The drug still hasn't been reviewed by the Food and Drug Administration

Eli Lilly has sued six companies, saying they are illegally selling versions of the unapproved weight-loss drug retatrutide.

Eli Lilly is suing six pharmacies alleging that they are selling illegal versions of retatrutide, its still-experimental but highly anticipated weight-loss shot.

The American drug giant is expected to send retatrutide to U.S. regulators early next year, with a Food and Drug Administration decision anticipated in 2027 or early 2028.

The drug, a once-weekly shot that combines GLP-1, GIP and glucagon, is the most effective yet, helping people lose up to 28% of their body weight in clinical trials. It is expected to be a massive hit for Lilly $(LLY)$, which already dominates the GLP-1 market for weight loss, and could bring in $5.3 billion in sales by 2030, according to the FactSet-compiled consensus. If approved, retatrutide will be the first weight-loss drug that includes glucagon.

But Americans don't want to wait, and some have turned to an active black market in which medical spas and pharmacies that produce other popular peptides for health and wellness also sell compounded versions of retatrutide. In other instances, people order raw ingredients classified as being for research only, often from labs in China, and mix them at home.

Retatrutide, which is a peptide like most GLP-1-based drugs, is commonly referred to as "reta" or "ratatouille" online. It's being tested as a treatment for Type 2 diabetes and chronic low-back pain.

"What is being sold on the black market is not a medicine - it is entirely unverified, unapproved and not worth the risk," David Hyman, Lilly's chief medical officer, said in a news release.

The company is also asking platforms like social-media companies, payment processors and credit-card companies, and shipping services to step in. The lawsuits were filed against Aesthetic Envy, Astra Peptides, Legendary Peptides, Striker Pharmacy, Texas Peptides and Lone Star Peptide.

Lilly and Novo Nordisk (DK:NOVO.B) (NVO), the other leading developer of GLP-1 drugs for weight loss, have both had issues with compounding pharmacies taking market share by legally making their drugs when they were in short supply or illegally when they weren't. Earlier this year, Novo sued Hims & Hers Health $(HIMS)$ after that company launched a compounded version of the Wegovy pill within weeks of its launch by Novo. Novo and Hims & Hers have since ended their dispute and now work together.

-Jaimy Lee