Many people with diabetes grapple with this particular question daily. The answer, unfortunately, is not always straightforward. The lifespan of an insulin vial varies, depending on the insulin type and the storage conditions.

Here, I will provide an overview of the durability of different kinds of insulin and offer some tips for preserving their potency. But first, let's determine the importance of knowing how long insulin vials last.

Why is It Necessary to Know How Long a Vial of Insulin Lasts?

The purpose of insulin is to regulate blood sugar levels in the body. When glucose levels get too high, it can lead to serious health complications like diabetic ketoacidosis (DKA). Therefore, people with diabetes need to have a steady supply of insulin.

However, insulin is a delicate hormone that can lose its potency if not stored properly. Knowing how long a vial of insulin will last is crucial, and taking steps to ensure that it remains potent for as long as possible.

As a diabetic, you need to be very careful about the expiration date of your insulin. Taking expired insulin exposes you to severe complications that happen when you take none!

Types of Insulin

There are multiple types of insulin, each with different duration of action.

Short-acting insulins

They are also known as rapid-acting or fast-acting insulin. They work quickly for blood glucose control and are typically used before meals, and last up to five hours. Examples of short-acting insulins are Humalog, Novolog, and Apidra.

Intermediate-acting insulins

They are also known as long-acting or slow-acting insulin. They have a longer duration of action and are typically used to cover the body's basal insulin needs. They can last for up to 18 hours. Examples of intermediate-acting insulins are N.P.H., Lantus, and Levemir.

Long-acting insulins

They are also known as ultra-long-acting insulin. They have an even longer action duration and can last up to 42 hours. They are typically taken once daily to cover the body's basal insulin needs. Examples of long-acting insulins include Tresiba and Basaglar.

What Happens When You Puncture an Insulin Vial?

One common question I get from diabetic patients is, how long does a vial of insulin last after opening?

The answer is simple: once you puncture an insulin vial, the clock starts ticking, and the insulin will begin losing its potency. How quickly this happens depends on the type of insulin and its storage.

Here are the lifespans of different insulin brands after opening the new vial or pen:

Rapid-acting insulin

  • Novolog: within 28 days of puncturing the vial
  • Humalog: within 28 days of puncturing the vial
  • Apidra: within 28 days of puncturing the new vial
  • Insulin Lispro injection (Admelog®): within 28 days of opening the vial or pen

Short-acting insulin

  • Humulin R: within 31 days of puncturing the vial
  • Humulin R U-500 concentrated: within 31 days of puncturing vial
  • Insulin human injection (Novolin® R): within 42 days of puncturing the vial (or 28 days of opening the pen)

Intermediate-acting insulin

  • Humulin N: within 30 days of puncturing the vial
  • Isophane insulin human suspension (Novilin® N NPH): within 42 days of opening the vial (28 days for pens)

Long-acting insulin

  • Lantus insulin: within 28 days of puncturing the vial
  • Insulin detemir injection (Levemir®): within 42 days of puncturing the vial or pen
  • Insulin Degludec injection (Tresiba®): within 56 days of opening insulin pens or vials

How to Store Insulin Properly (Insulin Storage Guide)

Temperature is the most critical factor when it comes to insulin storage. It's generally recommended to store unopened insulin in a cool, dry place at temperatures between 36 and 46 degrees Fahrenheit. But what if you're traveling or forget to place your insulin while heading toward the office? You can store it in a standard refrigerator for up to four weeks if the temperature stays between 36 and 46 degrees Fahrenheit. However, it would be best never to store your insulin in the freezer, as this can damage the hormone and render it ineffective.

If you're traveling with insulin, pack it in an insulated bag with an ice pack or an insulin cooler to keep it cool. It would be best to keep your insulin out of direct sunlight, as this can deteriorate its effectiveness. The American Diabetes Association posits that insulin stored in a cool and dark place will last longer than in bright sunlight.

How to Keep Your Insulin Cool While Traveling?

To manage diabetes and live a comfortable life, you should know how to use and store your insulin, especially when traveling. Here are some helpful guidelines to protect your insulin vials:

  • Store your insulin in a cool, dry place at temperatures between 36 and 46 degrees Fahrenheit.
  • There are multiple insulin-carrying bags available in the market. Make sure you use one of those.
  • If traveling by road, do not expose your insulin to direct sunlight or leave it in a hot car.
  • If you travel by air, keep your insulin in your carry-on bag. You can store your insulin at a given temperature after puncturing for up to 28 days.
  • Campers have small refrigerators, so if you are traveling by R.V., always store your insulin there.
  • Do not forget to pack extra insulin, syringes, and other supplies if you lose or damage your primary supply.

By following these tips, you can rest assured that your insulin will be stored at the optimal temperature range and remain potent while you are on the go.

