Key takeaways:
Insulin is a medication that balances blood glucose (sugar) levels in people with diabetes. Some people use a vial and syringe, and others use an insulin pen.
All types of insulin have a limited shelf life. The expiration date is how long the unopened insulin is good for. But, once you open a vial, you have a limited time to use it. That’s the use-by date.
Insulin can be less effective if you don’t properly store and use it. It’s important to keep track of both the expiration date on the vial and when you opened it.
Given the cost of an insulin vial, it might be tempting to cut corners on how you use it. Although it might seem wasteful to throw away expired or leftover insulin, using expired insulin comes with health and safety risks.
Expired insulin may not work as well, and this could cause your blood glucose (sugar) to rise. This is because insulin is a peptide hormone, and it can spoil when it’s not stored correctly or used within a certain time.
All types of insulin come with an expiration date on the vial. An unopened insulin vial should last until this date, if you store it properly.
Once an insulin vial has been opened and punctured, a new date applies. This is the use-by date. It will be different from the manufacturer’s expiration date on the vial, so you’ll need to keep track of both. And you may need to store your opened vial differently.
To avoid any issues with insulin, keep track of the expiration date when you open a new vial and follow manufacturer instructions. Your health depends upon it.
Categories of insulin
There are several types of insulin, as well as a variety of other injectable diabetes medications. The recommendations for how long they’ll keep varies. So, learning about insulin can be confusing at first.
Here’s what you really need to know: There are five categories of injectable insulin. And, as their names suggest, they differ in how long they’ll take to start working (onset) and how long their effect lasts (duration).
Insulin category | Onset | Duration |
|---|---|---|
Rapid-acting insulin | 15 minutes | 2-4 hours |
Short-acting insulin | 30 minutes | 3-6 hours |
Intermediate-acting insulin | 1 hour | 12 hours |
Long-acting insulin | 2-4 hours | 24 hours |
Ultra-long-acting insulin | 6 hours | 36-42 hours |
How long do open insulin vials last?
How long your open vial of insulin will be good for depends on the brand. If you’re not sure, ask your pharmacist or diabetes care team for help. And you can always find more information on your pharmacy paperwork or the medication insert that comes with the insulin vial.
Here’s a breakdown of how long you can use an open vial and how to properly store some common brands of insulin.
| After puncturing the vial | Storing open vials | |
|---|---|---|
| Rapid-acting insulin | ||
| Insulin aspart (NovoLog) | Use within 28 days | At room temperature or in the fridge |
| Insulin lispro (Humalog) | Use within 28 days | At room temperature or in the fridge |
| Insulin glulisine (Apidra) | Use within 28 days | At room temperature or in the fridge |
| Short-acting insulin | ||
| Insulin regular (Humulin R or Humulin R U-500 concentrated) | Use within 31 days | At room temperature or in the fridge |
| Insulin regular (Novolin R) | Use within 42 days | At room temperature |
| Intermediate-acting insulin | ||
| NPH insulin (Humulin N) | Use within 31 days | At room temperature or in the fridge |
| NPH insulin (Novolin N) | Use within 42 days | At room temperature |
| Long-acting insulin | ||
| Insulin glargine (Lantus) | Use within 28 days | At room temperature or in the fridge |
| Ultra-long-acting insulin | ||
| Insulin degludec (Tresiba) | Use within 56 days | At room temperature or in the fridge |
Best ways to store and use insulin vials
Insulin manufacturers recommend storing unopened vials in the refrigerator between 36°F to 46°F. Extreme temperatures can affect how well insulin works. So, it’s best to avoid them when possible.
Here are some more tips for protecting your insulin:
Don’t leave insulin in your car.
Don’t store insulin in a freezer or near the cooling element in your refrigerator.
Protect insulin from direct sunlight and extreme heat.
If you don’t have a refrigerator, storing insulin in a clay pot is a good option.
After opening, most insulin vials can be stored in the refrigerator or at controlled room temperature. Novolin N and Novolin R are two exceptions; they must be stored at room temperature.
To keep track of the day you opened your insulin, you can:
Use a permanent marker to write the opening date on the vial.
Put a digital reminder on your smartphone and/or add to your calendar.
