Eli Lilly Retatrutide: Who Makes It, Who Owns It and What Lilly Has Said

Eli Lilly and Company makes retatrutide. The Indianapolis drugmaker behind Mounjaro and Zepbound discovered it in its own labs under the code LY3437943, owns it, and is the lead sponsor on 32 of the 33 retatrutide studies listed on ClinicalTrials.gov. As of October 31, 2026, six of Lilly's Phase 3 retatrutide trials have reported positive results, but no approved version of Eli Lilly retatrutide exists yet, so Lilly doesn't sell it anywhere, LillyDirect included.

Who makes retatrutide?

Lilly's own FAQ answers it in four words: "Lilly is developing retatrutide." In the trial registry, none of the 33 retatrutide records on ClinicalTrials.gov lists a collaborator, and the Lilly releases we read name no licensing partner.

"Who makes it" hides a few separate questions, and they don't all have the same answer:

Lilly describes retatrutide as "an investigational once-weekly triple hormone receptor agonist," a single molecule that switches on the receptors for GIP, GLP-1 and glucagon. That's the "Lilly triple agonist" people search for. For what each of those receptors does, see how retatrutide works.

Who created retatrutide, and when?

The first full description came from Lilly's own scientists. Their paper in Cell Metabolism, published online August 18, 2022, introduced LY3437943 as "a novel triple agonist peptide" at the glucagon, GIP and GLP-1 receptors. All 20 authors list Eli Lilly as their employer: 19 at Lilly Corporate Center in Indianapolis and 1 in Vienna.

People were getting it years before that paper appeared. Lilly's first registered study in people, a single injection in healthy volunteers at the Lilly Centre for Clinical Pharmacology in Singapore (NCT03841630), started on March 13, 2019 and enrolled 45 people. A 12-week study in type 2 diabetes (NCT04143802) followed on December 18, 2019.

The big trial papers have outside lead authors. The Phase 2 obesity paper in the New England Journal of Medicine was led from Yale, with Lilly scientists among the co-authors, and it states plainly that it was "Funded by Eli Lilly." The first Phase 3 paper, TRANSCEND-T2D-1 in The Lancet, was led from a diabetes clinic in Ontario, Canada. TRIUMPH-1 (NEJM), TRIUMPH-2 (The Lancet) and their sleep apnea substudies (NEJM) followed in September and October 2026, and Lilly is the registered sponsor of every trial behind them.

How many Eli Lilly retatrutide trials are there?

We pulled every record that lists retatrutide as an intervention from the ClinicalTrials.gov API on October 31, 2026. There are 33, the same count as a month earlier, and Lilly is the lead sponsor on 32 of them:

Six of those Phase 3 studies have reported: TRIUMPH-1 to TRIUMPH-4, TRANSCEND-T2D-1 and, on October 28, TRANSCEND-T2D-2, which still shows as active; about 650 people are in a 24-week extension. Adding up Lilly's figures for each trial, 7,720 people were randomized across the six.

The odd one out, NCT07467447, is a Phase 2 study at one hospital in Shenzhen, China, sponsored by a company listed as Hudson Biotech. Its record names no Lilly role and doesn't say where its supply of the drug comes from.

Our read: when 32 of 33 registered studies carry Lilly's name and none lists a partner, the question of who makes retatrutide is settled. What's open is approval and price. The retatrutide clinical trials hub covers what each study is testing.

What Eli Lilly has said about retatrutide

Lilly's wording has hardened. Its December 2025 release had no legal-status line at all; every retatrutide release we read since March 2026 has one.

If you know it as GLP-3, that's a media nickname for the same Lilly molecule, not a brand. Our GLP-3 guide explains where it came from, and the brand name page covers the other names.

Does Lilly hold a patent on retatrutide?

Yes, as far as public records show. The Medicines Patent Pool, which negotiates voluntary licenses for low- and middle-income countries, reports that the primary retatrutide patent has been granted in at least 16 of those countries, including India, and is pending in 30 more. It expects the patent to expire in 2038, and its watchlist names Eli Lilly as the company behind retatrutide.

The US picture is harder to pin down. We couldn't confirm the US patent number or its expiry from a primary record, so we won't quote one. Nobody outside Lilly can say when a generic could reach US pharmacies. That turns on the US patents and on any FDA exclusivity, which can't start before approval.

