Does Mounjaro Need to Be Stored in the Fridge?

Both Mounjaro (tirzepatide) and Wegovy (semaglutide) are biological medicines supplied as pre-filled injectable pens. Because of their composition, temperature control matters throughout their shelf life.

Before first use: refrigerator storage

Unopened or unused pens should be stored in the refrigerator — typically between 2°C and 8°C. They should not be stored next to the freezer compartment or placed directly against the back wall of the fridge where temperatures can drop below freezing. A frozen pen should not be used; check your leaflet or the electronic Medicines Compendium (eMC) entry for your specific product if you are unsure whether a pen has been affected.

Out-of-fridge use: the room-temperature window

Once you remove a pen from the fridge, it can generally be kept at room temperature for a limited period — check the leaflet that came with your pen, but this is typically around 21 to 30 days depending on the product and storage conditions. After that window, the pen should be discarded even if medicine remains inside. Pens must also be kept away from direct sunlight and sources of heat.

What to avoid

• Do not freeze the pen or store it in contact with ice packs.
• Do not leave it in a hot car, on a sunny windowsill, or near a radiator.
• Do not use a pen if it has been frozen, dropped, or the medicine appears discoloured or cloudy in a way that is not normal for that product.

If you are travelling and need to transport your pen, an insulated cool bag (without direct contact with ice) is a practical solution — but always verify the specific guidance in your product leaflet or with your prescriber or doctor.

For more on how your pen should be looked after day-to-day, see our related guides on keeping your Mounjaro pen correctly refrigerated and how long Mounjaro can be stored in the fridge. You can also read more about when Mounjaro has to stay in the fridge and when brief periods out are acceptable.

One practical consequence of refrigerator storage is that it ties your pen closely to your weekly injection routine — and keeping that routine consistent matters. GLP Trackr's dose logging feature lets you record each injection as it happens, including the date and dose strength, so you always have a clear record of when your last shot was taken and which pen you are working through.

If you are managing a pen that is out of the fridge and within its room-temperature window, having a timestamped log of when you first removed it can be genuinely useful. The app also sends gentle dose reminders so your weekly schedule stays on track without you having to keep count manually.

Beyond dose logging, GLP Trackr's injection-site tracking helps you rotate sites correctly — something that matters just as much as correct storage for a comfortable, effective injection experience. Together, these features mean less mental load managing your treatment week to week.

For a broader look at how Mounjaro works and what to expect from your treatment, visit our guide on how Mounjaro works.

A note on safety: if you are ever uncertain whether a pen has been stored correctly — for example after a fridge failure or prolonged travel — do not use it without checking with your prescriber or doctor first. They can advise on whether the pen is still suitable to use. GLP Trackr helps you record your journey, but any decision about whether a pen is safe to use belongs with your healthcare professional.

Want a simple way to keep your injection schedule and dose history in one place? GLP Trackr is free to try for 7 days — available on the App Store and Google Play.