Semaglutide expiry dates: how to read them and what they mean for your treatment

What does the expiry date on a Wegovy pen actually mean?

The date printed on the box and on the pen itself (usually in the format MM/YYYY) means the pen is considered stable until the last day of that month. So a pen marked 04/2026 is within its shelf life on the 30th of April 2026, but should not be used from the 1st of May onwards. That stability guarantee applies only when the pen has been kept refrigerated throughout its life: cold chain from the manufacturer to the wholesaler, from the wholesaler to the pharmacy, and from the pharmacy to your door.

When a pen arrives through a GPhC-registered pharmacy's next-working-day service, it travels in insulated packaging designed to keep it within range during transit. Check when it arrives: the liquid inside should be clear and colourless. If it looks cloudy, discoloured, or has visible particles, do not use it, and contact the pharmacy. That visible check is something many people skip, and it is worth making a habit of.

The printed expiry date is the manufacturer's guarantee, but it is conditional, it assumes everything upstream has gone right. If you have any doubt about how a pen was stored before it reached you, our dedicated guide to Wegovy expiry walks through what to check and what those storage conditions actually mean in practice, before you talk to your prescriber or pharmacist.

Does semaglutide expire faster once you open the pen?

Yes. This is the part that catches people out. A Wegovy pen that has never been used and has sat in a properly functioning fridge can remain stable up to its printed date. But once the pen has been activated for the first dose, or once it has been taken out of the fridge for room-temperature storage, a separate, shorter clock starts. For the exact number of days that applies to your pen format, the Patient Information Leaflet is the authority, not a forum post, not a rough memory of what someone mentioned at a clinic.

Room-temperature storage is sometimes unavoidable: travel, a fridge breakdown, or simply forgetting to put the pen back. If you want a clear explanation of whether and how semaglutide expires, including the specific conditions that affect its stability, the Electronic Medicines Compendium carries the specific time windows and storage conditions the manufacturer has validated. What we can say clearly: if a pen has been left at room temperature for longer than the leaflet allows, it should not be used. The degradation of semaglutide is not something you can detect by looking at the liquid, the pen may appear perfectly normal while the active medicine is no longer at therapeutic strength.

Questions about Wegovy expiry after opening come up regularly, and the answer is always the same: check the leaflet for the exact window, keep a note of the date you first used or removed the pen from the fridge, and don't guess.

What should you do with an expired or compromised semaglutide pen?

Never inject an expired pen, and never dispose of it in your household bin. Used or expired injection pens contain sharps components and a residue of a prescription medicine. The right container for them is a sharps disposal bin, which your local council, GP surgery or pharmacy can usually arrange to collect or accept. This is true whether the pen is Wegovy or any other injectable medicine.

If you find yourself with an expired pen because a dose was missed or delivery was delayed, contact your prescriber before doing anything else. Missing a dose is a clinical question, not just a logistical one. A prescriber can advise whether to wait for the next scheduled injection, restart at a lower dose, or take a different step, the answer depends on where you are in your titration schedule and how long the gap has been. That is a decision made with clinical input, not by working it out from a website.

Cost is sometimes the reason people feel tempted to use a pen that is borderline. If you want to understand what drives the cost of Wegovy treatment in the UK, that page sets out the context honestly, but no price saving justifies injecting something past its verified safe-use period.

How does expiry relate to the way Wegovy is dispensed and delivered?

Wegovy is a prescription-only medicine. In the UK, the only legal route to it is a prescription issued after clinical assessment by a qualified prescriber. That means the pen you receive through a regulated pharmacy should have been dispensed with enough time on its shelf life to complete the intended course. A legitimate dispensing pharmacy checks this before packing your order.

At nume, every prescription is reviewed by a GPhC-registered Independent Prescriber before anything is dispatched. Orders placed before 12pm on weekdays are typically dispatched the same day and arrive the following working day via DPD in plain, unbranded packaging. You get a tracking notification before it arrives, so the pen is not sitting on a doorstep in a warm porch all afternoon. That matters for cold-chain integrity in summer months especially.

If you have a general question about your treatment, our FAQs cover the most common ones, and our aftercare team is available seven days a week. For questions specific to your prescription, the clinical team is the right first contact. You can find out more about how we approach clinical oversight on the clinical team page.

Semaglutide is also available as a once-daily tablet, the Wegovy pill. The storage rules for the tablet differ from the injection: no refrigeration is needed, which makes it more straightforward for travel. If you are curious whether the injection or the tablet might suit your circumstances better, that is a question worth raising at consultation. To explore your options, speak to our prescribers.