How old is sunscreen

That goes for both chemical and mineral sunscreens. Chemical sunscreens that contain ingredients such as oxybenzone, avobenzone, and homosalate "can oxidize and become less effective," Romanowski explains. Mineral sunscreens — those with zinc oxide or titanium dioxide on the label — don't have that problem, but they do still degrade.

That leads us to the second problem with expired sunscreen. Even if the active SPF ingredient is still technically good, changes in the formula over time can make it both ineffective and problematic for skin.

As the bacteria grows in the tube, it can cause breakouts, she says. Most sunscreens are designed to last three years, says Gilbert. So, the first thing to do is check for an expiration date on the container though not all brands have one, Gilbert warns. But even if your sunscreen is only a summer old, there are other factors that might make the SPF spoil faster than the date stamped on the tube. Regardless of the date, always test the consistency of your sunscreen before you use it.

The bottom line? Unfortunately, in the process of reporting this story I learned that only two of the seven sunscreens in my stockpile were actually usable. Even if yours does, the date can become basically illegible over time. Here, experts answer those questions and more.

The chemicals in any kind of sunscreen break down over long periods of time, eventually becoming less potent, John G. Zampella , M. Zampella has a pretty sweet analogy to drive home this point. All drug manufacturers including the ones who make sunscreen have to perform stability testing before they can sell their products, the U.

The FDA recommends drug manufacturers follow standardized guidelines for stability testing, like those outlined by the International Council for Harmonization. The guidelines are full of complicated technical terms and scientific hurdles for manufacturers to clear.

To sum it up, these recommendations essentially ask that manufacturers expose at least three batches of the product to multiple storage conditions over the course of months or years. Then manufacturers are supposed to conduct all sorts of tests—physical, chemical, microbiological, etc.

So behind that tiny expiration date on your sunscreen bottle is a lot of scientific effort to make sure the drug will be as effective as possible up to that point—but not after. Sign Up Now. An unexpected error has occurred with your sign up. Please try again later. Check here if you would like to receive subscription offers and other promotions via email from TIME group companies. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Service and Privacy Policy. Thank you!

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