Does Mounjaro need to be refrigerated?

Mounjaro (tirzepatide) is a medication prescribed to treat type 2 diabetes. It comes as a once-weekly injection in pre-filled pens that should be refrigerated. We spoke with Dr. Yael Cooperman, M.D. about how to store your Mounjaro pen. 

Yes, Mounjaro should be kept in the refrigerator. According to the manufacturer, Eli Lilly, Mounjaro pens should be stored in a cool dark place, between 36-46° Fahrenheit (2-8° Celsius). They should not be frozen. The manufacturer also recommends keeping in mind that some areas of the refrigerator can be colder than others so it may be a good idea to store the medication in the door rather than in the back of the fridge.

That said, Mounjaro can be stored unrefrigerated for up to 21 days, but should still not be exposed to temperatures above 86° Fahrenheit (30° Celsius). That means that if you’re traveling, you can take your medication with you, but if you’re flying, you should consider packing it in your carry-on, since baggage holds in planes can descend to below-freezing temperatures. 

Also, if you leave the medication out of the fridge, it’s still important to protect it from light. You can store it in the box it came in to ensure that the medication isn’t exposed to light.

If your Mounjaro pen was left out of the fridge but at room temperatures not exceeding 86 degrees Fahrenheit for up to 21 days, you can use your medication normally. If the medication remains unrefrigerated for more than 21 days, the active ingredients can start to break down, making it less effective. If you accidentally leave your medication out of the fridge for too long, dispose of it and speak with your healthcare provider to get a new supply. 

The shelf life of Mounjaro depends on the expiration date printed on the pen itself. If you notice that your Mounjaro pen has expired before you had a chance to use it, contact your pharmacist or healthcare provider who can tell you how to dispose of the medication and get you a refill. 

If you still have questions about your medication, you can speak with your pharmacist, or healthcare provider, or call Eli Lilly, the drug’s manufacturer, directly.

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Current version

November 13, 2023

Written by

Yael Cooperman, MD

Fact checked by

Felix Gussone, MD

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About the medical reviewer

Felix Gussone, MD, Ro

Felix Gussone is a physician, health journalist and a Manager, Medical Content & Education at Ro.