Description
MECHANISM OF ACTION
How Melanotan II Works
Understanding the biological pathways and mechanisms
MC1R Activation
Melanotan II is a non-selective melanocortin receptor agonist with high affinity for MC1R. Activation of MC1R on melanocytes stimulates eumelanin (brown/black pigment) production through the cAMP/PKA/MITF signaling cascade, resulting in skin darkening independent of UV exposure.
MC4R Effects
Melanotan II also activates MC4R in the hypothalamus, which modulates appetite suppression and sexual arousal pathways. MC4R activation stimulates oxytocin and dopamine release in brain regions associated with sexual function.
MC3R Metabolic Effects
Through MC3R agonism, Melanotan II influences energy homeostasis and fat metabolism. MC3R activation modulates feeding behavior, energy expenditure, and adipose tissue regulation through central nervous system signaling pathways.
KEY DISCOVERY
Synthetic Melanocortin Analog
Melanotan II is a cyclic heptapeptide analog of alpha-melanocyte stimulating hormone (α-MSH), developed at the University of Arizona. It acts as a non-selective agonist across melanocortin receptors (MC1R-MC5R), with primary research interest in melanogenesis, sexual function, and appetite modulation.
CLINICAL DATA
What Research Has Shown
Published findings from peer-reviewed studies on Melanotan II
7
Amino Acids (Cyclic)
5
MC Receptor Targets
99%+
Purity
Melanogenesis (MC1R)95%
Appetite Modulation (MC4R)82%
Metabolic Effects (MC3R)78%
Sexual Function Research76%
| Structure | Cyclic heptapeptide |
| Sequence | Ac-Nle-c[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂ |
| Molecular Weight | 1024.18 g/mol |
| Origin | University of Arizona |
| Receptor Profile | Non-selective MC1-5R agonist |
| Primary Research | Melanogenesis, sexual function |
SAFETY DATA
Safety Profile from Research
Reported adverse effects and safety considerations for Melanotan II
~25%
Nausea
~15%
Facial Flushing
~10%
Injection Site Reaction
~5%
Fatigue / Drowsiness
Nevi Changes
Melanotan II may cause changes in existing moles (nevi) including darkening, size changes, and new mole formation. Dermatological monitoring is strongly recommended in any research protocol involving melanogenesis.
Non-Selective Activity
As a non-selective MC receptor agonist, Melanotan II affects multiple systems (pigmentation, appetite, sexual function, inflammation). Researchers must account for these broad effects in study design.
Melanotan II has significant side effects including nausea, flushing, and mole changes. It is not FDA-approved and has been the subject of safety warnings from multiple regulatory agencies. All research use requires careful safety monitoring.
COMPOUND PROFILE
Compound Information
What is Melanotan II?
Melanotan II is a synthetic cyclic heptapeptide analog of α-MSH developed at the University of Arizona in the 1990s. Its cyclic structure (lactam bridge between Asp and Lys) provides enhanced metabolic stability compared to linear melanocortins. It acts as a non-selective agonist at melanocortin receptors MC1R through MC5R.
| Structure | Cyclic heptapeptide (lactam bridge) |
| Sequence | Ac-Nle-c[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂ |
| Molecular Weight | 1024.18 g/mol |
| CAS Number | 121062-08-6 |
| Formulation | Lyophilized Powder |
| Purity | 99%+ |
| Storage | -20°C |
Storage & Stability
Store lyophilized Melanotan II at -20°C protected from light. After reconstitution with bacteriostatic water, store at 2-8°C and use within 30 days. The cyclic structure provides good stability.
CURRENT STATUS
Where It Stands
Melanotan II is actively studied for melanogenesis, sexual dysfunction, and appetite modulation. It spawned the development of bremelanotide (PT-141), which was FDA-approved for HSDD. Melanotan II itself is not FDA-approved and has received regulatory warnings in multiple countries.
COMMON QUESTIONS
Frequently Asked Questions
Common questions about Melanotan II in research
What is Melanotan II?
Melanotan II is a synthetic cyclic peptide analog of alpha-MSH developed at the University of Arizona. It activates melanocortin receptors (MC1-5R) to stimulate melanin production, modulate appetite, and affect sexual function pathways.
How does Melanotan II differ from Melanotan I?
Melanotan I (afamelanotide) is a linear α-MSH analog selective for MC1R (melanogenesis). Melanotan II is a cyclic peptide that non-selectively activates all five MC receptors, producing broader effects including appetite and sexual function modulation.
What is the relationship to PT-141?
PT-141 (bremelanotide) is a metabolite/derivative of Melanotan II that was specifically developed for sexual function research. PT-141 received FDA approval in 2019 for hypoactive sexual desire disorder (HSDD) in women.
What are the safety concerns?
Key concerns include nausea (~25%), facial flushing, changes in existing moles (darkening, new formation), and non-selective receptor activation. Multiple regulatory agencies have issued warnings about Melanotan II.
Is Melanotan II FDA-approved?
No. Melanotan II is not FDA-approved and is sold for research purposes only. It has been the subject of safety advisories from FDA, TGA (Australia), and other regulatory bodies.
PUBLISHED RESEARCH
Sources & References
Peer-reviewed publications referenced in this overview
Life Sciences
Discovery and Development of Melanotan II
Annals of the New York Academy of Sciences
Melanocortin Receptors: Structure, Function, and Pharmacology
Journal of Sexual Medicine
Melanocortin Agonists and Sexual Function
Peptides
Cyclic Melanocortin Analogs: Structure-Activity Relationships
Important Research Notice
This product is sold strictly for research, educational, and scientific purposes only. It is not intended for human consumption, therapeutic use, or as a drug, food, cosmetic, or medical device. Not approved by the FDA for any clinical or diagnostic use. All research must comply with applicable local, state, and federal regulations. Buyer assumes full responsibility for ensuring legal compliance in their jurisdiction.
Verified Researcher –
Excellent purity and fast shipping. Melanotan II exceeded my research expectations.