How long can Wegovy stay in the fridge, and what happens if it doesn't?

The myth worth correcting first: the fridge is not just a preference

A lot of people assume keeping Wegovy in the fridge is helpful but optional, something you'd do if you remembered, not something that actually changes the medicine. That's not accurate. Semaglutide is a biological peptide, and temperature stability is a genuine manufacturing requirement, not a precaution added for convenience. Storing the pen outside the recommended 2°C–8°C range for longer than the permitted room-temperature window can degrade the active ingredient in ways that aren't visible to the eye. The pen won't change colour or texture to warn you.

A question our prescribers hear most weeks is some version of: "My pen was left out overnight, is it still safe?" The honest answer is that it depends on how long it was out and what temperature the room was. The Patient Information Leaflet gives a specific maximum duration at room temperature (up to 30°C). If that window has not been exceeded, the pen is generally considered usable. If it has, the guidance is clear: do not inject it. Contact your pharmacist or prescriber first.

For practical detail on what counts as "out of the fridge" and how to handle a pen you've been carrying, this page covers the room-temperature window in full.

What "up to 56 days in the fridge" actually means

The 56-day figure refers to the maximum period a Wegovy pen can be stored in the fridge once it has been dispensed to you, counted from when the pen leaves controlled storage, not from any injection. It does not override the expiry date printed on the pen. If the expiry date passes before 56 days are up, the pen should be discarded. If you reach 56 days before the expiry date, the same applies. The shorter deadline always wins.

In practice, most people using Wegovy inject once a week, so a single pen lasts four weeks. The 56-day window is most relevant for people who have received pens in advance, are travelling, or have missed injections and built up a small supply. More detail on storage duration and what to do with unused pens is worth reading if you're planning ahead.

Where you position the pen in the fridge matters too. Avoid placing it near the back or in a drawer directly beside a freezer compartment, temperatures at the edges of a domestic fridge can drop below 2°C. A sealed container in the main body of the fridge, away from direct airflow, is the safest spot. If you want a clear answer on how long Wegovy can stay in the refrigerator, that page sets out the limits in plain terms. The NHS provides clear guidance on semaglutide storage in its patient information on semaglutide.

Room temperature: the window exists, but it's finite

Taking your pen out of the fridge once a week for your injection is completely fine. The problem arises when the pen spends extended time at room temperature, during a holiday, in a bag left in a warm car, or simply forgotten on the kitchen counter for several days. The SmPC defines a maximum period at temperatures up to 30°C; beyond that the medicine should be discarded, not refrigerated again in the hope of salvaging it. Once semaglutide has been heat-stressed, returning it to the fridge does not reverse the damage.

For anyone travelling or managing storage away from home, this overview on Wegovy and refrigeration covers what to do when a fridge isn't available. A small insulated cool bag with a gel pack is widely recommended, never a bag of ice, which risks freezing the pen.

The NHS England guidance on weight management injections confirms that storage instructions should be followed carefully, and that patients should contact their prescriber if they're unsure whether a dose is still suitable to use. That's the right call before discarding an expensive pen without asking.

What to do if your pen has been stored incorrectly

Don't inject it without checking first. If the pen has been frozen (accidentally left next to an ice pack or positioned against the freezer wall in your fridge) it should not be used. Freezing disrupts the pen mechanism as well as potentially affecting the medicine itself. The same caution applies to any pen that has spent time in a hot car, in direct sunlight, or at room temperature beyond the window defined in the leaflet.

Contact your pharmacist or prescriber, describe what happened (how long, approximate temperature if known), and let them advise. If you're a nume patient, our team is reachable seven days a week for exactly this kind of aftercare question. You should also report any suspected quality issue with a dispensed medicine through the MHRA Yellow Card scheme, this helps regulators monitor real-world supply chain performance.

If you're thinking about starting Wegovy and want to understand what treatment involves before committing, the Wegovy overview covers the full picture, including what clinical assessment looks like and how prescription and supply work through a regulated online pharmacy. And if cost is part of your thinking, this page on obtaining Wegovy privately explains what a transparent price should include.