The first single-molecule triple agonist — GIP, GLP-1 and glucagon receptors together. An evidence-based overview of how it works, what the trials show, how it is dosed in studies, and how to buy it in Sweden and the EU with a batch Certificate of Analysis.
Retatrutide (development code LY3437943, CAS 2381089-83-2) is an investigational peptide that activates three metabolic receptors at once: GIP, GLP-1 and glucagon. That "triple agonism" is what sets it apart from GLP-1 agonists such as semaglutide (Ozempic/Wegovy) and the dual GIP/GLP-1 agonist tirzepatide (Mounjaro). It is currently in clinical development and is not an approved medicine; on this site it is sold strictly as a research compound.
GLP-1 — reduces appetite and increases satiety (the mechanism behind semaglutide).
GIP — improves insulin sensitivity and lipid handling (adds the tirzepatide effect).
Glucagon — raises energy expenditure via hepatic thermogenesis and reduces liver fat — the component unique to retatrutide.
The headline result comes from the phase-2 obesity trial published in 2023. Participants on the highest dose (12 mg/week) showed up to 24.2% mean body-weight reduction at 48 weeks — larger than figures reported for semaglutide or tirzepatide in comparable studies. A parallel phase-2 study in type-2 diabetes reported dose-dependent HbA1c reductions alongside weight loss.
| Study | Year | Key finding |
|---|---|---|
| Phase 2 — Retatrutide in obesity (Jastreboff et al.) | 2023 | Up to 24.2% weight loss at 12 mg over 48 weeks |
| Phase 2 — Retatrutide in type-2 diabetes | 2023 | Dose-dependent HbA1c reduction + weight loss |
Study protocols titrate the dose upward slowly to manage tolerability. A representative schedule from the trials:
| Week | Dose / week |
|---|---|
| 1–4 | 1–2 mg |
| 5–8 | 4 mg |
| 9–12 | 8 mg |
| 13+ | up to 12 mg (max studied) |
Administered subcutaneously once weekly. This reflects published research and is not medical advice; it does not describe recommended human use.
A vial is lyophilised (freeze-dried) powder that you reconstitute with bacteriostatic water (included) and draw with an insulin syringe — the lowest cost per mg and full control of the dose. A pen is pre-mixed at the factory with built-in dose adjustment — no mixing and no unit maths, but more per mg.
| Compound | Receptors | Class |
|---|---|---|
| Semaglutide | GLP-1 | Single agonist |
| Tirzepatide | GIP + GLP-1 | Dual agonist |
| Retatrutide | GIP + GLP-1 + glucagon | Triple agonist |
Pepixfi ships from a Swedish warehouse with a batch-specific Certificate of Analysis (HPLC ≥99%, mass spectrometry for identity), bacteriostatic water included, in neutral packaging. Prices in SEK:
Reconstitution calculator
Work out exact BAC-water volumes and units per dose.
A single-molecule triple agonist (GIP/GLP-1/glucagon), development code LY3437943. It produced greater weight reduction than semaglutide or tirzepatide in phase-2 research. It is a research compound, not an approved medicine.
Up to 24.2% at 12 mg/week over 48 weeks in the phase-2 obesity trial (Jastreboff et al., 2023).
Gradual titration from 1–2 mg/week to 8–12 mg/week, subcutaneous once weekly. Research reference only, not medical advice.
Vial = lowest cost per mg, mixed with included BAC water. Pen = pre-mixed, simplest to dose, more per mg.
Pepixfi ships from Sweden with a batch COA, vial (10/20/40 mg) and pen (20/40 mg), from 749 SEK. Sold for research use only.
Pepixfi