Skincare Expiry Dates, Explained: What the Open-Jar PAO Symbol, the Hourglass, and the FDA's Silence Actually Mean

Two labels that look alike and mean different things

The open-jar symbol is a period after opening

Article 19 of the EU Cosmetics Regulation (1223/2009) requires products with a minimum durability above 30 months to state "the period of time after opening for which the product is safe and can be used without any harm to the consumer," shown as the open-jar symbol plus months or years. "12M" means twelve months once opened. It is the maker's own assessment for that formula and package.

The hourglass covers the sealed product

At 30 months or less, the label must show a date of minimum durability, beside the hourglass or the words "best used before the end of." It is the date until which the product, "stored under appropriate conditions, will continue to fulfil its initial function."

The United States has no matching cosmetics rule

The FDA says "there are no U.S. laws or regulations that require cosmetics to have specific shelf lives or have expiration dates on their labels," and leaves shelf life to the manufacturer. Its practical signs of a product past its best are changes in color, odor or texture, separation in an emulsion, and hardening or cracking, all sped up by heat, light and air.

Sunscreen is the exception: a printed date or a three-year claim

US sunscreen is an over-the-counter drug. Under 21 CFR 211.137(h), the expiration-date requirement is not enforced for OTC drugs with no dosage limitations that are "stable for at least 3 years as supported by appropriate stability data." So a printed date should be followed, and an undated tube carries a three-year stability claim counted from manufacture, not purchase. That last point is our inference from the wording, not FDA advice; marking the purchase month is a cheap habit. Dose still outweighs age: see what the SPF number was measured at.

Why an opened jar ages faster than a sealed one

A 1990 study in Applied and Environmental Microbiology tested deliberately poorly preserved products in consumers' homes. Of 21 screw-cap skin-lotion containers, 71% were contaminated, against 39% of 18 flip-caps and 10% of 21 pump-tops. Because the products were unpreserved on purpose, this shows what packaging does, not how a normal moisturizer behaves. Still, a wide jar and fingers is the highest-exposure design.

The eye area runs on the shortest clock

The FDA notes that eye-area products tend to have shorter shelf lives and that infections from them can be serious. Manufacturers "usually recommend discarding mascara two to four months after purchase." Eye cream is a different product, but the finger-contact logic is similar.

A five-minute shelf check

Write the opening date on anything with a PAO symbol. Keep products away from heat, not in a hot car, as the FDA advises. Wash hands before using a jar. Discard anything that smells different, separates, changes color or hardens. A vitamin C serum can darken as it oxidizes, covered in the vitamin C stability article. The PAO number is a ceiling, not a promise.

Sources: Regulation (EC) No 1223/2009, Art. 19; FDA, "Shelf Life and Expiration Dating of Cosmetics"; 21 CFR 211.137(h); Appl Environ Microbiol 56(5), 1990. General information, not medical advice. Patch-test new products and see a dermatologist about a reaction or persistent skin condition.