Retatrutide vs Semaglutide vs Tirzepatide: A Research Compound Comparison

Research summary. Retatrutide, tirzepatide, and semaglutide are three incretin-pathway research compounds that differ chiefly in how many receptors each engages: semaglutide acts at one (GLP-1), tirzepatide at two (GIP/GLP-1), and retatrutide at three (GIP/GLP-1/glucagon). Published trials describe each at a different regulatory stage.

Author: Nox Amino Research Team Reviewed by: the Nox Amino Research Team Published: June 30, 2026 · Updated: June 30, 2026 Editorial methodology: /learn/editorial-standards

Research Use Only (RUO). All materials referenced on this page are intended exclusively for laboratory research and analytical use. They are not drugs, dietary supplements, or articles for human or veterinary consumption, and nothing here constitutes medical advice, a therapeutic claim, or a recommendation for use in or on the body. Statements below describe published third-party studies in their own terms; they are not claims about outcomes for any reader. See our Certificates of Analysis for identity and purity data on stocked reference materials.

How these three research compounds are classified

Within published literature, semaglutide, tirzepatide, and retatrutide are most often distinguished by receptor coverage: the number and identity of the incretin and metabolic receptors each peptide engages. This is a structural and mechanistic classification, independent of any individual's experience.

Semaglutide is described in the literature as a single-receptor glucagon-like peptide-1 (GLP-1) receptor agonist. In a 2021 report in The New England Journal of Medicine, Wilding and colleagues characterized once-weekly semaglutide as a GLP-1 receptor agonist and reported changes in body weight among study participants over 68 weeks (Wilding et al., NEJM 2021; PMID 33567185). "Ozempic" is a brand name associated with semaglutide formulations; as a research compound, the relevant identifier is the molecule, semaglutide, not any consumer brand.

Tirzepatide is described as a dual agonist acting at both the glucose-dependent insulinotropic polypeptide (GIP) and GLP-1 receptors. In the 2022 SURMOUNT-1 report, Jastreboff and colleagues characterized tirzepatide as "a novel glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptor agonist" and described weight-related findings across dose groups in study participants (Jastreboff et al., NEJM 2022; PMID 35658024).

Retatrutide (research code LY3437943) is described as a triple agonist engaging the GIP, GLP-1, and glucagon receptors. The 2023 phase 2 report by Jastreboff and colleagues characterized retatrutide as "an agonist of the glucose-dependent insulinotropic polypeptide, glucagon-like peptide 1, and glucagon receptors," studied in participants with obesity over 48 weeks (Jastreboff et al., NEJM 2023; PMID 37366315). A subsequent phase 3 obesity program, TRIUMPH, is registered on ClinicalTrials.gov (NCT05929066).

Comparison table: research compound profiles

The table below summarizes how the published literature classifies each compound. It describes research status and mechanism, not outcomes for any reader, and contains no dosing or therapeutic guidance.

Attribute (per literature)	Semaglutide	Tirzepatide	Retatrutide
Research code / identifier	Semaglutide	LY3298176 (tirzepatide)	LY3437943 (retatrutide)
Compound class	GLP-1 receptor agonist	GIP / GLP-1 dual agonist	GIP / GLP-1 / glucagon triple agonist
Receptors engaged (count)	1	2	3
Peptide structure	Single-incretin analog	Dual-incretin analog	Triple-incretin analog
Representative published trial	STEP 1 (Wilding et al., NEJM 2021)	SURMOUNT-1 (Jastreboff et al., NEJM 2022)	Phase 2 (Jastreboff et al., NEJM 2023)
Trial registry reference	PMID 33567185	PMID 35658024	PMID 37366315 · NCT05929066
Reported research stage (literature)	Multiple completed trials	Multiple completed trials	Phase 2 reported; phase 3 (TRIUMPH) registered

Table reflects how third-party publications and registries describe these compounds. It is not a statement of comparative effectiveness, safety, or suitability for any use in humans.

What the receptor-count difference means in research terms

The most cited structural distinction across these three compounds is the progression from single- to dual- to triple-receptor engagement. In the published descriptions above, semaglutide engages the GLP-1 receptor; tirzepatide adds GIP receptor activity; and retatrutide adds glucagon receptor activity on top of GIP and GLP-1. Investigators studying glucagon receptor co-agonism frequently frame it as a distinct mechanistic question, one reason retatrutide is often discussed separately from the two earlier compounds in the literature.

For laboratory work, these are reference materials characterized by identity and purity rather than by any human outcome. Identity (e.g., by mass spectrometry) and purity (e.g., by HPLC) are the attributes documented on a Certificate of Analysis, which is the appropriate basis for selecting a research compound for in-vitro or analytical protocols. You can review available COA data on our /coas page.

Sourcing COA-verified research compounds

Nox Amino stocks research-grade reference materials with batch-specific Certificates of Analysis. To view COA-verified retatrutide and other triple- and dual-agonist research peptides, see the product detail page at /shop/glp-3r, or browse the full catalog at /shop.

Create a free account to view COA-verified retatrutide, access batch-specific analytical data, and see member pricing. → Create your account

This article cites third-party research and registry records for informational and laboratory-research purposes only. Nox Amino sells research compounds intended for laboratory and analytical use only, not for human or animal consumption. Nothing on this page is medical advice or a therapeutic claim. Editorial methodology and review process: /learn/editorial-standards.

Frequently Asked Questions

What is the difference between retatrutide, tirzepatide, and semaglutide as research compounds?

Published literature distinguishes them by receptor coverage. Semaglutide is described as a single GLP-1 receptor agonist (Wilding et al., NEJM 2021, PMID 33567185); tirzepatide as a dual GIP/GLP-1 agonist (Jastreboff et al., NEJM 2022, PMID 35658024); and retatrutide as a triple GIP/GLP-1/glucagon agonist (Jastreboff et al., NEJM 2023, PMID 37366315). All three are reference materials for laboratory research use only.

Is retatrutide the same as Ozempic?

No. "Ozempic" is a consumer brand name associated with semaglutide, a single-receptor GLP-1 agonist as described in the published literature. Retatrutide (research code LY3437943) is a structurally distinct triple-agonist research compound engaging the GIP, GLP-1, and glucagon receptors, as characterized in Jastreboff et al., NEJM 2023 (PMID 37366315). As research materials, the relevant identifier is the molecule, not any brand.

What research stage is retatrutide at compared to the others?

According to published reports and registries, semaglutide and tirzepatide each have multiple completed trials, while retatrutide has a reported phase 2 obesity study (Jastreboff et al., NEJM 2023, PMID 37366315) and a registered phase 3 program, TRIUMPH (ClinicalTrials.gov NCT05929066). These references describe study status only and are not statements about use in humans.

What does "triple agonist" mean for retatrutide?

In the published literature, "triple agonist" refers to retatrutide engaging three receptors: glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1), and glucagon, as described by Jastreboff and colleagues in NEJM 2023 (PMID 37366315). This is a mechanistic and structural classification of the compound, not a claim about any effect in a person.

How do I verify the identity and purity of a research peptide like retatrutide?

Identity and purity are documented on a batch-specific Certificate of Analysis (COA), typically using methods such as mass spectrometry for identity and HPLC for purity. These analytical attributes, not human outcomes, are the appropriate basis for selecting a research compound. You can review available COA data on the /coas page, and create a free account to access batch-specific analytical data and member pricing.