Fake Ozempic and Mounjaro: How Counterfeits Reach Buyers and How to Check Your Pen

Fake versions of Ozempic, Wegovy, Mounjaro, and Zepbound are real, and they are not confined to obscure websites. The FDA has seized counterfeit Ozempic pens inside the legitimate U.S. supply chain three times since December 2023, and in February 2026 the U.K. medicines regulator traced fake Mounjaro pens to a registered online pharmacy in Birmingham.

What is inside a fake varies from case to case. Austrian patients were hospitalized in 2023 with low blood sugar and seizures, which regulators said pointed to insulin in pens labeled as Ozempic. Other fakes contain the right drug but are made without the manufacturing controls that keep an injection sterile and correctly dosed. In a 2024 study, semaglutide bought online without a prescription held 29% to 39% more drug than its label said.

The safest source is a state-licensed pharmacy, or in the U.K. a registered pharmacy, filling a real prescription. Before you inject, check the lot number on your pen and carton against regulator alerts, and call the manufacturer if anything about the pen or its packaging looks different from what your pharmacy usually dispenses. If you think you used a fake and feel shaky, sweaty, or confused, treat it as possible low blood sugar and get help.

People use "fake Ozempic" for several different products, and the risks differ.

A counterfeit (the World Health Organization's term is "falsified") pretends to be a brand-name product. It copies the Ozempic or Mounjaro name, carton, and pen, but the company did not make it. The fake pens the FDA and the U.K.'s Medicines and Healthcare products Regulatory Agency (MHRA) have warned about fall in this group.

An unlicensed product is sold under the drug's chemical name, such as "semaglutide" or "tirzepatide," by a maker no regulator has approved. Many "research use only" vials fit here. Our guide to research-use-only peptides explains why the FDA treats them as unapproved drugs.

A compounded drug is mixed by a pharmacy for an individual patient under state and federal pharmacy law. Compounded semaglutide and tirzepatide are legal in the U.S. only under specific conditions, and their quality depends on the pharmacy. They are not counterfeits, though some have had their own quality problems; see how to evaluate a compounding pharmacy.

This guide is mainly about counterfeits and the illegal online pharmacies that sell them alongside unlicensed products.

The most worrying cases are fakes that entered the regular supply chain, where pharmacists and patients had little reason to suspect them.

United States: In December 2023, the FDA said it had seized thousands of counterfeit Ozempic 1 mg pens labeled with lot NAR0074 and serial number 430834149057. Its analysis found that the needles were counterfeit, which meant their sterility could not be confirmed, and that the pen label, carton, and patient leaflet were fake as well. In April 2025, Novo Nordisk told the FDA that several hundred counterfeit Ozempic 1 mg pens were in U.S. distribution, labeled with the real lot number PAR0362 and a serial number starting with 51746517. In December 2025, the FDA reported seizing dozens more that carried another genuine lot number, PAR1229, and that could be identified by where the "EXP/LOT" text sat on the pen label: to the left of the date and lot number instead of above them. In both 2025 cases, the FDA said the fakes had been distributed outside Novo Nordisk's authorized supply chain.

Worldwide: In June 2024, the WHO issued its first alert on falsified semaglutide, covering three fake Ozempic batches found in Brazil and the U.K. in October 2023 and in the U.S. in December 2023. All had entered the regulated supply chain. The WHO said its monitoring system had seen more reports of falsified semaglutide in every region since 2022.

United Kingdom: In February 2026, the MHRA warned that fake Mounjaro KwikPen 15 mg pens, labeled with batch D873576, had been supplied by The Private Pharmacy Clinic, an online pharmacy in Birmingham. D873576 is a real batch number, but only for the genuine 7.5 mg pen. Lilly, which alerted the regulator, had received five reports of faulty pens, and in all but one the dose knob came off during use. Testing found tirzepatide in the fakes, but the MHRA said it could not confirm they were sterile. The General Pharmaceutical Council, which regulates British pharmacies, placed conditions on the pharmacy, and the MHRA said it had no reports of patients needing treatment.

