Asking For A Friend: Can You Use Last Year's Sunscreen? A Chemist Explains

Say what you will about social media, but it has undoubtedly democratized expert knowledge. I say this as someone who already has access to a rolodex of derms, estheticians, and product developers because of my job—you’d be surprised by how many people I still DM on Instagram with beauty-related queries. It’s like having an expert on call! 

Of course, it’s crucial to respect people’s boundaries (whether you’re a journalist or not), but plenty of professionals are more than willing to share their wisdom in a simple message. Ron Robinson is one of those pros. 

And because SPF is highly regulated by the FDA, it should be stamped with an FDA-approved expiration date. “Sunscreen expiration dates are required by the Food and Drug Administration,” Robinson agrees. 

If your bottle doesn’t have an expiration date (or perhaps it rubbed off from wear or sweat), he recommends writing the date of purchase on the bottle yourself. Most sunscreens typically have a shelf-life of around three years, give or take, so keep track of when you purchased and opened your bottle. 

So if you bought last year’s sunscreen last year, you should be OK. If it’s a four-year-old bottle, it’s probably time to toss it. 

However! Your sunscreen can expire well before its proposed shelf-life if you don’t store it right. “Sunscreen should be stored in a cool, dark place1 to maintain its stability and efficacy,” Robinson explains, as direct sunlight and heat can break down its UV-protective molecules. 

Meaning, if you frequently leave your sunscreen in a scorching hot car or outside by the pool, you might have a rancid SPF sooner than you think.