If the product is subjected to excessive heat or cold for short periods of time, it will not impact the product’s efficacy, though it may result in a thicker or thinner texture. While the products don’t have a formal expiration date, it is generally recommended that they be used within 3 years of manufacture or 6 months after opening for best product quality. Please note that you should replace your mascara and eyeliner every 3 months to prevent a bacterial infection.