SPRINGFIELD, Mo. -- Experts say many people do not check a sunscreen bottle for it's expiration date, and that can lead to sunburn.
Most sunscreen will last 3 years, and that's only if it is kept in a controlled room-temperature environment.
"Beyond the expiration date it doesn't become harmful, just less effective," says Cox pharmacist Tom Lale. "So, it's a roll of the dice because you don't know if it is 50 percent of its original strength or 10 percent of its original strength. Because it all depends on the conditions it was stored in over time."
Expiration date labels are not required by law, so it is a good idea to write down when you bought your bottle to be safe, says Lale.
What's more important to replace than sun repellents? Lip balm, because they are often stored in high temperature environments, says Lale.