Well, we're sorry to inform you that this is actually the beauty product's expiry date (which means, yes, after a year in lockdown, a lot of your haul is probably a little too old to use any more...)
Now, we know what you're thinking, how bad can it be? But celebrity skincare expert Lisa Harris, founder of Lisa Harris Skin Science, said that while it may be tempting to keep old beauty products, it's actually really unhygienic if we don't bin them when they go out of date.
"A lot of people keep their make-up for years," she said. "But if it's out of date, you should throw it away."
Usually, the tub on the back of the product will say 6M or 12M next to it, for example. This is called the 'period after opening' and basically means if it's been longer than the specified amount of time since you popped the lid on that product, you need to bin it.
Harris explains it's essential to stick to these rules, however unappealing it may be to throw your favourite moisturiser or blusher away.
This is because bacteria will be spreading within the actual pot itself - even more so if you use your fingers to apply it.
"With all make-up, I generally tell everybody it's about 12 months.
"It doesn't matter if it's powder or liquid when it comes to foundation, because you're still applying it onto the skin," she added.
This might not be good news for anybody who has been hoarding their barely-used makeup over the last year of lockdown, hoping to emerge with a fresh face of product.
But we think after Lisa's advice it might well be time for a shopping trip...
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