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§ Research summary · Metabolic

Retatrutide 40 mg pen

Also known as · LY-3437943 · Zapopharma Reta Pen

Metabolic·1 min read·reviewed 2026-05-07

Retatrutide is a triple agonist at the GLP-1, GIP, and glucagon receptors. The 40 mg pen is the highest-dose presentation in the Omega Grade catalogue — pre-reconstituted for researchers running extended protocols.

Chemistry quick-facts

CAS
2381089-83-2
Formula
C221H343N51O66
MW
4729.4 Da
Length
39 aa
Status
Investigational. Phase 3 trials (TRIUMPH programme, Eli Lilly). Not approved by any regulatory authority for any indication.
Purity (HPLC)
≥ 99.2%

Mechanism of action

Dose-dependent agonism at the GLP-1, GIP, and glucagon receptors. The GLP-1 and GIP components are shared with tirzepatide; the added glucagon-receptor agonism is proposed to increase energy expenditure and hepatic fatty-acid oxidation in preclinical models.

Research context

Retatrutide (LY-3437943) is an investigational once-weekly triple agonist at the GLP-1, GIP, and glucagon receptors, currently in Phase 3 (TRIUMPH programme) under Eli Lilly. The 39-amino-acid peptide carries a C20 fatty-diacid moiety that extends plasma half-life via albumin binding.

The pre-filled pen presentation matches the clinical format used in investigational trials. Omega Grade supplies lyophilised active peptide in clinical-grade pens sourced from Zapopharma, manufactured to a ≥ 99.2% purity specification verified independently by Janoshik Analytical.

Retatrutide is not approved anywhere and is not a medicine. The material is strictly for in vitro research, analytical method development, and reference-standard use.

Published studies

A non-exhaustive list of peer-reviewed studies referenced when curating this entry. Click through to the primary source for the full text.

  1. Jastreboff AM, Kaplan LM, Frías JP, et al. (2023). Triple-Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial. New England Journal of Medicine.
    PMID 37356066doi.org/10.1056/NEJMoa2301972
  2. Rosenstock J, Frias J, Jastreboff AM, et al. (2023). Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes. The Lancet.
    PMID 37385275doi.org/10.1016/S0140-6736(23)01053-X
  3. Coskun T, Urva S, Roell WC, et al. (2022). LY3437943, a novel triple glucagon, GIP, and GLP-1 receptor agonist. Cell Metabolism.
    PMID 36198295doi.org/10.1016/j.cmet.2022.09.012

Active clinical trials

  • NCT05929066Phase 3 · Ongoing

    TRIUMPH-1: Retatrutide in obesity

  • NCT05936151Phase 3 · Ongoing

    TRIUMPH-OUTCOMES: cardiovascular outcomes

Reconstitution

Solvent
Pre-reconstituted — no solvent required
Typical volume
N/A (pen)
  • · The pen is shipped cold-chain and must be refrigerated on receipt.
  • · Gentle swirl if any settling is observed before first use.

Storage

Lyophilised
Pre-filled pen — store 2–8 °C. Pen is shipped cold-chain; after first use it may be kept at 2–8 °C.
Reconstituted
Pens are pre-reconstituted. Once opened, use within the manufacturer-stated window (typically 4 weeks refrigerated).
Shelf life — sealed
See pen label — typically 18–24 months sealed under refrigeration.

FAQ

Why is this supplied as a pen rather than a vial?+

The pen format matches the clinical formulation used in Eli Lilly's Phase 3 investigational trials, making it the closest-to-reference analytical standard available in research supply. It is pre-reconstituted and cold-chain shipped.

Is the pen identical to the TRIUMPH clinical device?+

The active peptide and basic delivery format are equivalent. It is not a clinical device and is not intended for human administration.

Research-use disclaimer

This page summarises the research literature on Retatrutide 40 mg pen for in vitro laboratory investigation only. It is not medical advice, not a treatment recommendation, and not a substitute for a qualified physician. Material is sold for analytical chemistry and cell-culture research, not for human or veterinary administration.

View Retatrutide 40 mg pen in the catalogue →
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