Period-After-Opening Symbol: What the Open Jar Means

The open-jar symbol on a cosmetic is the period-after-opening mark, often shortened to PAO. The number next to it, such as 6M or 12M, is how many months the manufacturer suggests using the product after you first open it. It isn't an expiration date, and it's not required on US cosmetic labels, so plenty of products won't carry one.

This guide is general consumer information. Follow any directions on the product itself.

How to read the symbol

Look on the back or base of the packaging, or on the outer box. You'll see a small drawing of a jar with its lid open. Inside or next to it is a number, usually followed by "M".

What you see	What it means
Open jar with 6M	Use within 6 months of opening
Open jar with 12M	Use within 12 months of opening
Open jar with 24M	Use within 24 months of opening

The clock starts the first time you open the product. A sealed lipstick bought in January and opened in June starts counting in June.

A worked example. You open a moisturizer marked 12M in March 2026. Your review date is March 2027.

Other symbols you might see

An hourglass symbol appears on some packaging next to a date. In the EU, it marks a "best used before the end of" date, which is a different kind of label from PAO. An open book with a pointing hand means there's additional information in an insert or on a leaflet.

PAO, expiration dates and shelf life

These terms get mixed up, so here's how they differ:

Term	What it refers to	When the clock starts
Period after opening	How long the maker suggests using an opened product	When you first open it
Expiration or best-before date	A printed date set by the maker	A fixed calendar date
Shelf life	How long a product should look and work as expected	Depends on the product, its use and its storage
Batch code	A production code, not a date you can read directly	Not applicable

What the rules say

In the EU, the PAO mark applies to cosmetics with a minimum durability of more than 30 months. Products with a shorter durability carry a date instead.

In the US, the FDA says there are no laws or regulations requiring cosmetics to have specific shelf lives, and it doesn't require expiration dates on cosmetic labels. Manufacturers remain responsible for their products. The FDA also notes that drugs, including products that are both a drug and a cosmetic, are treated differently and must show expiration dates.

So a PAO mark on a product sold in the US often reflects the brand's own choice, or the fact that the same packaging also goes to markets where the mark is used. A missing symbol doesn't tell you anything about the product's quality.

What the number can't tell you

The number is a general estimate from the manufacturer. It doesn't track what happens to your particular jar. The FDA says shelf life varies with the product type, how it's used and how it's stored. Keep these limits in mind:

• It assumes ordinary use and storage.
• It can't see a jar left in a hot car or a bathroom full of steam.
• It doesn't know how often you dip into the product with your fingers.
• It says nothing about an unopened product's age, which is where the batch code helps. Brands can often tell you the manufacture date if you give them the code.

Eye-area products deserve particular attention. The FDA notes they tend to have shorter shelf lives than other cosmetics, and that manufacturers usually recommend discarding mascara two to four months after purchase. It also advises against sharing makeup.

How to track opening dates

A tracking habit only works if it takes seconds. Pick one of these methods.

Method 1: Label the product

Keep a fine permanent marker or small stickers in your makeup bag. When you open something, write the month and year on the base. Add the review date if you like, so you don't have to do the math later.

Method 2: Use your phone

Add a calendar reminder for the review date, with the product's name in the title. This suits items you use infrequently, like an occasional fragrance or a body scrub.

Method 3: Keep a simple list

A note or spreadsheet helps if you own a lot of products. Copy these columns:

Product	Shade	Date opened	PAO	Review date	Notes
Example lipstick	Rose	03/2026	12M	03/2027	Stored in drawer

A quick review checklist

When a review date arrives, or any time a product seems off, check these:

• Has the smell changed?
• Has the color shifted?
• Has the texture separated, thickened, dried out or gone grainy?
• Has the product been stored somewhere hot or damp?
• Has anyone else used it?
• Is it past the review date?

If you answer yes to any of the first three, replace it even if the review date hasn't passed. If a product irritates your skin or eyes, stop using it and ask a clinician or pharmacist.

Buy with your review date in mind

PAO is useful when you're tempted by a multi-buy. A good deal isn't much of a deal if you can't finish the product in its window, particularly with items you've opened. The beauty sales calendar can help you time a replacement so you aren't overbuying.

If a replacement is due, look for an alternative in the dupe database, or browse body care. Save the product to your shelf for price alerts, and you'll know when to buy it.