The FDA has established requirements for all over-the-counter drug products (sunscreens) to go through stability testing to assure products are stable and have appropriate expiry dating. All products with less than 3 years real time stability testing must include an expiry date on their packaging per federal regulations. After the product passes 3 year real time stability testing then a company is no longer required to include an expiry date as the testing supports stability for at least 3 years.