Melanotan 2 is a cyclic heptapeptide α-MSH analog binding MC1R, MC3R, MC4R, and MC5R — studied in preclinical models for melanin synthesis, sexual function, and appetite suppression via the melanocortin system.
Product definition
What is Melanotan 2?
Melanotan 2 is a cyclic heptapeptide α-MSH analog binding MC1R, MC3R, MC4R, and MC5R — studied in preclinical models for melanin synthesis, sexual function, and appetite suppression via the melanocortin system.
Melanotan 2 is a cyclic analog of α-MSH, developed by Victor Hruby's group at the University of Arizona as part of a program to create stable, potent melanocortin receptor agonists for studying the physiological roles of the MC receptor family. The cyclization via a disulfide bridge between cysteines at positions 4 and 10 dramatically increases potency over the linear α-MSH sequence and confers resistance to enzymatic degradation.
The compound's research profile spans three distinct biological systems: (1) pigmentation biology, where MC1R activation on melanocytes promotes eumelanin synthesis with documented rodent and early human volunteer tanning data; (2) sexual behavior pharmacology, where MC4R activation in hypothalamic and limbic structures produces erection and sexual motivation effects in rat models, leading to the derivative compound PT-141 (bremelanotide); (3) appetite and feeding behavior, where MC4R/MC3R activation in the arcuate nucleus and paraventricular nucleus produces food intake suppression in rodent feeding models.
Research context
How is Melanotan 2 described in the research literature?
Melanotan 2 activates melanocortin receptors with broad selectivity: MC1R activation drives eumelanin synthesis in melanocytes (tanning research); MC4R activation in hypothalamic circuits produces appetite suppression and sexual arousal effects in animal models. The compound's cross-receptor activity profile has made it a research tool across pigmentation biology, appetite neuroscience, and sexual function pharmacology.
Compound profile
Key facts about Melanotan 2
- Class
- Cyclic heptapeptide α-MSH analog
- Target
- MC1R, MC3R, MC4R, MC5R (broad melanocortin receptor agonist)
- Molecular weight
- ~1,025 Da
- Half-life
- ~30 minutes in vivo
- CAS
- 121062-08-6
- Research category
- Melanocortin pharmacology, pigmentation, sexual function, appetite
- Storage
- Lyophilized: −20°C. Reconstituted: 2–8°C, use within 30 days
Research areas
What research areas is Melanotan 2 associated with?
- Broad melanocortin receptor agonism (MC1R, MC3R, MC4R, MC5R) — research tool for full MC receptor pharmacology
- Studied for MC1R-mediated eumelanin synthesis and pigmentation in melanocyte and rodent models
- Investigated for MC4R-mediated sexual arousal and erection mechanisms in rat behavioral models
- Researched for appetite suppression and feeding behavior via MC3R/MC4R hypothalamic pathways
- Preclinical ancestor of PT-141 (bremelanotide, FDA-approved) — established pharmacological lineage
- Most extensively published broad-spectrum melanocortin receptor agonist in the preclinical literature
Research audience
Who researches Melanotan 2?
Melanotan 2 is used by researchers in melanocortin receptor pharmacology, pigmentation biology, sexual function neuroscience, appetite regulation, and hypothalamic circuit research. It is the reference broad-spectrum MCR agonist for studies requiring activation across the full MC receptor family.
Preclinical research overview
What does the preclinical literature say about Melanotan 2?
Melanotan 2 was developed in the 1990s by Victor Hruby's group at the University of Arizona as part of a systematic program to create stable melanocortin receptor agonists for studying the MC receptor family's diverse physiological roles. The original motivation was photoprotection: developing a pharmacological tanning agent that could reduce UV-induced skin cancer risk. This research produced compelling rodent pigmentation data that was subsequently evaluated in early human volunteer studies.
The sexual function research emerged unexpectedly: investigators studying MT-2's pigmentation effects in male rats observed spontaneous erections as a side effect, leading to the deliberate investigation of MC4R's role in sexual arousal mechanisms. This discovery produced the PT-141 development program, which ultimately achieved FDA approval as bremelanotide (Vyleesi) — making the Melanotan 2 research lineage one of the few cases where preclinical peptide research produced a regulatory-approved therapeutic.
The appetite research dimension arose from the observation that MC4R knockout mice develop severe obesity, establishing MC4R as a critical node in energy balance regulation. MT-2's effects in feeding behavior models, combined with MC3R co-agonism (which regulates energy partitioning), have supported investigation of the melanocortin system as a potential anti-obesity target.
Common questions
Frequently asked about Melanotan 2
How does Melanotan 2 differ from PT-141?
Both are cyclic melanocortin receptor agonists derived from the same development program. Melanotan 2 is a broad-spectrum MCR agonist with significant MC1R activity (tanning effect) alongside MC4R activity. PT-141 (bremelanotide) was specifically developed to retain MC4R activity for sexual function research while reducing MC1R activity — it is an α-MSH derivative without the α-amino group, shifting the receptor selectivity profile. For melanocortin receptor research requiring full MC1R-through-MC5R coverage, MT-2 is the appropriate compound; for selective MC3R/MC4R research with minimal MC1R confounding, PT-141 is preferred.
What is the published pigmentation research basis for MT-2?
Melanotan 2 produced dose-dependent increases in eumelanin content in melanocyte cell culture models and in rodent skin pigmentation studies. Early human volunteer studies (unpublished Phase I-equivalent trials at University of Arizona) documented increased skin tanning responses with subcutaneous administration. The mechanism is MC1R activation → adenylyl cyclase → cAMP → MITF transcription factor → tyrosinase upregulation → eumelanin synthesis.
What storage conditions are required for Melanotan 2?
Lyophilized MT-2 is stable at −20°C. Once reconstituted, store at 2–8°C and use within 30 days. The cyclic disulfide bond is relatively stable but should not be exposed to reducing conditions (DTT, BME) which can linearize the peptide and destroy activity. Protect reconstituted material from light.
Research Use Only
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