How to tell if your sunscreen has gone bad, according to the experts

Safe to say that we’re all well-versed in basic sunscreen commandments. Thou shall use broad-spectrum SPF 30 protection every day. And reapply said sunscreen every two hours. But something that often gets ignored when it comes to safe sunscreen practices is that tiny little label on the bottle known as the expiration date.

It’s natural to not want to waste any product, especially if you can’t physically see anything wrong with it. But using sunscreen—or any skincare product in general—past its shelf life can come with some major consequences. Below, the experts break down why everyone should take the expiration date seriously and how to get the most out of your favourite sunscreens before it’s time to toss them out.

Does sunscreen expire?

To put it bluntly: yes. There will come a time when even the best sunscreens are no longer effective. According to Krupa Koestline, founder and chief cosmetic chemist at KKT Labs, sunscreens are considered over-the-counter drugs with specific testing guidelines that they have to follow and adhere to. All sunscreens, Koestline says, are required to have expiration dates listed to enter the market and the sunscreen itself has to work up until that specified date.

Chemical vs mineral sunscreen shelf life

Hadley King, MD, a New York City-based board-certified dermatologist, says that the formula for physical sunscreens (AKA mineral sunscreens) is considered more stable than chemical sunscreens and thus have longer shelf lives. She explains that physical sunscreens that include ingredients such as zinc oxide and titanium dioxide won’t change their molecular structure when exposed to light and keep ingredients stable longer than those found in chemical sunscreens, which consist of more unstable molecules and can oxidize over time.

Ron Robinson, cosmetic chemist and CEO of BeautyStat, agrees, but says that both are still formulated to last up to three years if unopened and stored in a cool, dry environment that is not in direct sunlight.

Spray vs lotion sunscreen shelf life

While sunscreen shelf life can differ based on the type of sunscreen you choose, Robinson says there is no difference when it comes to spray and lotion formulations. King adds that powder sunscreen contains minerals that are more stable and longer lasting, while liquid formulations will be less stable. But you can expect sunscreens in general to last anywhere between two to three years.

Why does sunscreen expire?

All beauty products expire, says Robinson. He goes on to explain that most ingredients used in these products, especially sunscreen, will degrade over time and become less effective once they do.

How long does sunscreen last?

Robinson says that sunscreens are required to have an expiration date listed, as they are classified as over-the-counter drugs. Many, he adds, will even show a “period after opening” symbol on the package that will show you how many months the sunscreen has before it expires once you’ve opened it. (“This can be six or 12 months,” he says).