The PAO symbol, or period after opening, is the open-jar icon on cosmetic packaging that shows, in months, how long a product stays safe to use after it is first opened, printed as a figure such as 12M or 24M.
Also known as: period after opening, open jar symbol, 12M symbol, cosmetic expiry symbol
The period after opening (PAO) symbol is a small drawing of an open cream jar with a number and the letter M inside or beside it. 12M means the product is safe for twelve months after the first opening; 24M means two years. It is the shelf-life mark on most nail polish, lip gloss and eyeliner sold in Europe.
The rule comes from Article 19 of Regulation (EC) 1223/2009. A cosmetic with a minimum durability of more than 30 months does not need a best-before date. Instead it must show the period after opening for which the product is safe, using the open-jar symbol in point 2 of Annex VII followed by the period in months or years (EUR-Lex). Products that last less than 30 months carry an hourglass symbol with a best-before date instead.
The period differs by product type. Water-based liquid liners and open gel pots are vulnerable to microbes, and the industry norm for eye products is 6 to 12 months. Ophthalmologists go further and advise discarding a pencil used on the waterline after 3 months (Coveteur). Nail polish contains no water and dries out before it spoils, so its PAO is usually longer, though a thickened or separated lacquer is past its best whatever the label says.
Write the opening date on the base of a new bottle or tube with a marker. The PAO counts from that day, not from the date of purchase, and the symbol is the fastest way to decide whether an old gloss or liner should go.