Does Novolog Insulin Need to Be Refrigerated? When and Why? The Guide!

Posted April 10, 2020 by Michael Chamberlain - See Editorial Guidelines

It’s easy to get confused when storing medications. Given the different kinds of insulin available, it can make it confusing on whether or not each type can be refrigerated or has to be refrigerated after an amount of time.

With so many different insulins on the market, we’ve written this article to focus on whether or not Novolog needs to be refrigerated. First, here’s a quick summary answer for you to take away, then we’ll get into more detail.

Does Novolog need to be refrigerated? It’s not compulsory for Novolog to be refrigerated until 28 days have passed. Using Novolog that is not refrigerated doesn’t adversely affect a patient, but after 28 days, it’s recommended to refrigerate it to maintain the effectiveness. Bacterial growth can make Novolog less effective when it has not been refrigerated. 

Now that we’ve seen the quick answer let’s get into some more of the details about refrigerating Novolog.

Does Novolog Insulin Need to Be Refrigerated?

Does Novolog Insulin Need to Be Refrigerated

If this question focuses on whether Novolog insulin needs to be refrigerated as soon as you get it, then the answer would be no. Insulin does not need to be immediately placed in the fridge to ensure its effectiveness.

Most insulin manufacturers say that a vial of insulin – including Novolog – can be kept at room temperature (not refrigerated) for up to 28 days. However, for unopened insulin to maintain effectiveness until the expiration date, it should be refrigerated.

The room temperature for Novolog in-use can be kept at ranges between 59 degrees and 86 degrees Fahrenheit. The temperature for not-in-use Novolog insulin can range between 36 degrees and 46 degrees Fahrenheit.

novolog insulin

This temperature range can vary as it may depend on the place you live in and other environmental factors.

If the temperature gets colder or warmer than these recommended temperatures for Novolog insulin, then it means that the insulin will either freeze or will end up breaking down when it’s too warm.

“Breaking down” in this respect means that the insulin will allow the growth of bacteria, which will make the insulin less effective or potent.

So, if you live in a place that has a room temperature above or below the recommended temperature, it’s advisable to refrigerate your Novolog insulin to keep it at the recommended temperature.

However, overall, this clearly shows that Novolog, in most cases, doesn’t have to be refrigerated if it’s within the first 28 days.  It is recommended that the vials or pens of Novolog that are not in use should be kept in the fridge.

Note – When Novolog insulin is kept at room temperature, it’s important to make sure it’s kept away from sunlight, heat, and any other direct heat sources.

Now the next common question you might have is why Novolog has to be refrigerated.

Why Novolog Needs to Be Refrigerated

So, now that it’s clear that Novolog doesn’t have to be refrigerated within the first 28 days, let’s focus on why Novolog needs to be refrigerated.

Novolog insulin is like other insulins, which are proteins dissolved in liquids. So, just like many other proteins, after some time, this liquid can spoil.

This is the first main reason why it needs to be refrigerated after the recommended duration. This can be linked with a practical example. Just think of milk or other liquids that can easily spoil when kept outside, especially after opening.

By saying that the insulin will spoil, what we mean is that bacteria will begin growing in the insulin. This will, thereby, make insulin less effective or less potent for use. Less effective insulin can result in elevated blood sugars, which can lead to health complications.

So, when refrigerating Novolog insulin, what happens is the ability for bacteria to grow in it is mitigated or slowed. This way, the strength and the potency of the insulin will remain as long as the expiration date.

Another misconception that many have is that the Novolog might not work or make people sick when it’s not refrigerated.

Novolog insulin that’s kept out does not poison or make one sick. This just means that if the Novolog insulin is kept out longer than it should be, it might not work as expected. Simply put, when one uses Novolog insulin after it’s been kept out of the fridge for more than 28 days, it may not decrease the blood sugar as needed.

Even increasing the dose of Novolog may not work when it’s kept outside because of the bacterial growth. You should never increase your dose of insulin without consulting your doctor.

Another important thing to mention here is that simply refrigerating the Novolog insulin doesn’t mean it can be used after it has expired. All insulin, including Novolog, will have to be disposed of after the expiration date.

Now that everything is explained, we will now focus on what temperatures different Novolog insulins have to be refrigerated at.

All insulin, including Novolog, will have to be disposed of after the expiration date.

Refrigeration Guideline for Novolog FlexPen and Novolog Mix

When unused or unopened

Does Novolog Insulin Need to Be Refrigerated

Unused NovoLog Mix 70/30 FlexPen should be refrigerated between 36° to 46°F (2° and 8°C) until the expiration date.

When refrigerating, make sure it’s not directly adjacent to the refrigerator cooling element and never store it in the freezer. This can potentially freeze the medication, and it’s never advised to freeze insulin or use medication that is frozen.

Unused NovoLog Mix 70/30 FlexPen can be stored at room temperature below 86°F for a period of 14 days.

When In-use or opened

Keep NovoLog Mix 70/30 FlexPen at room temperatures below 86°F (30°C) up to 14 days after one has started to use it. You should not store in-use NovoLog Mix 70/30 FlexPen in the refrigerator.

Refrigeration Guideline for Novolog Vial

When not in use or not open

Unopened or unused vials should not be stored in the refrigerator between 36° to 46°F, until the expiration date.

When in-use or opened

Opened vials may be refrigerated until expiration, or kept outside at room temperature below 86°F (30°C) for up to 28 days. Never draw Novolog mix or any other insulin into a syringe and refrigerate it with the hope of using it later or for convenience.

novolog insulin


We hope this guide has been useful in understanding when, how, and why to refrigerate your Novolog insulin. Check out our blog page for more information regarding diabetes and other medical insight.

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