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Lilly Finds Bacteria, Other Impurities in Mounjaro, Zepbound Knockoffs

Lilly Finds Bacteria, Other Impurities in Mounjaro, Zepbound Knockoffs

With the increasing popularity of Indianapolis-based drugmaker Eli Lilly’s blockbuster diabetes medication Mounjaro and weight loss counterpart Zepbound, unauthorized, counterfeit medications continue to emerge, posing a growing safety concern. In an updated open letter addressing the public, the pharmaceutical company expressed deep concern over fake products that fraudulently claim to be original, FDA-approved tirzepatide medicines. Lilly stated that it does not sell any product referred to simply as tirzepatide (the active ingredient present in Zepbound and Mounjaro). 

The United States allows licensed pharmacies to produce compounded drugs legally when the branded version of a drug is in short supply. However, the company reiterated that it does not provide the active ingredient to any compounding pharmacies. The company said that it would continue to aggressively pursue legal actions against individuals who falsely claim to sell Zepbound, Mounjaro 2.5mg or FDA-approved tirzepatide medications.

Key Background 

In June, Novo Nordisk reported the discovery of a counterfeit Ozempic pen in a US pharmacy, which resulted in an adverse reaction in a patient. In October, Eli Lilly initiated legal action against 11 online pharmacies for the importation and sale of counterfeit tirzepatide medications. The widespread shortages of Wegovy, Ozempic, and Mounjaro may have contributed to the proliferation of counterfeit products. To address this issue, Novo Nordisk restricted Wegovy’s supply in May, leading to difficulties for some patients in filling their prescriptions. 

As a result of these shortages, some compounding pharmacies, weight loss centers, medical spas, and wellness clinics have resorted to producing compounded versions of these drugs, which are not approved by the FDA and may pose health risks. Drug compounding involves altering or combining a drug’s ingredients to tailor it to a patient’s specific needs. In the case of Ozempic and Wegovy, compounders incorporate a hazardous salt form of semaglutide into the injections. Consequently, Novo Nordisk took legal action in June against clinics and pharmacies that were selling compounded versions of semaglutide products.

Lawsuits Filed By Lilly against Fraud Companies 

As per reports of Reuters, Lilly said in a statement that it was suing 10 US wellness centers, medical spas and compounding pharmacies for selling fake products claiming to contain the active ingredient tirzepatide, which is used in Mounjaro and Zepbound. The drugmaker company is seeking orders prohibiting ReviveRX, Better Life Pharmacy, Wells Pharmacy Network and Rx Compound Store from selling tirzepatide. It also seeks damages against six wellness centers and medical spas from federal courts in Arizona, Georgia, Florida, Minnesota, Utah and South Carolina, accusing them of violating its trademark by advertising compounded tirzepatide as Mounjaro injection

The legal action follows a similar move by Novo Nordisk against entities selling counterfeit versions of its obesity treatment, Wegovy. The FDA has previously warned about the safety risks of using compounded versions of popular weight-loss drugs like Wegovy and Ozempic. Analysts predict that the market for weight-loss treatments like Wegovy and Mounjaro could reach $100 billion annually within a decade, with Lilly’s product potentially accounting for over half of those sales.

Counterfeit Zepbound and Mounjaro Found to Have Bacteria and High Levels of Impurities

On March 7th, 2024, Lilly targeted pharmacies and medical spas selling fake products. The US drug-making company took legal action against four medical spas, weight-loss clinics, and four compounding clinics to stop them from selling scam products containing tirzepatide. Compounded drugs are specially formulated medications that share the same ingredients as their branded counterparts. They are frequently less expensive but also come under less regulatory scrutiny. 

In an open letter, Lilly said some of these products had a different color and a different chemical structure. Lilly discovered compounded and counterfeit versions of its well-known tirzepatide medications that differ from the approved versions of Zepbound or Mounjaro in that they contain bacteria, distinct chemical structures and other concerning features. Additionally, Lilly stated, “In at least one instance, the product was nothing more than sugar alcohol.” A request for comment was not immediately answered by the Alliance for Pharmacy Compounding, which is the representative organization for compounding pharmacists and technicians. 

Safety Risks of Using Compounded or Counterfeit Tirzepatide

Lilly advises against the use of compounded or counterfeit tirzepatide products, as they may contain harmful substances posing significant health risks. The company emphasizes that it does not supply tirzepatide active pharmaceutical ingredient (API) to compounding pharmacies. Lilly’s diabetes and weight loss drugs, Mounjaro and Zepbound, are exclusively manufactured and distributed by Lilly. The company also highlights that medications labeled only as “tirzepatide” are not FDA-approved products. Lilly is actively pursuing legal action against entities making false claims about selling Zepbound, Mounjaro, or FDA-approved tirzepatide medications. Patients who suspect they may have obtained or used counterfeit or compounded tirzepatide are urged to consult a healthcare professional to address their concerns.

How do you Spot Fake Mounjaro and Zepbound Injections? 

To ensure your safety and protect your health, it is crucial to spot fake Mounjaro and Zepbound Injectable pens. To verify that your pens are legitimate and reduce the risk of using counterfeit Mounjaro and Zepbound injections, you can follow the tips given below: 

  • Check the packaging box: The Packaging of fake products may be different from the original packaging. Genuine pens come in professionally sealed packaging with clear labeling. Counterfeit pens may have a poor-quality label that doesn’t stick well to the product. 
  • Buy from trusted sources: Buy your medications only from reputable pharmacies or authorized healthcare providers. If you are looking to buy Mounjaro and Zepbound from the best Canadian online pharmacy, head to Polar Bear Meds. 
  • Examine the product: Check your injection for any discoloration or particles. Authentic injections have a consistent appearance. Don’t use the product if there is any unusual change in appearance, as it is suspected to be fake. 
  • Look for FDA approval: Ensure that the injection has an FDA-approval label. If the label is referred to as “generic Mounjaro” or “generic tirzepatide,” it’s not real Mounjaro.
  • Check the expiration date: Always ensure that the medication you are using is not outdated and was properly stored. 

If you are still uncertain about the authenticity of your Mounjaro or Wegovy pens, do not use the injection. Call your doctor or pharmacist to spot the fake products. You can also check on the manufacturer’s website to ensure the product you are using is not counterfeit. 


As the market for weight-loss treatments continues to grow, it is crucial to remain vigilant and informed to protect your health and well-being. Eli Lilly has raised concerns about the safety risks associated with counterfeit versions of its popular diabetes and weight-loss medications, Mounjaro and Zepbound. Counterfeit products have been found to contain harmful substances, including bacteria, high levels of impurities, and different chemical structures, posing significant health hazards to consumers. Lilly emphasizes the importance of purchasing medications from reputable sources and advises patients to consult healthcare professionals if they suspect they have used counterfeit or compounded tirzepatide products.

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