Comparison
Semaglutide vs Tirzepatide vs PX1-R (Retatrutide)
A structural comparison of three incretin-class research peptides by receptor classification, backbone length, molecular profile and supplied format.
Semaglutide vs Tirzepatide vs PX1-R (Retatrutide)
This page compares the compounds as materials: what class each belongs to, what the molecule looks like, and how each is supplied. It is a structural and analytical reference — it makes no efficacy claims and contains no protocols.
Side-by-side profile
| Property | Semaglutide | Tirzepatide (GLP-2) | Retatrutide (GLP-3) |
|---|---|---|---|
| Classification | GLP-1 receptor agonist | dual GIP/GLP-1 receptor agonist | GIP/GLP-1/glucagon triple receptor agonist |
| Other designations | — | LY3298176 | LY3437943 |
| Molecular weight | 4114 g/mol | 4813 g/mol | 4731 g/mol |
| Reported half-life | ~7 days | ~5 days | ~6 days |
| Supplied vial sizes | 5 mg / 10 mg | 10 mg / 15 mg / 30 mg / 60 mg | 10 mg / 15 mg / 20 mg / 30 mg |
| Purity specification | ≥99% HPLC | ≥99% HPLC | ≥99% HPLC |
| Research focus | GLP-1 receptor research | incretin and metabolic research | metabolic and body-composition research |
Reading the comparison
Receptor classification is the meaningful difference between these compounds; vial size and purity specification are supply characteristics, not properties of the molecule. Where molecular weights differ substantially, expect different reconstitution arithmetic for the same nominal vial mass — run each through the peptide calculator.
Individual references
- Semaglutide
- Tirzepatide (GLP-2)
- Retatrutide (GLP-3)
Documentation supplied by PX1 Research
Every PX1 lot ships with HPLC purity, LC-MS identity confirmation, residual solvent, moisture (Karl Fischer), sterility and endotoxin data. Lot records are published at /coa and /endotoxin-reports. Synthesis, purification, lyophilization and vial fill are performed in U.S. facilities — see /manufacturing-process.
Research use only. PX1 Research supplies compounds for laboratory and in-vitro research. Nothing on this page is medical advice, a dosing recommendation, or an offer for human or veterinary use.