Yes, sheet masks do expire. They SHOULD have an expiry date on the pack. I state should, as some brands opt not to, but they most certainly should.
The fact is an average sheet mask does have quite a long life expectancy, normally between one and three years, so unless they have been stashed at the back of the cabinet for a long time, you should be fine.
One key thing to remember is that many Korean sheet masks (considering most of these products are created and used in Korea) have a manufacturing date. This is the date it was created, so do not panic if you see a date from a long while ago. The first issue you will have to tackle (if you can’t read Korean) is to understand the difference between the symbols representing expiration date and manufacturing date, as well as ‘use by’, as any three could be present.
So why do Korean companies opt for manufacturing date instead? Well, when they work with brands, they want to show the products have been freshly made. For example, the product might not expire for a decade, but a store or company might think there isn’t much wrong with a 2 year expiry date until they realise it has been sat in storage for 8 years. For this reason, a produced date highlights that it is fresh and brand new, which normally also means there could be less damage to the products and the packaging.
An extra area to consider is that, regardless of the expiry date, once you open the product it will start to oxidise and therefore will have a vastly shorter lifespan. Sheetmasks should be used all in one go, however if you do decide to reserve some for another time then you should scrape the excess serum into an airtight container. It being airtight is critical, to stop oxygen reaching the mix. As well as being exposed to oxygen, it can also gather bacteria, which is the last thing you want to be putting on your face, so be careful if storing a previously opened product of this nature.
As you would with food in your fridge, always try to consider expiry date when deciding which product to use. You wouldn’t cook all your long life food first and leave vegetables and meat for the following week, so adapt your food policy to your beauty regime.
If your masks are coming up to their date, well it’s not a bad thing, it just means it is time to have a deep detox session and spend some time with masks on your face. Your skin will be incredibly grateful!