Technical Specifications
| Characteristic | Value |
|---|
| CAS Number | 121062-08-6 |
| Molecular Weight | 1,024.18 Da |
| Molecular Formula | C₅₀H₆₉N₁₅O₉ |
| Purity | ≥98% by RP-HPLC |
| Form | Lyophilized powder, 10 mg per vial |
| Sequence | Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂ |
Melanotan-2 (MT-II) is a synthetic cyclic heptapeptide analog of alpha-melanocyte-stimulating hormone (α-MSH), originally developed at the University of Arizona in the early 1990s as an investigational photoprotective agent. The compound was rationally engineered through D-amino acid substitutions, norleucine replacement of methionine, and lactam bridge cyclization to dramatically enhance metabolic stability, receptor potency, and bioavailability relative to the endogenous linear α-MSH peptide. Intended strictly for qualified researchers as an investigational tool, MT-II functions as a non-selective pan-agonist at melanocortin receptors MC1R, MC3R, MC4R, and MC5R, exhibiting 100–1000-fold greater potency than native α-MSH at these subtypes. Two key structural modifications confer an extended in vivo half-life of approximately 33 hours: norleucine at position 4 eliminates an oxidation-susceptible sulfur, while D-Phe at position 7 confers proteolytic resistance. MT-II has been validated in over 400 peer-reviewed publications and served as the structural template for bremelanotide (PT-141, approved 2019) and afamelanotide (Scenesse, EMA-approved for erythropoietic protoporphyria).
Key Research Highlights
| Research Area | Key Finding |
|---|
| MC1R Melanogenesis | Binds MC1R (Ki = 0.67 nM), activating cAMP/PKA/CREB/MITF cascade; upregulates tyrosinase, TRP-1, TRP-2/DCT; preferentially produces photoprotective eumelanin (Dorr et al., 1996; Mun et al., 2023) |
| MC4R Metabolic Signaling | Intracerebroventricular administration increases glucose disposal (151±20 vs. 108±20 µmol/min/kg); GLUT4 mRNA upregulated ~3-fold in skeletal muscle (Heijboer et al., 2005) |
| Adipose Tissue Biology | Peripheral treatment altered retroperitoneal and epididymal WAT compartments in high-fat-fed mice; pair-fed controls retained more adipose tissue, indicating direct lipolytic mechanisms (Strader et al., 2007) |
| Neuroprotection | 20 µg/kg per 48h enhanced sensory recovery after sciatic nerve crush injury; partially protected against cisplatin-induced neuropathy (Ter Laak et al., 2003) |
| Vascular Inflammation | Reduced 18F-FDG uptake in atherosclerotic plaques, shifted macrophages to M2 phenotypes, enhanced endothelium-dependent relaxation independent of metabolic changes (Rinne et al., 2014) |
Research Applications
- Melanocortin Receptor Pharmacology (MC1R–MC5R signaling, SAR studies)
- Melanogenesis and Photobiology Research
- MC4R Hypothalamic Energy Homeostasis Studies
- Adipose Tissue Lipolysis and Body Composition Research
- Neuroprotection and Peripheral Nerve Regeneration Models
- Atherosclerosis and Vascular Inflammation Research
- Alcohol Use Disorder Neuropharmacology
- Antidepressant Target Research (MC4R/HPA Axis)
Research Use Only. This product is supplied for in vitro laboratory investigation by qualified researchers. Not for human or veterinary consumption, diagnosis, treatment, prevention, or cure of any condition. Not approved by the FDA for human use. Classified as a prohibited substance under the WADA 2025 Prohibited List.
