Q: Do over-the-counter skincare products have an expiration date?
A: Basically, dear reader, an OTC skincare product expires when you decide it does. Though most are formulated to last about two years, there is no federal regulation or clear guideline establishing expiration dates, says our friend cosmetic chemist Mort Westman, of Westman Associates in Oak Brook, Illinois. (That is not the case for products like sunscreen, which contain OTC drugs; the FDA mandates expiration dates for the active ingredients.) Westman points out, however, that there are definitely signs that a cream or lotion should be pitched: The consistency has changed (it's thinner, or has become lumpy or separated into layers), the color has darkened, or the smell has either minimally or wildly (and unpleasantly) altered from when you bought it. Lotions containing retinol and antioxidants, like vitamins C and E, are particularly vulnerable, so they must be stored carefully. What does "stored carefully" mean? A cool (but not freezing), dry place away from sunlight.
Keep in mind: To maximize a product's life, try to keep your fingers out of it. There's less risk of bacterial contamination that way.