When you use a moisturiser with SPF 20, a sunscreen with SPF 30, and a basis with SPF 15, what SPF do you get?
30 + 20 + 15 = 30.
Wait, what? Shouldn’t it’s SPF 65? Not fairly.
SPF math isn’t like common math. You possibly can’t simply add up all of the numbers and count on superhero-level solar safety. Right here’s why:
Does Layering Sunscreens Enhance Solar Safety?
Brief reply: No. However there’s extra to the story.
Layering sunscreens will NOT provide you with added SPF safety.
It’s a typical false impression, and truthfully, it is sensible why folks imagine it. We’re used to considering that extra layers = extra safety. When you put on two sweaters, you keep hotter. When you apply two coats of nail polish, you get a extra opaque shade. However SPF doesn’t work like that.
Within the phrases of Mona Gohara, a dermatologist and an affiliate medical professor of dermatology at Yale College, “SPF isn’t an equation. Your solar safety is barely as sturdy as your highest SPF.”
Within the instance above, the very best SPF is that of your sunscreen, SPF 30. That’s what you’re getting. It doesn’t matter what else you apply, that quantity gained’t go up.
Why? Sunscreen works by limiting the variety of UV rays that hit your pores and skin.
- SPF 30 blocks 97% of UVB rays (those that trigger sunburn).
- SPF 50 blocks 98% (not an enormous distinction, proper?).
- SPF 15 solely blocks 93%, which suggests much more UV rays are nonetheless getting by means of.
- Even SPF 100 isn’t excellent. It nonetheless lets 1% of rays by means of.
Discover how the distinction between SPF 30 and SPF 50 is just one%? That’s why sunscreen layering doesn’t provide you with a magic increase in SPF—it’s all about how a lot truly will get absorbed by your pores and skin.
Cease losing your money and time on stuff that doesn’t work. Click on on the picture under to obtain “Skincare That Works” and eventually get your finest pores and skin day – each day.
How SPF Layering Works in Actual Life
Let’s see what this implies in sensible phrases utilizing the instance under.
Your basis has SPF 15. That enables 7% of UV rays to achieve (and hurt) the pores and skin. However you’ve discovered a moisturiser with SPF 20 beneath. That enables solely 5% of UV rays to achieve the pores and skin. 2% of the rays that made it by means of your basis are actually neutralised by your moisturiser.
However you’ve gotten a 3rd layer on. Your sunscreen with SPF 30 solely lets 3% rays by means of, neutralising an additional 2% that made it previous your basis and moisturiser with SPF.
The upper the SPF, the less % of UV rays attain the pores and skin. Sadly, no sunscreen blocks 100% of them. Even SPF 100 nonetheless lets 1% by means of.
If utilized appropriately, that’s…
Associated: Take A Quantity: What Stage Of SPF Is Proper For You?
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Is Layering Sunscreens Ineffective?
Layering merchandise with SPF won’t add up SPF, however it might enhance your total protection.
That is the place layering can be useful. Regardless that it doesn’t increase your SPF stage, it may well make it easier to cowl areas you might need missed the primary time round.
Let’s say you’re in a rush and making use of sunscreen shortly. It’s straightforward to overlook a spot or two. These spots don’t have any safety and are truthful sport for UV rays.
However for those who slather on a second SPF product, you’ve gotten extra possibilities of overlaying each little nook and cranny.
I personally don’t do that as a result of I’m very diligent with sunscreen software, however for those who assume you want it, go forward.
WARNING! When you don’t apply the really useful quantity (1/4 of a teaspoon for the face alone), it’s possible you’ll get higher protection, however you gained’t get the SPF said on the label.
Associated: Are You Making use of Sunscreen The Proper Approach?
The Drawback With Layering Sunscreen
When you determine to layer sunscreens to get that additional little bit of solar safety, watch out.
Not all UV filters work properly collectively. Some can deactivate one another and compromise the extent of safety you’re getting.
That is the place it will get tough. Sunscreen formulation are rigorously designed to stability totally different UV filters in a method that makes them steady and efficient. However for those who begin mixing totally different manufacturers and sorts of sunscreens, you could possibly be messing with that stability with out even realizing it.
Particularly, beware of blending Avobenzone with Octinoxate, Zinc Oxide, and Titanium Dioxide.
When you’ve simply checked the label of your fave sunscreen and observed it accommodates just a few of those (for instance, Avobenzone and Octinoxate), don’t throw it within the bin but!
Beauty chemists know every kind of methods to make UV filters get alongside. For instance, by coating them so that they provide the finest safety with out getting too shut to one another.
It’s once you use separate merchandise that have been by no means meant to be combined collectively that you could be get in hassle.
One other difficulty? Totally different sunscreens have totally different textures and finishes. When you layer a thick, occlusive sunscreen beneath a light-weight gel formulation, it’d capsule or rub off. Worse, in case your first layer is just too greasy, the second layer won’t adhere correctly, which means you’re getting much less safety than you thought.
How To Layer Sunscreens The Proper Approach
I’m not a fan of utilizing totally different sunscreens. It could assist, however except you already know extra in regards to the formulations and the way UV filters work together with each other, it’s possible you’ll scale back – slightly than enhance – solar safety. Ouch!
However for those who nonetheless wish to do it, right here’s the way to do it proper:
- Reapply the identical sunscreen twice: You continue to get the identical stage of SPF, cowl each nook and cranny, and run no danger of deactivating UV filters.
- Use two sunscreens with the identical (or comparable) UV filters: You’ll nonetheless get the very best SPF stage of the 2, higher protection, and a a lot decrease danger of something deactivating UV filters.
And most significantly, apply sufficient.
- 1/4 teaspoon of sunscreen to your face.
- 1 shot glass of sunscreen to your physique.
- Reapply each 2 hours.
It doesn’t matter how costly or fancy your sunscreen is, for those who’re not making use of sufficient, you’re not getting the complete SPF on the label. Interval.
The Backside Line
SPF works by limiting the quantity of UV rays that truly attain your pores and skin. Layering sunscreens and merchandise with SPF gained’t provide you with the next SPF. However it might provide you with higher protection.
About Gio
Hello, I am Gio. I am a no-nonsense, tell-it-like-it-is pores and skin coach and author on a mission that will help you obtain your finest pores and skin day ever – each day. I bust skincare myths and debunk advertising and marketing jargon that will help you determine what’s definitely worth the splurge and what’s finest left on the shelf – utilizing science, not hype. I additionally supply skincare consultations that will help you create the perfect skincare routine to your distinctive wants.