Peptide basics

Retatrutide vs tirzepatide: one is approved, the other is still in trials

By Emma Johari, Editor

6 min

Articles are summaries, researched and drafted from the sources listed on each page. How this site is written.

Secondary sources · 12 sources

On this page
  1. What this comparison measures
  2. Registered human trials
  3. Furthest phase reached
  4. Regulatory status
  5. Publication trend, 2017 to 2026
  6. Attention against evidence
  7. Common questions

Tirzepatide has 222 registered studies, phase-4 records, and two approved US products. Retatrutide has 20 registered studies, a furthest phase of 3, and no approved product.

Retatrutide's Wikipedia article is read more often than tirzepatide's — 49,387 views a month against 38,322. Its evidence record is roughly a tenth the size.

The difference between phase 3 and phase 4 is not a small one. Phase 4 exists only after approval, so it marks a decision a regulator has already made; phase 3 marks a decision still pending.

This page compares records. It makes no claim that either compound works, is safe, or is right for anyone, and an unapproved compound is not thereby a worse one — it is an unfinished one.

What follows is a comparison of two public records: registrations, phases, approvals, publications and readership. It does not describe effects, does not weigh benefits, and cannot be used to choose between the two compounds.

What this comparison measures

This page sets two records side by side: how many studies were registered under each name, how far those studies progressed, what regulators have approved, how many papers were indexed, and how many people read about each compound.121011

Registered human trials

In the snapshot of 1 August 2026, a registry search for retatrutide returned 33 loose matches, of which 20 were confirmed to name retatrutide as an intervention. Tirzepatide returned 270 loose matches, of which 222 were confirmed.12

Retatrutide's 20 studies are concentrated in late-stage work rather than spread across the development pipeline: the snapshot records 14 phase-3 registrations, 2 phase-2 and 3 phase-1. That distribution is unusual and reflects a compound whose sponsor moved a large programme into phase 3 at once.1

  • Retatrutide: 20 verified registered studies from 33 raw registry matches.
  • Tirzepatide: 222 verified registered studies from 270 raw registry matches.
  • Registration records a plan, not a result. A registered phase-3 study has not by that fact reported anything.12

Furthest phase reached

Retatrutide's furthest registered phase is 3. Tirzepatide's is 4, with 38 phase-4 registrations in the snapshot alongside 47 at phase 3.12

The gap between those two labels is a regulatory boundary rather than a step on a ladder. Phase-4 studies are conducted after a product has been approved and marketed, so a phase-4 record is downstream evidence that an approval decision was made. Phase 3 is where the evidence for that decision is still being assembled.27

Retatrutide's programme includes an outcomes trial in cardiovascular and kidney endpoints, registered in 2024 and listed as active. Trials of that design run for years, which is one reason a phase-3 programme can be large and still be years from reporting.5

Regulatory status

Tirzepatide is the active ingredient of two approved US applications in Drugs@FDA: ZEPBOUND under NDA 217806 and MOUNJARO under NDA 215866. The approved labelling states what each product was approved to treat.78

The equivalent search for retatrutide as an active ingredient returns no approved application in Drugs@FDA. PepRack's snapshot records the same, with no brand name and no application number. This is the single hardest difference between the two records, and it is a matter of public fact rather than judgement.91

Publication trend, 2017 to 2026

A PubMed title/abstract search across 2017 to 2026 returns 157 records for retatrutide and 2,314 for tirzepatide. Retatrutide's series starts in 2023 with 16 records and has risen every year since; tirzepatide's starts in 2020 and reaches 905 in 2025. Both 2026 figures are partial, the year being incomplete when the data was collected.1011

The retatrutide literature is anchored by a phase-2 trial report published in 2023 and by the registry record it corresponds to. A young literature built around a single prominent trial behaves differently from a mature one: individual papers carry more of the total, and revisions move the picture further.34

Retatrutide has the largest gap between readership and registered evidence of any metabolic compound tracked here.

Tirzepatide reaches phase 4 and holds two approved US applications, which places its record in a different class from a compound still in phase 3.

Attention against evidence

Between February and June 2026, the retatrutide Wikipedia article averaged 49,387 views a month against tirzepatide's 38,322, and peaked at 61,307 against 46,922. The compound with a fraction of the registered studies and no approval is the more-read of the two.1212

That inversion is the reason readership is reported on this site at all. Search interest tracks novelty, coverage and expectation. It does not track evidence, and on this pair it moves in the opposite direction.12

Common questions

Is retatrutide approved?