A counterfeit can contain the wrong drug, the right drug at the wrong strength, or the right drug made without sterility controls, and the documented cases include all three.

The wrong drug: In October 2023, Austria's medicines regulator (the BASG) reported that several patients were hospitalized after using suspected fake Ozempic 1 mg pens. The reported low blood sugar and seizures, it said, suggested the pens contained insulin instead of semaglutide. Austrian police traced that batch to a physician, not a pharmacy. The WHO has also warned that falsified semaglutide pens may contain an undeclared drug such as insulin. Insulin lowers blood sugar directly, so someone who injects it without knowing can be caught off guard by a dangerous low.

The right drug at the wrong strength: In a study published in JAMA Network Open in August 2024, researchers from the University of Pécs in Hungary and the University of California San Diego ordered semaglutide from six websites that verification services flagged as illegal or unsafe. All three products that arrived contained semaglutide, but at 7% to 14% purity rather than the advertised 99%, and with 29% to 39% more drug than the label stated. One sample had raised levels of endotoxin, a bacterial toxin, though no live bacteria grew.

The right drug made unsafely: The fake Mounjaro pens in the U.K. contained tirzepatide, but no one could vouch for how they were made, and the fake U.S. Ozempic pens came with counterfeit needles of unknown sterility. With any injected product, poor manufacturing raises the risk of infection and allergic reactions.

For most of the U.S. seizures, the FDA did not publish what the pens contained. Its 2025 notices said testing was underway.

Illegal online pharmacies: In the 2024 JAMA Network Open study, a search for semaglutide turned up 317 online pharmacy links, and 134 of them belonged to illegal operations. None of the six test sellers asked for a prescription. The three that advertised Ozempic pens never shipped anything. Instead, they demanded $650 to $1,200 more to "clear customs," which customs agencies confirmed was a scam. The illegal market keeps growing: on November 5, 2026, NL Times reported that RTL Nieuws had found 203 illegal Dutch-language shops selling tirzepatide, semaglutide, and retatrutide. More than half were under six months old, and none were on the Dutch register of authorized online pharmacies.

Social media: Lilly has said it never sells genuine Mounjaro or Zepbound through social media, so a pen offered in a direct message or a social media shop is not the real thing.

Clinics and individuals outside pharmacies: The Austrian insulin case came through a physician, not a pharmacy. Lilly and Novo Nordisk have both sued med spas and wellness centers over knockoff versions of their drugs, Good Morning America reported in June 2024.

Bulk shipments: In a weeklong operation announced in August 2025, U.S. Customs and Border Protection and the FDA seized 54,843 counterfeit products at the Port of Cincinnati, including 16,740 prefilled pens, Newsweek reported. On October 31, 2026, Thai customs seized 8,900 unregistered GLP-1 pens from a passenger's two suitcases at Suvarnabhumi Airport in Bangkok. Dutch customs told the broadcaster BNR it had stopped hundreds of peptide shipments through September 2026, most of them arriving by courier, and BNR reported that the illegal Dutch shops are mainly supplied from China.

Because most illegal sites are run from abroad by anonymous operators, regulators struggle to shut them down, and the U.K. has turned to blocking orders, which are court orders that require internet service providers (ISPs) to stop their customers from reaching a website.

In a 2026 judgment, Novo Nordisk v. British Telecommunications, the High Court ordered major U.K. ISPs to block four websites selling counterfeit and unlicensed semaglutide and other prescription drugs. It was the first such order for medicines. According to the law firm Mishcon de Reya's summary, the MHRA had tried and failed to take the sites down before asking Novo Nordisk for help. On June 23, 2026, the court added seven more websites. It also let Novo Nordisk add new sites that meet confidential criteria without returning to court, because operators had set up copy ("mirror") sites to dodge the first order. Evidence before the court pointed to more than 130 further websites selling counterfeit or unlicensed medicines to U.K. buyers.

Lilly filed its own case in the English High Court that became public on November 5, 2026, naming BT, EE, Plusnet, Sky, TalkTalk, and Virgin Media as defendants, City AM reported. Lilly told the paper it was acting to block black-market sites selling fake versions of its medicines.

