Yes, insulin does expire.
Insulin vials are marked with an expiration date, indicating when the medication is no longer guaranteed to be fully potent. However, this isn't the only factor to consider when it comes to insulin's effectiveness.
Understanding Insulin Expiration
While the stamped expiration date is a crucial guideline, insulin's potency can also be affected by how it is stored and how long it has been in use. The following table summarizes key factors to consider:
| Factor | Impact |
|---|---|
| Expiration Date | The date printed on the vial indicates when the manufacturer guarantees full potency. Do not use insulin past this date. |
| Opened Vial Usage | According to the American Diabetes Association, after a vial is opened and in use, it can lose some of its effectiveness after 30 days, even if the expiration date is still in the future. This is especially true if not stored properly at room temperature. |
| Storage Conditions | Insulin should generally be stored in a refrigerator to maintain its efficacy. If stored at room temperature, potency can degrade faster. |
| Appearance | Always check the insulin before use. Discard if it is cloudy, discolored, or contains particles (except for NPH insulin, which is normally cloudy). |
Practical Insights
- Refrigeration: Store unopened insulin vials in the refrigerator.
- Opened Vials: Once an insulin vial is opened, it is advisable to use it within 30 days and store at room temperature, as per the ADA guidance (12).
- Temperature Matters: Avoid exposing insulin to extreme heat or cold.
- Visual Inspection: Prior to injection, make sure the insulin looks as it is supposed to.
- Always follow specific directions from your doctor or pharmacist.
Key Takeaways
- Insulin vials have a printed expiration date.
- Opened insulin vials may lose potency after 30 days, especially if stored at room temperature (12).
- Proper storage is essential for maintaining insulin's effectiveness.
