Can Insulin Freeze? Risks and Prevention of Frozen Insulin

While much has been discussed about the dangers of exposing insulin to heat and the need to keep it refrigerated, the risks of insulin freezing are equally crucial to understand.

See, insulin is a temperature-sensitive injection that must be protected from extreme temperatures, whether hot or cold. And just like warm insulin loses its efficiency, insulin that has frozen isn’t good nor safe for use anymore.

So, today, this article finally addresses these important questions:

Can insulin freeze?
What happens if insulin freezes?
How to tell if it has frozen?
What are the risks of using thawed insulin?
At what temperature does insulin freeze?
How to keep insulin from freezing?

Can You Freeze Insulin?

Despite lingering questions, the consensus is clear: insulin can’t be frozen. Across the board—doctors, drug manufacturers, pharmacists, and those with diabetes are unanimous. If your insulin has frozen, it's unfortunately not safe anymore and you shouldn’t use insulin that has frozen.

What happens if insulin freezes?

What exactly happens when insulin freezes is a question that often comes up in discussions about insulin stability.Freezing temperatures are detrimental to insulin integrity and effectiveness.

Amin Zayani, an engineer and advocate for people with Type 1 diabetes, has spearheaded initiatives to safeguard temperature-sensitive medicines, and especially insulin. He actually calls the refrigerator "insulin frenemy”, explaining that “cold is really the one overlooked problem” with insulin. While insulin must be kept refrigerated, too much cold can be just as harmful as heat.

When insulin is frozen, it becomes unstable. The molecules form crystals, which is an irreversible change that disrupts their biological activity. This crystallization effectively breaks the insulin molecule, causing it to lose its effectiveness and potency. As a result, frozen insulin loses its capability to lower blood glucose levels efficiently, posing serious risks and side effects for your health.

Related article: How to Tell If Insulin Has Gone Bad?

Watch on video on the topic!

Insulin Freezing Point

So, now the question is: at what temperature does insulin freeze? Understanding the freezing point of insulin is vital to diabetes management and proper insulin storage.

As you know already, the temperature range is crucial when storing insulin. The recommended refrigeration range for unopened insulin pens, vials, and cartridges is between 36–46°F (2–8°C). After opening, insulin pens, cartridges, and vials are safe at room temperature, provided it doesn't exceed 77°F (25°C).

The freezing point of insulin is the same as for water: 32°F (0°C). However, it is recommended to always maintain a buffer zone and keep your insulin stored safely above 36°F (2°C) to ensure it doesn't approach its freezing point. Remember that, just as for water, insulin can freeze in a few hours only.

Under no circumstances should insulin be stored at or below the freezing mark of 32°F (0°C), as this could lead to your insulin being accidentally frozen and rendered unsafe for use.

Is Insulin Still Good and Safe if it Freezes?

No, frozen insulin isn’t good or safe for use anymore. Using frozen insulin, even if it has frozen only briefly and it has thawed afterwards, can seriously affect your blood sugar levels and consequently pose risks to your health. But let’s dig a bit deeper and see what the drug manufacturers themselves say about it. It's pretty straightforward. All agree you should not use insulin that has been frozen.

“Do not use Novolog if it has frozen”

According to Novo Nordisk the manufacturer of Novolog fast-acting insulin aspart, Novolog should not be frozen: "Unused NovoLog® should be stored in a refrigerator between 2° and 8°C (36° to 46°F). Do not store in the freezer or directly adjacent to the refrigerator cooling element. Do not freeze Novolog and do not use NovoLog® if it has been frozen".

“Do not allow Lantus to freeze”

According to S a nofi, the manufacturer of Lantus, Lantus long-acting insulin glargine can't be frozen either: "Do not allow Lantus to freeze. Do not put Lantus in a freezer or next to a freezer pack. If you see frost or ice crystals in your Lantus solution, throw it away."

“Do not use Humulin if it has frozen”

According to Eli Lilly, the manufacturer of Humulin, an isophane intermediate acting insulin, the same goes for your vials and pens "Storing the Humulin R U-500 vial: Do not use if it has been frozen.”.

And the same goes for all insulin types and brands, including, Apidra, Humalog, Novorapid, Tresiba, Levemir, Toujeo, and others. All insulin manufacturers firmly recommend not to use insulin that has frozen.

Can You Use Thawed insulin?

Is thawed insulin still safe for use? The answer is resoundingly negative. If insulin has been frozen and returns to a liquid state, it should not be used. The initial freezing compromises the insulin's efficacy irreversibly, rendering it ineffective for blood sugar regulation, even if it has thawed afterwards.

The concern with thawed insulin extends beyond its reduced effectiveness. The structural integrity of the insulin is damaged during freezing, meaning it can no longer reliably perform its role in blood glucose management. Using thawed insulin can result in unpredictable and potentially dangerous blood sugar levels.

Highlighting the seriousness of this issue, a case study published by the Postgrad Med reports that a patient who defrosted accidentally frozen insulin with a microwave subsequently ended up in emergency care due to a total loss of blood sugar control.

