Two deaths have been reported to the US Food and Drug Administration after patients took products sold as bootleg retatrutide, an experimental weight-loss drug being developed by Eli Lilly.
The reports do not establish that retatrutide caused either death, and the information has not been independently verified. However, they highlight the risks associated with an expanding illicit market for products that are not approved for general use.
Retatrutide has not been approved by the FDA and is generally intended to be available only as part of a formal clinical trial. Federal law prohibits the commercial sale of unapproved medicines, yet products claiming to contain the drug have been marketed online and through health and wellness businesses.
Reports of cardiac arrests
In the first case, reported in July, a healthcare professional told the FDA that a 41-year-old woman with obesity had suffered a cardiac arrest after obtaining retatrutide “from an unreliable source”. The report listed the product as a suspected cause and said she died after attempts to resuscitate her failed.
The woman was described as apparently otherwise healthy. The report also said she had been drinking kava, a plant-based drink associated with relaxing effects, when the medical emergency occurred.
A second report, received by the FDA in September, concerned a 49-year-old patient who allegedly bought retatrutide after a registered nurse provided a link to an online peptide vendor, sold her vials and recommended doses.
The patient reportedly suffered severe dehydration and malnutrition before experiencing cardiac arrest and dying. The nurse’s name, location and licence number were redacted from the document.
Both reports were submitted to the FDA’s Adverse Event Reporting System, which is used to monitor the safety of approved medicines. Neither death was connected to a formal clinical trial, according to the documents and Eli Lilly.
The FDA declined to say whether it had verified the information. In a statement, the agency said: “We review adverse event reports, gathering additional information when needed,” adding that it “generally does not discuss potential or ongoing compliance matters”.
Concerns over black-market retatrutide
Pieter Cohen, an associate professor at Harvard Medical School, said the reports were concerning because of “the breakdown of our drug-approval process in the United States of America”.
“The FDA should do whatever it possibly could do to get their hands on the actual drug that was injected by both of these patients, and they should get that analyzed,” he said. “If the FDA is not aggressively investigating these cases, that’s deeply concerning.”
America’s Poison Centers recorded 862 reported exposures to retatrutide in the three months ending in September. That compared with 460 in the previous three months and 249 in the first three months of 2026.
In clinical trials, retatrutide has helped participants lose more weight than some of the most effective weight-loss drugs currently on the market. The results have fuelled interest in the medicine, although it remains unapproved.
Eli Lilly said the reported deaths showed that the patients had been taking “black-market retatrutide”. The company said it had found suspect products containing too much, too little or the wrong active ingredient, as well as contaminants that could put patients at serious risk.
The company is taking legal action against businesses selling unauthorised versions of retatrutide, saying adverse reactions to those products could be associated with its future medicines.
One of the FDA reports included an image of a vial bearing the name AlphaLabs, a business that advertises peptides for research use only. Its owner, Joseph Samara, initially said the company did not sell retatrutide.
Lawyer Sinead Killeen later said there was insufficient information in the redacted report to establish whether Alpha Labs had supplied the product. She said the vial shown did not match the company’s current packaging and that the business had not been contacted by the FDA.
“A licensed healthcare professional should never recommend research-use-only products to a patient, provide dosing instructions for them, administer them, or sell them,” Ms Killeen said.
