Retatrutide (LY3437943) is an investigational triple GIP/GLP-1/glucagon receptor agonist in Phase 3 clinical trials. Available as a research peptide from Eternal Peptides for laboratory use only.

Is retatrutide available in Australia for research?

Retatrutide is available as a research peptide from Eternal Peptides Wholesale (10mg and 20mg vials, Janoshik COA-verified). For qualified laboratory research use only — not approved for human therapeutic use in Australia.

Retatrutide Research Overview | Triple Receptor Agonist

A summary of published research on retatrutide (LY3437943), a synthetic peptide under Phase 3 investigation as the first triple GIP/GLP-1/glucagon receptor agonist in clinical trials. For research purposes only — not for human therapeutic use.

Eternal Peptides Research Team

Published April 2026 · Updated April 2026 · For research use only

What Is Retatrutide?

Retatrutide (LY3437943) is a synthetic, acylated peptide developed by Eli Lilly and currently in Phase 3 clinical investigation. It is the first triple receptor agonist targeting GIP, GLP-1, and glucagon receptors simultaneously to enter large-scale clinical trials, distinguishing it from dual agonists (tirzepatide) and single agonists (semaglutide) currently in clinical use. Its C18 fatty diacid modification enables albumin binding and an approximately one-week half-life — consistent with once-weekly dosing.

Triple Receptor Mechanism

GLP-1R Agonism

Enhances glucose-dependent insulin secretion, suppresses glucagon, slows gastric emptying, and acts centrally to reduce energy intake. Shared with semaglutide and tirzepatide.

GIPR Agonism

Potentiates insulin secretion, modulates adipose tissue metabolism. Shared with tirzepatide — hypothesised to improve tolerability and adipose-specific effects.

GCGR Agonism — The Distinguishing Mechanism

Glucagon receptor activation increases hepatic glucose output and thermogenesis. When combined with GLP-1R agonism, glycaemic effects are buffered while thermogenic and hepatic lipolytic effects are preserved — a unique metabolic research profile absent from both semaglutide and tirzepatide.

Phase 2 Published Data

Results published in the New England Journal of Medicine (Jastreboff et al., 2023) from a randomised Phase 2 trial across dose cohorts (1mg, 4mg, 8mg, 12mg once weekly) showed:

~24% mean body weight reduction from baseline at 48 weeks in the highest dose cohort
Dose-dependent reductions in liver fat fraction (MRI-PDFF), triglycerides, and systolic blood pressure
Adverse events consistent with GLP-1 class — predominantly gastrointestinal, dose-dependent

Source: Jastreboff AM et al. N Engl J Med. 2023;389(6):514-526. Phase 2 data only.

Phase 3 Programme: TRIUMPH Trials

TRIUMPH-1

Adults with obesity (no T2D). Primary endpoint: % body weight change at 72 weeks.

TRIUMPH-2

Adults with T2D and obesity. Glycaemic and weight outcomes at 52 weeks.

TRIUMPH-3

Cardiovascular outcomes trial — MACE in high-CV-risk population.

TRIUMPH-NASH

Biopsy-confirmed MASH/NASH — histological liver improvement at 48 weeks.

Retatrutide vs Tirzepatide

Feature	Tirzepatide	Retatrutide
GLP-1R Agonism	✓	✓
GIPR Agonism	✓	✓
GCGR Agonism	✗	✓
Regulatory Status (AU)	TGA Approved	Phase 3
Dedicated NASH Trial	✗	✓

Available for Laboratory Research

Eternal Peptides Wholesale is one of Australia's only dedicated wholesale research peptide distributors supplying Janoshik-verified Retatrutide for laboratory research.

Retatrutide is available as a research peptide from Eternal Peptides Wholesale. All batches are submitted to Janoshik Analytical for third-party HPLC purity verification, sterility testing, endotoxin testing, and heavy metals analysis.

Retatrutide 10mg — View Product Retatrutide 20mg — View Product

Frequently Asked Questions

What is retatrutide?

Retatrutide (LY3437943) is an investigational triple GIP/GLP-1/glucagon receptor agonist in Phase 3 clinical trials. It is the first triple incretin agonist to enter large-scale trials. Available as a research peptide from Eternal Peptides for qualified laboratory use only.

How does retatrutide differ from tirzepatide?

Tirzepatide is a dual GIP/GLP-1 agonist. Retatrutide adds glucagon receptor agonism as a third mechanism. Phase 2 data showed greater body weight reductions with retatrutide at 48 weeks. Phase 3 trials will establish the clinical significance of the additional glucagon component.

Is retatrutide approved for use in Australia?

No. As of 2026, retatrutide has not received TGA registration. It is available as a research peptide for qualified laboratory research purposes only — not for human therapeutic use.

Where can I source retatrutide for research in Australia?

Retatrutide (10mg and 20mg per vial, box of 10) is available wholesale from Eternal Peptides with full Janoshik COA documentation. For qualified laboratory research use only.

Key References

Source: Jastreboff AM et al. N Engl J Med. 2023;389(6):514-526. PMID: 37184382

Jastreboff AM et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity. N Engl J Med. 2023;389(6):514-526.
Coskun T et al. LY3437943, a novel triple GIP, GLP-1, and glucagon receptor agonist. Cell Metab. 2022;34(9):1234-1247.
ClinicalTrials.gov. TRIUMPH-1: NCT05882045.

Retatrutide: Triple Receptor Agonism and Phase 3 Clinical Development