Eli Lilly (LLY) has filed lawsuits against six US companies it accuses of selling illegal versions of its experimental weight-loss drug retatrutide.
The Indianapolis drugmaker is targeting California’s Aesthetic Envy Cosmetic Centers alongside five Texas-based firms: Astra, Striker, Lone Star Peptide, Legendary Peptides and Texas Peptides.
The lawsuits cover compounding pharmacies, medical spas and online sellers that claim their knockoff products are for “research-use only” while selling them for human use.
Retatrutide remains in Phase 3 clinical trials for obesity, type 2 diabetes and other related conditions, and no regulators have approved it for human use.
Federal law prohibits the commercial sale of unapproved drugs, but telehealth firms, clinics and online peptide vendors have pressed ahead regardless.
Promising results from Lilly’s clinical trials have fuelled a social media craze for the next-generation drug, driving demand through unregulated and illegal channels.
Some sellers have marketed retatrutide through websites, social media posts and businesses presenting themselves as legitimate medical providers, despite sourcing products from unregulated manufacturers.
“What is being sold on the black market is not a medicine — it is entirely unverified, unapproved and not worth the risk,” said Lilly Chief Medical Officer Dr. David Hyman.
Lilly said it has already reported more than 200 entities engaged in the illegal market to the FDA, the Department of Justice, state attorneys general, law enforcement and professional licensing boards.
The company has also reported more than 14,000 websites, advertisements, social media posts and product listings that unlawfully market retatrutide across more than 100 countries to internet service providers, platforms and e-commerce companies.
“This is a global problem and it’s an enormous one,” said Max Denning, an associate vice president at Eli Lilly, calling on regulators, social media companies, payment processors and others to help stem illicit sales.
Lilly is urging social media platforms, credit card companies, payment processors and logistics carriers to join its efforts to protect patients from the illegal market.
The FDA had warned healthcare professionals about the illegality of compounded retatrutide as early as March 2025, with further guidance issued by June of that year.
These latest lawsuits mirror legal action Lilly previously took in 2023, when it sued eight companies across five states for producing or selling compounded versions of its weight-loss drug Mounjaro.
Lilly followed those initial filings with further lawsuits against six additional companies for false advertising less than a year later, demonstrating an increasingly aggressive enforcement posture.
The company plans to file for regulatory approval of retatrutide early next year, after the compound delivered up to 29% weight loss in Phase 3 trial results.