Lilly fighting black market for its next obesity drug

Eli Lilly and Co.’s next weight-loss medication is not available. It has not been submitted for regulatory approval. It has not even completed late-stage clinical trials.

But if you search “reta” or “retatrutide” on Instagram or TikTok, you will find yourself swimming through a sea of videos by biohackers, bodybuilders and wellness coaches extolling its virtues.

Retatrutide, an experimental injectable medication that has helped clinical trial participants lose more weight than any previous obesity medication, has a booming black market. Medical spas and online retailers sell products often sourced from China, while some dealers find buyers through chat groups on apps like Telegram and WhatsApp.

Retatrutide is still in Phase 3 trials. Lilly plans to file for approval in the first quarter of 2027. However, black markets for unapproved pharmaceutical products can form when compounders use ingredients listed on publicly available patent documents.

Demand for black-market retatrutide is so high that Indianapolis-based Lilly is taking steps to reclaim control of the situation. Experts say the action is imperative in order to prevent a potential blockbuster medication’s reputation from being soiled before it becomes available for sale.

The booming black market “is a harbinger of trouble,” said George Ball, associate professor of operations and decision technologies at Indiana University’s Kelley School of Business in Bloomington. “If they’re facing this before it’s even approved, that’s pretty remarkable.”

On Aug. 12, Lilly filed the first six lawsuits in its battle against the retatrutide black market. The company used the same strategy last year when it sued two compounding pharmacies and four telehealth companies over compounded versions of tirzepatide, the active ingredient in Lilly’s FDA-approved obesity drug Zepbound and Type 2 diabetes medication Mounjaro.

The new complaints target suburban Houston-based compounding pharmacy Striker Pharmacy; Sacramento, California-based medical spa chain Aesthetic Envy; and online Texas sellers Astra Peptides, based in Austin; Texas Peptides and Lone Star Peptide Co., both based in Houston; and Legendary Peptides, based in Lumberton.

While those companies’ websites say the product is “for research use only,” the Lone Star complaint, for example, says the website provides a “Retatrutide Dosage Calculator” with instructions that say, “Enter the vial strength, the bacteriostatic water you added, and your target dose.”

“And despite the pretext Lone Star uses, the substance it sells is not a chemical intended for research use but instead a drug it intends and sells for human use—making Lone Star’s product an illegal drug,” the complaint says. “Retatrutide cannot legally be sold for human use to anyone, anywhere, for any reason.”

Legendary Peptides declined to comment on Lilly’s lawsuit. Four of the other businesses did not respond to requests for comment from IBJ. An email sent to Astra was returned as undeliverable.

“Retatrutide is being rigorously studied as part of a comprehensive clinical trial development program,” Lilly Chief Medical Officer Dr. David Hyman said in an announcement of the lawsuits. “We take the responsibility of evaluating the safety and efficacy of our investigational medicines seriously. What is being sold on the black market is not a medicine — it is entirely unverified, unapproved and not worth the risk.”

Casting a wide net

In addition to the lawsuits, Lilly referred more than 200 people and entities to the U.S. Food and Drug Administration, U.S. Department of Justice, state attorneys general and law enforcement.

Lilly has reported more than 14,000 websites, advertisements, social media posts and product listings that market retatrutide in more than 100 countries.

Lilly also wants drug regulators, customs agencies, law enforcement, social media platforms, e-commerce platforms, credit card companies, shipping and logistics companies, health care providers and others to combat the illegal retatrutide market.

The FDA has warned telehealth companies, active pharmaceutical ingredient distributors and outsourcing facilities for their roles in compounding retatrutide, which the agency said is illegal.

However, Ball said the FDA needs to put more pressure on those who are producing and selling retatrutide.

“If I were Lilly, I would be not only chasing after every single one that pops up, but I would be lobbying or leveraging any influence I have on the legislatures to say, ‘Why is the FDA not helping us more?’” Ball said. “This is why they exist. This is their job. They should have entire divisions of people trying to find counterfeit weight-loss drugs and shutting those companies down quickly.”

Lilly spokesperson Jared Shapiro said online platforms need to do more to disrupt the retatrutide black market.

