How to Store Your Mounjaro Pen: Temperature, Conditions and What to Check

Mounjaro is a prescription-only, once-weekly injectable medicine supplied as a pre-filled pen. Storing it correctly helps ensure it remains effective and safe to use throughout your treatment. The core storage principles below are drawn from the product information; always cross-check against your own leaflet, as guidance may be updated.

Before first use: refrigerated storage

Unopened Mounjaro pens should be stored in a refrigerator. Keep them away from the freezer compartment and avoid storing them against the back wall of the fridge, where temperatures can dip below freezing. Freezing damages the medicine and the pen should not be used if it has been frozen.

After removal from the fridge: room-temperature storage

Once taken out of the refrigerator, a Mounjaro pen can generally be kept at room temperature (below a specified threshold — check your leaflet, but typically cited as up to around 30 °C / 86 °F) for a defined period before it must be used or discarded. The exact number of days is stated in your patient information leaflet and on the electronic Medicines Compendium (eMC) — do not rely on memory; check the source.

General storage conditions

• Keep the pen in its original carton to protect it from light.
• Store out of reach of children.
• Do not use a pen that has been frozen, dropped, or visibly damaged.
• Do not use it after the expiry date printed on the carton or pen label.

Wegovy storage

Wegovy (semaglutide) pre-filled pens follow a similar refrigerated-storage principle. If you are on Wegovy, check your own patient information leaflet for the specific temperature thresholds and out-of-fridge timelines, as they may differ slightly from Mounjaro.

If you ever have questions about whether your pen has been stored correctly — for example after a power cut or a warm journey home — contact your prescriber or pharmacist before using it. For a broader look at everything to know about Mounjaro, including how it works and what to expect, our Mounjaro hub is a good starting point. You may also find our page on Mounjaro and temperature guidance useful for more detail on what happens if the cold chain is broken.

Knowing when you took your last dose — and therefore which pen you are currently using — makes it much easier to monitor how long a pen has been out of the fridge. GLP Trackr's dose logging feature lets you record the date, time, and dose strength of each injection the moment you take it, so you always have an accurate record rather than trying to remember.

That log also feeds into the app's dose reminders, which help you stay on your once-weekly schedule. Missing a dose or accidentally doubling up is easier to avoid when every injection is noted in one place. If you do think you may have missed a dose, log it in the app and discuss next steps with your prescriber — dose decisions always belong with the person who knows your full medical history.

Over time, having a clear injection history can also be genuinely useful to bring to appointments, giving your prescriber an accurate picture of your schedule and any patterns you have noticed. If you are curious about whether Mounjaro comes in tablet form or other formats, take a look at our page on Mounjaro and tablet options for context.

Always follow the guidance in your patient information leaflet and the advice of your prescriber or pharmacist on storage. If you are unsure whether a pen has been kept at the right temperature, do not use it without checking with your healthcare professional first.

Ready to keep a cleaner record of every dose? Download GLP Trackr on the App Store or Google Play — there is a free 7-day trial waiting for you.