Skin Care Myths: Adding Sunscreens Adds SPF

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?

A. 15

B. 30

C. 60

D. 45

E. 70

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:

Antioxidants treat wrinkles

Cuts heal better when you let the air at them

You cannot be allergic to a product you have used for years

Plucking Hair Makes it Grow Back Thicker

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Photo credit: Tread

4 thoughts on “Skin Care Myths: Adding Sunscreens Adds SPF”

  1. In general, the above is true.

    A note about SPF: SPF is on a logarithmic scale; there is a bigger difference between SPF 25 and SPF 30 than there is between SPF 30 and SPF 45. SPFs below 15 are basically worthless.

    When I am on the water, I apply a sunscreen containing avobenzone, wait a few minutes, and then apply one containing zinc oxide and titanium dioxide. This seems to work well for me: My arms and legs (with just avobenzone sunscreen) get darker while my face (with both) doesn’t get darker at all.*

    *A study has shown zinc and titanium to degrade avobenzone, but the time period was over a week and in aqueous solution. Avobenzone gets absorbed into the upper layers of the skin while titanium dioxide and zinc oxide don’t.

  2. I never knew this – thanks.

    I still like the multi-colored zinc used Australia – at least you can see its still there which is greats when your dealing with kids

  3. I didn’t know this but I suppose it makes sense–the total SPF equals the SPF of the strongest sunscreen applied. But wouldn’t weaker sunscreens dilute the stronger one?

  4. for me its a very informative information i am always very conscious about my skin.. i use a variety of thing to keep my skin healthy and i have found some useful tips on the skincare4style(dot)com site like using herbal and other home made thins for your skin..looking forward for more informative content form you.

    i am a free car manager.

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