Storage of Insulin
Unopened Insulin
Insulin is very sensitive to sunlight, indoor lights, and extremely hot or cold temperatures.
Insulin should not be used if exposed to very hot or cold weather. The manufacturers of insulin in the United States say unopened insulin is best stored in the refrigerator (2° to 8° Celcius [36° to 46° Fahrenheit]) and is good until the expiration date printed on the label.
Figure 1. Cartridges for an insulin pen, like the one pictured, are also best stored in the refrigerator and will last until the expiration date.
Opened Insulin
Once opened, storage needs vary for each type of insulin product (i.e., vials, pens, cartridges [Figure 1]) which can lead to confusion. Therefore, it is important for you to understand how to store the insulin product that you use.
What Does "Opened" Mean?
"Opened" does not mean it was removed from the box. Vials are considered opened when the insulin cap is removed and the rubber stopper is punctured with a needle. Opened vials can be stored in the refrigerator or at room temperature. Insulin kept in the refrigerator should be removed and allowed to reach room temperature before injection. Pens and cartridges are considered opened after their first use. Once used, insulin pens (or cartridges) should not be stored in the refrigerator. Instead, they should be stored at room temperature.
Safety Tips for Storing Insulin
Do not keep insulin in hot places. Do not leave insulin in a hot place such as a car. Heat makes insulin breakdown and it will not work well to lower your blood sugar.
Do not keep insulin in places that freeze. Never store insulin products in a freezer. If insulin is frozen, do not use even after thawing. Freezing temperatures will breakdown the insulin and then it will not work well to lower your blood sugar.
Do not leave insulin in the sun. Sunlight can make insulin breakdown and then it will not work well to lower your blood sugar.
Never use insulin if it is expired. The expiration date will be stamped somewhere on the vial, pen, or cartridge. Remember once the insulin is opened, the expiration date printed on the vial, pen, or cartridge does not apply. Opened insulin must be thrown away after 28 days.
Write the date you open the insulin on the product. On the day you open the insulin vial, pen, or cartridge, or start keeping it outside the refrigerator, write the date on the label. This will help you remember when to stop using it. Insulin expires 28 days after it is opened.
Inspect your insulin before each use. Look for changes in color or clarity. Look for clumps, solid white particles, or crystals in the vial, pen, or cartridge. Insulin that is clear should always be clear and never look cloudy. (Some insulin products are cloudy, so make sure you know what type you have and if it should be cloudy or not.)
