What Is Melanotan II?
Melanotan II (MT-II; CAS 121062-08-6) is a synthetic cyclic lactam heptapeptide analog of alpha-melanocyte-stimulating hormone (alpha-MSH). Its amino acid sequence is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, with a molecular weight of 1024.18 Da and molecular formula C50H69N15O9. Melanotan II was originally developed at the University of Arizona by researchers including Drs. Victor Hruby and Mac Hadley in the late 1980s and early 1990s as part of a program to design potent, metabolically stable melanocortin receptor ligands.
As a non-selective melanocortin receptor agonist, Melanotan II binds to multiple melanocortin receptor subtypes (MC1R through MC5R), which accounts for its diverse pharmacological profile in preclinical research. The compound is classified within the melanocortin peptide category and has been one of the most extensively studied synthetic melanocortin ligands in the scientific literature.
Melanotan II is sold exclusively for research use only (RUO). It is not approved by the FDA for any therapeutic indication. Wholesale buyers supplying dermatology research labs, pharmacology departments, and receptor biology programs can access institutional pricing through our wholesale peptide catalog.
Mechanism of Action
Melanotan II exerts its effects through activation of the melanocortin receptor family, a group of five G protein-coupled receptors (MC1R-MC5R) that play diverse roles in pigmentation, energy homeostasis, sexual function, inflammation, and adrenal steroidogenesis. The cyclic structure of Melanotan II confers enhanced binding affinity and metabolic stability compared to the linear alpha-MSH parent sequence.
At MC1R, expressed on melanocytes in the skin, Melanotan II stimulates the cAMP/PKA/CREB signaling cascade, leading to upregulation of tyrosinase and increased eumelanin synthesis. This pathway has made Melanotan II a primary tool compound in pigmentation biology research. At MC3R and MC4R, which are densely expressed in the hypothalamus, the peptide modulates energy balance and feeding behavior circuits. MC4R activation is also linked to the erectile and sexual function pathways studied in behavioral neuroscience.
The non-selective nature of Melanotan II across melanocortin receptor subtypes distinguishes it from more selective analogs like PT-141/Bremelanotide, which was derived from Melanotan II but engineered for preferential MC3R/MC4R activity. Researchers frequently use both compounds in comparative receptor selectivity studies. Additional melanocortin pathway compounds in our catalog include peptides relevant to cosmetic and skin research.
Research Applications
Melanotan II has been investigated across a remarkably broad range of preclinical research domains:
Melanogenesis and Pigmentation Research
The most extensively documented application involves Melanotan II’s effects on melanocyte biology. Researchers have studied the peptide in melanocyte cell cultures and animal models to elucidate MC1R-mediated signaling, eumelanin versus pheomelanin switching, and UV-independent pigmentation pathways. These studies are foundational to understanding melanocyte function, melanoma biology, and photoprotection mechanisms. Related cosmetic-skin peptides such as GHK-Cu are sometimes studied in parallel for skin biology applications.
Melanocortin Receptor Pharmacology
As a potent, non-selective melanocortin agonist, Melanotan II serves as a critical reference compound in receptor binding assays, functional cAMP assays, and structure-activity relationship (SAR) studies. Researchers use it alongside selective MC receptor agonists and antagonists to map the contributions of individual receptor subtypes to physiological functions.
Energy Homeostasis and Appetite Regulation
Preclinical studies in rodent models have documented Melanotan II’s effects on food intake and body weight through MC3R/MC4R pathways in the hypothalamus. These findings are relevant to researchers studying central melanocortin circuits in obesity and metabolic regulation. Related weight management compounds such as Semaglutide and Retatrutide target overlapping metabolic pathways through distinct receptor mechanisms.
Sexual Function Research
Melanotan II has been studied in animal models for its effects on male erectile function and female sexual behavior through central MC3R/MC4R activation. This research directly informed the development of PT-141/Bremelanotide, a structurally related but more receptor-selective compound.
