If you're still using the bottle of Witch Hazel that's been sitting in your bathroom cupboard since 2001, this one's for you, friend.
Because here's the thing - beauty products don't last forever, and if you're continuing to use them well past their prime, you're going to have a bad time.
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In fact, expired skincare can get NASTY, causing everything from weird reactions and rashes to inflammation and a whole load of other things we don't want for your cute face.
So, how do you actually know when your products have reached their expiration?
We spoke to Dr Sue Feng, Palmer's Chief Scientific Officer, and asked her about how well different skincare products hold up - and when it's time to replace your stash.
How do you know when your skincare is expired?
Figuring out what products you need to ditch is surprisingly easy. "The simplest way to know whether your skincare is expired is to check for an expiry date," said Dr Feng.
The ol' expiry date. Where do you find it?
Well, the symbol usually looks like a small tub or jar with a number inside it, and can usually be found on the underside or back of the product.
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"If a product is open, you can check on the packaging for the little jar icon – the number printed within the jar icon indicates how many months the product can be safely used. Generally, water-based products like lotions are suitable for use for 12 months after opening, and oils are 24 months," explained Dr Feng.
So, what happens if you have some unopened stuff kicking around for ages? Is it still good to go or nah?