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 Improve 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 sensible why individuals imagine it. We’re used to considering 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 coloration. However SPF doesn’t work like that.
In the words 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 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 only one%? That’s why sunscreen layering doesn’t offer you a magic enhance in SPF—it’s all about how a lot really 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 at last 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 beneath.
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 at the moment are neutralised by your moisturiser.
However you will have 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 accurately, that’s…
Associated: Take A Number: What Level Of SPF Is Right For You?
How efficient is your sunscreen? Signal as much as the e-newsletter beneath to obtain the “Sunscreen Audit” Worksheet and discover out in case your sunscreen is admittedly as much as the job:
Is Layering Sunscreens Ineffective?
Layering merchandise with SPF won’t add up SPF, however it could enhance your general protection.
That is the place layering can be useful. Regardless that it doesn’t enhance your SPF stage, it might 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 rapidly. It’s simple to overlook a spot or two. These spots don’t have any safety and are truthful sport for UV rays.
However if you happen to slather on a second SPF product, you will have extra probabilities of overlaying each little nook and cranny.
I personally don’t do that as a result of I’m very diligent with sunscreen utility, however if you happen to suppose you want it, go forward.
WARNING! In case you don’t apply the really helpful 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 Applying Sunscreen The Right Way?
The Drawback With Layering Sunscreen
In case you determine to layer sunscreens to get that additional 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 steadiness totally different UV filters in a manner that makes them steady and efficient. However if you happen to begin mixing totally different manufacturers and kinds of sunscreens, you could possibly be messing with that steadiness 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 seen it comprises just a few 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 in order that they provide the finest safety with out getting too shut to one another.
It’s if you use separate merchandise that have been by no means meant to be combined collectively that you could be get in bother.
One other concern? Totally different sunscreens have totally different textures and finishes. In case you layer a thick, occlusive sunscreen beneath a light-weight gel system, it’d tablet or rub off. Worse, in case your first layer is just too greasy, the second layer won’t 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 could assist, however except you realize extra concerning 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 if you happen to nonetheless wish to do it, right here’s methods 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 related) UV filters: You’ll nonetheless get the 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 in your face.
- 1 shot glass of sunscreen in your physique.
- Reapply each 2 hours.
It doesn’t matter how costly or fancy your sunscreen is, if you happen to’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 offer you a better 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 – each day. I bust skincare myths and debunk advertising and marketing jargon that will help you work out what’s well 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 the very best skincare routine in your distinctive wants.
