Retzoundi and Retkouro: What Lilly’s Trademark Filings Show

The short answer

Retzoundi, Retkouro and Senmounto are names that Eli Lilly and Company applied to register as trademarks with the U.S. Patent and Trademark Office (USPTO) on April 23, 2024. All three are live applications. [1] [2] [3] A fourth name filed the same day, Emwilzy, was abandoned in October 2024. [4]

Online posts say Retzoundi and Retkouro could be the brand names for retatrutide, Lilly’s investigational weekly triple agonist that acts on GIP, GLP-1 and glucagon receptors. That is a community guess. None of the four USPTO records names a medicine, and Lilly’s October 28, 2026 announcement of its latest retatrutide trial results calls the drug only retatrutide. [6]

What the USPTO records show

The USPTO’s public database, Trademark Status and Document Retrieval (TSDR), shows the same filing pattern for all four names. Each was filed on April 23, 2024 by Eli Lilly and Company as plain words with no logo, under the heading for pharmaceutical preparations (class 5), on an intent-to-use basis. That means Lilly told the USPTO it plans to use the name and had not yet done so. [1] [2] [3] [4]

The earlier extensions on the three live records were granted in April 2025, October 2025 and August 2026. “Under examination” is the USPTO’s label for a live application that has been assigned to an examiner. It does not mean a drug regulator is reviewing a medicine.

What the records leave out

Each record describes the goods as pharmaceutical preparations “for the treatment of” a long list of conditions. On the three live records the list includes diabetes and obesity. It also includes Alzheimer’s disease, cancer, heart failure, kidney and liver diseases, migraines and many more. [1] Emwilzy’s list is a little longer. [4]

A description that broad cannot tell you which medicine a name is meant for, or how many. None of the records names a medicine, a development code or an ingredient. That is why this page does not say any of these names belongs to retatrutide or to any other medicine.

How an intent-to-use application works

• The USPTO examines the application and publishes the mark so others can object.
• If nobody objects, it issues a notice of allowance.
• The applicant then has six months to file a statement of use, which shows the name is really in use.
• If the applicant is not ready, it can ask for more time. The USPTO allows five extension requests in all, each for six months, up to 36 months after the notice.{5}

For a notice dated November 12, 2024, the outer limit is November 2027. Lilly has used four of the five extensions on each live name, and the records show no statement of use for any of them. Extensions show that Lilly still wants the names. They do not show a launch date, and they do not show which product a name is for.

Where the retatrutide idea comes from

Posts on Reddit, X and Instagram have connected Retzoundi and Retkouro to retatrutide and point to the trademark filings as the reason. Under this site’s evidence tiers, that is Tier 6: community-reported information with no identifiable primary source behind the link itself.

The reasoning is not absurd. Lilly will eventually need a brand name for each new medicine, and it is holding names it has not used. But a company can reserve a name years before choosing a product, can reassign it, and can drop it, as Lilly did with Emwilzy. The filing shows that Lilly wanted these names. It does not show what for.

Is it a street name, a brand name or a scientific name?

This site treats names people search for as their own entities and asks the same questions of each. For Retzoundi and Retkouro the answers are short, because no product exists.

Dosing as studied in retatrutide trials is on the retatrutide page. This article gives no dosing information.

Where retatrutide stands

Retatrutide (development code LY3437943) is not approved anywhere. Lilly has reported phase 3 results in obesity, sleep apnea and type 2 diabetes, and says it plans to submit it to the FDA in the first quarter of 2027. [7] Its trial results, mechanism and reported dosing are on the retatrutide page. The retatrutide and tirzepatide comparison sets it beside the approved dual agonist.

In the United States the FDA evaluates a proposed brand name for confusion with other drug names. [8] Retatrutide has not reached the approval stage, and no Lilly or FDA statement the writer found names a brand for it.

Other Lilly names that get mixed up

What is still not public

• Which medicine, or medicines, Lilly intends each live name for.
• Whether any of the names is meant for retatrutide.
• Why Lilly abandoned Emwilzy and kept the other three.
• Whether Lilly filed the same names outside the United States. Only USPTO records were read for this article.
• When Lilly will announce a brand name for any new medicine.

Questions readers ask

The next meaningful signal would be a Lilly statement naming a brand for a specific medicine, a statement of use filed with the USPTO, or an FDA approval record. Until then, the filings are a fact about Lilly’s naming plans, not about retatrutide.

Independent educational reporting. This article provides no purchasing, dosing, administration, or self-experimentation guidance. Trademark records document filings; they do not establish approval, safety, or efficacy.

Related reading

• Retatrutide on PeptideBlog.net
• LY4086940: trials and status
• LY4086940 timeline: the public record, in order
• Compare peptides side by side
• Retzoundi and Retkouro on The Weight Loss Atlas
• Retatrutide TRIUMPH-1 phase 3 results on The Weight Loss Atlas