Why Your Sunscreen with SPF 50 Probably Isn’t Giving You Full SPF 50 Protection

By July 11, 2018

It’s actually so confusing understanding how much sunscreen to apply. There are a lot of factors that come into play when you’re trying to understand how much sunscreen is enough to protect you. Keep reading to see why you may want to consider splurging for that higher SPF level.

About a month ago, we created an Instagram post that showed readers how much of each skin care product you should apply…

ATTENTION: The size of your face may affect the size of the portion! 😅 And for sunscreen, make sure to remember that it’s better to be safer than sorry! Using approximately 2 tablespoons (for your whole body) and 1 teaspoon (for your face and neck) is the best way to assure that you’re getting the level of SPF promised on the bottle. *EDIT* thanks to research sent over by @kindofstephen 🙏🏻 SPF EXPLAINER: The reason why it’s such a large amount is because when companies test the effectiveness of sunscreens, they have to put about that much to achieve the SPF number listed on the packaging. This is why it’s so important to reapply throughout the day! 🌤 #theklog #sunscreen #sunprotection #skincareblogger #skincarejunkie #skincare #kbeauty #abbeauty #kbeautyblog #asianbeautyproducts #skincaretips101 #vacationskincare #abblogger #kbeautyaddict #sunscreens #skincareobsessed #koreanskincareproducts #koreanbeautyblog #skincareaddicts

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About a minute after posting it, we got a flurry of comments expressing complete shock and denial about how much sunscreen you should be applying. We said you should be applying about a tablespoon of sunscreen to adequately protect your face and your neck. People couldn’t believe that you actually need that much to protect your face. But the reason why we listed such a large amount was because when a sunscreen company tests its sunscreen, it uses a lot to ensure that the skin is getting the full SPF protection that’s listed on the bottle. So, if a company is testing the effectiveness of its SPF 50 sunscreen, that company applies a pretty decent amount of sunscreen to ensure that skin is actually getting that protection level.

Eventually, we were corrected by the great Stephen Ko, who said that you actually should apply a full teaspoon of sunscreen to your face to get full protection. But he still stresses the fact that we mostly don’t apply enough sunscreen to get the protection level that’s listed on the bottle, and places great importance on re-applying throughout the day. In his post on the difference between physical and chemical sunscreens, he says, “The reason why reapplication is recommended is because we often don’t apply enough in the first place and it’s constantly being removed from our skin. Reapplication helps ensure that we have a minimum density of 2 milligrammes per square centimetre of sunscreen on our skin and that we maintain that density throughout the day.”

Additionally, Stephen recommends actually applying your sunscreen twice in two layers. Here’s an excerpt from his post on research-backed tips to get the most out of your sunscreen:

“Most people don’t apply enough sunscreen! Across multiple studies people only apply ¼ to ½ the amount needed for the protection on the sunscreen’s label. You may have wondered why the US FDA and other organizations keep the amount needed for SPF testing so high, as it turns out 2.0 mg/cm2 is a bit of a sweet spot when it comes to reproducibility and reliability of the results. An easy way to help get the amount needed on the skin is to apply your sunscreen twice. Apply a layer, let it dry, then apply a second layer.”

But why exactly does applying a light layer of SPF 50 sunscreen not actually give you SPF 50 protection? I reached out to Joshua Zeichner, the director of cosmetic dermatology at Mt. Sinai Hospital in New York City, to explain it to us.

“In order to get the protection labels on the bottle of sunscreen you need to apply enough,” he says. “For the face, this means about a quarter size to dollop. For the body, it is about one ounce or the amount of a standard shot glass. If you are putting on less, then the SPF value gets diluted out. So when you are applying the product with SPF 50, if you don’t use enough, you may be getting protection equivalent of an SPF of 30.” In fact, Zeichner advises patients to buy a high level of SPF to be careful. “I recommend that consumers use sunscreens with the highest level of SPF they can get,” he says. “This acts like an insurance policy to give the best protection possible.”

You may be thinking, “Oh my gosh, that’s so much sunscreen and so much money!” Yes, if you continue using SPF 50, it is a lot of sunscreen. But it doesn’t have to cost you that much. Thankfully, a lot of Korean sunscreens offer superior protection without a super high cost. One of my favorite Korean brands for affordable sunscreens is Missha. The Missha Waterproof Sun Milk SPF 50+/PA+++ is $18 and goes on super smooth and won’t fade away through sweat.

If you have drier skin and are looking for a pollution-fighting sunscreen, try the Missha Near Skin Dustless Defense Sun Block SPF 50+/PA+++. This sunscreen is only $15 and creates a protective barrier on your skin to prevent fine dust particles from damaging your pores.

Bottom line:

I hope this clears up any confusion about how much sunscreen to apply. Just remember: You need a lot of sunscreen to actually get the full SPF 50 you need, so always apply at least a full teaspoon to a quarter-sized amount to your face and neck and even consider applying two layers of sunscreen in the morning, just to be safe. If you feel like this is too much work, you may want to consider purchasing a sunscreen that has a higher SPF level so you won’t really have to apply so much. And don’t forget to re-apply a layer every two hours!

+ Do you have any more questions about how much sunscreen to apply? Share them below!

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