“Social media, e-commerce platforms, and other businesses must stop enabling and fueling this illegal market, and must take proactive steps to cut off the infrastructure enabling this illegal trade,” Shapiro said in an email. “While Lilly has reported thousands of websites, advertisements, social media posts and product listings, platforms are not doing enough to block this content and protect vulnerable users from the risks of black-market retatrutide.”

Powerful medicine

Retatrutide is a once-weekly injectable medication designed to target three hormone receptors that control appetite and metabolism: GLP-1, GIP and glucagon.

Lilly’s Zepbound targets GLP-1 and GIP, while Denmark-based Novo Nordisk’s Wegovy affects GLP-1. Neither targets glucagon. Lilly also produces the once-daily weight-loss pill Foundayo, which targets the GLP-1 receptor.

The results of a Phase 3 clinical trial released in May indicate retatrutide could be the most powerful obesity medication yet. In the study of 2,339 patients, people who took 12 milligrams of retatrutide lost an average of 70.3 pounds, or 28% of their body weight, after 80 weeks, according to Lilly. Nearly half of the patients in that group lost an average of 30% of their body weight. Additionally, people who took a 4 milligram dose lost an average of 47.2 pounds, and participants who took a 9 milligram dose lost an average of 64.4 pounds.

Participants in an extension study who had a body mass index of 35 or higher lost an average of 85 pounds, or 30.3% of body weight, after 104 weeks. Lilly reported that 11% of participants in the retatrutide trial stopped taking the medication because they felt they were losing too much weight.

Comparatively, patients who use Wegovy or Zepbound can lose up to about 20% of their body weight.

Shabbir Imber Safdar, executive director of the San Francisco-based Partnership for Safe Medicines, said weight-loss medications developed by Lilly and Novo represent a “once-in-a-generation event.”

“To say it’s life changing is probably not even a big enough statement. It’s generational in its consequence,” he said. “The entire food industry is having to realign its offerings to account for this.”

Safeguarding innovation

The Washington Poison Center has reported a growing number of calls related to illegal retatrutide, and Australian health authorities this summer reported six cases of liver toxicity in people who used the unapproved drug.

During clinical trials, about 11% of participants taking the highest dose of retatrutide discontinued treatment due to side effects, according to Lilly’s report in May. The most common side effects people reported in the trial were gastrointestinal problems, such as nausea, diarrhea, vomiting and constipation.

“Retatrutide is currently being rigorously studied as part of a comprehensive clinical trial development program and has not yet been approved by FDA or any other regulator,” Shapiro said. “Patients have reported serious harms after taking black-market retatrutide they purchased online, including hospitalizations.”

Additionally, a pre-print paper published in August by three Boston-area researchers says use of black-market versions of retatrutide is associated with lower weight loss and increased cardiovascular symptoms.

Ball said this could cause trust in Lilly’s retatrutide to erode by the time it receives approval and becomes available to patients.

“It’ll affect the quality of the reputation of the drug. It’s a lose-lose for them,” he said. “If it’s bad now before the drug is approved, it’ll get a lot worse once it’s approved.”

That is a sentiment put in writing in Lilly’s lawsuits.

“By the time Lilly brings its FDA-approved retatrutide product to market, [black-market producers and sellers] will have already conditioned the public to associate retatrutide as an ingredient with danger, illegality, and reduced or total lack of efficacy,” the complaints say. “Lilly will thus be forced to overcome not only the ordinary challenges of a new product launch, but the additional burden of rehabilitating a product that has been tarnished by [the companies’] unlawful conduct.”

Safdar said he fears black markets will threaten the ability of pharmaceutical companies to continue developing new medications. On average, it takes 10 to 15 years and costs $2.6 billion to develop a single FDA-approved medicine, according to Lilly.

He referred to the AIDS crisis of the 1980s and how it is now possible for people to take one pill a day or one shot every two months that makes HIV undetectable.

“You don’t get that kind of innovation if anyone can knock off your product before you even bring it to market,” Safdar said. “I think that’s a real risk. I fear that people won’t appreciate that until it’s too late.”