You’ve probably heard the general rule for "how often should I reapply sunscreen": You’re supposed to reapply sunscreen every two hours, unless you’ve been swimming or sweating, in which case you should reapply more often.
Is It True?
You might be thinking, do I really have to apply sunscreen that often? What if you’ve slathered on a generous shot of lotion? You might think that you can get away without reapplying it. You can’t. On the other hand, reapplying more often doesn’t increase the SPF of your sunscreen. Spraying on an SPF 15 every 30 minutes isn’t going to give you the same protection as SPF 50.
The Best Kind of Sunscreen
A 2001 study found that if your sunscreen comes off easily, it doesn’t offer you enough protection no matter how frequently you reapply it. So what kinds of sunscreens are better? Modern water-resistant or waterproof formulas bind to the skin, making them more likely to stay put.
Is Every Two Hours the Hard and Fast Rule?
But if you’re wondering, how often should I reapply sunscreen, the answer might surprise you. The best way to apply these products is to cover your skin generously 15 to 30 minutes before heading out in the sun. Once you’re basking in the rays, reapply the sunscreen about 20 minutes after your sun exposure began. If you follow this procedure, you will get about 25 percent less sun exposure (and up to 40 percent less) than if you waited two hours to reapply.
Does that mean that you have to keep reapplying every 20 minutes? That’s a lot of sunscreen. The answer is no. If you’ve applied sunscreen before you left the house and then reapplied 20 minutes after sun exposure, you can continue to reapply every 2 hours or after swimming, sweating or vigorous scrubbing with a towel.
Remember that as you pull off your rashguard or shimmy out of your beach cover up for a swim, some of your sunscreen is going to rub off onto your clothes. Have you ever gotten a sunburn in the shape of your flip flops because the straps buffed off the lotion? Don’t forget to reapply your sunscreen after changing clothes or kicking off your shoes.