How long before Wegovy expires — and what to do when it does

Why the printed date is the only date that matters

There is a common assumption that pharmaceutical expiry dates are cautious estimates with plenty of margin to spare, the way some people treat a best-before date on a tin of soup. With Wegovy, that assumption is worth setting aside. Semaglutide is a protein-based molecule sensitive to temperature, light and time. The expiry date is not a conservative guess; it is the point up to which Novo Nordisk's stability testing confirms the medicine meets its licensed specification. Beyond it, potency and safety can no longer be guaranteed.

You can check the date on two places: the outer carton your pen arrived in and the label on the pen itself. If the two dates differ for any reason, treat the earlier one as binding and contact your pharmacist. The question of whether Wegovy truly expires sometimes comes up in online conversations, and the short answer is: yes, unambiguously.

One practical point worth noting, if your pen has been stored correctly and is still within date, it is fine to use. The expiry date is a threshold, not a countdown that makes the medicine less effective in the weeks leading up to it. Use it as directed until that date arrives, then reassess.

What happens if your pen expires before you inject it

Missing a weekly dose is frustrating enough without also discovering the pen in the crisper drawer has passed its date. If you find yourself holding an expired Wegovy pen, the guidance is straightforward: do not inject it. Contact your prescriber or dispensing pharmacy as soon as you can. They can advise whether a replacement is appropriate and, if a dose has been skipped as a result, how to resume, that timing question is one for the clinician, not a rule you should apply yourself.

Expired pens need proper disposal. Do not put them in household waste or flush them. A sharps container is the correct route for the pen itself; your local pharmacy can usually accept filled sharps bins for safe disposal. Your local council website will list the nearest collection point if needed.

At nume, every repeat order goes through a fresh clinical review before dispatch, so your prescriber already knows your current treatment schedule and can move quickly if a replacement pen is needed.

Storage as the real driver of shelf life

The expiry date assumes the pen has been stored as instructed throughout its life. Correct Wegovy storage before first use means keeping the pen refrigerated at 2–8 °C, away from the freezer compartment and away from direct light. A pen that has been left at room temperature for longer than the leaflet allows, or that has been accidentally frozen, may be compromised before its expiry date arrives. The colour or clarity of the solution can indicate a problem, if it looks cloudy, discoloured or contains particles, do not use it regardless of the printed date.

Once you have started using a pen, the rules change slightly. After it leaves the fridge, the pen can be kept at room temperature for a defined period; the exact window is stated in the Patient Information Leaflet included with your medicine. The NHS guidance on semaglutide is clear that the leaflet is the authoritative source for this figure, and our prescribers at nume say the same. If you are ever unsure whether a pen has been stored within those limits, the safer choice is always to speak to your pharmacist rather than guess.

For anyone who travels regularly, it is worth reading about how long Wegovy can safely be left out before injecting, since travel schedules often disrupt the usual fridge routine.

Planning ahead so expiry is rarely the issue

The most straightforward way to avoid an expired pen is to order close enough to when you need it. That sounds obvious, but people sometimes hold back from ordering a repeat because they are not sure they want to continue, or because they are waiting to see how the current dose is working. Both are valid reasons to pause, just make sure you discuss them with your prescriber rather than letting a pen quietly expire in the back of the fridge.

If you are considering whether treatment is still right for you, the results people see over time are worth understanding properly before making that call. Cost is sometimes part of the thinking too; you can find a straightforward breakdown of what Wegovy costs in the UK and what an honest price should include. And if you are ready to talk through your situation with a prescriber, checking your eligibility takes a few minutes and costs nothing.

The NHS semaglutide guidance covers storage and expiry in straightforward terms, and the full instructions are in the Patient Information Leaflet inside your pack. If anything is unclear, the right person to ask is your dispensing pharmacist or prescriber, not a forum.