Retatrutide vs Semaglutide
Quick Answer
The core difference is receptor breadth. Retatrutide (LY3437943) is a triple agonist of the GLP-1, GIP, and glucagon receptors; semaglutide is a single GLP-1 receptor agonist. In metabolic research the triple-agonist profile makes retatrutide a distinct study target rather than a newer version of the same one. Retatrutide is supplied by Peptide.Express at ≥99% HPLC-verified purity for in-vitro research only. Semaglutide is not part of the Peptide.Express catalog and is included here for mechanistic comparison.
Retatrutide vs Semaglutide: At a Glance
| Attribute | Retatrutide | Semaglutide |
|---|---|---|
| Receptor agonism | Triple: GLP-1 / GIP / glucagon | Single: GLP-1 |
| Research code | LY3437943 | NN9535 |
| Class | Triple incretin agonist | GLP-1 receptor agonist |
| CAS number | 2381089-83-2 | 910463-68-2 |
| Research area | Energy balance, metabolic signaling | GLP-1 metabolic signaling |
| Available at Peptide.Express | Yes — ≥99% HPLC verified, batch CoA | No — not stocked |
How Retatrutide and Semaglutide Differ in Research
Retatrutide and semaglutide are both incretin-pathway compounds, but they differ in receptor breadth. Semaglutide is a single GLP-1 receptor agonist, whereas retatrutide (LY3437943) is a triple agonist acting at the GLP-1, GIP, and glucagon receptors simultaneously.
For metabolic research, that triple-agonist mechanism is what makes retatrutide a distinct entity rather than an incremental version of the same target. The glucagon-receptor arm in particular contributes an energy-expenditure component that a pure GLP-1 agonist does not have, which is why study designs investigating multi-receptor energy balance treat the two as mechanistically different tools.
One point of housekeeping, because comparison pages often blur it: semaglutide is not part of the Peptide.Express catalog. It appears on this page as the reference compound the triple agonist is measured against, not as a product. Retatrutide is stocked, supplied at ≥99% HPLC-verified purity with a batch-specific Certificate of Analysis, and intended strictly for in-vitro laboratory research and educational use.
Frequently Asked Questions
What is the difference between Retatrutide and Semaglutide?
Retatrutide is a triple GLP-1/GIP/glucagon receptor agonist, while semaglutide is a single GLP-1 receptor agonist. The added GIP and glucagon activity is the defining mechanistic distinction, and the glucagon arm is the one with no counterpart in semaglutide at all. For laboratory research use only.
Is Retatrutide stronger than Semaglutide?
They are not ranked here — they are mechanistically different research tools (triple versus single receptor agonism). Comparative potency claims in humans sit outside research-use framing and are not made on this site.
Does Peptide.Express sell Semaglutide?
No. Semaglutide is not in the Peptide.Express catalog and appears on this page only as the comparison reference. The incretin-pathway compounds that are stocked are retatrutide and tirzepatide, both at ≥99% HPLC-verified purity with a batch-specific Certificate of Analysis.
References
- Jastreboff AM, Kaplan LM, Frías JP, et al. "Triple-Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial." New England Journal of Medicine, 2023. Read the retatrutide Phase 2 trial in NEJM
- "Retatrutide — A Game Changer in Obesity Pharmacotherapy." Review of the triple GLP-1/GIP/glucagon receptor agonist pharmacology and the trial evidence available prior to Phase 3 readout. Read the retatrutide obesity pharmacotherapy review on PMC
- "Efficacy and safety of retatrutide, a novel GLP-1, GIP, and glucagon receptor agonist." Systematic review of the published retatrutide efficacy and adverse-event data. Read the retatrutide efficacy and safety review on PMC
- Coskun T, Urva S, Roell WC, et al. "LY3437943, a Novel Triple Glucagon, GIP, and GLP-1 Receptor Agonist for Glycemic Control and Weight Loss: From Discovery to Clinical Proof of Concept." Cell Metabolism. 2022. Read the Coskun 2022 retatrutide discovery and receptor pharmacology paper in Cell Metabolism