Research Use Only. GLP-3 (Retatrutide) is a research peptide intended strictly for laboratory and scientific use. Not approved for human consumption or therapeutic application.
What is GLP-3 (Retatrutide)?
GLP-3, sold at Peppy University under its research designation, is the compound widely known in clinical research as Retatrutide — a next-generation triple agonist peptide developed by Eli Lilly currently in Phase 3 TRIUMPH trials as of 2026. Unlike semaglutide (GLP-1 only) and tirzepatide (GLP-1 + GIP dual agonist), GLP-3 simultaneously targets three metabolic receptors: GLP-1, GIP, and glucagon — making it the most advanced GLP peptide studied to date for metabolic research.
Phase 2 trial data published in JAMA showed Retatrutide produced a mean body weight reduction of 24.2% at 48 weeks at the 12mg dose — surpassing both semaglutide (~15%) and tirzepatide (~20-22%) in head-to-head metabolic endpoints. Continuous weight loss through 48 weeks was observed with no plateau, a result that has driven significant interest in the research community.
GLP-3 vs Semaglutide vs Tirzepatide
Understanding where GLP-3 (Retatrutide) sits in the GLP peptide landscape is essential for research protocol design:
- Semaglutide (GLP-1 agonist) — targets GLP-1 receptor only. Drives insulin secretion, appetite suppression, and gastric motility. ~15-17% average weight reduction in trials.
- Tirzepatide (GLP-1/GIP dual agonist) — targets GLP-1 + GIP receptors. Enhanced insulin response and adipose tissue signaling. ~20-22% average weight reduction in trials.
- GLP-3 / Retatrutide (GLP-1/GIP/Glucagon triple agonist) — targets all three receptors. Adds glucagon receptor activation which increases energy expenditure and drives hepatic fat oxidation. ~24.2% average weight reduction in Phase 2 trials.
GLP-3 (Retatrutide) in Preclinical & Clinical Research
- Triple receptor agonism — Retatrutide simultaneously activates GLP-1, GIP, and glucagon receptors, offering a uniquely broad metabolic signaling profile for laboratory investigation.
- Body composition studies — Phase 2 data showed continuous, unplateaued weight loss through 48 weeks, with dose-dependent responses across 0.5mg, 4mg, 8mg, and 12mg weekly protocols.
- Hepatic fat reduction — The glucagon component drives hepatic fat oxidation pathways not activated by GLP-1 or GIP alone, relevant to NAFLD and metabolic liver disease research models.
- Glucose and insulin regulation — Research has documented Retatrutide’s effects on fasting glucose, postprandial glucose, HbA1c, and insulin sensitivity in metabolic dysfunction models.
- Cardiovascular pathways — Emerging research examines GLP-1/GIP/glucagon receptor expression in cardiac tissue and potential cardioprotective signaling mechanisms.
- Lean mass preservation — Early data on lean mass preservation during weight loss protocols has generated significant interest compared to GLP-1-only compounds.
Why GLP-3 Over Semaglutide or Tirzepatide for Research?
For researchers designing metabolic studies in 2026, GLP-3 (Retatrutide) offers several research advantages over single or dual agonists:
- Enables investigation of glucagon receptor contributions to metabolic outcomes — a pathway not accessible with semaglutide or tirzepatide protocols alone
- Allows study of triple vs dual vs single agonist comparative endpoints within the same research framework
- More aggressive metabolic effects provide cleaner signal differentiation in body composition and glucose metabolism models
- As an investigational compound not yet FDA-approved, GLP-3 remains available for research-grade laboratory procurement without the supply constraints affecting compounded semaglutide and tirzepatide
Molecular Profile
- Mechanism: GLP-1/GIP/Glucagon triple receptor agonist
- Form: Lyophilized powder
- Purity: 99% (HPLC verified)
- Storage: -20°C, protected from light and moisture
- Reconstitution: Bacteriostatic water or sterile saline
Sourcing GLP-3 (Retatrutide) for Research
Peppy University supplies GLP-3 in two research sizes:
- GLP-3 10mg — ideal for initial protocol testing and dose-response studies
- GLP-3 30mg — best value for extended research protocols
Both available with 99% purity, HPLC verified, and full research documentation. Also available as part of the Metabolic Stack combined with Tesamorelin 10mg and Reconstitution Solution.
All products at Peppy University are intended strictly for laboratory and scientific research purposes only. Not for human consumption. Research Use Only.
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