In the U.S., the Patent and Trademark Office is asking companies for ideas for a national campaign about counterfeit medicines that could recruit influencers and celebrities, Newsweek reported on November 5, 2026. The notice is market research, not a contract, and responses are due November 16.

The FDA's BeSafeRx program lists four signs of a safe online pharmacy: it always requires a prescription from your doctor, gives a physical address and telephone number in the United States, has a licensed pharmacist available to answer questions, and is licensed by a state board of pharmacy. BeSafeRx also links to each state's license lookup, so you can confirm the license yourself instead of trusting a logo on the website.

The FDA's warning signs are the reverse of that list. A site may be unsafe if it does not require a prescription, is not licensed in the United States, has no pharmacist to answer questions, or offers discounts that seem too good to be true. Medicine that looks different from what your local pharmacy dispenses, or that arrives damaged, labeled in a foreign language, or without an expiration date, is another warning sign.

In the U.K., pharmacies must be registered with the General Pharmaceutical Council. The Birmingham case shows that registration is not a guarantee, since the fake Mounjaro came through a registered online pharmacy, but a registered pharmacy can be traced, inspected, and sanctioned in a way that an anonymous website cannot.

Many legitimate telehealth services in the U.S. send prescriptions for brand-name pens to the manufacturers' own pharmacies or to licensed pharmacies. Our telehealth landscape guide covers those options. A site offering brand-name Ozempic or Mounjaro with no prescription is not one of them.

No home check can prove that a pen is genuine, but the following steps would have caught the fakes that regulators have described so far:

• Match the lot number to published alerts: Compare the lot and serial numbers on the carton and the pen with FDA, MHRA, or WHO alerts. Because several fakes have used real lot numbers, a match to a known fake tells you more than a lot number that merely looks normal.
• Check that the lot fits the strength: The fake U.K. Mounjaro carried a batch number that belongs to the genuine 7.5 mg pen, printed on a 15 mg pen.
• Look closely at the label and carton: The WHO listed spelling mistakes on the carton, labels that are poorly printed or peeling, and a dose scale that sticks out of the pen while the dose is being set. The FDA's December 2025 fakes printed the \"EXP/LOT\" text in the wrong place on the pen label.
• Compare it with your last refill: If the pen, the needle, the color of the liquid, or the packaging looks different from what your pharmacy usually dispenses, ask the pharmacist before you use it.
• Treat faults as a warning: A dose knob that comes off, or a pen that will not deliver a dose properly, is a reason to stop, and the MHRA advises patients not to try drawing medicine out of a faulty pen.
• Call the manufacturer: Novo Nordisk's customer care line is 1-800-727-6500 (weekdays, 8:30 a.m. to 6 p.m. Eastern), and Lilly's is 1-800-LillyRx (1-800-545-5979).

Buying from a licensed pharmacy is still the best protection, and when fakes have reached the regular supply chain, regulators have published the lot numbers so that pharmacies and patients can check their stock.

Stop using the pen, but keep it in a safe place along with its carton, because regulators and manufacturers need the product itself to test what was inside.

Watch for the problems that the documented fakes have caused:

• Low blood sugar, which an insulin-filled pen could cause, shows up as shakiness, sweating, a fast heartbeat, confusion, or unusual drowsiness. Eat or drink something with sugar if you can, and call 911 if symptoms are severe, if the person cannot swallow safely, or if there is a seizure.
• Infection, either at the injection site or throughout the body, can cause spreading redness, swelling, warmth, fever, or chills.
• An allergic reaction can cause a rash, itching, swelling of the face or throat, or trouble breathing.
• Side effects that are much stronger than usual, such as heavy vomiting, could mean the pen held more drug than its label said. Our guide to GLP-1 dosing errors explains what to expect and when to get care.

In the U.S., Poison Help (1-800-222-1222) answers around the clock and can advise on symptoms. Tell your prescriber and pharmacist what happened, report any side effects to the FDA through MedWatch, and report the seller through the FDA's online form for unlawful sales. In the U.K., report a suspected fake or a side effect through the MHRA's Yellow Card scheme.