Article by: Perry Romanowski

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.


About the Author

Perry Romanowski

Perry has been formulating cosmetic products and inventing solutions to solve consumer problems since the early 1990’s. Additionally, he has written and edited numerous articles and books, taught continuing education classes for industry scientists, and developed successful websites. His latest book is Beginning Cosmetic Chemistry 3rd Edition published by Allured.


  1. Avatar

    So would it be incorrect to think that you could add in one of those EO as an SPF booster to a formula already containing zinc oxide or another tried and true sunscreen ingredient?

    1. Avatar
      Perry Romanowski

      Yes, that would be incorrect. SPF value is more complicated than just the ingredients used. It also depends on how the ingredients are mixed together and processed. You can’t simply add EO’s to boost the function of a sunscreen.

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