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 an independent lab report.
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. The schedule used in the phase-3 TRIUMPH trials:
| Week | Dose / week |
|---|---|
| 1–4 | 2 mg (start) |
| 5–8 | 4 mg |
| 9–12 | 6 mg |
| 13–16 | 9 mg |
| 17+ | 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 one fixed dose (6 mg) — no mixing and no unit maths, but more per mg, and 6 mg is not a starting dose (trials start at 2 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. Batch RT15800 was tested by an independent lab, Janoshik Analytical: 99.787 % purity (report on our lab page). Bacteriostatic water included, in neutral packaging. Prices in SEK:
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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).
Phase-3 trials start at 2 mg/week and step up every four weeks — 2 → 4 → 6 → 9 → 12 mg — to target doses of 4, 9 or 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 (10/15/30/60 mg) and pen (30 mg), from 849 SEK. Sold for research use only.
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