The problem with cosmetic ingredient research – Chemists Corner


I was scanning through the various science magazines I follow and stumbled on this interesting article about a couple of essential oils and their effect on skin. The researchers looked at geranium and calendula essential oil for their potential as antioxidants and sunscreen ingredients. It turns out the authors discovered that Geranium essential oil had a SPF value of around 6 while the Calendula essential oil had an SPF of around 8.

Interesting, right?

Well, I guess but then the authors go ahead and claim that

“The SPF of CEO was higher than GEO, and the results of SPF show that these essential oils can be employed in sunscreen formulations to protect the skin from sunburn. “

This is where they lose me and also where I think cosmetic science research often goes wrong. Assuming that these oils indeed have the experimentally determined SPF values, this is far less effective than ingredients that have already been proven to protect against the sun!  Why would a formulator use an inferior performing ingredient when they have perfectly good, validated ingredients to choose from?

No, people should not use geranium and calendula essential oils as sunscreens.  They should use Zinc Oxide and Titanium Dioxide and Avobenzone or any of the other 16 approved sunscreens by the FDA.

Cosmetic Science Research

And this demonstrates a big problem with cosmetic science research. Often, the research is being done by someone who is keen to prove some point. In this case, the authors wanted to demonstrate that a natural essential oil can be used as sunscreen. And maybe they proved it. However, the really important question of what should people use as sunscreen actives is ignored. Cosmetic science research too frequently answers the wrong question. We want to know what is the best technology to use, not whether some ingredient has a modest effect.

When doing research on ingredients, the authors should find the best technology available and compare whatever they are investigating to the best available. The best sunscreen available is Zinc Oxide. Geranium and Calendula essential oil pales in comparison.


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