She goes on to explain that sunscreen formulas work so that UV filters are applied evenly over your skin. Once that sunscreen has hit its expiration date, the formula will begin to separate and those active ingredients that filter out the UV rays may end up clustering in one area upon application.
King adds that expired sunscreen could potentially irritate the skin. Ingredients could have broken down into irritating chemicals once past their expiration date or there could be bacteria and yeast growing in the product, which could lead to infection and forms of skin irritation such as bumps and rashes.
Both experts and the FDA strongly advise using expired sunscreen and tossing it all together. If there is a chance where you have no other option for sun protection, King says that using it might be okay if it’s only slightly past the expiration date and if the sunscreen looks, feels, and smells normal. Just do a test patch first to make sure you don’t react badly to it and still have a plan to replace it with new sunscreen ASAP.
“Expiration dates are stamped on sunscreen containers to specify the time limit for the product’s stability and efficacy,” emphasizes King. “For optimal sun protection as well as texture, stability and sterility, use sunscreen prior to the expiration date.”
How can you tell if your sunscreen has expired?
The easiest way to tell if your sunscreen has expired is by looking at the label. But if there isn’t a specific expiration date listed, King says that you can assume it’s good for three years past its purchase date, just as the FDA advises.
Other signs that point to sunscreen being past its prime are changes in color, consistency, smell, and texture. Even if this occurs before the expiration date, it’s most likely no longer safe to use and you’re better off grabbing a new one.
How do you properly store sunscreen?
Just like you would with any other skin care product, the best way to prolong the shelf life of your sunscreen is to store it properly. Both Koestline and King say that you’ll want to put sunscreen away from direct light as the sun can cause some formulations to break down and separate before the expiration date. Koestline says to keep products in a place that’s dry and at room temperature at a minimum. For best results, King says to opt for a cool, dark place.