use capsules) to protect from air. I would even avoid products in plastic tubes unless you know they’re used some kind of laminate to act as a barrier to oxygen transmission.

Avoid clear packages to protect from light. If it’s a glass jar make it dark.

Watch out for irritation

As we said, AA can cause redness and stinging. Be prepared to switch to another type if irritation is to great. The alternative may be less effective but you’ll be likely to use it more often if it’s gentle to your skin.

Don’t rush it!

After applying a VC product you should wait a while before applying any other products.

That’s because other ingredients can trigger oxidation and if they’re applied on top of the AA before it can be absorbed into your skin it could become inactive.

So based on the data we’ve seen, ascorbic acid is the best version of  Vitamin C to use in an anti-aging product.

But, just having ascorbic acid on the ingredient list doesn’t make a product “the best.” A well formulated product based on other derivatives could be better than a poorly formulated product based on ascorbic acid.

You need to keep in mind that the efficacy of any vitamin C based product depends on not only the type of Vitamin C, but also the concentration, the other ingredients in the formula and the packaging.

But following our 5 tips should help you pick a product that’s more likely to work at a price you can afford.

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Buy your copy of It’s OK to Have Lead in Your Lipstick to learn more about:

  • Clever lies that the beauty companies tell you.
  • The straight scoop of which beauty myths are true and which are just urban legends.
  • Which ingredients are really scary and which ones are just scaremongering by the media to incite an irrational fear of chemicals.
  • How to tell the difference between the products that are really green and the ones that are just trying to get more of your hard earned money by labeling them “natural” or “organic.

Click here for  all the The Beauty Brains podcasts.

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