On makeup and skincare packaging, “6M,” “12M” or “24M” usually refers to the Period After Opening, often shown with an open-jar symbol. It means the manufacturer is indicating how long the product is expected to remain suitable after it has first been opened, under appropriate conditions.
It is not a universal promise that the product is safe no matter how it is stored or used. It is also not the same thing as a printed expiration date or minimum-durability date. Label rules differ by region, so the safest habit is to read the local product label and watch for changes in the product itself.
What the open-jar symbol means
The Period After Opening symbol is commonly shown as a small open jar with a number and the letter “M.” The “M” stands for months.
- 6M means six months after opening.
- 12M means twelve months after opening.
- 24M means twenty-four months after opening.
In the European Union, cosmetic labeling rules require a date of minimum durability for products with a shorter minimum durability period. For products with minimum durability of more than 30 months, EU rules generally require an indication of the period after opening for which the product can be used safely, except where the concept is not relevant.
That EU context matters. PAO labeling should not be described as a global legal requirement. A product sold in another region may use different label conventions, different wording or no open-jar symbol.
PAO is different from an expiration date
A printed expiration date or “best used before” style date relates to product durability before or regardless of opening, depending on the label. A PAO symbol starts counting after the product is opened.
For example, a sealed product may have a printed date on the box, while the tube or compact also has a 12M open-jar symbol. Once opened, the 12-month clock helps you judge use after opening, but the printed date and the product’s condition still matter.
Do not treat either label as a guarantee under poor storage. The FDA notes that cosmetic safety may expire before a date if a product has not been properly stored, such as after exposure to high heat or sunlight.
Why the clock starts after opening
Opening a product changes how it is exposed. Air, fingers, brushes, applicators, water and bathroom humidity can all affect a formula. Every use creates another opportunity for contamination or drying, especially with products used around the eyes or mouth.
That does not mean every opened product becomes dangerous quickly. It means the label is based on expected use and storage, not unlimited handling.
A simple habit helps: write the opening month and year on the product with a fine marker or small label. If you rotate several mascaras, lip products or cream complexion products, this tiny note is more reliable than memory.
Storage and hygiene habits
Good storage cannot make a product last forever, but poor storage can shorten its usable life.
Keep products closed when not in use. Store them away from heat, direct sun and standing water. Avoid adding water or saliva to revive a dry product. Use clean hands or clean applicators, and avoid dipping shared or dirty tools into jars and pans.
For products used near the eyes, hygiene matters more. The FDA advises not sharing eye cosmetics and says to stop using eye cosmetics if they cause irritation. It also advises discarding eye cosmetics used during an eye infection and not adding water or saliva to dried mascara.
If you use brushes or sponges, product age and tool hygiene work together. A clean product can still be applied with a dirty tool, so it helps to clean makeup brushes regularly.
Signs to discard before the PAO ends
Visible or sensory changes can justify discarding a product before the PAO period is over. Watch for:
- a new or unpleasant smell;
- separation that does not resolve as the label describes;
- unexpected thickening, drying or graininess;
- color change;
- mold-like spots or contamination;
- broken packaging that cannot close properly;
- irritation from a product that previously felt comfortable; or
- performance changes, such as clumping, dragging or uneven application.
These signs do not diagnose exactly what has happened chemically or microbiologically. They are practical reasons not to keep applying the product to your face, lips or eyes.
Do not rely on the symbol alone
A product should not automatically be treated as safe merely because the PAO period has not passed. Storage, contamination and the condition of the product matter.
The reverse is also nuanced. The FDA explains that expiration dates are rules of thumb and that products stored under ideal conditions may remain acceptable after a date. For a consumer deciding what to put near the eyes or on irritated skin, however, caution is reasonable. If a product looks or smells wrong, do not keep using it just because the calendar says it might be within range.
If a product causes burning, swelling, rash or persistent irritation, stop using it. For a new skincare product, a cautious patch-test may help you notice obvious irritation before applying it widely, but it cannot guarantee that a product will never cause a reaction.
Mascara and eye products
Mascara and other eye-area cosmetics deserve extra caution because applicators repeatedly move between the product and the eye area. The FDA says some industry experts recommend replacing mascara three months after purchase, and that manufacturers usually recommend discarding mascara after two to four months. It also warns against adding water or saliva to dried mascara.
Those statements are not a fixed global schedule for every eye product. They are a caution that eye products have more limited shelf-life concerns than many other cosmetics. Follow the specific label and discard products used during an eye infection.
Key takeaways
- 6M, 12M and 24M usually mean months after opening.
- PAO is different from a printed expiration or minimum-durability date.
- EU cosmetic rules provide an important PAO labeling context, but label rules vary by region.
- Storage, contamination and visible changes can make a product unsuitable before the PAO period ends.
- Eye products and shared applicators deserve extra hygiene caution.