Other companies have filed patent applications that name retatrutide, though not on the molecule itself. Google Patents shows at least two applications filed in China in December 2023 by other firms for ways to synthesize it (CN117903284A and CN117777248A). A process patent, if granted, lets its owner stop others copying a method. It doesn't let anyone sell retatrutide for people; that takes a regulator's approval, and none has been given.

Can you get Eli Lilly retatrutide through LillyDirect?

No. On October 31, 2026, LillyDirect listed 10 Lilly medicines: Zepbound, Mounjaro, Foundayo, Trulicity, Basaglar, Rezvoglar, Humalog, Humulin, Lyumjev and Emgality. Retatrutide isn't on the list, and Lilly's FAQ says "no one can legally sell it for human use."

That leaves two legal routes. One is a trial; our near me page lists recruiting sites. The other is Lilly's single-patient expanded access program (NCT07629401), which is narrow: adults with a BMI of 35 or more despite the highest available dose of weight treatment, at least 2 serious obesity-related complications, and no way into a trial. Your doctor applies, not you, through the Lilly Answers Center at 1-800-LillyRx (1-800-545-5979). How to get retatrutide walks through both.

If you want a Lilly weight medicine now, LillyDirect's self-pay prices as of October 2026 start at $299 a month for Zepbound 2.5 mg (KwikPen or vial) and $149 a month for Foundayo 0.8 mg. Those are approved drugs your doctor can prescribe today, and switching from tirzepatide covers a later move to retatrutide.

Who makes the retatrutide sold online?

Not Lilly. Its August 12, 2026 release says sellers are "selling illegal drugs, frequently made by unregulated foreign manufacturers," and Lilly says it has reported more than 14,000 listings in more than 100 countries. The FDA adds that retatrutide can't be used in compounding under federal law, so a pharmacy can't legally make it for you either. Whether retatrutide is legal where you live is covered country by country.

What's inside those vials is the real problem. In a September 2026 alert, Australia's Therapeutic Goods Administration said it tested a vial sold as retatrutide after a buyer needed hospital treatment for uncontrollable vomiting and a torn esophagus. It held no retatrutide, and it held semaglutide at about 8 times the level in approved semaglutide products. In Victoria, a June 2026 health alert linked 6 cases of acute liver injury to products labeled as retatrutide.

If you're weighing a listing for retatrutide for sale, start there: whatever the label says, Lilly didn't make or check what's in the vial. That page covers batch test reports and red flags.

What Lilly has scheduled next

After the October 28 head-to-head with Ozempic, in which A1C fell 2.2 points on both retatrutide doses against 1.8 (efficacy estimand, Lilly's release), two more readouts are close by the registry's estimates. TRIUMPH-5, which pits retatrutide against Lilly's own tirzepatide in about 800 adults with obesity, has an estimated primary completion date of November 2026. Until then, retatrutide vs tirzepatide compares the separate trials. TRANSCEND-T2D-3, in about 320 people with type 2 diabetes and kidney impairment, was due to reach primary completion in October 2026; Lilly had announced no result by October 31.

The filing route is less settled than it looked in September. Lilly last said, on September 29, 2026, that it plans to submit retatrutide to the FDA in the first quarter of 2027 as a Biologics License Application (BLA). On October 2, 2026, the FDA decided that retatrutide is a drug, not a biological product, so an application would need to be filed under section 505 of the Federal Food, Drug, and Cosmetic Act. Lilly's appeal on that question is pending in the Seventh Circuit, and we found no ruling as of October 31, 2026. Our FDA approval and release date pages work through what that means for timing.

Price is the open question. Lilly's October 2026 FAQ says only that retatrutide will be "priced to reflect the overall value to the healthcare system" after review. No number, no launch date; the retatrutide price page tracks what's known.

Our read: even on Lilly's own timeline the filing is months away, with an FDA review after it, so the legal options for the next year or so are a trial, expanded access, or an approved drug such as Zepbound. The Ozempic comparison is in. The tirzepatide one, which matters more to anyone already on Zepbound, waits on TRIUMPH-5.

The Lilly Answers Center, 1-800-LillyRx, is the number Lilly gives both for expanded access requests from doctors and for reporting products sold as retatrutide.