Comparison
Melanotan I vs Melanotan II
A structural comparison of Melanotan I and Melanotan II by classification, peptide structure and supplied format.
Melanotan I vs Melanotan II
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 | Melanotan I (Afamelanotide) | Melanotan II |
|---|---|---|
| Classification | linear α-MSH analog | cyclic melanocortin analog |
| Other designations | — | — |
| Molecular weight | See lot COA | See lot COA |
| Reported half-life | — | — |
| Supplied vial sizes | 10 mg | 10 mg |
| Purity specification | ≥99% HPLC | ≥99% HPLC |
| Research focus | MC1R-selective research | melanocortin receptor 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
- Melanotan I (Afamelanotide)
- Melanotan II
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.