Vs. tirzepatide

Retatrutide vs tirzepatide: what does the research show?

In their respective obesity programmes the triple agonist reported larger mean reductions: retatrutide reached about 24.2% at 48 weeks in Phase 2 (NEJM 2023) and 28.3% at 80 weeks in Phase 3 TRIUMPH-1, while tirzepatide reported about 20.9% at 72 weeks in SURMOUNT-1. The difference is widely attributed to retatrutide’s added glucagon-receptor arm, which raises energy expenditure on top of appetite suppression. These are cross-trial descriptive comparisons, not head-to-head results.

Retatrutide vs tirzepatide at a glance

Attribute Retatrutide Tirzepatide Compound class Triple GLP-1 / GIP / glucagon receptor agonist Dual GIP / GLP-1 receptor agonist (imbalanced agonism) Pivotal Phase 3 result 28.3% mean weight reduction at 80 weeks, 12 mg (TRIUMPH-1, 2025) 20.9% mean weight reduction at 72 weeks, 15 mg (SURMOUNT-1, NEJM 2022) Half-life ~6 days ~5 days (116.7 h mean) Evidence tier Tier 1 (human RCT) Tier 1 (human RCT) Reference-drug regulatory status Investigational — not approved as a medicine in any jurisdiction Reference drug (Mounjaro/Zepbound) is FDA-approved; the research-grade material supplied for laboratory use is unapproved and is not the finished pharmaceutical

Cross-trial descriptive comparison from separate clinical programmes, not a head-to-head trial result. Figures describe the reference-drug clinical literature, not a claim about the research-grade material.

Why the extra receptor matters

Tirzepatide activates the GIP receptor at full potency and engages the GLP-1 receptor with a cAMP-biased signal. Retatrutide adds a third arm — the glucagon receptor — which drives hepatic thermogenesis and energy expenditure on top of the appetite-suppression effects both compounds share via GLP-1/GIP.

Frequently asked questions

How is retatrutide different from tirzepatide or semaglutide?

Semaglutide targets one receptor (GLP-1), tirzepatide targets two (GLP-1 and GIP), and retatrutide targets three (GLP-1, GIP, and glucagon). The glucagon arm is what drives the additional hepatic thermogenesis and liver-fat clearance that set retatrutide apart in published research.

Tirzepatide vs retatrutide — what is the difference?

Tirzepatide is a dual GIP/GLP-1 agonist, while retatrutide is a triple agonist that adds a third arm — the glucagon receptor — on top of GIP and GLP-1. In its respective Phase 2 obesity programme retatrutide reported larger mean body-weight reductions than tirzepatide did in SURMOUNT-1, but retatrutide remains earlier in clinical development.

References

Jastreboff AM et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity. N Engl J Med (2023)

Jastreboff AM et al. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). N Engl J Med (2022)

TRIUMPH-1 pivotal Phase 3 trial. ClinicalTrials.gov (NCT05929066)

Related research

Retatrutide mechanism this hub

Retatrutide research & evidence this hub

Full side-by-side comparison table

Retatrutide product page

Tirzepatide product page

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