Sure, it might not be as glamorous as a facial mist, mask, or a luxurious oil — but when it comes to protecting your skin from the sun's harmful rays, good ol' SPF always has your back. Figuring out the right sunscreen for you can be difficult, though, especially when you need it to withstand a sweaty outdoor run or a two-hour beach volleyball session. Luckily, our friends over at Rank & Style did all the work for us and determined which sunscreen will go the extra mile for your skin. The site uses customer reviews, editors' picks, and overall buzz to figure out which products are going to work the hardest for you. Consider its authors beauty lovers with a penchant for math. After crunching the numbers, Rank & Style has named Skinceuticals Sport UV Defense SPF 50 the winner. Not only is this serious SPF an editor favorite, but the product has also received rave reviews online. On Amazon, user Skin Connoisseur wrote, "If you are looking for a waterproof, sweatproof, awesome sunscreen, you have found it. I am always outside, working out, in the water...and I was looking for something with zinc oxide in it. This SkinCeuticals Sport UV Defense is perfect, because it has the zinc oxide, but you can't even tell you're wearing anything." This broad-spectrum, water-resistant sunscreen was even tested on marathon runners, which makes it pretty legit in our book. But, just because this sunblock is a tried-and-true winner doesn't mean you can skimp on application. One layer of SPF won't protect you all day, so make sure you're reapplying every couple of hours. Skinceuticals Sport UV Defense SPF 50, $28.18, available at Amazon.