How long can you store semaglutide in the fridge — and what actually matters

The misconception: every minute out of the fridge shortens how long it lasts

It's a reasonable worry. You leave the pen on the counter while you prepare your injection, then wonder whether you've lost a week off its life. In practice, the fridge storage window and the room-temperature window are counted separately, not as one combined clock. The fridge life runs from dispensing to the expiry date on the label, provided the pen stays refrigerated and, critically, never freezes. The room-temperature period only begins once you take the pen out, and the SmPC sets a specific maximum duration for that exposure. You haven't used up any of the fridge life by injecting once or by letting the pen warm up briefly before use.

The detail that catches people out is the in-use shelf life once a Wegovy pen has been started. This is not the same as the overall expiry date. For the exact figure (which can differ between the standard Wegovy pen and the newer 7.2mg single-dose format) the Mounjaro and Wegovy SmPCs on the eMC are the authoritative source, and your Patient Information Leaflet will state it clearly. Our general guidance: read the leaflet for your specific pen on day one, before you need to know in a hurry.

If you are unsure which format you have been prescribed, our Wegovy overview covers the pen options currently available in the UK.

What the fridge itself needs to do right

The 2–8°C requirement isn't a suggestion. Below 2°C the medicine freezes, and a frozen semaglutide pen is not recoverable, the ice crystals that form during freezing can permanently alter the solution's structure. It should go in the bin. Don't put it in the door compartment if your door runs colder than 2°C, and keep it away from the ice-box shelf. Some fridge drawers (especially the salad drawer at the bottom) can sit just above freezing. A basic fridge thermometer costs very little and removes the guesswork entirely.

Above 8°C, you are eating into the room-temperature window even if you haven't removed the pen. If your fridge regularly fluctuates or you have a power cut, treat that time as part of the out-of-fridge exposure. The NHS medicines guidance on semaglutide reinforces that correct cold-chain storage is essential to the medicine working as intended.

For travel (a common question our prescribers hear most weeks) a dedicated medicine cool wallet keeps a pen within range for short journeys. How long semaglutide can safely be out of the fridge is covered in detail in a companion page, because the rules for travel differ from simply leaving a pen on the worktop.

What happens at the end of the fridge window

An expired pen is not a borderline situation. Using a semaglutide pen past its expiry date is not recommended under any circumstances, and the same applies to a pen that has exceeded its room-temperature limit. Neither the appearance of the solution nor the way the pen feels tells you whether the medicine is still active. Semaglutide is a peptide, it degrades without obvious visible change.

If you are trying to work out the timing across a course of treatment, or you are weighing up how long Wegovy can be stored when you order ahead, the clearest approach is to order in step with your dose-review schedule rather than stockpiling. That way expiry dates stay comfortable and any clinical changes to your prescription (a dose increase, for example) are reflected in what you actually have at home.

Disposal matters too. Used pens and any pen that needs to be discarded before expiry should go into a proper sharps container, not a household bin. Your local pharmacy or GP surgery can advise on collection.

Starting treatment: storage guidance begins at the consultation

Storage is one of those topics that feels administrative until it isn't. A pen that arrives in good condition but is then kept at the wrong temperature, or used after its in-use window has closed, is one that may not work the way the clinical trial evidence suggests it should. The STEP 1 trial, published in the New England Journal of Medicine, reported around 15% average body-weight reduction at 68 weeks under controlled conditions, conditions that include correct storage and handling throughout. Real-world results depend, in part, on how the medicine is treated between the fridge and the injection site, so it is worth reading our guide on how to mix and prepare a semaglutide injection before you begin.

At nume, our prescribers cover storage and handling as part of the same-day clinical review that follows your consultation, not as an afterthought. There is no charge for the consultation itself. If you have questions about whether Wegovy is suitable for you, or you would like to understand how to access it through a regulated UK pharmacy, the right place to start is a proper clinical assessment. When you are ready, start your free consultation and a GPhC-registered prescriber will review your answers the same day.