Quick math question: what SPF do you get if you use a sunscreen with SPF 30, a moisturizer with SPF 20 and foundation with SPF 15?
30 + 20 + 15 = 30.
In the words of Mona Gohara, a dermatologist and an associate clinical professor of dermatology at Yale University, “SPF isn’t an equation. Your sun protection is only as strong as your highest SPF.”
Why Layering Sunscreens Doesn’t Increase Sun Protection…
Layering sunscreens will NOT give you added SPF protection. When you use several products with SPF, you end up only with the SPF of the highest sunscreen you applied.
You see, sunscreens work by limiting the number of UV rays that hit your skin. If you wear a SPF 20, for example, only 5% of UVA rays hit your skin. If you use SPF 50, 2% still get through.
So even if you use SPF 20 + SPF 50, you still get 2% of UV rays hitting your skin.
… But It May Still Gives You Better Sun Protection (When Done Right)
Layering products with SPFwill not add up SPF, but it may increase your overall coverage.
Let’s say you’re in a rush and applying sunscreen quickly. It’s easy to miss a spot or two. Those spots have no protection and are fair game for UV rays.
But if you slather on a second SPF product, you have more chances of covering every little nook and cranny. I personally don’t do this because I am very diligent with sunscreen application, but if you think you need it, go ahead.
Don’t Layer Mineral Sunscreens!
It’s easy to spot a mineral sunscreen. There are two mineral UV filters: titanium dioxide and zinc oxide.
I love them because they provide excellent protection without causing irritations. They’re so gentle, even babies can use them!
But – when they are uncoated – they don’t play with other synthetic filters like avobenzone and oxybenzone. They inactivate them so you get LESS sun protection.
FYI, in case you’re panicking because your sunscreen contains both titanum dioxide and avobenzone, relax. I said titanium dioxide inactivates avobenzone only when it’s uncoated. In a sunscreen that uses both, titanium dioxide is already coated.
But when you’re playing around with sunscreens at home, don’t take any chances. If you don’t know for sure if your mineral sunscreens are coated or not, layer them only with other mineral sunscreens.
The Bottom Line
SPF works by limiting the amount of UV rays that actually reach your skin. So adding up products with SPF won’t give you more protection. But it may give you better coverage.
Do you stick to sunscreen only or do you layer several products with SPF every day? Let me know in the comments below.
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