My insulin was left in a hot car for four days. Should I throw it away or attempt to use it?

Patty Bonsignore


Insulin is made up of proteins that do not respond well to overheating or freezing. Insulin should never be frozen, left in a car overnight or stored in direct sunlight. A car can get very hot in the summer months and the heat will cause the insulin proteins to break down and deteriorate. So even though it may look fine, it will no longer work the way it should. It is best to keep insulin at temperatures less than 86 degrees and greater than 36 degrees. Room temperature is best for vials or pens that are in use. Unopened insulin pens and vials should be stored in the refrigerator and are good until the expiration date on the bottle. The longer the insulin is left in a very hot or cold environment the more the proteins will break down. Because your insulin was in a hot car for four days, it should not be used. The best option at this point is to throw it away and start with a new bottle or new insulin pen.