How to Check Your Wegovy Batch Number — and Why It Matters

Where to find the batch number on your Wegovy pen

Novo Nordisk prints the batch number (sometimes labelled "Lot" or "Batch") on two places: the outer cardboard carton and on the body of the pre-filled pen itself. Open your box and look along the bottom edge of the carton, you will usually see the lot number followed by an expiry date in MM/YYYY format. The pen's label repeats this information, typically near the coloured pen cap.

A legitimate UK pack also carries a 2D matrix barcode (a small square of dots, distinct from a standard barcode) that encodes the product code, batch number, expiry and a serialisation number. This is part of the EU Falsified Medicines Directive serialisation requirements that still apply to UK-sold medicines under retained law. If your pack has no 2D barcode, or the printing looks smudged or faded in a way that makes the characters unreadable, do not use the pen. Contact the pharmacy that supplied it first.

Pens bought through social media or websites that supply medicines without a prescription have repeatedly lacked correct batch markings in MHRA enforcement operations. The MHRA's Yellow Card scheme lets you report a suspect pen and check whether a batch has been flagged, it takes about three minutes online.

How to cross-reference a Wegovy batch against MHRA recalls

The MHRA publishes medicines recalls and alerts on GOV.UK, and individual batch numbers appear in the relevant alert notice. The process is straightforward. Go to GOV.UK and search "MHRA drug alerts" or navigate directly to the medicines recalls and alerts database. Filter by product name (search "semaglutide" or "Wegovy") and scan the listed batch numbers against the one on your carton, and if you want background on the molecule itself, our page covering the semaglutide CAS number and what it identifies explains how the compound is formally registered.

If your batch appears in an active recall, do not inject the medicine. Contact the pharmacy that supplied you and your prescriber the same day. If you cannot reach either quickly, call NHS 111 for guidance on next steps.

It is equally worth checking the NHS semaglutide medicines page for any linked safety communications, the NHS updates this resource when MHRA issues guidance affecting patients. A batch number not listed in any current recall is a good sign, though it confirms only that particular lot has not triggered an alert, not that the pen is definitely genuine if the wider supply route was questionable.

If you started on Wegovy elsewhere and want to transfer to a more closely monitored arrangement, our Wegovy check-up service covers exactly this kind of review.

Red flags that suggest a pen may not be genuine

MHRA enforcement through 2024 and 2025 found counterfeit weight-loss pens across the UK, including pens purporting to be semaglutide that contained insulin instead. The consequences for someone who is not diabetic can be life-threatening. Knowing what a legitimate pack looks like is a practical safety skill, not an abstract precaution.

Look closely at the following. The batch number and expiry date should be printed clearly, not handwritten, not a sticker placed over another sticker. The pen's colour-coded cap should match the strength shown on the label (Novo Nordisk uses a consistent colour-coding system across its Wegovy range). The Patient Information Leaflet inside should be in English, with a UK/MHRA authorisation number. A leaflet in another language, or no leaflet at all, is a serious warning sign.

The flow check symbol on the Wegovy pen is a separate pre-injection step, but a genuine pen also has this mechanism intact. If the device has been tampered with or the needle thread feels wrong, do not proceed. Our general FAQs cover more on pen handling queries.

One thing a question our prescribers hear fairly often: "the pen looked fine, but I bought it cheaply online, is that okay?" The honest answer is that price and packaging appearance are not reliable safety tests. The only reliable test is an unbroken, verifiable supply chain starting with a prescription from a registered prescriber at a GPhC-registered pharmacy.

What to do if you suspect your Wegovy pen is counterfeit or recalled

Do not inject it. That is the straightforward first step. Set the pen aside somewhere it cannot be used accidentally, particularly if there are children or others in the house.

Then: contact the pharmacy that supplied you. A GPhC-registered pharmacy will have a returns and recall procedure and will arrange a replacement where one is available. You can verify any online pharmacy's registration at the GPhC pharmacy register before you place an order, at nume, our GPhC premises registration number is 9012878, verifiable there directly.

Report the suspect pen via the Yellow Card scheme. This matters because your report adds to MHRA's intelligence picture and can trigger action that protects others. You can report a suspected counterfeit and a suspected side effect through the same portal. If you have already injected from a pen you now believe is fake, seek medical attention promptly and mention what you injected and when.

For a longer look at how Wegovy works and what clinical assessment involves, our Wegovy overview covers the full picture. If you are thinking about starting treatment for the first time, you can also read about getting Wegovy through a registered online pharmacy and what that process looks like in practice, and if you are planning to travel with your medication, our guide to whether you can put Wegovy in checked luggage walks through the rules. Treatment information is also on our weight-loss treatments overview.