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Retatrutide

Also known as LY3437943.

The FDA and the EMA have not approved retatrutide. So who filled your vial?

TyrAibGlnGlyThrPheThrSerAspTyrSerIleLeuLeuAspLysLysAlaGlnAibAlaPheIleGluTyrLeuLeuGluGlyGlyProSerSerGlyAlaProProProSer
39 amino acids, in order. A double ring marks a mirror-image, modified or non-standard one. End caps, bridges and anything attached to the chain are not drawn. Source: ChEMBL.
Human evidence
Grade B

Some trials

Completed randomized trials
5+

The plus sign marks a floor: the record counts more trials than it lists.

Approved?
No

Not approved in the US or the EU

Sport (WADA)
Not named

Not named on WADA's list. That is not clearance.

Checked on .

How we count a trial
Short answer

As of October 2026, the FDA and the EMA have not approved retatrutide. It is still in Phase 3 trials, and Eli Lilly plans to file with the FDA in early 2027. One Phase 3 trial, TRIUMPH-2, is now published in full in The Lancet (September 2026). The other results are company topline releases. If a vial sold as retatrutide reached you, those trials did not test it, and you cannot tell from the outside who filled it.

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What is retatrutide?

Retatrutide is an experimental lab-made peptide from Eli Lilly, designed to switch on three gut and pancreas hormone receptors at once: GIP, GLP-1 and glucagon. That puts it one step beyond drugs that act on two, such as tirzepatide. The FDA and the EMA have not approved it, and as of September 2026 it is still in Phase 3 trials.

Does retatrutide work?

Eli Lilly reports substantial weight loss in its Phase 3 trials. One is published in full: in TRIUMPH-2, in adults with obesity and type 2 diabetes, body weight fell by 18.8% over 80 weeks in the top group, against 5.1% on placebo (The Lancet, September 2026). The other results are topline releases, and the FDA and the EMA have not reviewed any of them.

What we found. 5+ completed randomized trials counted on the record. 4 study rows listed below, so the number shows with a plus sign until every trial is listed. One, TRIUMPH-2, is published in full in The Lancet (September 2026). The other three are topline releases from the company.

Studies on the retatrutide record: each study, what it was tested in, its status and what it shows.
TRIUMPH-2, Phase 3 trial in obesity with type 2 diabetesPeoplePublished in full, The Lancet, September 2026Body weight fell 18.8% over 80 weeks in the top group, against 5.1% on placebo
TRIUMPH-1, Phase 3 trial in obesityPeopleTopline results released. Not yet published in a peer-reviewed journal as of September 2026The company reported substantial weight loss in adults with obesity or overweight
TRIUMPH-4, trial in knee osteoarthritisPeopleTopline results reportedThe company reported weight loss and less knee osteoarthritis pain
TRANSCEND-T2D-1, trial in type 2 diabetesPeopleTopline results reportedThe company reported blood sugar and weight benefits in people with type 2 diabetes

A topline release is the company's own announcement of a result. TRIUMPH-2 is the first Phase 3 trial published in full. Review by a regulator is still pending.

How we count a trial

Is retatrutide safe?

Trial reporting has raised stomach and gut side effects, of the kind typical for this drug class. In TRIUMPH-2, published in full, stomach and gut side effects were more common on retatrutide than on placebo. Because the FDA and the EMA have not approved it, no long-term safety data from use after approval exist. Over the long term, nobody knows. All of that concerns the drug inside Eli Lilly's trials. A vial that carries the same name is a separate matter, taken up below.

What is in a vial sold as retatrutide?

Every result above comes from Eli Lilly's own trials. No retatrutide product has FDA or EMA approval. If a vial sold as retatrutide reached you, none of those trials tested it, and this record cannot say who filled it. The checklist lists what to ask the seller.

What don't we know?

  • What the full data of the other trials show. Only TRIUMPH-2 is published in full so far.
  • Whether the FDA will approve it. No filing has been made yet.
  • What long-term use does. No long-term safety data from use after approval exist.
  • What is in any vial sold as retatrutide.

The other side

Retatrutide is in Phase 3 trials, and one of them, TRIUMPH-2, is now published in full in The Lancet. The FDA filing is still to come. Until a regulator reviews the data, the evidence is the trials' own reports.

What would change this record?

  • A formal FDA submission, planned for the first quarter of 2027, and the approval decision that follows.
  • Full publication of the trial results in a peer-reviewed journal.

Change log

  • TRIUMPH-2 is now published in full in The Lancet (September 2026). The short answer, the study table and the gap say so. Still not approved, still in Phase 3. The Lancet, TRIUMPH-2 (opens in new tab)
  • Record checked. No change logged yet.
Every change on the Table

Three questions to ask next

Ask better questions.

More questions about retatrutide

Is retatrutide FDA approved?

No. As of September 2026 the FDA has not approved retatrutide, and it has no EMA marketing authorisation. Eli Lilly plans to file with the FDA in the first quarter of 2027.

Has retatrutide been tested in people?

Yes. Eli Lilly has released topline results from several Phase 3 trials, in obesity, type 2 diabetes, knee osteoarthritis pain, obstructive sleep apnea and metabolic liver disease. One of them, TRIUMPH-2, is published in full in The Lancet (September 2026).

When will retatrutide be approved?

Nobody knows. Eli Lilly targets the first quarter of 2027 for its FDA filing. The company says it needs more time to compile manufacturing and quality-control data first.

Is retatrutide the same as tirzepatide?

No. Retatrutide is designed to act on three hormone receptors, one step beyond dual-acting drugs such as tirzepatide. Tirzepatide is an approved medicine in the US and the EU.

Is retatrutide banned in sport?

It is not named on WADA's list. That is not clearance.

THE PEPTIDE TABLE

RECORD · RETATRUTIDE

Checked
20 OCT 2026
Sources read
4
Approved?
NO
Sport (WADA)
NOT NAMED
COMPLETED RANDOMIZED TRIALS
5+
GRADE
B

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Sources

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Metabolic and weight

In the same group

All 12 in this group
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