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The Truth About Vitamin C

January 9, 2018 Reviewed by Marta 14 Comments

Vitamin C is the body's most major aqueous antioxidant. And because it is most plentiful in the extracellular matrix of your skin, there are a slew of beneficial effects that it brings. Vitamin C is the only antioxidant that boosts collagen - it is, in fact, a precursor to collagen. Despite its many advantages, it was once a chemist (and consumer's) nightmare due to instability and high concentrations leading to skin irritation and dryness. Happily, there are now modern versions of vitamin C that give us the benefits without the downside. The truth about vitamin C is that nowadays you don't need to look out for high percentages, but for the names of the newer versions.

L-ascorbic acid

This is the version that was the only one available back in the day. The poor stability required high concentrations to be used and caused skin reactions for many of us. What's more, as a water-soluble antioxidant, it has some limitations: it cannot scavenge free radicals within the cell membrane, and works best in formulas that remain anhydrous, or water-free.

These days, good L-ascorbic aciid formulations do not rely on 20% concentrations or even 10%, but use special delivery-enhancing ingredients that help it penetrate the skin or be released over time. See the section on boosters below.

Ascorbyl palmitate

Ascorbyl palmitate (AP) is one of the more common derivatives that you may have encountered in the Vit C world. However, unlike AA, ascorbyl palmitate is lipophillic, or fat soluble, which means that it may make it difficult for it to actually penetrate your skin (preferring to stay in the formula's cream base). As such, it works best in oil-in-water emulsions and at a percentage between 1-2%. However, it is found to produce different short- and long-term effects from ascorbic acid. And there is much doubt that the concentrations of ascorbyl palmitate are present in high enough to get the same effects of collagen producing.

Ascorbyl phosphate

Ascorbyl Phosphate (aminopropyl ascorbyl phosphate) is a superior (and more stable) form of water soluble vitamin C. A relatively new derivative of Vitamin C, it’s preferred by many for having superior stability and effectiveness. It’s particularly lauded for reducing melanin production- the culprit behind age spots, Melasma and hyper-pigmentation. It’s also been shown to be more effective than water soluble Vitamin E in protecting against hydroxyl free radicals.

Magnesium ascorbyl phosphate

AKA MAP, magnesium ascorbyl phosphate is gentle on the skin, effective in significantly lower concentrations, and stable at a neutral pH. For example: Like AA, it shows suppression of melanin formation by inhibition of tyrosine. One study found that it needs to be at 10% concentration to suppress melanin formation. However, at present, I haven't found any products on the market that contain 10%.

What's more, it keeps up to 60-75% of its stability after 365 days of storage in the dark, and there is compelling evidence that it does indeed cross the epidermis where it is effectively converted into ascorbic acid where it is able to promote collagen synthesis and wound healing, lighten skin pigmentation, and protect against UVB induced tumor formation in the skin.

Like AP, MAP has been found to produce different short- and long-term effects from ascrobic acid. In one study in particular, researchers discovered that it was statistically more effective than ascorbyl tetra-isopalmitoyl (ATIP) in free radical-quenching activity, although less than AA. One thing it does have going for it that ascorbic acid does not is that it seems to better quench the deeper layers of skin than AA.

Ascorbyl tetra-isopalmitoyl

Similar to AP, ascorbyl tetra-isopalmitoyl (or ATIP) is fat soluble and effective at lower concentration.  In this case, all you need is a formula at 3% concentration. While MAP is better at free-radical quenching in aqueous solutions, ATIP is better in lipid solutions. But in a very real sense this is almost irrelevant since vitamin E outperforms ATIP in terms of free-radical quenching, and works beautifully and synergistically with vitamin C.

Tetrahexyldecyl ascorbate

As another fat-soluble derivative, you would think that tetrahexydecyl ascorbate would suffer from many of the same problems (such as not being able to readily penetrate the skin in real life use). It is known to be more stable than AA. t is also considered to be more potent than L-asorbic acid and other Vitamin C compounds, and has a higher rate of penetration (because it is lipid soluble, like human skin) than other derivatives; it also has a higher rate of conversion to vitamin C within the dermis.

