Water-soluble vitamin C (ascorbic acid)
This is the form of vitamin C found in standard vitamin supplements. Although I recommend taking this form of vitamin C as a nutritional supplement, ascorbic acid has some serious drawbacks when used as topical ingredient. It cannot protect cell membranes, nor can the skin maintain adequate levels when we experience oxidative stress, either from internal sources such as poor diet and stress, or from external sources such as sunlight.
Ascorbic acid can also create a powerful free radical known as a hydroxylradical, via a Fenton reaction with iron in the body. It is also irritating to skin and unstable when used in topical formulations.
Fat-soluble vitamin C ester
Unlike the ascorbic acid form, fat-soluble vitamin C ester realizes this essential nutrient’s full potential as an anti-aging agent. It displays greater antioxidant activity in our cells than ascorbic acid does, and performs this vital work at lower doses. In fact, compared with ascorbic acid, vitamin C ester delivers 8 times higher levels of vitamin C activity.
And because vitamin C ester can reside in our cells' fatty membranes, it continuously regenerates the vitamin E depleted by that fat-soluble antioxidant’s ongoing fight against free radicals.
Vitamin C ester also possesses superior ability to stimulate growth of the cells (fibroblasts) that help produce collagen and elastin, the strands of tissue that give the skin its strength and flexibility.
Last but not least, vitamin C ester is also more stable in topical solutions, maintaining its efficacy while it delivers its incomparable benefits. And it does not produce the negative Fenton reaction that occurs when products containing water-soluble ascorbic acid are applied to skin.
