Reading a Julian date code
Many US-made products use a Julian date code: the year followed by the day of the year. For example, 23145 means the 145th day of 2023 (25 May 2023). Some brands use a single year digit (e.g. 3145).
Frequently asked questions
Where is the batch code on cosmetics?
Usually it is a short code stamped or embossed on the bottom of the product or printed on the crimp of a tube, often near the barcode on the outer box. It is different from the barcode.
What does the open-jar symbol (e.g. 12M) mean?
That is the PAO, or Period After Opening. It is the number of months a product stays good once opened, regardless of when it was made.
Do cosmetics really expire?
Yes. Preservatives weaken over time and actives such as vitamin C, retinol and sunscreen filters lose strength. Expired products can irritate skin, harbour bacteria (especially mascara) or simply stop working.
Batch-code formats are based on publicly documented manufacturer conventions and can change. If in doubt, contact the brand with your code. Shelf-life figures are industry averages.