Does insulin go bad if not refrigerated?
No, as long as it’s not exposed to heat, insulin won’t go bad if it's not refrigerated. That said, manufacturers recommend storing insulin in the refrigerator for best results. But, according to the American Diabetes Association, if insulin is kept at room temperature, it should last about a month.
Recent research suggests that insulin may be more stable at higher temperatures than previously thought. Insulin can keep most of its potency when kept at or below 77° F for several months.
There’s a need for more research on insulin stability in extreme conditions though. Travel, climate change, and access to refrigeration are major considerations for people who use insulin. So, these are areas that would benefit from further study.
Risks of using expired insulin
When insulin is stored incorrectly or it expires, it begins to break down and become less effective. This is true whether the insulin vial is open or closed.
Using expired insulin that’s less effective can lead to:
Difficulty managing blood sugars
Higher blood sugar levels than normal
Symptoms of high blood sugar, including increased urination and thirst, headache, tiredness, and blurry vision
Diabetic ketoacidosis (DKA), which is life-threatening
Don’t take a chance with your lifesaving medications. If you’re struggling to afford insulin, know that you have options. You’re not in this alone. There are lots of resources and solutions.
What can you do with expired, open insulin vials?
Unfortunately, there’s not much you can do with open insulin vials. On average, they’re good for about 1 month. After that, you’ll need to throw them away, even if there’s insulin leftover in the vial.
What about unopened vials?
You should throw out unopened vials that are past their expiration date.
Sometimes, an unopened vial that isn’t expired may look spoiled. For example, you may notice that the insulin is discolored or has crystals inside the vial. If this happens, take it back to your pharmacy for an exchange or refund. Don’t be tempted to use it.
How much does a vial of insulin cost?
The cost of a vial of insulin varies quite a bit. It depends on the manufacturer, insulin type, and dose. For example, retail prices of short- and intermediate-acting insulin vials range from $24 to hundreds of dollars. Retail prices of long-acting insulin vials are higher.
The good news is, there are ways to save on insulin costs, even if you don’t have insurance. These include GoodRx coupons, manufacturer coupons, and patient assistance programs. And, thanks to biosimilars, the overall retail price of insulin has declined by over 40% since 2020, according to GoodRx research.
Frequently asked questions
Yes, you can buy insulin vials over the counter (OTC). Synthetic human insulins are available OTC. Examples include Novolin R (regular insulin) and Humulin N (insulin NPH). These older insulins aren’t subject to regulations, unlike prescription insulins. That said, they may be a good option for people who urgently need insulin but don’t have a prescription.
Yes, insulin vials are typically cheaper than insulin pens. But, with copay cards, coupons, and unbranded biologics, there are ways to save on insulin pens, too.
Yes, you can buy insulin vials over the counter (OTC). Synthetic human insulins are available OTC. Examples include Novolin R (regular insulin) and Humulin N (insulin NPH). These older insulins aren’t subject to regulations, unlike prescription insulins. That said, they may be a good option for people who urgently need insulin but don’t have a prescription.
Yes, insulin vials are typically cheaper than insulin pens. But, with copay cards, coupons, and unbranded biologics, there are ways to save on insulin pens, too.
The bottom line
Insulin vials have a limited shelf life, both before you open them and after. They’re also sensitive to temperature extremes and direct sunlight. So, take care when deciding where to store your insulin. Expired or spoiled insulin may not work as well and could put your health at risk.
Check the expiration date on your insulin vial before opening it. Take note of the date that you opened a new vial, and use it within the correct time frame. And follow the storage instructions for your specific type of insulin. Reach out to your pharmacist or other healthcare professional if you have any questions.
Why trust our experts?
References
American Diabetes Association. (n.d.). Insulin storage and syringe safety.
American Diabetes Association. (n.d.). Leading the fight for insulin affordability.
Bahendeka, S. (2019). Silver EADSG guidelines: Insulin storage and optimisation of injection technique in diabetes management. Diabetes Therapy.
Christopher, M. W., et al. (2024). One-year thermostability of commercial glargine and human insulin. Diabetes Care.
Richter, B., et al. (2023). Thermal stability and storage of human insulin. Cochrane Database of Systematic Reviews.
