Written by the Core Power Peptides Research Team — biochemists and laboratory specialists compiling and verifying peptide research data. Learn about our quality standards →
Melanotan 2 was designed at the University of Arizona in the 1980s with a specific public health goal: a tanning agent that could reduce skin cancer incidence by inducing pigmentation without UV exposure. What researchers found instead was a nonselective melanocortin agonist with effects spanning pigmentation, sexual function, appetite, and immune signaling — and that breadth is precisely why MT-2 became the structural template for PT-141.
Melanotan 2: A Nonselective Melanocortin Agonist
Melanotan 2 (MT-2; sequence: Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2) is a cyclic lactam analog of α-melanocyte stimulating hormone (α-MSH) developed at the University of Arizona in the 1980s as part of a program aimed at creating a safe tanning agent to reduce skin cancer incidence. Unlike its parent compound melanotan I (afamelanotide, which selectively targets MC1R), MT-2 is a nonselective melanocortin agonist activating MC1R, MC3R, MC4R, and MC5R — producing a broader set of physiological effects that have driven its extensive use as a research tool for the melanocortin system.
MT-2 served as the structural template from which PT-141 (bremelanotide) was derived — with PT-141 retaining the MC4R and MC3R activity while losing the cyclic structure’s MC1R potency. This lineage makes MT-2 uniquely valuable for comparative melanocortin receptor research.
Mechanism of Action
- MC1R Agonism: Stimulates melanocytes to produce eumelanin (dark brown-black pigment), increasing skin pigmentation — the originally intended pharmacological application
- MC3R Agonism: Influences energy balance, feeding behavior, and immune modulation through hypothalamic MC3R
- MC4R Agonism: Primary mediator of MT-2’s effects on sexual arousal, energy expenditure, and appetite suppression — the same receptor targeted by PT-141
- MC5R Agonism: Implicated in exocrine gland function and immune responses
- Nitric Oxide Release: MC4R activation increases hypothalamic NO, contributing to erectile/genital effects
Research Applications and Data
Pigmentation Research
- Demonstrated reliable tanning effect in Phase 1/2 human trials (Hadley et al., University of Arizona)
- Increased Melanin Index scores vs. placebo in fair-skinned participants
- Established as the primary research tool for MC1R biology and eumelanin synthesis pathways
Sexual Function Research
- Phase 1/2 studies demonstrated erection facilitation in men with psychogenic and organic ED
- Mechanistic studies established MC4R as the primary receptor mediating sexual arousal effects
- Served as proof-of-concept for the melanocortin-sexual function axis, leading to PT-141 development
Metabolic and Feeding Research
- MC4R-mediated appetite suppression documented in rodent feeding behavior studies
- Used extensively as a pharmacological probe for MC3R/MC4R function in energy balance research
- Nausea via area postrema MC3R activation — a key adverse effect that informed PT-141’s design to reduce emetic potential
Immune Research
- Documented anti-inflammatory effects via MC3R/MC5R in models of joint inflammation and sepsis
- MC1R activation on immune cells modulates macrophage and dendritic cell inflammatory cytokine production
MT-2 vs. PT-141 vs. Afamelanotide — Research Comparison
| Parameter |
Melanotan 2 (MT-2) |
PT-141 (Bremelanotide) |
Afamelanotide (MT-1) |
| Structure |
Cyclic heptapeptide |
Cyclic heptapeptide (linear analog) |
Linear tridecapeptide |
| MC1R potency |
High |
Low |
High (selective) |
| MC4R potency |
High |
High (primary target) |
Low |
| FDA approval |
None |
Yes (Vyleesi — HSDD) |
Yes (Scenesse — EPP) |
| Primary research use |
Pan-MC receptor pharmacology |
MC4R-mediated sexual function |
MC1R, photoprotection |
HPLC Verified
Melanotan 2 Acetate (MT-2) 10mg
Purity: 99%+ HPLC
Format: Lyophilized Powder
Testing: Third-Party COA
$105
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Frequently Asked Questions
How does MT-2 relate to PT-141?
PT-141 (bremelanotide) was derived directly from MT-2, retaining the MC4R and MC3R activity that mediates sexual function while losing much of the cyclic structure’s MC1R pigmentation potency. That structural narrowing is what allowed PT-141 to reach FDA approval where MT-2 did not.
Why is MT-2 still used in research if PT-141 is approved?
Because pan-receptor activity is sometimes the point. MT-2 engages MC1R, MC3R, MC4R, and MC5R, making it a useful pharmacological probe for melanocortin system research broadly — whereas PT-141 is largely restricted to MC4R-mediated pathways.
What causes the nausea reported in MT-2 research?
Area postrema MC3R activation. This adverse effect directly informed PT-141’s design, which sought to reduce emetic potential relative to the parent compound.
Scientific reference only. Melanotan 2 from Core Power Peptides is supplied strictly for in vitro and laboratory research — not for human consumption, and not medical guidance.
