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Dual GIP and GLP-1 receptor agonist

Tirzepatide — evidence

What has been published, classified by the kind of document it is. This is not a protocol, not a score, and not a recommendation for use.

Evidence overview

3 records in this file

  • CLINICAL TRIAL2
  • REGULATORY1

Research areas. Approved-drug Phase 3; United States approval.

Publication span. 2021–2023.

What we know

  • Two FDA-approved products exist (Mounjaro, Zepbound). SURMOUNT-1 and SURPASS-2 are published Phase 3 trials in NEJM.
  • SURPASS-2 compared tirzepatide with semaglutide 1 mg in type 2 diabetes, not with the 2.4 mg STEP dose.

Editorial reading of the records below, labelled as Therapept analysis. How records are built

What remains uncertain

  • As with semaglutide, approved-product trials do not describe compounded or research-chemical copies.

Regulatory notes

FDA-approved drug substance

  • Approved prescription drug substance. Mounjaro approved 13 May 2022; Zepbound 8 November 2023.
  • Not placed in FDA's Category 2 of bulk substances that may present significant safety risks.
  • FDA proposed in April 2026 to exclude tirzepatide from the 503B bulks list.

Regulatory status describes how a substance is classified. It is not a safety assessment of any particular material.

Studies and documents

  1. REGULATORY2023Approved-drug labelling

    Drugs@FDA — Mounjaro (NDA 215866), Zepbound (NDA 217806)

    U.S. Food and Drug AdministrationDrugs@FDA

    Objective
    To record the two approved United States products.
    Endpoint investigated
    Marketing authorisation

    Mounjaro approved 13 May 2022; Zepbound 8 November 2023. Sequence modifications and molecular weight are stated in the FDA-approved labelling.

    Limitations. Labelled products only. Not a description of compounded copies.

    Drugs@FDA — approved drug productsReviewed 12 September 2026

  2. CLINICAL TRIAL2022Randomised, double-blind, placebo-controlled trial

    Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1)

    Jastreboff AM, Aronne LJ, Ahmad NN, et al.New England Journal of Medicine

    Population
    Adults with obesity, or overweight plus a weight-related complication, without diabetes
    Sample
    n = 2,539
    Objective
    To test once-weekly tirzepatide versus placebo for body-weight change in SURMOUNT-1.
    Endpoint investigated
    Body-weight change in the SURMOUNT-1 trial

    Phase 3 randomised trial of approved tirzepatide doses versus placebo, published in NEJM. Evidence for the approved products, not for unapproved look-alikes.

    Limitations. Approved-product trial. Population, dose and manufacture are those of the labelled programme.

    DOI 10.1056/NEJMoa2206038Jastreboff et al., N Engl J Med (2022) — SURMOUNT-1Reviewed 12 September 2026

  3. CLINICAL TRIAL2021Randomised, open-label, active-controlled trial

    Tirzepatide versus semaglutide once weekly in patients with type 2 diabetes (SURPASS-2)

    Frías JP, Davies MJ, Rosenstock J, et al.New England Journal of Medicine

    Population
    Adults with type 2 diabetes
    Sample
    n = 1,879
    Objective
    To compare once-weekly tirzepatide with once-weekly semaglutide 1 mg on glycaemic endpoints in SURPASS-2.
    Endpoint investigated
    Glycaemic and related endpoints versus semaglutide 1 mg

    Phase 3 active-controlled trial in type 2 diabetes, published in NEJM. Open-label. The comparator dose of semaglutide is 1 mg, which is not the 2.4 mg STEP dose.

    Limitations. Open-label; diabetes population; comparator is semaglutide 1 mg, not 2.4 mg. Approved products only.

    DOI 10.1056/NEJMoa2107519Frías et al., N Engl J Med (2021) — SURPASS-2Reviewed 12 September 2026

Last reviewed 3 September 2026 · Compiled by Therapept Editorial · How these records are built