What Is Melanotan II?
Melanotan II (MT-II) is a cyclic, lactam-bridged analogue of α-melanocyte-stimulating hormone (α-MSH), a naturally occurring neuropeptide derived from POMC (pro-opiomelanocortin). It was originally developed at the University of Arizona in the 1980s and 1990s as a potential systemic photoprotective agent — the idea being to stimulate pigmentation prior to UV exposure, reducing skin cancer risk.
Mechanism of Action
MT-II is a non-selective melanocortin receptor agonist, binding MC1R, MC3R, MC4R, and MC5R with varying affinity:
| Receptor | Effect | |---|---| | MC1R | Melanogenesis (pigmentation), anti-inflammatory | | MC3R | Energy homeostasis, appetite modulation | | MC4R | Sexual function, erection, appetite suppression | | MC5R | Exocrine gland regulation |
MC4R activation is responsible for both the libido-enhancing and appetite-suppressive effects observed in research subjects.
Research Findings
- Tanning: Clinical studies showed dose-dependent increases in skin melanin density with minimal UV exposure in fair-skinned subjects
- Erectile function: Phase II trials for MC4R-mediated erectile dysfunction demonstrated significant improvements versus placebo; this work led directly to Bremelanotide (PT-141) development
- Appetite suppression: Preclinical rodent studies show strong anorectic effects via hypothalamic MC4R
- Adverse effects studied: Nausea, facial flushing, spontaneous erection, and yawning are the most commonly documented research observations
Research Notes
Melanotan II is available for in-vitro and preclinical research. Store lyophilised peptide at −20°C.
Related compounds: PT-141 (Bremelanotide), Selank.