In the event 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 or not it’s SPF 65? Not fairly.
SPF math isn’t like common math. You’ll be able to’t simply add up all of the numbers and anticipate superhero-level solar safety. Right here’s why:
Does Layering Sunscreens Enhance Solar Safety?
Quick reply: No. However there’s extra to the story.
Layering sunscreens will NOT offer you added SPF safety.
It’s a typical false impression, and actually, it is smart why folks consider it. We’re used to pondering that extra layers = extra safety. In the event you put on two sweaters, you keep hotter. In the event you apply two coats of nail polish, you get a extra opaque coloration. However SPF doesn’t work like that.
Within the phrases of Mona Gohara, a dermatologist and an affiliate scientific 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 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 received’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 implies much more UV rays are nonetheless getting by means of.
- Even SPF 100 isn’t good. It nonetheless lets 1% of rays by means of.
Discover how the distinction between SPF 30 and SPF 50 is only one%? That’s why sunscreen layering doesn’t offer you 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 beneath to obtain “Skincare That Works” and eventually get your finest pores and skin day – day-after-day.
How SPF Layering Works in Actual Life
Let’s see what this implies in sensible phrases utilizing the instance beneath.
Your basis has SPF 15. That enables 7% of UV rays to succeed in (and hurt) the pores and skin. However you’ve realized a moisturiser with SPF 20 beneath. That enables solely 5% of UV rays to succeed in the pores and skin. 2% of the rays that made it by means of your basis at the moment are neutralised by your moisturiser.
However you may have a 3rd layer on. Your sunscreen with SPF 30 solely lets 3% rays by means of, neutralising an extra 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 is not going to add up SPF, however it could improve your general protection.
That is the place layering can be useful. Though it doesn’t increase your SPF degree, it will probably enable you to cowl areas you might need missed the primary time round.
Let’s say you’re in a rush and making use of sunscreen rapidly. It’s simple to overlook a spot or two. These spots don’t have any safety and are truthful recreation for UV rays.
However for those who slather on a second SPF product, you may have extra possibilities of protecting each little nook and cranny.
I personally don’t do that as a result of I’m very diligent with sunscreen utility, however for those who assume you want it, go forward.
WARNING! In the event you don’t apply the beneficial quantity (1/4 of a teaspoon for the face alone), chances are you’ll get higher protection, however you received’t get the SPF said on the label.
Associated: Are You Making use of Sunscreen The Proper Means?
The Drawback With Layering Sunscreen
In the event you resolve to layer sunscreens to get that further little bit of solar safety, watch out.
Not all UV filters work nicely 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 fastidiously designed to stability totally different UV filters in a approach that makes them steady and efficient. However for those who begin mixing totally different manufacturers and sorts of sunscreens, you possibly can be messing with that stability with out even realizing it.
Particularly, beware of blending Avobenzone with Octinoxate, Zinc Oxide, and Titanium Dioxide.
In the event you’ve simply checked the label of your fave sunscreen and seen it accommodates a couple of of those (for instance, Avobenzone and Octinoxate), don’t throw it within the bin but!
Beauty chemists know all types of tips 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 whenever you use separate merchandise that have been by no means meant to be blended collectively that you could be get in bother.
One other difficulty? Totally different sunscreens have totally different textures and finishes. In the event you layer a thick, occlusive sunscreen underneath a light-weight gel system, it would tablet or rub off. Worse, in case your first layer is simply too greasy, the second layer may not adhere correctly, which means you’re getting much less safety than you thought.
How To Layer Sunscreens The Proper Means
I’m not a fan of utilizing totally different sunscreens. It could assist, however except you realize extra concerning the formulations and the way UV filters work together with each other, chances are you’ll cut back – fairly than improve – solar safety. Ouch!
However for those who nonetheless need to do it, right here’s methods to do it proper:
- Reapply the identical sunscreen twice: You continue to get the identical degree 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 best SPF degree 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 total 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 received’t offer you the next SPF. However it could offer you 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 – day-after-day. I bust skincare myths and debunk advertising and marketing jargon that will help you work out what’s definitely worth the splurge and what’s finest left on the shelf – utilizing science, not hype. I additionally provide skincare consultations that will help you create one of the best skincare routine to your distinctive wants.
