September 2003
Dear Paula,
I have been a fan of your newsletter and products for several years now. However, I have a question concerning sunscreen products with an SPF of 15. Why do the amounts of active ingredients vary so much from product to product? For instance, Paula's Choice Essential Non-Greasy Sunscreen has 7.5% octinoxate, 5% octisalate, 2% oxybenzone, and 2% avobenzone for a grand total of 16.5% active sunscreen ingredients. On the other hand, Purpose Intensive Daily Moisturizer SPF 15 has 7.5% octinoxate and 3% avobenzone for a total of 10.5% active sunscreen ingredients. And Cetaphil Daily Facial Moisturizer SPF 15 has 10% octocrylene and 3% avobenzone for a total of 13% actives.

I realize that the FDA monitors all SPF products but I can't help wonder if one product will provide better SPF 15 protection than another due to a the higher percentage of active ingredients. Also, if a person has sensitive, acne-prone skin (which I do), would it make sense to use the product with the lowest percentage of active ingredients as long as it is an SPF 15?

Karen, via email

Dear Karen,
You sound like the consummate researcher. In the past, I had the exact same question, and the answer is an interesting one. Your initial reaction that more sunscreen ingredients provide more protection is generally correct. Overall, the goal with any sunscreen formulation is to get it through the rigorous testing mandated by the FDA, and still have it maintain the SPF number you want to place on your label. Companies have different goals in this regard. Some use the least amount of active ingredients they can to achieve the SPF on their label, while others use a larger amount to go over and beyond the SPF on their label to ensure they exceed the SPF testing. For example, some sunscreen products exceed their SPF testing. The decision to place SPF 15 on the label when it really ends up being is an SPF 16 or 17 (or higher) is intended to reduce consumer confusion when it comes to comparing sunscreen products.

The other factors in a sunscreen formulation affecting the SPF are the inactive ingredients. Products with identical percentages of active ingredients can have a range of SPFs depending on what other ingredients are used in the base! Some ingredients help keep a formulation more stable. Knowing how to use the same amount or less of sunscreen active ingredients and still obtain a high SPF number in a functional, cosmetically elegant base is the crowning talent of cosmetics chemists, revealing their skill and knowledge of cosmetic formulations.

Someone with acne-prone skin need not be concerned with choosing a sunscreen with the lowest amount of active ingredients. A percentage point here or there, up or down, is not necessarily going to affect your skin?s overall reaction to the sunscreen ingredients, which may be to a specific ingredient or a specific mixture. What is important is to avoid sunscreen ingredients in any percentage that you suspect have caused breakouts in the past. As a general rule, however, choosing a sunscreen with a lower percentage of active ingredients is no guarantee that you will minimize breakouts.