One of the first posts I ever wrote for Applied Glamour detailed the dangers of hanging on to old cosmetics, how they can harbor bacteria, and general guidelines for makeup expiration. The FDA doesn't require expiration dates on beauty products, but many cosmetic companies have started expressing shelf life guidelines with the Period After Opening (PaO) symbol. The PaO symbol tells you how many months the product will be useful after you open it the very first time. It's typically found on the back of product packaging, where the rest of the information is listed. It's not yet a requirement in the United States so not every product will have a PaO symbol, but many do. It looks like this:
Have you noticed it before? I can't believe I never have! I looked through the products in my makeup bag, and sure enough, there it was! NARS pressed powder and eyeshadows are good for 36 months, my moisturizer should last 12, and I was shocked to discover that my Urban Decay Brightening Face Primer only lasts three months. I bought it, oh, nine months ago! Uhm, whoops... I was also shocked to see that Rimmel thinks their mascara is good for 12 months. Ladies, NO. Mascara should always, always, always be tossed after four months. Period.
Clearly the PaO system isn't perfect, but it's cool that companies are trying, right? At least most are off to a good start. Still, it's important to familiarize yourself with traditionally accepted guidelines for makeup expiration. Use your own judgement, and for goodness sake, if a product ever changes color, consistency, or smell, throw it out immediately!