Insulin Storage Temperatures Explained: How to Keep Insulin Safe

Whether it’s sitting in your fridge or tucked in your pocket, insulin is incredibly sensitive to its surroundings. Extreme heat or cold can affect its potency, making it useless before you even realize there’s a problem.

Let’s take a closer look at how to keep your insulin safe from hot and cold temperatures.

What is the right storage temperature for unopened insulin?

The ideal temperature for a vial or pen of insulin is between 36-46 degrees Fahrenheit when it’s being stored in your refrigerator. Temperature also varies in different areas of your fridge, so you might want to avoid keeping your insulin in the back of the fridge, for example because things can get a little too cold back there. Instead, consider keeping your box of insulin pens or vials on the middle shelf where the temperature tends to be most stable.

Most insulin pens and vials start breaking down after 28 days

As soon as you open a vial or pen of insulin, it has about 28-30 days when stored at room temperature before it starts to gradually break down and become what’s called “denatured”—even if you continue to store it in the fridge between doses. Check your brand of insulin for the manufacturer’s expiration date, as some formulas may last slightly longer.

This doesn’t mean you necessarily have to throw out all open insulin after 28 days, but be very mindful of your blood sugars. Many insulin users have shared using insulin past the 28-day mark, but remark that day 45 is when it truly loses its effectiveness, which can cause higher blood sugars. 

Many people report using a pen or vial completely before the 28-day mark without any challenges, but it’s important to monitor your blood sugar diligently if you decide to go that route.

As insulin breaks down, it becomes less effective at managing your blood sugar. When this becomes noticeable in your blood sugar, whether it’s day 10 or day 28, it’s time to swap that vial or pen out for a new one.

Using denatured insulin is dangerous

The tricky thing about insulin that has been denatured by hot or cold temperatures is denatured insulin doesn’t smell, doesn’t change color, and doesn’t offer any telltale signs that it’s denatured, except for its lack of impact on your blood sugar. You won’t know it’s denatured until you use it but still see your blood sugar levels spiking.

For people with type 1 diabetes, this can mean a rapid spike in blood sugar levels, or possible complications like diabetic ketoacidosis (DKA).

For people with type 2 diabetes, using denatured insulin can mean a rapid spike in blood sugar levels and ongoing difficulty managing blood sugars, depending on how long you continue it.

Be mindful of insulin temperature in day-to-day life

If insulin is exposed to hot or very cold temperatures for too long outside of the recommended refrigeration window of 36-46 degrees Fahrenheit, it can break down very quickly, to the point of not having any real impact on your blood sugar. This is why it’s extremely important to be mindful about when and where you store your insulin.

Remember, 65 degrees outside can mean it’s 80 degrees in your car.

And on the flip side, a cold winter’s day could mean the inside of your car or your jacket pocket on the ski slope is 10 degrees, easily cold enough to freeze, and thus destroy, your insulin.

Avoid leaving your insulin or diabetes kit:

• In your pocket during outdoor winter activity (sledding, skiing, skating, playing in the snow)
• Sitting in direct sunlight during outdoor summer activity (beach, swimming pool, picnic, playground)
• Resting directly on your skin in hot weather or during exercise if you use an insulin pump (Omnipod is an exception)
• Near a heater or heating vent
• In a suitcase during air travel. (Don’t let your insulin get stored under the plane with checked baggage. Always keep it with you!)

Accessories to protect the temperature of your insulin

Remember, even if your insulin is in a diabetes kit or pouch, it’s still vulnerable to extreme temperatures. Medication-cooling accessories are extremely helpful for travel. Some popular options include:

• Frio Pack accessories for pens & vials
• Vivi Cap 
• Medicool
• Insulin Safe
• Pump clothing to keep your pump off your skin, like BandiWear

If you don’t want to buy something new, you can always keep an ice pack with you when you’re out and about in the summer. Keep the ice pack in the same bag as your diabetes kit containing your insulin. It doesn’t have to be complicated or expensive, but it needs to be a priority for anyone taking insulin.

Managing diabetes is difficult enough without your medication failing you. By keeping your insulin in the “safety zone,” you remove a major variable from the blood sugar equation. Treat your supply with care, and it will take care of you.

Have any tips and tricks to share on keeping your insulin cold on the go? Share them in our community apps!