How Long Can You Keep Mounjaro in the Fridge?

Mounjaro (tirzepatide) is a once-weekly injectable medicine supplied in pre-filled pens. Storage instructions are provided in the patient information leaflet and the official product information, and following them is important for keeping the medicine effective.

Unopened pens in the fridge

Unopened pens are typically stored in a refrigerator at around 2°C to 8°C (36°F to 46°F) and can generally be kept there until the expiry date on the label. Check your leaflet to confirm the exact conditions, as these are the authoritative figures for the product you have been dispensed.

After removal from the fridge

Once a pen has been taken out of the fridge, it can usually be kept at room temperature below a certain threshold for a limited period — commonly cited as up to around 30 days in general product information, though the precise figure in your leaflet is what counts. For a fuller look at keeping Mounjaro at room temperature, including what temperatures are considered safe, see that dedicated page.

Key things to avoid

• Do not freeze Mounjaro pens — freezing can damage the medicine.
• Keep pens away from direct sunlight and heat sources.
• Do not use a pen if it has been frozen, dropped, or damaged, or if the liquid looks cloudy or discoloured — contact your prescriber or pharmacist if you are unsure.
• Once the pen has been used for the first time, the same post-refrigeration window applies.

For more on the best way to store your pen in the fridge — including practical tips on temperature consistency — that page goes into more detail. You may also find it useful to read about how long a course of Mounjaro typically lasts to help plan your supply storage sensibly.

Keeping track of when you started a pen — and how long it has been out of the fridge — is easy to lose sight of across a weekly injection schedule. GLP Trackr's dose logging feature lets you record every injection with its date, time, and dose strength, giving you a clear timeline of each pen from first use onwards.

That log is genuinely useful in two ways: it helps you notice if a pen has been at room temperature longer than intended, and it gives you an accurate record to refer to — or bring to your prescriber — if you have any questions about your supply. The app also sends dose reminders so a weekly injection is never missed or delayed without you realising.

If you ever have a concern about a pen that has been stored incorrectly, the right step is to contact your prescriber, pharmacist, or another healthcare professional — they can advise on whether the pen is still suitable to use. GLP Trackr records your journey; it does not replace that clinical guidance. For a broader understanding of how Mounjaro works and what to expect during treatment, the main guide covers the full picture. You can also explore how long Mounjaro is typically prescribed for to think about longer-term pen storage planning.

Keep your injection history organised and your weekly schedule on track — GLP Trackr is free to try for 7 days on the App Store and Google Play.