Navigating your way around the wonderful world of sunscreen is way more complicated than you might think. This is why we chatted with dermatologist Dr. Anita Sturnham of the Nuriss Clinic in London to get the dirt on all things sunscreen-related. Be warned, some of these facts are damn crazy, so hold on to your tea!
It becomes inactive after two hours.
"Reapply your sunscreen" is something we've all heard and read a million times before, but do you know how fast it actually stops working? Apparently, reallllyyy fast. "Most sun protection products degrade after two to three hours of application, making it essential that you reapply regularly throughout the day in order to get full protection," explains Dr. Sturnham. "In reality, most people only apply their product once in the morning, so from late morning onwards their protection expires."
The SPF in your foundation isn't protecting you from UV damage.
Just because a foundation has an SPF rating doesn't mean it's providing you with broad spectrum coverage. Dr. Sturnham explains: "Many people rely on their foundation to provide them with sun protection. Makeup brands often add ingredients like zinc oxide to their formulations, which may offer small levels of protection, but these brands do not include UVA filters in their bases because they make the product more difficult to apply and alter the finish on the skin. Your foundation labeled as SPF15 will not be protecting you from UVA rays—only a small level of protection against UVB, which wears off throughout the day."
There isn't a lot of difference between SPF30 and SPF50.
According to Dr. Sturnham, "There is only an additional one to two percent protection when you move from an SPF30 to SPF50." The British Association of Dermatologists back this claim, too, saying that: "SPF 30 blocks 97 percent of UVB rays, while SPF 50 blocks 98 percent." So is 30 the new 50? Not quite. However, Dr. Sturnham does state "if you have very fair skin, are prone to pigmentation, or are on photosensitive medications, the additional one to two percent protection is worthwhile."
You can get major sun damage in the plane.
If, like me, you're partial to a window seat on your flight, then be warned because this one is going to ruffle your feathers in the worst way. UVB rays (the ones associated with dreaded sunburn) are blocked by windows, however, much to our horror, UVA rays aren't. "UVA rays can pass through the windows on a plane and cause damage in the deeper skin layers, without your awareness," says Dr. Sturnham. Keep in mind UVA is responsible for increased skin aging, dark spots, and hyperpigmentation. Throw in the fact that you're 40,000 feet up in the air and are closer to the ozone layer, so the sun is more powerful and causes more damage. In other words, you need to be wearing SPF on every flight—especially if you're a seasoned window-seater.
Sun damage is making you break out, not your SPF.
Spoiler alert: those pesky breakouts popping up while you're on vacay are not the result of your sunscreen clogging your pores. You're breaking out because your skin produces more oil after enduring UV damage (aka, sitting in the sun). Mind. Blown. "Yes, oil-based products can give you breakouts, which is why I recommend looking for water-based formulations, labeled as 'non-comedogenic,'" Dr. Sturnham explains. "However, sun damage can send your complexion into meltdown by causing inflammation and damaging the epidermal barriers. This means your skin's immune and defense system will be off-kilter, which can cause breakouts."
The thicker your sunscreen, the better the protection.
Skincare rule 101: Thicker sunscreens don't automatically = better formulas. In fact, Dr. Sturnham explains that thicker textures have often been altered by the manufacturers in an attempt to make them appear heavier and more luxurious. The same also goes for moisturizers—just because it's whipped into a creamy, heavenly state, doesn't give it greater skin-saving abilities. Go figure. "Ideally the product should have skin-protecting and nourishing benefits, too. Look for ingredients such as glycerin, squalene, vitamin E, and aloe on your sun care label."
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This article originally appeared on Cosmopolitan.com/uk. Minor edits have been made by the Cosmo.ph editors.