In an open letter to the public, Lilly decries use of tirzepatide products Mounjaro and Zepbound for nonmedical purposes and warns of counterfeit formulations.
“Lilly stands against use of its medicines for cosmetic weight loss,” the company stated in an open letter to the public released online late Thursday afternoon referring to the 2 formulations of its dual incretin mimetic tirzepatide, marketed as Zepbound for chronic weight management and as Mounjaro to reduce hyperglycemia in persons with type 2 diabetes (T2D).1
The drugs “are indicated for the treatment of serious diseases; they are not approved for – and should not be used for – cosmetic weight loss,” the statement continued. “Lilly does not promote or encourage use of Mounjaro, Zepbound, or any Lilly medicines outside of a medicine’s FDA-approved indication.”
The company detailed the indications specified in the approved FDA labeling for both drugs and also warned the public about the circulation of counterfeit and compounded tirzepatide.
“Patient safety is Lilly’s top priority, and we actively engage in monitoring, evaluating and reporting safety information for all our medicines,” the letter stated. “We are aware of certain practices relating to our tirzepatide medicines that we wish to address publicly to ensure that our medicines are prescribed and used safely.”
As reported on Patient Care, the FDA approved tirzepatide as an adjunct to diet and exercise to improve glucose control in adults with type 2 diabetes, in May 2022, as Mounjaro, and for chronic weight management in addition to a reduced-calorie diet and increased physical activity among adults with obesity or overweight with one weight-related comorbidity (eg, hypertension, what else), in November 2023.
The 2 Lilly drugs entered both medical and consumer markets primed by previous FDA approvals of the Novo Nordisk incretin mimetic semaglutide for the same 2 diseases. Semaglutide for adults with T2D is marketed as Ozempic and for adults and with overweight or obesity as Wegovy. Initial reports of the significant weight loss that accompanied improvement in symptoms of T2D with Ozempic triggered an outsized media response that continues around all 4 drugs, driving off-label prescribing for cosmetic weight loss and nationwide shortages, making it more difficult for those with both diseases to obtain them.
The demand, driven in large part by viral online promotion by celebrities and social media influencers, has also led to an illegal market of counterfeit products including potentially dangerous formulations prepared by compounding pharmacies. The company states it has found “high amounts of impurities” in compounded tirzepatide samples it has tested including one instance where the product was “nothing more than sugar alcohol.” “Tirzepatide products not manufactured by Lilly may expose patients to potentially serious health risks,” the letter warned.
The company also said it is currently engaged in legal action against actors including medical spas, wellness centers, and compounding pharmacies making or selling products that claim to contain the active ingredient for tirzepatide as well as against organizations that import or distribute the products.
Lilly’s concern follows by less than a month an FDA drug safety alert about reports of adverse events following use of compounded semaglutide (Ozempic, Wegovy), a communication that reviews previous steps FDA had taken on the matter in April and October 2023.2
The Lilly letter urges anyone who suspects they may have purchased or used counterfeit or compounded tirzepatide to contact their health care professional to discuss further action.1
The company advises health care professionals to review the Instructions for Use for both Mounjaro and Zepbound and consider carefully the information on risks associated with tirzepatide detailed in the Full Prescribing Information and Medication Guide for both products. The drugs should only be prescribed by a licensed health care professional and use should be discussed in a clinician-patient consultation to determine the patient’s eligibility for either formulation. The letter also cautions that Mounjaro and Zepbound have not been evaluated in individuals with severe gastrointestinal disease, including severe gastroparesis, and so should not be recommended for same.