Vitamin C Skin Benefits
Posted on February 08 2019
This article discusses the potential roles of vitamin C in the skin and summarizes the current knowledge about vitamin C in skin health.
Vitamin C is a normal skin constituent that is found at high levels in both the dermis and epidermis. Aging, however, causes a decline in vitamin C content in both the epidermis and dermis. Excessive exposures to UV light or pollutants (e.g., cigarette smoke and ozone) may also lower vitamin C content, primarily in the epidermis.
Vitamin C can be provided to the skin through topical application. The stratum corneum is the primary obstacle to efficient vitamin C absorption from external sources. Preparations with a pH below 4.0 aid in transport by promoting the uncharged form of vitamin C, ascorbic acid. Maximal absorption was achieved with a 20% vitamin C solution, with higher concentrations showing lower absorption. Topical application of ascorbic acid will cross the epidermis into the underlying dermal layers.
The stability of vitamin C in topical solutions is a concern, as exposures to air, heat, and/or light may slowly degrade vitamin C. Although the natural form of vitamin C, ascorbic acid, is the most effective for topical administration, it is the least stable in solution. Yet, the stability of topical vitamin C solutions may be increased by the addition of other antioxidant compounds.
Human studies with subjects using topically applied solutions of 0.6%-10.0% vitamin C or its synthetic derivatives have not reported adverse effects.
Vitamin C is not a “sunscreen” because it does not absorb light in the UVA or UVB spectrum. UV light decreases vitamin C content of skin, an effect that is dependent on the intensity and duration of UV exposure.
Human studies often assess skin health by changes in depth or number of wrinkles and by the individual’s perception of skin health. Two observational studies found that higher intakes of vitamin C from the diet were associated with better skin appearance, with notable decreases in the appearance of skin wrinkling. The use of vitamin C (3-10%) in topical applications for at least 12 weeks has been shown to decrease the appearance of wrinkling and decrease apparent roughness of skin. However, the effects of topical vitamin C are not apparent in all individuals, and interestingly, one study found that individuals with high dietary intakes of vitamin C showed no or little effect of a topical administration.
Topical application of vitamin C appears to be an effective route for delivering ascorbic acid to the skin because ascorbic acid appears to be taken up readily at an acidic pH. Lastly, the greatest effects of vitamin C supplementation are seen when it is combined with other micronutrients, such as vitamin E and zinc.
Written in September 2011 by:
Alexander J. Michels, Ph.D.
Linus Pauling Institute
Oregon State University