Institutions needing high-volume supply can view pricing at the Melanotan II wholesale page.
Available Formats and Bulk Options
Wholesale Bulk Peptides supplies Melanotan II in multiple research-ready formats:
- 5 mg lyophilized vials — suited for receptor binding studies, cell-based assays, and pilot in vivo experiments
- 10 mg lyophilized vials — appropriate for dose-response studies and extended research protocols
- Bulk lyophilized powder — available in gram quantities for CROs, peptide resellers, and private-label peptide brands
Custom vial configurations and labeling are available for qualified accounts. Apply through the wholesale program application.
Wholesale Pricing Summary
Melanotan II wholesale pricing follows a volume-tiered structure for B2B buyers, research institutions, and peptide resellers. Pricing decreases significantly at higher volume tiers. For detailed pricing, MOQs, and delivery schedules, visit the Melanotan II wholesale page. New accounts can apply at the wholesale program portal.
Quality Assurance, Testing, and COAs
Every batch of Melanotan II undergoes rigorous analytical testing:
- HPLC — confirms purity of 98% or greater with full chromatographic profile including lactam cyclization verification
- Mass Spectrometry — validates the 1024.18 Da molecular weight and confirms cyclic structure integrity
- Amino Acid Analysis — quantifies residue ratios including the D-Phe stereochemistry
- Endotoxin Testing (LAL) — ensures suitability for cell-based and in vivo research applications
Batch-specific COAs are provided with every order. Access our COA library and testing methodology page for complete analytical details. The Peptide COA Guide provides interpretation guidance.
Storage and Stability
Store Melanotan II lyophilized powder at -20 degrees Celsius in a light-protected, sealed container. The cyclic peptide structure provides enhanced stability compared to linear analogs, with a shelf life exceeding 24 months under proper storage conditions. Reconstitute with bacteriostatic water or sterile saline and store at 2-8 degrees Celsius for use within 30 days. The Trp residue in Melanotan II is photosensitive; minimize light exposure during handling and storage. Aliquot reconstituted solutions to avoid repeated freeze-thaw cycles.
Compliance and Intended Use
Melanotan II is sold by Wholesale Bulk Peptides strictly for research use only (RUO). It is not intended for use as a drug, tanning agent, dietary supplement, food additive, or cosmetic product. This compound has not been approved by the FDA or any equivalent regulatory body for human or veterinary use. All purchasers are responsible for ensuring compliance with applicable regulations and maintaining proper RUO labeling on all product packaging and documentation.
Related Compounds
Researchers working with Melanotan II frequently investigate related melanocortin and metabolic peptides:
- PT-141/Bremelanotide — a Melanotan II derivative with preferential MC3R/MC4R selectivity for sexual function research
- KPV — the C-terminal tripeptide fragment of alpha-MSH with anti-inflammatory properties via MC1R
- GHK-Cu — a copper-peptide complex studied for skin biology and tissue remodeling applications
- AOD-9604 — an hGH fragment studied for lipolytic effects complementary to MC receptor-mediated metabolic regulation
Browse the complete melanocortin peptide catalog and explore our Start a Peptide Brand resource for white-label opportunities.
Frequently Asked Questions About Melanotan II
Our technical team addresses the most common wholesale buyer questions about Melanotan II, covering purity specifications, reconstitution protocols, storage requirements, and regulatory considerations. For product-specific FAQs, see the Melanotan II wholesale page. For general program questions, visit the wholesale peptides hub.
Disclaimer: This material is provided for informational and research purposes only. Melanotan II is sold as a Research Use Only (RUO) compound. It is not intended for human or veterinary diagnostic or therapeutic use, nor is it intended as a tanning product. All buyers are responsible for ensuring compliance with applicable laws and institutional guidelines. Wholesale Bulk Peptides makes no claims regarding the safety or efficacy of this compound for any purpose other than qualified laboratory research.