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

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.

Show notes

Beauty Science News

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

Question of the week: What kind of vitamin C works best on skin?

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?”

What’s the deal with Vitamin C?

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?

How to prove an anti-aging ingredient works – the Kligman questions

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.

Is there a mechanism that explains how Vitamin C works?

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.

Ascorbic Acid (AA)

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….

Sodium Ascorbyl Phosphate (SAP)

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.)

Magnesium Ascorbyl Phosphate (MAP)

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.

Ascorbyl Palmitate (AA-PAL)

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.

Ascorbyl Tetra-Isopalmitate (VC-IP)

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.)

Ascorbyl Glucoside (AA-2G)

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. 

Ascorbyl 2-Phosphate 6-Palmitate (APPS)

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.

3-O-Ethyl Ascorbate (EAC)

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.

Tip #1 for finding the best product: Ask for Ascorbic Acid

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…

Tip #2 for finding the best product: Concentrate on the concentration

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.

Tip #3 for finding the best product: Watch out for water

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.

Tip #4 for finding the best product: Look for low pH

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.

Tip #5 for finding the best product: Purchase proper packaging

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.

Bonus tips:

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.

The Beauty Brains bottom line

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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{ 20 comments… add one }

  • farawayspices May 20, 2014, 8:25 am

    Thanks for an informative article. I understand that the formulation is important when it comes to delivery and stability in the bottle. However, I’ve heard there is some concern that once applied, vitamin c can oxidize on the skin when it is exposed to sunlight, possibly leading to skin damage. Is this true?

    • Randy Schueller May 22, 2014, 6:24 am

      Since vitamin C is naturally occurring in skin this seems unlikely but if you have a reference to where you read this I can check it out.

  • Antoinette May 20, 2014, 9:46 am

    I’ve been seeing homemade formulations vitamin C serums for years now. Can they be an effective alternate to expensive (and sometimes ineffective) store bands? This one is a really popular recipe.


    • Randy Schueller May 22, 2014, 6:23 am

      I checked out the recipe and it looks pretty reasonable. There are just a couple of watch outs:

      1. The formula appears to be about 30% ascorbic acid. We know that at concentrations above 20% skin absorption is reduced so this is somewhat of an issue.

      2. She says to use distilled water but that’s not pure enough because it may contain trace organics which could destabilize the mixture. You should use deionized water which is more pure.

      3. When mixing vitamin C products at home you need to make sure you’re not using any utensils that could contribute anything that could destabilize the mixture. For example use glass bowls instead of metal.

  • Christina May 21, 2014, 10:55 pm

    Thank you for the breakdown of the difference between the different Vitamin C options!

    I have the misfortune of breaking out from all forms of Vitamin C.I am a huge advocate for it however.

    I noticed that Ester C didn’t make it on the lineup for review.

    Ascorbic Acid is the most effective water-soluble form of Vitamin C but what are your thoughts on Ester C as an effective fat-soluble form of Vitamin C?

    • Randy Schueller May 22, 2014, 6:04 am

      Ester-C is the calcium salt of ascorbic acid and it’s typically sold as a dietary supplement, taken orally. I’ve never seen any data related to using it topically. Of course there’s also Ester-X which travels back from the future to fight free radicals. But we’ll have to wait until this weekend to find out if that really works or not.

      • Christina May 22, 2014, 9:29 am

        Skincare companies are just starting to market that they have Ester C in them stating that it’s a higher Ph (Ph 7) and that since it is fat-soluble it is more effective and stable on skin.

        Dr. Perricone started it a few years ago with his product “Vitamin C Ester 15″..here are it’s claims.

        What is it: Vitamin C Ester 15 represents one of Dr. Perricone’s most advanced revolutionary technologies. Patented for topical application, Vitamin C Ester 15 is formulated with the highest concentration of Vitamin C Ester available in any Dr. Perricone product, at 15%–making it a powerful treatment to help fight free radical attack.

        Why is it different: Vitamin C Ester is composed of natural vitamin C fused with a fatty acid derived from palm oil. This combination creates a fat-soluble chemical bond that works on three levels. One, it works on the skin structure to maintain firmness and tone; two, it dramatically improves texture; three, it restores the radiance and glow of youthful skin in only seven days.

        Now, for the record..I have a love/hate relationship with anything related to Dr. Perricone so I automatically eye roll at his blow hard write-ups then wonder if I should reach for my wallet.

        Other brands jumping on the Ester C train are JASON Skincare, Serious Skincare and Kiss My Face.

        Since this is a newer trend I am still trying to gather data before I recommend it to clients.

        I personally think the Ester-X sounds like an amazing ingredient and prefer Professor X to Perricone any day!

      • melissa December 26, 2014, 7:55 pm

        In skin care vitamin c ester was also used in the form of ascorbly palmitate, and now the very popular ascorbly tetraisopalmitate or tetraheclydecly ascorbic.

        See my question below.

  • Pedro May 23, 2014, 3:39 am

    An interesting not is these vitamin C derivatives in general (almost all were developed in Japan) are classified as “quasi-drugs” by the Japanese government. If a company wants to say the ingredient X is a “quasi-drug”, this company must send studies about the mechanism of action, safety, efficacy etc. to the Japanese gov. and wait for approval… It’s MUCH easier to approve a quasi-drug than a drug in Japan, but you still have to show some scientific evidence that the ingredient works. So, it’s not a drug, but it’s a bit more “serious” than just a cosmetic.

