How Important Is Vitamin C?

Vitamin C is one of the most common antioxidants found in skin care products, and its beneficial effects have been well documented.
According to the International Journal of Pharmaceutics, vitamin C has many skin-related benefits, including triggering collagen production and thereby increasing skin firmness, suppressing pigmentation (by inhibiting the enzyme tyrosinase), and scavenging free radicals.

According to a study in the British Journal of Dermatology, topical application of vitamin C has been shown to prevent UVA-mediated phototoxic reactions in pig skin, as well as to supplement depleted vitamin C levels after UVA exposure. According to the Journal of Photochemistry and Photobiology, UVA-induced damage includes the release of oxidative species, resulting in age spots, photoaging, and skin cancer.

In addition, according to the study in the British Journal of Dermatology, topical application of vitamin C also protected skin from UVB-induced damage. According to the Journal of Photochemistry and Photobiology, UVB-mediated damage can result in redness (sun-burn), age spots, photoaging and skin cancer.
Based on a 2005 study, vitamin C is less effective at reducing oxidative stress than similar concentrations of idebenone or vitamin E, kinetin, or ubiquinone. I reported the full results of this study under idebenone.

L-ascorbic acid is the most common form of vitamin C used in skin care. It is water-soluble. The advantage to L-ascorbic acid is that its concentrations are well-established in skin care products. Unfortunately, it is well known (and reported in the journal Die Pharmazie) that L-ascorbic acid changes upon exposure to light, heat, or air, and becomes inactive, or worse, irritating.
Ascorbyl palmitate is a fat-soluble ester of L-ascorbic acid; it is L-ascorbic acid combined with palmitic acid, a fatty acid. According to a 1997 study, the ascorbyl palmitate is more stable than L-ascorbic acid. A 2001 study in the International Journal of Pharmaceutics found that the stability of ascorbyl palmitate was increased further when ascorbyl palmitate was used in high concentrations (1-2%). I also found that ascorbyl palmitate concentrations are generally 0.05-1%, unless a higher concentration of ascorbyl palmitate is established for a product.

According to a study reported in 2008 International Journal of Cosmetic Science, ascorbyl palmitate is not the most stable form of Vitamin C out there. They reported that ascorbyl esters showed significant differences: sodium ascorbyl phosphate and magnesium ascorbyl phosphate are more stable derivatives of vitamin C than ascorbyl palmitate and may be easily used in cosmetic products.
However, even though some of the other products I looked at had a slightly more stable form of vitamin C, they did not have all the other ingredients to fight all the signs of aging. Ascorbyl palmitate, if used as directed, is a more than adequately active and effective form of Vitamin C. Keeping a holistic approach in mind, I think the two top products that fight all anti-aging needs are LifeCell and Revitol.

So does Vitamin C reduce wrinkles?

I could only find one study. According to Cosmetic Dermatology (a derm textbook), 10% L-ascorbic acid was used in a split face study for three months, and was found to decrease wrinkles (as measured by photo assessment). However, the study was not blinded because many of the study participants reported stinging on the side treated with L-ascorbic acid. Having said that, even though it stung, it did reduce wrinkles on the treated side vs. the untreated side. Well, no pain, no gain, I guess. (Author’s note: LifeCell and Revitol use ascorbic palmitate which does not irritate, not L-ascorbic acid which can cause irritation.)

Also according to Cosmetic Dermatology textbook, vitamin C and vitamin E are network antioxidants that have been found to synergistically enhance the power of one another.  Vitamin C and E have also been reported to prevent skin cancer and enhance sunscreen protection.

Lastly, vitamin C and been shown to reduce skin pigmentation and age spots. A study in the International Journal of Dermatology, found that combination therapy of 4% hydroquinone (only available by prescription), vitamin C, vitamin E, and 10% glycolic acid was effective in treating signs of age spots.