Does Mounjaro Need to Be Kept in the Fridge?

Mounjaro (tirzepatide) is a prescription-only, once-weekly injectable medicine supplied in pre-filled pens. According to the product information, unopened pens should be kept in a refrigerator — typically at 2°C to 8°C — and protected from light and freezing. Freezing a pen can damage it, so it should never be stored in the freezer or placed directly against a freezer compartment inside a fridge.

Once taken out of the fridge

A pen that has been removed from refrigerated storage can generally be kept at room temperature for a period of time — check the leaflet that came with your pen, but the eMC typically indicates this is around 30 days at a temperature not exceeding 30°C. After that window, the pen should be discarded even if product remains inside. Your patient information leaflet is the definitive guide for your specific pen.

A few practical points worth knowing

• Never use a pen that has been frozen, even if it has thawed — freezing can alter the medicine.
• Keep pens away from direct sunlight and heat sources such as radiators or car dashboards.
• If you are travelling, a dedicated medication cool bag (not a freezer pack in direct contact with the pen) can help maintain the right temperature range.
• Always check the expiry date on the pen before use.

For more detail on day-to-day storage questions, see whether Mounjaro needs to be kept in the fridge and the related guide on putting Mounjaro back in the fridge after removing it. You can also read about whether keeping Mounjaro in the fridge is a strict requirement for more context on the rules.

One practical way to stay on top of storage is to know exactly when each pen was taken out of the fridge — and that is where logging your doses in GLP Trackr helps. When you record each injection in the app, including the date and time, you create a clear timeline of when each pen entered room-temperature storage. That record makes it straightforward to check whether a pen is still within its out-of-fridge window before your next dose.

The app also sends gentle dose reminders so your weekly schedule stays on track, and it logs each injection site to help you rotate correctly — keeping your records organised in one place rather than relying on memory.

If you ever have a question about whether a pen has been stored correctly, or whether it is safe to use, always bring it to your prescriber or doctor or contact the pharmacist who dispensed it — they are best placed to advise based on the specific circumstances. Never use a pen you are unsure about; your healthcare professional can guide you.

For a broader overview of managing your Mounjaro journey, visit the Mounjaro hub.

Ready to keep a precise record of every dose and when each pen was opened? Download GLP Trackr on the App Store or Google Play and explore it free for your first 7 days.