Fake GLP-1 Pens Are Turning Up in the UK. How to Spot One
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On October 14, UK officials raided a site in Birmingham and seized more than 12,000 fake weight loss pens (MHRA). They were ready-to-inject pens. Fake Ozempic pens have turned up in the US drug supply chain before, too. Officials haven't said where the Birmingham pens were headed, and there's no sign they were bound for the US. It still helps to know how fakes get made and how to check the pen in your hand.
Who This Helps
This is for anyone who uses a GLP-1 pen, such as Ozempic, Wegovy, Mounjaro or Zepbound. It's also for anyone tempted by a cheaper pen from a website, a social media seller or a friend of a friend.
What was found in Birmingham
The UK's drug regulator and local police seized the pens from a unit on an industrial estate, along with packaging for about 30,000 more (MHRA). The haul was valued at around £2 million. The pens were labeled as tirzepatide, the drug in Mounjaro and Zepbound, and as retatrutide, a drug that isn't approved in any country yet.
Tim Duffield, who leads intelligence for the MHRA's criminal enforcement unit, called the site a "filthy warehouse" and said there's "no guarantee of what they contain" (MHRA). The agency said none of them had been checked for safety, quality or whether they work.
Retatrutide isn't approved anywhere, so any retatrutide sold to the public is unapproved and illegal to sell. Lilly, which is developing it, supplies it only through clinical trials and a small early-access program. The UK regulator notes it isn't approved there (MHRA), and Lilly says no regulator in the world has approved it (Lilly).
Where the fakes come from
This wasn't a one-off. A year earlier, UK officials shut down what they called the country's first illegal factory for these drugs, in Northampton. They found tens of thousands of empty weight loss pens ready to be filled, plus raw chemical ingredients (MHRA). That suggests a basic process: fill empty pens with bulk ingredients and pack them.
The fakes also spread through places that look real. In February, UK officials found fake Mounjaro pens that had reached patients through one online pharmacy (MHRA). Only five pens were found, and the MHRA said it had no reports of harm needing treatment. In an operation across 90 countries that ended in May 2025, police and regulators shut down about 13,000 websites, social pages and bots selling illegal medicines. They also saw more diabetes and weight loss drugs sold on social media and online markets (Interpol).
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Why the US could see more
Fakes have made it into the normal US supply chain before. The FDA has warned about fake Ozempic pens more than once, including thousands of units in late 2023 and dozens more in December 2025 (FDA). The FDA said the December 2025 fakes were found in the legitimate US drug supply chain. In the 2023 seizure, even the needles were fake, so the FDA couldn't confirm they were sterile (FDA).
In September, federal prosecutors charged two men in a scheme they say brought fake Ozempic into the US from unauthorized sources in China between 2023 and 2024 (US Department of Justice). The charges are only allegations, and the men haven't been convicted. During one week in 2025, US border officers in Cincinnati also seized 16,740 counterfeit pre-filled pens, including fake Ozempic, retatrutide and tirzepatide (CBP). The full haul, which also held other drugs, was headed to 40 states, and Hong Kong was the top source, then China.
Novo Nordisk, which makes Ozempic and Wegovy, says this kind of crime is often driven by high demand from patients (Novo Nordisk). Our own read is that high prices make a cheap fake tempting in the US, and interest in retatrutide, which can't be bought legally anywhere, gives sellers a product with no approved version to check against. The UK raids show that sellers can now fill and pack pens in bulk. No official has said those pens are headed here, but the same playbook could be used anywhere.
How to spot a fake pen
Fakes can look very much like the real thing, Lilly says, so check more than the look (Lilly). These are the checks the WHO, FDA and MHRA point to:
- Look at the label and box. The World Health Organization says fake labels can be poor quality, and the box may have spelling mistakes (WHO).
- Check the pen itself. On some fakes, a scale sticks out of the pen when you set the dose (WHO). On the fake Mounjaro pen found in the UK, the dose knob came off during use in four of the five cases (MHRA).
- Check the lot and serial number, but don't stop there. The FDA has listed lot numbers tied to fakes (FDA). Fakers also copy real lot numbers. One lot number on fake pens seized in 2025 was also used on real ones (FDA).
- Think about where it came from. The FDA says to fill your prescription at a state-licensed pharmacy (FDA). A pen from social media, a website with no prescription step, or a deal that seems too cheap is a red flag.
- There is no approved retatrutide pen. Any pen or vial sold to the public under that name is unapproved, since no country has approved it yet (GLP Winner).
If something looks off, you can check with the maker. Novo Nordisk's customer care line is 1-800-727-6500 (FDA), and Lilly's is 1-800-545-5979 (Lilly).
Why fakes are dangerous
A fake can hurt you as well as fail. In 2023, UK officials said a very small number of people ended up in the hospital after using pens thought to be fake, some with blood sugar so low it caused shock or coma. They thought the pens may have held insulin (MHRA). In Lebanon, 11 people had dangerously low blood sugar that same year after injecting what health officials suspected was fake Ozempic (Reuters).
Even when a fake has the right drug in it, nobody knows the dose or whether it's clean. The UK's fake Mounjaro pens did contain tirzepatide, but officials couldn't be sure the pens were sterile (MHRA). We've seen the same problem with vials: in an Australian lab test we covered last month, only one of 18 vials sold as retatrutide matched its label (GLP Winner).
What to do if you think your pen is fake
- Stop using it and call your prescriber or the maker.
- Keep the pen, since the maker may ask for the sample (Novo Nordisk).
- Report the problem and any side effects to the FDA through MedWatch (FDA).
- If you feel faint, confused or very unwell after a dose, get medical help right away.
Final Takeaway
UK officials have found illegal pens being filled and packed in bulk, and fake Ozempic pens have slipped into the US supply chain before. You can't always tell by looking. Buying from a state-licensed pharmacy with a real prescription cuts the risk a lot, though fakes have reached licensed channels before. If a pen looks or works differently from the last one, stop, keep it, and call the maker or your prescriber.
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Frequently Asked Questions
How can I tell if my Ozempic or Mounjaro pen is fake?
Look for a poor-quality label, spelling mistakes on the box, or a pen that works differently, such as a dose knob that comes loose. Fakes can look very real, so buy from a state-licensed pharmacy and call the maker if something seems off.
Are there real retatrutide pens?
No approved ones. Retatrutide hasn't been approved in any country. Outside Lilly's clinical trials and early-access program, any pen or vial sold as retatrutide is unapproved.
Is a lot number enough to prove my pen is real?
No. The FDA found a real lot number printed on fake pens, so a matching lot number doesn't prove a pen is genuine. Check the pen, the box and the seller as well.
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Written by
Lauren PescarusLauren Pescarus is a team member with GLP Winner where she works on marketing, content creation, and operations. She has over 10 years experience in the content creation space, including in the GLP-1 space where she works to stay on top of access news, research updates, and lifestyle tips guided by science.