The definitive reference for researchers studying Retatrutide — the triple GLP-1/GIP/glucagon agonist. Covers mechanism of action, phase 2 clinical data, head-to-head comparisons with semaglutide and tirzepatide, and research applications.
Retatrutide (LY3437943) is a synthetic peptide developed by Eli Lilly that simultaneously activates three distinct metabolic receptor systems: GLP-1R (glucagon-like peptide-1 receptor), GIPR (glucose-dependent insulinotropic polypeptide receptor), and GCGR (glucagon receptor). This triple agonist mechanism makes it the most multi-targeted metabolic peptide currently in advanced clinical development.
Unlike semaglutide (GLP-1 single agonist) or tirzepatide (dual GLP-1/GIP agonist), Retatrutide's third agonist target — the glucagon receptor — adds a qualitatively different biological effect: direct stimulation of energy expenditure through thermogenesis and hepatic fat oxidation. This means Retatrutide simultaneously addresses caloric intake reduction (via GLP-1/GIP) and caloric expenditure increase (via glucagon) — a combination not achieved by any other single peptide molecule.
Retatrutide is currently in Phase 3 clinical trials as of 2026. Phase 2 results were published in the New England Journal of Medicine in 2023, characterizing the metabolic profile of triple-receptor agonism across multiple dose levels over 48 weeks.
Research Use Only: Corevanta's Retatrutide is sold exclusively for laboratory and scientific research purposes. It is not an approved drug, not a dietary supplement, and is not intended for human consumption or therapeutic use.
Retatrutide is a fatty-acid acylated peptide — a single molecule engineered to bind three separate G-protein coupled receptors with high affinity. Each receptor coupling triggers distinct intracellular signaling cascades:
The critical mechanistic insight is that the three pathways are additive rather than redundant. GLP-1 and GIP primarily reduce caloric intake; glucagon receptor activation increases caloric expenditure. A true triple agonist operates on both sides of the energy balance equation simultaneously.
Understanding what each receptor agonist contributes independently is essential for interpreting Retatrutide's research outcomes relative to single and dual agonists.
| Receptor | Primary Effects | Weight Loss Contribution |
|---|---|---|
| GLP-1R | Appetite reduction, gastric slowing, insulin secretion | Reduces caloric intake via satiety signaling |
| GIPR | Insulin amplification, insulin sensitivity, adipose regulation | Enhances GLP-1 effects; improves metabolic efficiency |
| GCGR | Hepatic lipolysis, brown fat thermogenesis, triglyceride mobilization | Increases energy expenditure independent of intake |
The glucagon component is the key differentiating factor between Retatrutide and all other current GLP-1-based compounds. Glucagon is the counter-regulatory hormone to insulin, and its receptor is highly expressed in hepatocytes — making hepatic fat metabolism a primary research target for GCGR agonism.
Importantly, the GLP-1 and GIP components help counterbalance glucagon's hyperglycemic potential: by stimulating insulin secretion in a glucose-dependent manner, they prevent the blood glucose elevation that glucagon alone would produce. This balance is part of why triple agonism is being studied rather than glucagon agonism in isolation.
Retatrutide's phase 2 trial was published in the New England Journal of Medicine in June 2023 (Jastreboff et al.). The trial enrolled 338 adults with obesity (BMI ≥27) across five dose cohorts and ran for 48 weeks. Key results at 48 weeks:
| Dose | Mean Weight Reduction | Placebo-adjusted |
|---|---|---|
| Phase 2 dose-response and effect-size data is documented across multiple dose levels in the NEJM 2023 publication. Specific values are intentionally omitted here — refer to the primary literature for research-design reference. | ||
Specific effect-size readouts across dose levels are documented in the NEJM 2023 publication. The mechanistic differentiator — addition of glucagon-receptor agonism on top of GLP-1 and GIP — is the primary subject of comparative metabolic research vs single and dual agonists.
Secondary outcomes included improvements in waist circumference, blood pressure, triglycerides, and HbA1c. The most common adverse events were gastrointestinal (nausea, diarrhea, vomiting), consistent with GLP-1 class effects and concentrated during dose escalation phases.
Phase 3 trials (TRIUMPH program) are ongoing as of 2026, with results expected to provide longer-duration and larger-cohort efficacy and safety data.
Semaglutide is a selective GLP-1 receptor agonist — the mechanism behind Ozempic and Wegovy. Its phase 3 data (STEP trials, Wegovy 2.4mg weekly) showed approximately 15% body weight reduction over 68 weeks.
Semaglutide targets only GLP-1R — reducing caloric intake. Retatrutide additionally activates GCGR, which increases energy expenditure via thermogenesis and hepatic fat oxidation. One side of the energy equation vs both sides simultaneously.
The mechanistic comparison is straightforward: Retatrutide adds two additional receptor pathways to semaglutide's single-target mechanism. GIP adds incretin amplification and adipose tissue effects; glucagon adds energy expenditure and hepatic fat oxidation. The result at the highest Retatrutide dose is approximately 24% weight reduction vs 15% for semaglutide — a 9 percentage point difference in a shorter trial period.
For researchers, the relevant question is the mechanistic attribution: how much of Retatrutide's advantage comes from GIP vs glucagon agonism. Tirzepatide data (GLP-1+GIP, ~21%) vs Retatrutide data (GLP-1+GIP+glucagon, ~24%) suggests approximately 3 percentage points are attributable to the glucagon component — representing the direct metabolic expenditure increase driven by GCGR activation.
Read the full Retatrutide vs Semaglutide comparison →
Tirzepatide (Mounjaro/Zepbound) is a dual GLP-1/GIP agonist approved clinically for type 2 diabetes and obesity management. Its SURMOUNT-1 trial showed approximately 20-21% body weight reduction at the highest dose (15mg) over 72 weeks.
Comparing Retatrutide to tirzepatide isolates the contribution of the third receptor — glucagon. The result: Retatrutide's 12mg dose achieves ~24% weight reduction at 48 weeks vs tirzepatide's ~21% at 72 weeks. Even accounting for trial duration differences, the glucagon component appears to contribute 3-4 additional percentage points of body weight reduction.
The hepatic fat research angle is particularly interesting: GCGR activation directly reduces liver fat independent of caloric restriction — a mechanism that dual agonists lack. This makes Retatrutide specifically relevant for non-alcoholic fatty liver disease (NAFLD/NASH) research where hepatic lipid metabolism is a primary endpoint.
Read the full Retatrutide vs Tirzepatide comparison →
Retatrutide is primarily studied in the following research areas:
Corevanta's Retatrutide is provided as a lyophilized (freeze-dried) powder in clear borosilicate glass vials with rubber stoppers and aluminum crimp seals.
As with all research peptides, peptide integrity depends significantly on proper storage and handling. Solvent quality, solubilization technique, and storage temperature all affect the stability of the final solution.
Corevanta's Retatrutide is produced in GMP-compliant facilities and independently tested by third-party laboratories using HPLC purity analysis and LC-MS identity confirmation. All batches are verified at ≥99% purity before they enter inventory.
| Specification | Details |
|---|---|
| Purity | ≥99% (HPLC verified) |
| Identity verification | LC-MS mass spectrometry |
| Form | Lyophilized powder |
| Vial format | Clear borosilicate glass, rubber stopper, aluminum crimp |
| Available sizes | 5mg, 10mg, 20mg, 30mg |
| Certificate of Analysis | Available on product page |
All Corevanta products are sold exclusively for laboratory research purposes. They are not approved drugs, not dietary supplements, and are not intended for human consumption, therapeutic use, or any in-vivo application in humans. Always comply with applicable local regulations.