Start with the lot number and the label layout. FDA has flagged three counterfeit lots of Ozempic 1 mg in the U.S. supply chain: NAR0074, PAR0362 and PAR1229 [1]. The December 2023 seizure ran to thousands of units. PAR1229 is also an authentic lot, so the tell is on the pen itself. Counterfeit labels print “EXP/LOT” to the left of the date and lot number, while authentic ones print it above.
A pen that passes those checks is not proven genuine, because they only catch fakes FDA has already described. The safer rule concerns the source, and it is set out in the three gates an online GLP-1 seller should pass.
The three FDA alerts, by date
December 21, 2023: FDA had seized thousands of units of counterfeit Ozempic 1 mg [1]. It named lot NAR0074 with serial number 430834149057. The needles were counterfeit, so their sterility could not be confirmed and the infection risk was higher.
That alert also listed the pen label, the patient and professional information, and the carton as confirmed counterfeit components [1]. FDA knew of five adverse events from that lot, and none was serious.
April 14, 2025: Novo Nordisk told FDA of several hundred counterfeit units on April 3 [1]. FDA seized them on April 9, and the alert named lot PAR0362 with serial numbers starting 51746517.
December 5, 2025: FDA had seized dozens of units labeled lot PAR1229 [1]. That number also appears on authentic pens. The counterfeit prints the “EXP/LOT” text on the left side of the expiration date and lot number.
FDA says pens from lot PAR1229 received through Novo Nordisk’s Patient Assistance Program are authentic [1]. Testing of the seized product was still under way when that alert was posted.
What to check on a pen or package
Each check below is a condition, and a product that fails any one of them should not be injected.
The form must match the label. Ozempic injection is supplied as multi-dose pens and single-dose prefilled syringes [3]. A vial labeled Ozempic is not a listed presentation on that label.
The solution must be clear and colorless. The label says not to use Ozempic if particles or coloration are seen [3].
The lot and serial must not match an FDA alert. The layout test applies to lot PAR1229. Pharmacists can confirm a batch with Novo Nordisk customer care at 1-800-727-6500 [1].
The package must look like earlier fills. FDA lists medicine that looks different from before, or arrives broken or without instructions, as a warning sign [2]. So is a label with spelling errors or a wrong pharmacy address.
What fake semaglutide has contained
The harm on record is not only a weak dose. In Italy, a 31-year-old woman was admitted in a hypoglycemic coma after injecting “Ozempic” bought from a website [4]. Toxicology found insulin in the vial instead of semaglutide.
Two Dutch cases followed the same pattern [5]. Neither patient had diabetes or obesity, and both had obtained semaglutide without a prescription. Both arrived in a coma with severe hypoglycemia, caused by synthetic insulin. Up to two days of continuous glucose infusion was needed.
Semaglutide alone does not cause significant hypoglycemia in healthy people, the Dutch authors note [5]. A low blood sugar after an injection sold as semaglutide is therefore a sign that something else was in it.
What the European reports add
A study searched the EU’s pharmacovigilance database from 2018 through 2025 [6]. It found 234 reports tied to potential counterfeit semaglutide, and 89.3% of the suspected reactions were serious.
Vomiting, nausea and hypoglycemia were reported most often [6]. Against genuine semaglutide, the potential fakes carried higher reporting of hypoglycemia and of “drug ineffective”. Those are signals from voluntary reports, not measured rates.
Where the risk sits
FDA separates counterfeits from a second problem [2]. Some compounded semaglutide and tirzepatide carries a label naming a pharmacy that does not exist. Other labels name a licensed pharmacy that did not make the product.
FDA’s standing advice is to fill a prescription at a state-licensed pharmacy [2]. The measured risks of buying online are set out in whether it is safe to buy semaglutide online. What arrived from no-prescription sites is in whether semaglutide can be bought without a prescription.
A suspected fake should be kept, not injected, and reported to FDA’s MedWatch program [1]. The adverse-event reporting behind compounded products is described in the FAERS analysis of compounded GLP-1 reports.