Ohhh so this is what that little round symbol on your cosmetics actually means.

We need to talk about your makeup bag.

Specifically, the lip balms, powders, and tubes of mascaras that have been gathering handbag lint since the dawn of time.

If you look very closely at the packaging of your favourite moisturiser, lipstick, foundation, nail polish etc, you will find an outline of a small jar with a number inside it.

That number, my friends, is the number of months you should be keeping that product after opening it. A ‘best before date’ for makeup and skincare, if you will.

So, if you bought a lipstick for your cousin’s wedding, say, five years ago, it might be an idea to check the date on that bad boy. Because chances are it’s getting ready to walk itself to the bin.

Here are some more examples:

NARS Powermatte Lip Pigment has a shelf life of 24 months.

This lovely spring-appropriate OPI Infinite Shine 2 nail polish in Don't Toot my Flute will also be good for 24 months after opening (although we all have that funky looking bottle of polish that we've kept for 5+ years).

Designer Brands' Feel the Heat Mix Tape Eyeshadow Palette will keep your eyelids looking pretty for 12 months.

This is because cosmetics, skincare and beauty products sold in Australia are required by the National Industrial Chemicals Notification and Assessment Scheme (NICNAS), a division of the Department of Health and Ageing, to comply with correct ingredient labelling laws.

However, whether you obey that little number is of course completely up to you.

In the interest of hygiene, it's more important that you follow the rule for any liquid or cream products (which are more susceptible to bacteria buildup), especially your mascaras, eyeliners and anything you apply to your lips. When it comes to powder products, you do have a bit more leeway but keep in mind you might notice the quality degenerate after the 'best before' date.

And it goes without saying, if it smells funky, has changed colour, consistency or texture, or is giving you a reaction of any kind, then it's definitely time to bin it and repurchase.

You know you have to do.

Did you know this beauty fact? Is your makeup bag due for a clean out? Tell us in a comment below.

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