Sodium ascorbyl phosphate

Some research has shown to improve acne and acne scarring (where as ascorbic acid has been shown to cause acne), and to be an effective antioxidant and collagen stimulator. What's more, like all other derivatives, it's more stable and but unlike a number of others will convert to ascorbic acid once in the skin. The final concentration of sodium ascorbyl phosphate in end-use products could be up to 5% depending on the application, but is typically 0.01 to 0.1% in most preparations.

Vitamin C boosters

Formulators are discovering a slew of ingredients that can help boost the efficacy of viitamin C, including ascorbic acid. The antioxidant glutathione, an antioxidant recycles and regulates other antioxidants, such as vitamin C, to make them work harder. Lucas Meyer, an ingredient manufacturer, has a vitamin C “transporter” called SVCT-1. This is, in fact, one of the key proteins that enables vitamin C uptake. A new version of ascorbic acid is 3-O-ethyl ascorbic acid, a stable form that has also been credited with halting the melanin-biosynthesis pathway in skin, hence it can prevent hyperpigmentation.


  • January 12, 2018

    by Marta

    Hi Vanessa, the L in L-ascorbic acid simply means that it is derived from a natural source.

  • January 12, 2018

    by vanessawood

    Aspects Vitamin C Serum (Extreem C?) and many of aspects other products have Tetrahexyldecyl Ascorbate . Aspect Chrial correct ingredients - I think this helps reduce the chances of irritation and improves/purifies ingredients at the molecular level to ensure all the good stuff stay in and the bad stuff (like what causes irritation) is thrown out.. Correct me if I'm wrong, but L-ascorbic Acid, is a chiral corrected ascorbic acid, where they have taken one side (the left side maybe for l?) of the molecule and removed the other side - Can anyone explain that a bit better than me - or correct me, Im really interested in this stuff.

  • January 10, 2018

    by Marta

    Hi Susan, with these new non-irritating forms, it is definitely worth trying to reintroduce it. I would not use it at the same time as retinol as they are both ingredients that can be drying.

  • January 9, 2018

    by Susan

    I have been wanting to reintroduce vitamin c into my skin-care regime after abandoning it several years ago because of the irritation it caused. But now I don't know where it should fit with all the other products I use. I see that it is often recommended at night time, but that is when I apply a retinol (SkinMedica). Can I use a vitamin c product with a retinol? Is there an optimal time of day to apply vitamin c?

  • January 20, 2016

    by Lena

    Tetrahexyldecyl Ascorbate is the form of vitamin C (at 15% concentration) used in YoungPharma's (Young Pharmaceuticals) medical grade serum. For added UV protection, they have incorporated Ferulic Acid into the C serum formula (by far, my favourite ingredient due to results).

    Another product, the Intense Radiance Serum by Alyria (Sanofi Consumer Health Inc., Made in Canada) is also amazing, containing a fairly non-irritating 20% L Ascorbic Acid + Ceramide + Palmitoyl Oligopeptide formula.

    I like to switch between both products. Both are available through dermatologists / plastic surgeons medical clinics.

  • February 13, 2015

    by Jen Justjen

    Ascorbyl tetraisopalmitate IS tetrahexyldecyl ascorbate, not two separate derivatives.

  • July 30, 2012

    by Melissa

    Thanks for the great information, Tobina. I have found that products with tetrahexyldecyl ascorbate work much better on my skin without the irritation of higher concentrations of other forms of c.
    I am using VisaoMD Vital C , carried by my doctor, and it's made a huge difference on my sensitive, oily, sun damaged skin.

  • June 8, 2012

    by Mark

    Steve - please share with us the name of the product you refer to containing the Tetrahexyldecyl Ascorbate? Thanks!

