Topical vs. Oral Antioxidants for Sun Protection – Which Is Better?

Eating the right foods can protect your skin from the sun. (Photo by Extra Medium)

While studies on antioxidants are generally pretty disappointing when it comes to life extension, they do have some use as anti-aging treatments for the skin.

While all or most antioxidants appear to protect from the harmful effects of the sun, some antioxidants are more effective than others. Carotenoids are a case in point. One example is lycopene, which is found in tomatoes. For example, one study showed that people who ate tomato paste daily had 33% more protection against sunburn compared to the control group.

Among carotenoids, lutein seems to give the best bang for the buck. In addition to photo-protection, lutein increases skin hydration and lipid levels while reducing lipid peroxidation.

But is it better to use antioxidants topically or orally? Some folks swear by their skin creams, while others maintain that eating the right foods is the best way to improve the skin. In the lutein study, the combination of taking a lutein supplement and using a lutein cream gave the best results. Not all that surprising – by using topical and oral treatments you're covering both grounds and playing it safe, after all.

However, a recent paper got me thinking whether "attacking the problem from all angles" is really the best way to go at it. The study looked at carotenoid levels in the skin after using carotenoids topically and systemically (link). 129 healthy women, aged between 21 and 72 years, were divided into seven different groups and given topical creams, oral supplements, both, or a placebo.

The first cream contained a basic mixture of antioxidants from sources such as vitamin E, vitamin C and green tea. The second cream contained the same antioxidant mix complemented by beta-carotene and lycopene. Similarly, the first supplement contained antioxidants from sources like green tea, green coffee, and pongamia pinnata seeds, while the second also contained carotenoids.

The placebo treatments did not increase carotenoid concentration in the skin, while the carotenoid cream increased it by 30% in the forehead and 35% in the cheek. That's not bad – until you look at the results in those subjects who used the tablets instead. Taking the antioxidant supplement containing carotenoids resulted in an 80% increase in the forehead and 70% in the cheek after just four weeks.

The interesting part is the group who used both the cream and the supplements. After four weeks, the results were similar to the group using only the supplement, with the supplement-only group actually scoring better in some areas. After eight weeks the group using both treatments saw the best results.

However, whereas the effect from using the cream lasted for only 10 days after stopping treatment, the results from taking the supplement were sustained for up to 5 weeks. The authors also point out that "surprisingly, the combined application of both tablets and creams containing carotenoids did not reach the satisfying result obtained with the application of tablets only".

The result is indeed unexpected, since using the antioxidant + carotenoid cream along with the antioxidant + carotenoid supplement did in fact yield the largest carotenoid concentration. However, using the antioxidant + no carotenoids cream together with the antioxidant + carotenoid supplement gave worse results than skipping the cream altogether. That is, using the cream somehow negated some of the benefits of the supplement.

According to the authors, it's possible that systemically applied antioxidants are absorbed and transported onto the skin surface with sweat and sebum and that applying a cream won't increase the concentration any further. This is because the strateum corneum, the outermost layer of the epidermis, acts as a reservoir for topically applied substances.

Hence, when you apply a skin cream, it penetrates into this layer and saturates the reservoir, which makes it impossible for systemically absorbed antioxidants to penetrate into the same layer through sweat and sebum. The authors state that compared to taking only an oral supplement, taking a supplement and applying a cream results in a lower carotenoid concentration.

To avoid this problem, the authors suggest that the formulation of the topical cream should be such that it does not saturate the reservoir and prevent the oral antioxidants from being transported into the skin. In effect, they advise against using lipid-rich formulations.

Many people seem to have seen good results in photo-protection from using oral supplements only. While combining it with topical creams may potentially give the optimal result, this study suggests that finding the right kind of product is important.

For more information on skin care, see these posts:

Tretinoin Results After a Year – Experiment Update
BioSil, JarroSil & Beer – Silicon Experiment Conclusion
Topical Vitamin C for Skin: Re-examining the Case
How to Get Natural Sun Protection by Eating the Right Foods