Vitamin C - Acid vs. Esters Q: Hello Ivana....I know you are going to Europe and bon voyage. Wishing you wonderful excursion! You can address this qstn on your return; no hurry. I read somewhere that we need pure Vit C molecule delivered at right concentrations. And since Vitamin C seems to represent 1/3 to 1/6 of the equation needed to realize best skin benefits, it is really worth trying to get it right. {Melbourne Dermatology}.

In further searching most sources I've read state Vit C is an antioxidant inherently unstable and prone to rapid and visible osicization and Absorbic Acid doesn't absorb properly in a cream. That Absorbic Acid in excess of 20% is a potential skin irritant. Goes on to state that Vit. C. and incorporating and maintaining it's 'therapeutic potential' is extremely difficult and only a few patented methods exist and they are licensed to a severely limited number of companies. That ascorbyl Palmitate is a neutral PH non-acidic molecule and fat soluble and penetrates skin rapidly. That C-esta can be applied without any irritation.

I've read your ingredient glossary....which is much more understandable to me than Paula Begoin's {Cosmetic Cop}. That woman confuses the fire out of me. She says studies on Cesta 'not published in peer-reviewed journals' and that studies have shown that Ester C to have no difference when compared to Ascorbic Acid...yet she just got through pointing out that Ascorbic Acid was/could be an irritant. She says "vitamin C not the answer to your skincare concerns; "no conclusive or even vaguely convincing research that skincare mfgs. claim to be....and there are other antioxidants more potent". I beg to differ with her. I've read many documented reports on Cesta .......{Jan Marini's Cesta Fact Sheet comes to mind}. Then she goes on in next paragraph to extol all of its virtues. She really confuses me to pieces.
She has done extensive research and is very qualified/knowledgeable....and her efforts are greatly appreciated by many....but I think some of the opinions can be a tad misleading/confusing. So many 'experts' are not "chemists" and obviously haven't actually used what they are discussing. There seems to be many forms of Vit C.: Ascorbic Acid, L-ascorbic, Tetrahexydecl ascorbic, ascorbyl palmitate, ascorbic phosphate and magnesium Asc. phosphate...................geesh!! What is an Ester? Are the esters simply Ascorbyl Palmitate and Ascorbyl Stearate? What makes an Ester and exactly how does it 'become' an Ester? I feel Vit C is a very important/vital component in skincare, but once you delve into it it seems rather confusing to say the least. It is obvious I don't really have a workable understanding of it and wonder how many others are confused with the sea of Vit C products available.......which is which, what is what....whys and wherefors. I'm especially interested in better grasp of understanding esters. I've read tons on it, but I still don't quite 'get it'. Thanks so much for your wonderful contribution and input. Jeflin

A: Dear Jeflin,

Back from my vacation, I am fresh and eager to sort out some of the confusion that seems to be plaguing your curious and inquisitive mind over vitamin C. I emphasize some since the confusion is not only yours.

We have already established that there is nothing simple in human physiology. When it comes to vitamins, the starting point for understanding them is that for each vitamin there is a group of similar compounds that exhibit similar physiological effects. One of them is going to be the most potent, the others will have a lesser or drastically reduced effect. There will be also similar compounds that will have no effect whatsoever. That is how things go in Nature - an overwhelming plentitude that somehow still manages to work.

L-Ascorbic acid is the most potent form of vitamin C. L-Ascorbic acid is a weak acid but nonetheless all acids are acidic. Since the effectiveness in skin care requires rather high concentrations of vitamin C, at around 10% L-Ascorbic acid can be irritating to the skin. The higher the concentration the more irritating the acid becomes. Another problem with this acid comes from its instability, especially when exposed to light and water. Even if it's hidden away from the light in a tightly closed jar, the creams contain water, which will make for quick oxidation of the vitamin and render it ineffective. This is where other chemical forms, such as esters, come into play. Ester is an organic compound created by a reaction between an acid and an alcohol. Just like salts (compounds formed between an acid and an alkali), esters are often an answer to a problem of solubility, stabilty or irritation of the original compound. Esters of L-Ascorbic acid are more stable and less irritating, although not equally potent. The search for more stable and highly effective form of vitamin C is still on. All this at the level of formulating poses a lot of difficulties and I, for one, am often reformulating the products with vitamin C.

Being an anti-oxidant is only one avenue for vitamin C in skin care. Equally or even more important is its role in collagen synthesis. If you consider that not all forms of vitamin C will perform equally well at both tasks, that some of them are more prone to oxidation than others, that the level of absorption is crucial for effectiveness, that no two persons are going to experience equal benefits from even the best vitamin C cream, then the confusion should hopefully move to a more general level of: definitive answers are hard to come by in the field of skin care. Better understanding of the processes is what we can aim at, and I hope that this has helped.

All the best,

Ivana K.

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