Insulin is very sensitive to sunlight, indoor lights, and extremely hot or cold temperatures.
Insulin is not OK to use if exposed to very hot or cold weather. The three drug manufacturers of insulin in the United States say UNOPENED insulin is best stored inside the refrigerator[2° to 8° Celcius (36° to 46°Fahrenheit)]. UNOPENED insulin stored in the refrigerator is good until the expiration date printed on the insulin box. The expiration date will usually be 1 year from the date of purchase, but you have to check the box to find out.
Once open, there are different storage needs for insulin. Vials, pens and insulin cartridges have different needs for storage. These differences can lead to confusion. Therefore, it is very important for you to become familiar with the recommendations for the insulin product that you use.
Open does not mean it was removed from the box. Vials, pens and cartridges are considered opened when the insulin cap is removed and the rubber stopper is punctured with a needle. Open 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. Once used for the first time, insulin pens should not be stored in the refrigerator. Instead, they should be stored at room temperature.
Do not keep in hot places. Do not leave insulin in a hot places such as a closed car. Heat makes insulin break down and will not work well to lower your blood sugar.
Do not keep in freezing places. Never store in a freezer. If insulin is frozen, do not use. You will not be able to inject the insulin if it is frozen. Do not use even after thawing. Freezing temperature will break down the insulin and then it will not work well to lower your blood sugar. Throw frozen insulin in the garbage.
Do not leave in sunlight. Light can make insulin break down and then it will not work well to lower your blood sugar.
Never use insulin if expired. The expiration date will be stamped on the vial or pen. Remember if not in the refrigerator, the date on the vial or pen does not apply. You must throw away after 28 days since outside the refrigerator.
Write the date on the insulin vial. On the day you open the insulin vial or start keeping it outside the refrigerator, write the date. This will help you remember when to stop using it. Throw the insulin away 28 days after opened or since kept out of the fridge.
Inspect your insulin before each use. Look for changes in color or clarity. Look for clumps, solid white particles or crystals in the bottle or pen. Insulin that is clear should always be clear and never look cloudy.