How Can I Tell if My Insulin is Spoilt? 

Some insulins are cloudy in appearance, while others are clear. You're the doctor of yourself, and there is no one better to know when your insulin is spoiled. If you see that the color of your insulin is changed, or it has some particles or chunks like dust, it could mean your insulin is spoilt, and you shouldn't use it. You can also tell your insulin is damaged when your blood sugars keep rising, even when taking the prescribed dosage.

Many insulin manufacturers now attach expiration dates on their products only after conducting extensive tests to ensure the insulin is potent for at least that long. So you can trust any unexpired product as long as you meet the storage recommendations.

Guidelines About Insulin Pumps

Insulin pumps come with their own storage and special care. You should always check your insulin pump user manual for more specific storage instructions. In general, however, most pumps use insulin cartridges that can last up to two weeks after they are punctured.

Different brands offer different expiration. For instance, insulin aspart (Fiasp) expires in six days, while other brands like insulin glulisine (Apidra) expire in 48 hours or two days.

Insulin Pump Treatment

As a diabetic, knowing how long your insulin will last and taking steps to ensure it remains potent for as long as possible is essential. You can save your insulin and your life with little or no effort. So, check the expiration date on your insulin before using it, and always store it in a cool, dark place.

Frequently Asked Questions

What Should I Do if My Insulin Expires?

If your insulin expires or you feel it spoilt, do not use it. Expired insulin has lost its potency and can no longer be used safely. If you need a new insulin supply, look out for the details on the label of your vial or get a doctor's prescription to get new ones.

Why is Insulin Essential for Blood Glucose Control?

The answer is simple. The insulin regimen helps adjust the insulin doses per the fasting blood glucose levels and variable glucose responses. This, in turn, helps to maintain the blood sugar levels within the normal range with little or no effort.

How Can I Adjust Insulin Regimens?

You can adjust insulin regimens by monitoring your fasting blood glucose levels and adjusting insulin doses as per the response. However, insulin glargine (Lantus) and detemir (Levemir) should not be mixed. You can use either (of them) alone or in combination with other insulins as per your doctor's prescription.

Can You Keep Insulin in the Fridge?

Yes, you can store unused vials of insulin in the refrigerator, as long as you don't get them frozen. However, you must ensure not to turn your fridge off and on. Once you put your insulin in the refrigerator, you should make it operational for the whole month, even during vacations.

When Does Insulin Expire?

Knowing the expiry date of your insulin pen or vial will help you avoid failed doses and potential complications. Unfortunately, many diabetics find insulin expiration dates a bit confusing.

When it comes to insulin injections, there are two expiration dates:

The expiration date is printed on the insulin box. This date indicates how long UNOPENED insulin pens or vials last if appropriately stored (usually one year after the production date).

The expiration date of OPENED insulin; This date typically depends on the insulin type or brand. However, an unsealed insulin package's expiration date is usually between 28 and 56 days (if stored properly).

Can Insulin Still Be Used After Its Expiration Date?

Taking expired insulin shots is not medically advised because no one can precisely predict how many doses would work to regulate your sugar levels. You don't want to rely on "hope" as a strategy to avoid the severe health complications associated with high blood sugar levels.

What Happens if I Use Expired Insulin?

The primary function of insulin is to eliminate the risk of high blood sugar, which causes severe diabetes complications. You are susceptible to kidney and heart diseases if your insulin is expired and doesn't work.

However, it is noteworthy that expired insulin doesn't necessarily lose its full potency. Each expired dose could work, but not as it should. That explains why expired insulin is linked to fluctuations in blood sugars, which can get too high despite taking your shots judiciously. Thus, the strict medical recommendation is to discard your insulin vials or pens once they surpass their expiration date.


If you are using insulin, it is crucial to know how long it will last and take steps to ensure it remains potent for the entire duration. Sadly, many people with diabetes take things on a lighter note and bother not to check the expiry date of their insulin products. Such negligence could result in fatal health consequences. So, the advice is simple: ALWAYS CHECK EXPIRY DATES, and never use any insulin that exceeds the indicated date.


At Diabetic Me, we are committed to delivering information that is precise, accurate, and pertinent. Our articles are supported by verified data from research papers, prestigious organizations, academic institutions, and medical associations to guarantee the integrity and relevance of the information we provide. You can learn more about our process and team on the about us page.

  1. Diabetes Voice How insulin storage, use and lifespan affect your safety

About the Author

Ely Fornoville

Hi, I'm Ely Fornoville, and I am the founder of Diabetic Me. Being a type 1 diabetic since 1996, I developed a passion to help people learn more about diabetes. I write about diabetes and share stories from other diabetics around the world. I currently use a Medtronic Guardian 4 CGM and a MiniMed 780G insulin pump with Humalog insulin.

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