How Long Should You Keep Your Open Insulin Vials?

Given the cost of an insulin vial, it might be tempting to cut some corners on how you use it. While it may 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 your blood glucose can 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. 

Regardless of the type of insulin you’re using, there will be an expiration date on the vial. If stored properly, an unopened insulin vial should last until this date. 

But once it’s opened and punctured, a new date applies. This “use-by” date 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 expiration dates, when you open a new vial, and follow manufacturer instructions. Your health depends upon it.

Categories of insulin 

There are several different types of insulin — and a variety of other injectable diabetes medications. The recommendations for how long they 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 take to start working (onset) and how long their effect lasts (duration).

How long can you keep an open insulin vial?

Just how long your open vial of insulin will be good depends on the brand. If you’re not sure, ask questions — storing and using insulin correctlycan be tricky. You can learn more by talking to a pharmacist or your care team. And you can always find more information on your pharmacy paperwork or by reading 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. 

Best ways to store and use insulin vials

If you’re using an insulin vial, it’s recommended to store it in the refrigeratorbetween 36°F and 46°F before opening it. Once it’s opened, most insulin vials can be stored in the refrigerator or at controlled room temperature. Novolin N and Novolin R are two exceptions.

Here are some simple tips for keeping track of the day you opened your insulin:

• Use a permanent marker to write the opening date on the vial.

• Put a digital reminder on your smartphone.

The American Diabetes Association offers some more tips for protecting your insulin, like avoiding extreme heat (above 86°F) and extreme cold (below 36°F). This means that insulin should never be left inside of your car, stored in a freezer or near the cooling element in your refrigerator, or be left in direct sunlight. 

Risks of using expired insulin

When insulin is stored incorrectly or 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 is 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, tiredness, and blurry vision

• Diabetic ketoacidosis (DKA) with Type 1 diabetes

Don’t take a chance with your lifesaving medications. If you’re struggling to afford insulin, the American Diabetes Association is here to help you. 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 is in date but may look spoiled. For example, you may notice the insulin is discolored or has crystals inside the vial. In these cases, it’s worth taking it to your pharmacy. They may replace it. But don’t be tempted to use it.

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Written by:

Jewels Doskicz, RN, BA

Jewels Doskicz, RN, is an Arizona-based registered nurse with more than 20 years of hospital-wide clinical nursing experience. She has spent over a decade in medical writing and editing, with a focus on diabetes and autoimmune disease.

Edited by:

Sophie Vergnaud, MD

Sophie Vergnaud, MD, is the Senior Medical Director for GoodRx Health. A pulmonologist and hospitalist, she practiced and taught clinical medicine at hospitals in London for a decade before entering a career in health education and technology.

Reviewed by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

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