Lilly tells the public its tirzepatide drugs are not for cosmetic weight loss

Eli Lilly published an open letter on January 4, 2024 saying its tirzepatide medicines, Mounjaro and Zepbound, are not approved for and should not be used for cosmetic weight loss ^[1][2]. The company said it "does not promote or encourage use of Mounjaro, Zepbound, or any Lilly medicines outside of a medicine's FDA-approved indication" ^[2].

What the labels cover

Mounjaro is indicated to be added to diet and exercise to improve blood sugar control in adults with type 2 diabetes ^[1][2]. Zepbound is indicated for adults with obesity, defined as a body mass index of 30 kg/m2 or greater, or adults who are overweight with a BMI of 27 kg/m2 or greater and at least one weight-related condition ^[2]. Those conditions can include hypertension, dyslipidemia, type 2 diabetes, obstructive sleep apnea or cardiovascular disease, and Zepbound is meant to be used with a reduced-calorie diet and increased physical activity ^[2].

Lilly said neither drug has been studied in people with severe gastrointestinal disease, including severe gastroparesis, and is therefore not recommended in those patients ^[1][2]. The drugs should only be prescribed by licensed health care professionals, the company said ^[1][2].

"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," the letter states. "Mounjaro and Zepbound are indicated for the treatment of serious diseases; they are not approved for – and should not be used for – cosmetic weight loss" ^[2].

Compounded and counterfeit products

Much of the letter dealt with tirzepatide that Lilly did not make. Products claiming to contain tirzepatide, Mounjaro or Zepbound that are made or distributed by compounding pharmacies have not been reviewed by the FDA or global regulators for safety, quality or efficacy, the company said ^[1][2]. Lilly said testing found compounded tirzepatide with higher amounts of impurities, and that in at least one instance the product was just sugar alcohol ^[2].

In October 2023, Lilly filed a complaint with the US International Trade Commission against 11 online pharmacies, seeking to stop them from importing, selling or distributing products containing tirzepatide ^[1]. Lilly said it would also seek legal action against medical spas, wellness centers, compounding pharmacies, importers and distributors ^[2]. Lilly said it is the only drugmaker authorized by the FDA to sell tirzepatide ^[1].

Fake versions of other GLP-1 drugs have also caused harm. In October 2023, several people were hospitalized in Austria after taking a suspected counterfeit of Novo Nordisk's Ozempic; reports said the patients had hypoglycemia and seizures, effects that indicated the product contained insulin rather than semaglutide ^[1]. Novo Nordisk warned in June 2023 about a counterfeit Ozempic pen found in the US ^[1][2].

Why it matters for patients

The letter sets out who the tirzepatide drugs were studied in, and notes that people outside those groups are outside the tested population. It also means the supply chain matters: compounded and counterfeit products are not FDA-approved, and Lilly said their safety or efficacy cannot be assured ^[1][2]. Lilly said patients who are concerned they may have received compounded or counterfeit tirzepatide should contact their health care provider, and that reports can be made to the Lilly Answers Center at 1-800-LillyRx (1-800-545-5979) ^[1].

Clinicians have also pointed to cultural pressure around these medicines. Jennifer Salvon, RPh, a clinical pharmacist and adjunct professor at the University of Connecticut School of Pharmacy, told Pharmacy Times that media coverage and social media can shape how the drugs are seen, especially by younger children ^[2]. She cited an article about Kim Kardashian, who "took semaglutide and lost a bunch of weight to fit in Marilyn Monroe's dress," adding, "That's not good for young [children] to see" ^[2].

Use of anti-obesity medicines has risen by about 300% over the past three years, according to Pharmacy Times, while coverage of the drugs remains limited because obesity is not labeled a chronic disease for insurance purposes ^[2]. Presenters at a 2023 conference described obesity as a chronic disease involving dysregulated adipose tissue, with genetic risk estimated at 70% ^[2].

What happens next

The outcome of Lilly's International Trade Commission complaint and its other legal actions has not been reported ^[1][2]. Lilly has not said how it will measure whether the open letter changes prescribing or use.