As the incidence of diabetes continues to rise around the world, more and more people have to inject insulin on a regular basis to regulate their bodies’ blood sugar levels. For those diabetic people who do require insulin injections, it is essential to know how that insulin can best be stored to make sure it does its job when required.

When thinking about insulin storage, lots of different questions arise: Should insulin be refrigerated? What is the correct temperature for storing insulin? Do different types of insulin have different guidelines? What happens when insulin spoils or when it gets frozen? In this article, we will take a look at all of those issues and give you some other helpful hints and tips about insulin storage. So, read on for your full guide to everything you need about storing your insulin.

Should insulin be refrigerated?

The simple answer to this question is yes, insulin should be kept refrigerated whenever possible. According to the U.S. government’s Food and Drug Administration (FDA), storing insulin in a refrigerator is the best way to ensure it maintains its effectiveness for as long as possible.

However, if there are circumstances in which you cannot keep your insulin in a refrigerator, it is still possible to keep it and use it for up to one month provided that it is not stored in a place that is either too cold or too hot (see below for the temperature ranges for storing insulin to maintain its effectiveness).

What is the ideal temperature for storing insulin?

The FDA states that the correct temperature for storing insulin is between 36°F to 46°F. In Celsius, that equates to a range from 2°C to 8°C.

However, as mentioned above, it is possible to store insulin outside a refrigerator at room temperature if you have no alternative. If you are storing insulin outside a fridge, then the acceptable range is between  59°F and 86°F (i.e., 15°C and 30°C). Insulin stored in that way will, however, only be good for a limited period (see below for more details on how long insulin can be stored in normal circumstances).

Regardless of where you are storing it, insulin must not be exposed to either direct sunlight or direct heat.

Also, if you are following the recommendations and storing your insulin in the refrigerator, you may wish to take it out for a few minutes to let it warm up a little before injecting it. That’s because some people find that injecting insulin at room temperature is less painful and also easier to cut out any air bubbles.

How long can insulin be stored?

Just because you are storing insulin in the refrigerator at the right temperature does not mean that you can store it like that for as long as you want. As with any other medication, insulin has a lifespan, meaning that it will spoil after a certain amount of time.

The factors that affect how long insulin can be stored include the temperature at which it has been stored, the type of insulin that it is, whether or not it has been opened, and whether or not is still in the original container provided by the manufacturer.

  • An unopened disposable insulin pen that has been stored at the correct temperature in a refrigerator can be used up until the expiry date that the manufacturer has printed on the pen, vial, or cartridge that the manufacturer has provided with the product.
  • However, when a disposable insulin pen like that has been opened, it will only last for a maximum of four weeks, even when stored in a refrigerator. That’s why even refrigeration, despite being important, is not a guarantee that your insulin will last until its expiry date.
  • The type of insulin also affects how long it can be stored. Specifically, rapid-acting insulin (such as Humalog and NovoLog) go off quicker than regular insulin (which are also known as neutral or soluble insulin). Bearing that in mind, it’s extra important to try to keep rapid-acting insulin refrigerated as much as possible.

Insulin that has been stored outside the refrigerator but within the safe temperature ranges given above will last for up to 28 days, provided that it is still in the original vials or cartridges supplied by the manufacturer (whether they have been opened or not, what matters is that it is still in the original container).

If the insulin being stored outside the refrigerator is not in the manufacturer’s original container, then it will only be good for two weeks before it should be discarded, according to the FDA.

Are there any special considerations for insulin contained in pump devices?

The FDA also states that any insulin that is stored in the infusion set of a pump device (such as tubing, reservoir, or catheter) should be thrown away after just 48 hours. Similarly, if such insulin is exposed to a temperature over 96.8°F (i.e., 36°C), then it should also be discarded and replaced as soon as possible.

What happens if you don’t store insulin correctly or keep it for too long?

The insulin that diabetic people inject basically consists of dissolved proteins in a liquid form. As with any other type of protein, insulin can go off, meaning that it loses its effectiveness and fails to do its crucial job of lowering blood sugar levels.

A useful way to think of it is to imagine insulin as a food. Any food will ultimately go off if it is not stored in the right way or kept for too long. That’s why, as with most foods, the best place for insulin is in the refrigerator where it can be stored at the ideal temperature.

When insulin is not stored in the right way, bacteria will ultimately start to grow inside it. That bacteria breaks down the proteins in the insulin, which makes it less effective when it is injected. Put simply, insulin that has bacterial growth inside it cannot provide its full dose to the person injecting it.

Consequently, that person may find that their blood sugar level does not lower in the way that it is meant to after the insulin injection.

Another important thing to keep in mind is that you should check your insulin first before you use it. Insulin should be clear and not cloudy in appearance. If you see any solid white particles or any clumps that shows you that the insulin is no longer good to use.

What should you do if your insulin freezes?

Obviously, like any other liquid, insulin can freeze if it is stored in a place that is too cold. That’s why it is important to never store insulin in the freezer. If you live in a cold climate, you also need to be careful to not leave your insulin supplies outside.

Even storing insulin inside your fridge does not guarantee that it won’t freeze unless you make sure that it is stored at the right temperature consistently. The European Association for the Study of Diabetes found that the temperature inside fridges sometimes fluctuates unexpectedly. That’s why it’s important to check that your fridge maintains the correct temperature consistently, which can be achieved by putting a thermometer in there.

If your insulin does get frozen despite your best efforts, then you must not use it. Obviously, insulin cannot be injected in its frozen state, but even after it has thawed, you still should not use it. The freezing breaks down the insulin, meaning that it has been spoiled just as it would be if it was left in a hot place for too long.

As with any spoiled insulin, anything that has been frozen will no longer work to reduce your blood sugar level. So, the only solution is to throw it away and replace it with insulin that is still within date and has been stored correctly.


The injection of insulin is becoming increasingly common around the world as the incidence of diabetes continues to rise. For diabetic people who rely on insulin injections, it is essential to know.

All medical authorities recommend that insulin should be stored in a refrigerator at temperatures ranging from 36°F to 46°F (i.e., 2°C to 8°C). Storing insulin in that way guarantees that it maintains its effectiveness for as long as possible. However, it is also possible to store insulin at room temperature for a period of up to four weeks if absolutely necessary.

Other factors that affect how long insulin can be stored include what type of insulin it is and whether it has been opened or not. If your insulin has become spoiled or frozen, it will not work so it’s essential that you don’t use it. It should be thrown away and replaced by fresh supplies that will meet your needs for blood sugar regulation.

As always, if you have any questions, doubts, or concerns about insulin storage, you should contact your doctor or another medical professional.