This underscores the necessity of discarding any insulin that has been frozen, to prevent severe health risks.

Insulin cooling cases with anti freeze security

How To Tell if Insulin Has Frozen?

Identifying frozen or thawed insulin is crucial for anyone relying on this medication for their diabetes management. So, if you find yourself in doubt of whether your insulin has frozen or not, there are fortunately a few signs to confirm your suspicions. Insulin that has frozen will exhibit distinct visual changes from its usual clear appearance.

Frozen insulin typically takes on a more solid and opaque appearance, similar to how water changes when it freezes. This transformation into a crystalline state is a clear indicator that your insulin isn’t good anymore. When your insulin is frozen, you technically can't inject it, as it wouldn’t pass through the needle.

But it's a bit more complicated to tell if your insulin has frozen and then thawed. After it melts, your insulin gets back to its liquid state. In that case, look for changes in color and texture. Bad insulin generally looks cloudy, show clumps, or have white particles suspended in it—these are all indications that it may have been frozen. However, some insulin types are naturally cloudy, so make sure you know the natural appearance of your specific insulin.

Moreover, unusually high blood sugar readings could be an indirect sign that your insulin may have been compromised by freezing temperatures.

So, always be vigilant and if you have doubts, do not use the insulin. Instead, replace it with a fresh vial or pen from your refrigerator. The risks of using bad insulin far outweigh the benefits of using up what you have. Prioritize your health and well-being by ensuring the insulin you use is in optimal condition for effective blood sugar control.

What to do if your insulin has frozen?

Oops, has your insulin turned into an ice cube? And now what? What should you do with frozen or thawed insulin?

First off, even though it’s super tempting to just thaw it out and hope for the best, we’ve made it clear above that frozen insulin is a no-go for your health. So, it’s time to say goodbye to that vial or pen and dispose of it.

Insulin vials and disposable insulin pens can be thrown away in the regular trash. But don’t forget to remove the needle first as this one goes into a sharps container. Unfortunately, these items do not recycle, and there’s generally no take-back program on insulin because of its delicate and strict storage instructions.

How to Keep Insulin from Freezing?

You might be surprised how often insulin can freeze accidentally. Maybe there’s a power outage and your home loses heat during very cold winter days, or perhaps you forgot your insulin in the car overnight. Whether you’re traveling through cold climates or it just slips next to an ice pack in your medicine cooler, there are countless scenarios of accidentally frozen insulin. Here's how you can protect your insulin from freezing and save hundreds of dollars worth of medicine.

Never store insulin in or near the freezer

Typical domestic refrigerators do not maintain uniform temperatures like medical-grade fridges do. Temperature variations can be significant, especially near the freezer compartment or in the drawers, which tend to be the coldest parts of the fridge.

To ensure your insulin is stored safely and remains effective, place it on the middle shelf of your refrigerator. This area is least likely to get close to freezing temperatures and offers the most stable temperature conditions for sensitive medications like insulin.

Besides, you should absolutely avoid storing insulin in the freezer at all times. There is an exception, however: during a power outage, if your fridge stops working, you can temporarily store insulin in the freezer—but only if it has stopped running and there’s no alternative to keep it cold. This is a last-resort measure to prevent insulin from becoming too warm if the power is expected to be out for a prolonged period.

Use your body heat to protect insulin in cold weather

Traveling to or living in a chilly climate? One of the simplest and most effective ways to keep your insulin from freezing is to use your own body heat. Keeping your insulin close to your body can naturally keep it at a safe temperature. Store insulin pens or vials in your inside jacket pockets, or even directly against your skin under your clothes for added warmth.

If you're using an insulin pump, remember that the insulin within the tubing and reservoir is also at risk of freezing! Insulin pumps like the Tandem T:S l im are designed with built-in temperature sensors to alert you if they become too cold. These sensors help ensure your insulin doesn’t freeze, no matter how cold the weather gets!

Ensure your insulin cooler has anti-freeze protection

When temperatures rise above 77°F (25°C), a portable insulin cooler becomes an essential item to protect your insulin from the heat. However, be cautious—some coolers may inadvertently freeze your insulin if not designed properly.

To avoid such risks, choose a cooler with built-in anti-freeze security. Products like those from 4AllFamily are engineered for safety. These travel medicine fridges utilize special crystals that freeze at 2°C / 35.6°F, slightly higher than the insulin’s freezing point at 0°C / 32°F. This clever design ensures that even if your insulin comes in direct contact with the cooling element, it always remains just above freezing!

Insulin coolers with anti freeze protection

Investing in a high-quality insulin cooler with these features can make a significant difference in maintaining the effectiveness of your insulin, providing peace of mind whether at home or on the go and regardless of whether it's summer or winter!

We'd Love to Hear from You!

Do you have tips or personal stories about dealing with frozen insulin? Share your experiences! How did you handle it, and what advice would you give to others in the same situation? Let’s learn from each other and build a supportive community!

Last updated on April, 25, 2024.

May 20, 2021

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