do skin care products expire?
according to Dermalogica skin care experts, yes!
OK, so why don't a lot of skin care products have expiration dates? That's because, in the USA, expiration dates are only required on over-the-counter (OTC) drug products, i.e., acne treatments or sunscreens. (For our European friends: Products deemed OTC drugs in the USA may only be considered "cosmetics" in the European Union.) Also, expiration dates only indicate when the active ingredients in the formula are likely to expire; the product might still perform otherwise.
Once you reach that date, there is no guarantee that the level of activity is still present. The only way to truly know whether your product is still guaranteed effective for its intended use is to test it in a lab. Of course, you probably don't have a lab at your disposal, which is why we’ll recommend to always look at the expiry date and Period After Opening (PAO) – and go with whichever is earlier.
Go through your skin care regimen annually, and toss formulas that are no longer fresh. Remember to always store them in a cool place, out of direct sunlight and heat!