  • June 3, 2012

    by Marta

    Hi Steve, of course I am dying to know what the product was.

  • June 3, 2012

    by Steve

    Great Article... Just wanted to provide some feedback on my experience with the following forms of Vitamin C... specifically Tetrahexyldecyl Ascorbate, Ascorbyl Phosphate and L-Ascorbic Acid. I have used many products containing L-Ascorbic acid and they seem to work fairly well in the 10-15% concentration range. But it was not until I tried a product with Tetrahexyldecyl Ascorbate that I became a true believer. What a difference. I have sun damaged skin, large pores, etc. I must admit that the Tetrahexyldecyl Ascorbate made an amazing improvement to my skin. It is not even funny. People always ask me what I did to improve my skin. :) Just sharing my personal experience. THANK YOU Tetrahexyldecyl Ascorbate!! It is simply powerful.

  • June 3, 2012

    by Nancy

    I personally use and sell Circadia (Dr. Pugliese) Skin Care. Their Vitamin C Serum is 12% Magnseium Ascorbyl Phosphate. Both my clients and I LOVE IT!! 1-2 drops will treat your entire face, neck, & decleote (sp?) Very "rich" formula and results are fantastic. It's be BEST Vit. C Serum I have found to-date. PS: I am a Licensed Skin Care Specialist in Florida

  • October 13, 2010


    Confused, Just bought Vit C Serum Magnesium Ascorbyl phosphate. Jan Marini products market that the Ascorbyl Palmitate penetrates skin works better. I don't know.

  • April 8, 2009

    by Sarah

    I was reading the above. The BBC documentary was just shown in Australia. The product Firewall which won is by an English cosmeceutical company called Medik8 ( It is separated in two parts which react together apparently which is why it is so good. I use the C-tetra product they produce as it is cheaper and virtually the same thing according to the trials I have read about. This is also tetrahexadecyl ascorbate. I have to say it's all very confusing. Wish the BBC documentary explained it all as it leaves you with as many questions as answers. The most interesting thing was they stuff like zelens and prevage to be quite low potency for the money.

  • April 7, 2009

    by Tobina

    Dear Editor,

    I found your 4 part series educational and interesting however i disagree with some of your conclusions.

    Firstly, L-ascorbic acid (AA) is very irritating to many people and highly unstable often becoming pro-oxidant long before a colour change. Even when stabilised with ferulic acid, the drop in activity halves in two weeks after first use according to studies performed by my professor at our institution. We use four free-radical assays to measure activity.

    Second you state that ascorbyl isotetrapalmitate and tetrahexadecyl ascorbate as separate molecules. they are infact the same chemical. There is a great deal of evidense supporting the use of this derivative in place of AA. Only the other day (March 2009) there was another study from a major journal (Journal of Cell Biochemistry) which proved the greater effectveness of tetrahexadecyl ascorbate over AA. They found "Administration with VC-IP of 10-50 microM to human fibroblasts NHDF achieved the enhancement of collagen synthesis, repression of matrix metalloprotease-2/9 activity, and increasing of intracellular Asc contents more markedly than that with Asc itself of the same concentrations." See the link here for yourself:

    and another study published in another reputable journal - the Journal of Dermatological Science showed similar findings in 2006:$=relatedarticles&logdbfrom=pubmed

    Further, Sodium Ascorbyl Phosphate shows hormesis at varying concentrations and we have results to show that less can acheive more quenching activity. I am surprised you do not mention antioxidant hormesis on your site at all.

    Lastly, your article does not explain the problem with antioxidant interactions. As was shown on the infamous BBC Horizon documentary, the pot-pourri of many great-sounding formulae often have little activity because of interative neutralisation. Therefore if I were recommending formulae to anyone, i would first suggest they ask the manufacturer if there has been any trials performed on the FINISHED product (not the ingredients individually). I know there is one company who does this (i forget the name but they have a product called Firewall which was on the documentary).

    Great site - keep it going.

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