When you’re buying sunscreen, do you look for words like ‘waterproof,’ ‘sweatproof’ and ‘sunblock?’ If so, don’t bother — they may not be as bulletproof as they seem.

Last year, the FDA mandated that sunscreen manufacturers had to stop using the above descriptions because no product is truly waterproof or sweatproof, and even the best sunscreens don’t completely block harmful rays. And although the ban was supposed to be in place this summer, makers now have until this winter to comply.

Products claiming to be ‘waterproof’ or ‘sweatproof’ will have to prove it with standard testing and state exactly how long a product will stay on the skin after being exposed to water or perspiration.

In addition, terms like ‘sunblock’ will be replaced with ‘broad spectrum’ as long as a product has an SPF rating of at least 15 and protects the user from both UVA rays (associated with skin cancer) and UVB rays (which can cause sunburn).

That said, sunscreens on the shelves are still effective and the FDA encourages their use, saying, “The ingredients in FDA-approved sunscreens marketed today have been used for many years, and FDA has no reason to believe these products are not safe.”

[Time]