The chasing arrows icon tells us when a cosmetic product’s bottle is recyclable, but determining the shelf life of the ingredients inside isn’t so obvious. Some cosmetic companies are now voluntarily labeling products with an icon known as the Period After Opening (PAO) symbol. The image is an open-lidded jar that contains a number followed by the letter M, which indicates the number of months a product remains usable after it has been opened. The FDA currently only requires companies to print expiration dates on products that contain active ingredients, like sunscreen and anti-aging treatments. But some believe including a PAO on all products makes good sense.

"You have to be up front about the length of time a product is completely effective,” says Shel Pink, founder of SpaRitual, an eco-friendly cosmetics company that includes PAO’s. 

But determining the life expectancy of a product is not an exact science. Companies are free to set their own parameters, and they will vary according to the type of product. Expiration dates also don’t account for how a product is stored or used; direct sunlight can compromise the efficacy of vitamin A in cosmetics, for example, and exposure to air can cause many ingredients to oxidize. 

You’ll also need to know the date you first opened the product, since an expiration date without reference provides no benefit at all. But ultimately, PAO’s are helpful rules of thumb. Besides, says Pink, “I like to know when my food expires, and I feel the same way about my beauty products.”

Story by J.T. This article originally appeared in Plenty in October 2007.

Copyright Environ Press 2007