Always read the instructions that come with your insulin. Bottles of insulin, either open or unopened, generally last for one month when stored at room temperature (15 to 30°C). A bottle is considered open if its seal has been punctured. If you remove the cap but don't puncture the seal, the bottle is still considered unopened.
If stored in a refrigerator, unopened bottles are good until the expiration date printed on the bottle. Opened bottles that are stored in a refrigerator should be used within one month of being opened. Many people store their unopened bottles in the refrigerator and keep open bottles at room temperature because they find it uncomfortable to inject cold insulin.
Don't use bottled insulin past the expiration date printed on the label. And no matter what the expiration date is, throw away a bottle one month after you open it. To help you keep track, write the date that you opened the bottle on the bottle's label.
With insulin pens and their cartridges, storage life ranges from seven days to one month.
There are two ways to tell when insulin is no longer good: poor performance and unusual appearance.
If your blood sugar stays high even though you're following your treatment plan, your insulin may have lost its effectiveness. Poor performance could be due to two things:
If your insulin has an unusual appearance, it's probably no longer effective. Here are some warning signs:
If you think your insulin has gone bad, don't take any chances: throw the bottle away immediately and open a new one.
Smart Tips for Insulin Storage