Does Wegovy Expire — and What Happens if Your Pen Is Out of Date?

You pull the pen from the fridge and notice the date

You're running a few days late with your weekly dose, or you've come back from a trip away and the pen you left at home is sitting in the fridge with a date that's closer than you'd like. This is the moment most people google the question. The short answer: the expiry date printed on a Wegovy pen is the manufacturer's guarantee that the medicine inside is stable and fully potent up to that point, under correct storage conditions. After the date passes, Novo Nordisk can no longer stand behind its stability. Semaglutide is a protein-based molecule, and like most biological medicines it can degrade over time, meaning the dose you inject may be weaker, or the medicine may have changed in ways that aren't visible to the eye.

The NHS medicines page for semaglutide is clear that you should not use a Wegovy pen after its expiry date. That guidance exists for a reason. An expired pen is not a risk worth taking when the medicine is meant to support a process that takes months, not days. If you are unsure about when your pen expires, our page on what to do with an expired Wegovy pen walks through the next steps.

What the expiry date actually measures, and why storage changes everything

The printed date is calculated under the assumption that the pen has been stored correctly from the moment it left the manufacturer. For Wegovy, that means refrigerated at 2 to 8°C in its original packaging, away from light. Once a pen is removed from the fridge and kept at room temperature, the clock accelerates. Your Patient Information Leaflet gives the exact window for room-temperature storage, always defer to that document rather than any general guidance you find online, because pen formats and batch specifications can differ.

This matters particularly if a pen has been left out accidentally, carried in a bag without a cooler on a warm day, or stored in a bathroom cabinet where temperature and humidity fluctuate. In those situations the pen may effectively expire before the date on the label. There is useful detail on how fridge storage affects Wegovy's shelf life if you want to understand what the right conditions look like day to day. One practical note: keeping pens in the fridge door rather than at the back can expose them to repeated temperature shifts every time the door opens, a small thing, but worth knowing.

Semaglutide's expiry behaviour is shared across the GLP-1 class. If you are curious how the same rules apply to the molecule more broadly, our page on semaglutide expiry covers the pharmacology in more detail.

When does Wegovy expire once the pen is in use?

The expiry question changes slightly once a pen has been activated. Wegovy pens are single-dose devices (each weekly injection is one pen) so there is no multi-dose vial to worry about. But the date on the pen's label is still the controlling limit: the pen must be used before that date regardless of when you started it. For the oral semaglutide tablet format (the Wegovy pill approved by the MHRA in June 2026), storage is simpler because no refrigeration is required, but expiry dates still apply and the same principle holds: do not use past the printed date.

If a delivery arrives and you notice the pen's date leaves less time than expected, contact your pharmacy promptly. A legitimate, regulated pharmacy will address this. At nume, every order is clinically reviewed before dispatch and our aftercare team is available seven days a week, you can reach us via the contact page if a storage or expiry concern comes up between doses.

For those comparing semaglutide pen formats, our Wegovy click charts page covers how to confirm the pen is functioning correctly, a useful companion read when you're checking everything before injecting.

What to do with a pen you cannot use

If a pen has expired, or if you have reason to believe correct storage was not maintained, do not inject it. Disposing of it correctly matters too: unused or expired pens should not go into household recycling or general waste. They are sharps and must be placed in an approved sharps container for collection or pharmacy return. Our weight loss treatments overview includes broader guidance on managing your treatment safely, and the question of what comes next (whether to request a replacement or check your eligibility for a dose review) is one to take to your prescriber. The MHRA's Yellow Card scheme is also available if you want to report a quality concern about a specific pen or batch.

Getting treatment right over months matters far more than getting a single pen used. If you are thinking about starting Wegovy through a regulated private route, take a look at what the Wegovy treatment page covers, or check how Wegovy pricing works in the UK private market to understand what a legitimate service includes. When you are ready, our prescribers are here.