Metabolic Research Peptides: Tirzepatide, Retatrutide and Cagrilintide

The metabolic peptide research landscape has evolved significantly over the past decade, driven by the clinical success of GLP-1 receptor agonists and subsequent investigation of multi-receptor targeting strategies. Tirzepatide, Retatrutide, and Cagrilintide represent three distinct but related approaches to metabolic regulation, each with a different receptor profile and evidence base.

This article provides a comparative research overview of these three compounds. All Bloom Vitality products are supplied strictly for in vitro laboratory and research use only.

Tirzepatide: Dual GIP/GLP-1 Agonist

Tirzepatide acts at both the GIP receptor (GIPR) and GLP-1 receptor (GLP-1R). Developed by Eli Lilly and approved as Mounjaro® in multiple jurisdictions for type 2 diabetes, Tirzepatide has one of the most robust clinical datasets of any research peptide currently available.

• Receptors: GIPR + GLP-1R
• Key clinical data: SURPASS programme (T2D) and SURMOUNT programme (obesity) — mean weight reductions up to 20.9% at 72 weeks (SURMOUNT-1, 15mg)
• Regulatory status: Approved (EU, US, UK) for T2D; approved in some jurisdictions for obesity management

Full overview: Tirzepatide Research Overview | Products: 30mg / 60mg

Retatrutide: Triple GIP/GLP-1/Glucagon Agonist

Retatrutide (LY3437943) adds glucagon receptor (GCGR) agonism to the GIP/GLP-1 dual mechanism of Tirzepatide. The additional glucagon receptor component is proposed to increase thermogenesis and energy expenditure beyond dual agonism alone.

• Receptors: GIPR + GLP-1R + GCGR
• Key clinical data: Phase 2 RCT (NEJM, 2023) — mean body weight reduction of 17.5% at 24 weeks (12mg group); Phase 3 TRIUMPH programme ongoing
• Regulatory status: Not approved; Phase 3 trials ongoing

Full overview: Retatrutide Research Overview | Products: 30mg / 40mg

Cagrilintide: Amylin Analogue

Cagrilintide is a long-acting synthetic analogue of amylin, a peptide hormone co-secreted with insulin by pancreatic beta cells. Unlike Tirzepatide and Retatrutide, Cagrilintide does not act at GLP-1 or GIP receptors — it targets the amylin receptor (and calcitonin receptor), representing a mechanistically distinct approach to appetite and metabolic regulation.

• Receptors: Amylin receptor (AMY1–3), calcitonin receptor
• Proposed mechanisms: Slows gastric emptying, suppresses glucagon, acts centrally to reduce appetite via area postrema and hypothalamic pathways
• Key research: Phase 2 data for cagrilintide monotherapy showed dose-dependent weight reduction; the combination of cagrilintide + semaglutide (CagriSema) has entered Phase 3 investigation
• Regulatory status: Not independently approved; under investigation in combination regimens

Product: Cagrilintide

Researchers investigating GHRH-axis compounds within the metabolic context may also find our Tesamorelin Peptide UK: Research Overview, GHRH Mechanism & Clinical Evidence relevant.

Comparative Summary

Compound	Receptors	Development Stage	Approval Status
Tirzepatide	GIPR + GLP-1R	Post-approval	Approved (T2D, obesity)
Retatrutide	GIPR + GLP-1R + GCGR	Phase 3	Not approved
Cagrilintide	Amylin/calcitonin receptor	Phase 3 (combination)	Not approved

Batch-specific Certificates of Analysis for all metabolic research compounds are available on request via our Testing & Quality page.

For research and laboratory use only. This article is provided for informational purposes and does not constitute medical advice.