This product is stable for at least two years from date of manufacture if stored unopened between -15 to – 25°C. Internal studies have shown the reconstituted enzyme is stable as a frozen solution between -15 to – 25°C for at least 1 year. Additional studies have shown the enzyme can go through a freeze-thaw cycle at least once without loss of potency by neutral protease (NP) assay. The product is shipped on dry ice to provide the most stable conditions during shipment.