Not in the record checked here. Drugs@FDA returns no approved application with retatrutide as an active ingredient, and PepRack's snapshot of 1 August 2026 records no brand name or application number. Tirzepatide holds two approved US applications.

Does 20 trials versus 222 mean retatrutide is less well studied?

It means far less has been registered, which is what you would expect of a younger programme. It says nothing about the quality of the studies that do exist, and nothing about what either compound does.

Why is retatrutide read more than tirzepatide?

This page cannot answer that from its data. Readership is a count of Wikipedia pageviews; it records how much attention a name attracts, not why. What can be said is that the attention is not tracking the size of the evidence record.

When will the phase-3 results settle this?

They will not settle a comparison, because no registered trial administers both compounds. Phase-3 reports will describe retatrutide against its own comparators, which is a different question from ranking it against tirzepatide.

Sources

  1. Secondary source
    ClinicalTrials.gov registry search: studies with an intervention matching “Retatrutide”U.S. National Library of Medicine, ClinicalTrials.gov, 2026clinicaltrials.gov/search?intr=Retatrutide ↗↩ Back to text
  2. Secondary source
    ClinicalTrials.gov registry search: studies with an intervention matching “Tirzepatide”U.S. National Library of Medicine, ClinicalTrials.gov, 2026clinicaltrials.gov/search?intr=Tirzepatide ↗↩ Back to text
  3. Primary study
    Triple-Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 TrialJastreboff AM, Kaplan LM, Frías JP, et al.. New England Journal of Medicine, 2023 · doi:10.1056/NEJMoa2301972 · PMID 37366315doi.org/10.1056/NEJMoa2301972 ↗↩ Back to text
  4. Primary study
    A Study of LY3437943 in Participants Who Have Obesity or Are Overweight (NCT04881760)ClinicalTrials.gov registry record, 2021clinicaltrials.gov/study/NCT04881760 ↗↩ Back to text
  5. Primary study
    The Effect of Retatrutide Once Weekly on Cardiovascular Outcomes and Kidney Outcomes in Adults Living With Obesity, TRIUMPH-Outcomes (NCT06383390)ClinicalTrials.gov registry record, 2024clinicaltrials.gov/study/NCT06383390 ↗↩ Back to text
  6. Primary study
    Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1)Jastreboff AM, Aronne LJ, Ahmad NN, et al.. New England Journal of Medicine, 2022 · doi:10.1056/NEJMoa2206038 · PMID 35658024doi.org/10.1056/NEJMoa2206038 ↗↩ Back to text
  7. Product label
    ZEPBOUND (tirzepatide) injection — Prescribing Information, NDA 217806U.S. Food and Drug Administration, 2023www.accessdata.fda.gov/drugsatfda_docs/label/2023/217806s000lbl. ↗↩ Back to text
  8. Regulatory
    Drugs@FDA application records for products whose active ingredient is tirzepatide (openFDA)U.S. Food and Drug Administration, 2026api.fda.gov/drug/drugsfda.json?search=products.active_ingredient ↗↩ Back to text
  9. Regulatory
    Drugs@FDA: FDA-Approved Drugs — searched for retatrutide as an active ingredient, no approved application returned on the accessed dateU.S. Food and Drug Administration, 2026www.accessdata.fda.gov/scripts/cder/daf/index.cfm ↗↩ Back to text
  10. Secondary source
    PubMed title/abstract search: “Retatrutide”, publication years 2017–2026National Library of Medicine, PubMed, 2026pubmed.ncbi.nlm.nih.gov/?term=%22Retatrutide%22%5Btiab%5D%20AND% ↗↩ Back to text
  11. Secondary source
    PubMed title/abstract search: “Tirzepatide”, publication years 2017–2026National Library of Medicine, PubMed, 2026pubmed.ncbi.nlm.nih.gov/?term=%22Tirzepatide%22%5Btiab%5D%20AND% ↗↩ Back to text
  12. Secondary source
    Wikimedia REST API — English Wikipedia pageviewsWikimedia Foundation, 2026wikimedia.org/api/rest_v1/#/Pageviews%20data ↗↩ Back to text

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