The Open Jar Symbol: How Long Makeup Lasts After Opening

The open jar symbol on your makeup packaging is not an expiry date - it's showing how long a product is usable after you first open it. Maybe you've noticed changes in your mascara, or the foundation is flaking. That symbol, 6M or 24M, is the countdown from first opening.

Reading the open-jar symbol

Cosmetics that can last for 30 months or more from manufacture are likely to show this PAO (period after opening) period, instead of a "best before end" style date. It will look like an open jar with the number of months inside, such as 6M, 12M, 18M, 24M and so on. The number tells you how long the product will remain safe to use after being unsealed.

This doesn't mean a product is gone off as soon as the clock runs down. Nor is the PAO symbol the same as a minimum durability date. That is shown on cosmetics with a shelf life of 30 months or less, and is the date before which the product should remain stable under appropriate storage conditions.

Products with a lifespan covering more than 30 months after purchase will tend to come with PAO rather than a durability date. With durability dates, it's generally safe to use the product for a short while after the date has passed, assuming it's stored correctly and it hasn't been opened. With a PAO, this is the expected minimum period for which you can use the product after opening.

What major markers say about typical post-opening timeframes

Truth is, shelf life varies quite a bit for different products. This is why ranges appear in published consumer guidance, rather than universal hard-and-fast expiry rules. According to consumer advice sources, most lipstick, mascara, and eyeliner should be discarded within one year of opening.

The Cleveland Clinic warns that products with short PAOs such as 6M should be thrown out right away once the months run down, typically for powder makeup and lipstick.

When makeup should be discarded

That said, it's also important to look out for visible signs of spoilage, such as changes in texture, smell, or the formation of mould. The problem is, specific safety warning signs for each product type are not sourced, and should be included as a consumer safety warning.

Under optimal storage conditions, the product should be safe to use until this date. However, the product may show signs of spoilage before this date, so the jar should still be checked for any of these signs before using. These include changes in colour or scent, separation of the ingredients, and formation of mould.

How to use the open jar on your own bag

To sum up: to date your own collection, look for both the minimum durability date and the PAO. These should be written clearly on the packaging, usually near the bottom of the packaging. They may be accompanied by other information, such as a batch number, manufacturer's name and address, and instructions for use.

If the product shows a PAO, use up the product when the months have elapsed from the date of opening. If the product shows a "best before end" date, then use up the product within a couple of months of the date.

If you're not sure, it's best to err on the side of caution and discard any products that have been open for longer than the recommended PAO. At the same time, be aware that some of the guidance on specific product shelf lives may be based on industry standards rather than tested science. Store your makeup in appropriate conditions, and if you’re not sure whether something is going off, throw it out.