  • PinkCarnation May 23, 2014, 11:23 am

    After reading your article I googled and found this


    From the review this seem like a good product. Would you recommend this?? I am a little worried because the the Vit C percentage is 20% which you mentioned is the max amount. Your thoughts would be greatly appreciated.

  • Valentina May 23, 2014, 2:26 pm

    What should I look for as “stabilizing agent” if my serum contains water?

  • Ildiko May 26, 2014, 5:55 am

    Thank you for your proper answers, finally I had time to translate it properly. :) Do you have some information about Tetrahexyldecyl Ascorbate? This is on the 3rd place in my favourite serum.
    http://www.paulaschoice.com/shop/skin-care-categories/antioxidants/_/RESIST-Super-Antioxidant-Concentrate-Serum Do you think is effective? It is an anhydrous system. It contains tocopheryl acetate, and ferulic acid. I read it makes a vitamin C product more effective. Unfortunately the Paula C15 Super Booster cannot buy in Europe.

    • Randy Schueller May 26, 2014, 9:20 am

      That version of Vitamin C wasn’t covered in the research paper that we found. In general, Paula’s products are well researched and formulated.

      • Ildiko May 27, 2014, 3:15 am

        Thank you for your answer! :) You are like supersmart chemist heroes. ;)

  • Ana Terra December 9, 2014, 5:12 am

    Hello, Randy,

    I would like to know which hour is better to apply the Vitamin C serum. Some people says at morning, before going out and other people defends that is better to use before going to sleep. I’ll be glad if you can help me.
    Bye :)

    • Randy Schueller December 9, 2014, 7:09 am

      Hi Ana. The time of day to apply vitamin C doesn’t matter in terms of how well it works. The only potential issue is that some people may find certain forms of vitamin C to be irritating and that irritation may be worsened with sun exposure. So, if you experience discomfort when using vitamin C try applying it night. If you don’t have that problem then anytime of day should be fine.

      • Melissa December 26, 2014, 7:47 pm

        Confused. If you are using it do defend against free radicals including sun exposure, perhaps smoke, and certain day time pollutions, then use it in the AM, yes? I realize there is no time that free radicals are not going to work on every part of us, but yeah that’s one of the points that C must pass so why waste it?. If all you care about it collagen promotion, use at night.

  • Melissa December 26, 2014, 7:41 pm

    I don’t think this question has been covered. Does ascorbly palmitate really promote cell damage/death when exposed to UVB radiation?
    This study would have me worried about that.

    Since ascorbly isotetrapalmitate is similar due to the palmitic acid, but penetrates even deeper than ascorbly palmitate due to the 4 palmitic attatchments, and if the first question is true, does it reason that ascorbly isopalmitate can do even more damage to the skin in the presents of UVB radiation? Tetraheclydecly ascorbic is now is EVERYTHING either along with AA or by itself and up to 30% concentrations of tetra-C, so this question needs some attention.

    Unfortunately the question of any type of vitamin c is more confusing than I think has been recognized here. Im certainly sickened with it as I don’t know how many years of using possibly harmful products and wasting money has gone on and what to do now. I’ve read in cosmetic derm journals that AA should not even be used in ANY cosmeceutical unless the patient mixes it them selves (Ive personally would not do this). Ive read that no one should ever attempt to mix themselves and only use medical grade products which I always have. But that is also contradicted by the fact that about 90% of the time a dermatologists office will sell me a product that has long oxidized, is orange, brown and gritty. Skinceuticals, Obagi, Glytone, Revision, DCL, they all have been sold to me this way and my understanding is that using oxidized vitamin c in any natural or derivative form is terribly pro oxidant NOT simply ineffective. YET, dermatologists offices will insist the oxidized product you just payed over $100 for is neither pro-oxidant or ineffective. Really? That’s the standard of their knowledge and passing along the manufacturers marketing dismissal is ok?

    Its always said that you should really be at least periodically under a derms supervision when using these products long term, and generally I agree. However, when I go to either try to evaluate the effectiveness of my skin care program or try to get help untangling the vitamin c mess, I find them to be incredibly uninformed.

    Please help.

    • Randy Schueller December 27, 2014, 9:18 am

      Thanks for the link to the Nature article, Melissa. Very interesting! According to the researchers, “The lipid component of ascorbic acid-6-palmitate probably contributes to the generation of oxidized lipid metabolites that are toxic to epidermal cells.” The lipid component comes from using the palmitate version of vitamin C so presumably using other forms that don’t have the lipid attached (like ascorbic acid) would’t cause the same problem.

      I share your frustration about getting to the bottom of this vitamin C mess. There is a lot of conflicting information and we tried to digest it and present the best of what we found in this podcast/blog post. The bottom line, as we said, is that the ascorbic acid version appears to have the best evidence. I’m afraid that’s about as much help as we can provide until we see further studies that say another form is better (or that AA shouldn’t be used at all.)

      If you find any more relevant studies, please let us know!

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