Try this little derm math quiz:
If you apply a facial moisturizer with an SPF of 15 then add a facial sunscreen with an SPF of 30 and then apply a makeup with an SPF 15 what is the total SPF protection you are getting?
The answer is B, the total SPF protection you are getting is 30. Unfortunately, layering sunscreens does not give added SPF protection. Applying two sunscreens with an SPF of 15 gives you a total SPF of 15, not 30. The SPF you end up with is only the SPF of the highest sunscreen that you applied.
Turns out you don’t need math at all.
Post written by Jeffrey Benabio, MD. You might also like these other skincare myths:
Photo credit: Tread