In case 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’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 provide you with added SPF safety.
It’s a typical false impression, and truthfully, it is sensible why folks consider it. We’re used to pondering that extra layers = extra safety. In case you put on two sweaters, you keep hotter. In case 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 scientific professor of dermatology at Yale College, “SPF isn’t an equation. Your solar safety is barely as robust 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 via.
- Even SPF 100 isn’t excellent. It nonetheless lets 1% of rays via.
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 enhance 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 greatest pores and skin day – day by 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 via your basis are actually neutralised by your moisturiser.
However you’ve a 3rd layer on. Your sunscreen with SPF 30 solely lets 3% rays via, 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% via.
If utilized accurately, that’s…
Associated: Take A Quantity: What Degree Of SPF Is Proper For You?
How efficient is your sunscreen? Signal as much as the e-newsletter under to obtain the “Sunscreen Audit” Worksheet and discover out in case your sunscreen is de facto as much as the job:
Is Layering Sunscreens Ineffective?
Layering merchandise with SPF is not going to add up SPF, however it could enhance your total protection.
That is the place layering can be useful. Despite the fact that it doesn’t enhance your SPF stage, it could actually provide help to cowl areas you may need missed the primary time round.
Let’s say you’re in a rush and making use of sunscreen shortly. It’s simple to overlook a spot or two. These spots don’t have any safety and are truthful sport for UV rays.
However in the event you slather on a second SPF product, you’ve extra probabilities of masking each little nook and cranny.
I personally don’t do that as a result of I’m very diligent with sunscreen software, however in the event you suppose you want it, go forward.
WARNING! In case you don’t apply the beneficial 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 acknowledged on the label.
Associated: Are You Making use of Sunscreen The Proper Means?
The Downside With Layering Sunscreen
In case you resolve to layer sunscreens to get that additional little bit of solar safety, watch out.
Not all UV filters work effectively collectively. Some can deactivate one another and compromise the extent of safety you’re getting.
That is the place it will get difficult. Sunscreen formulation are fastidiously designed to stability totally different UV filters in a means that makes them steady and efficient. However in the event you begin mixing totally different manufacturers and forms of sunscreens, you would be messing with that stability with out even realizing it.
Specifically, beware of blending Avobenzone with Octinoxate, Zinc Oxide, and Titanium Dioxide.
In case you’ve simply checked the label of your fave sunscreen and observed it incorporates 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 greatest 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 combined collectively that you could be get in hassle.
One other subject? Completely different sunscreens have totally different textures and finishes. In case you layer a thick, occlusive sunscreen below a light-weight gel components, it would capsule or rub off. Worse, in case your first layer is simply too greasy, the second layer may not adhere correctly, that 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 might assist, however until you realize extra in regards to the formulations and the way UV filters work together with each other, it’s possible you’ll cut back – fairly than enhance – solar safety. Ouch!
However in the event you nonetheless need 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 threat 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 threat of something deactivating UV filters.
And most significantly, apply sufficient.
- 1/4 teaspoon of sunscreen on your face.
- 1 shot glass of sunscreen on your physique.
- Reapply each 2 hours.
It doesn’t matter how costly or fancy your sunscreen is, in the event you’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 really attain your pores and skin. Layering sunscreens and merchandise with SPF gained’t provide you with the next SPF. However it could 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 greatest pores and skin day ever – day by 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 greatest left on the shelf – utilizing science, not hype. I additionally provide skincare consultations that will help you create the perfect skincare routine on your distinctive wants.
