Melanotan II in Australia: Research Guide & Where to Buy

Melanotan II (MT-2, sequence: Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2) is a synthetic cyclic heptapeptide analogue of α-MSH (alpha-melanocyte-stimulating hormone), developed by Victor Hruby and colleagues at the University of Arizona in the late 1980s as part of a programme investigating melanocortin receptor agonists. It is a cyclised, shortened, and stabilised derivative of the 13-amino-acid α-MSH sequence, with substantially improved potency and metabolic stability compared to the native hormone.

MT-2 acts as a non-selective agonist across the melanocortin receptor family (MC1R, MC3R, MC4R, and MC5R) with particularly high potency at MC1R (the primary pigmentation receptor) and MC4R (the central receptor governing appetite and sexual function). This broad receptor profile has made it a valuable research tool for studying melanocortin system biology, and also the parent compound from which the more selective PT-141 (Bremelanotide) was later derived.

Understanding MT-2 requires understanding the five melanocortin receptors (MC1R–MC5R), each with distinct tissue distribution and functional roles:

• MC1R, expressed on melanocytes; activation stimulates eumelanin (brown/black pigment) synthesis via the cAMP-PKA-MITF signalling cascade; primary target for MT-2's pigmentation effects
• MC3R, expressed in the hypothalamus, limbic system, and peripheral tissues; involved in energy homeostasis and natriuresis
• MC4R, expressed throughout the CNS, particularly in the hypothalamus; central regulator of appetite, energy expenditure, and sexual function; activation suppresses food intake and body weight in animal models
• MC5R, expressed in exocrine glands; involved in exocrine secretion regulation

MT-2 activates all four of these receptors, producing a multi-system response that has been studied across pigmentation biology, metabolic research, and sexual function research simultaneously.

• Melanogenesis and skin pigmentation, Phase 1 human trials conducted at the University of Arizona demonstrated that subcutaneous MT-2 administration produced dose-dependent increases in skin pigmentation in fair-skinned subjects, with effects beginning within days and persisting for weeks after cessation; eumelanin content of skin biopsies increased significantly
• Sexual function, early clinical research at the University of Arizona documented pro-erectile responses in male subjects in a double-blind crossover trial (Wessells et al., 1998, Journal of Urology); this finding drove subsequent development of the more selective PT-141 (Bremelanotide), which received FDA approval in 2019
• Appetite suppression and body weight, MC4R activation by MT-2 reduces food intake and body weight in rodent models; this has been studied both as an independent effect and as a potential confound in pigmentation research protocols
• Nausea and gastric motility, a consistent finding in both animal and human studies; MT-2 produces dose-dependent nausea via central MC3R/MC4R activation, which was a primary driver for developing more receptor-selective analogues for therapeutic applications
• Photoprotection research, MC1R activation upregulates eumelanin, which provides greater UV photoprotection than pheomelanin; this has been studied in models of UV-induced DNA damage and skin cancer risk

PT-141 (Bremelanotide) was derived directly from MT-2 research. The key difference is receptor selectivity:

• MT-2, non-selective; activates MC1R, MC3R, MC4R, MC5R; produces pigmentation, appetite suppression, sexual effects, and nausea simultaneously
• PT-141, selective for MC3R and MC4R; minimal MC1R activity means reduced pigmentation effects; FDA-approved for HSDD in premenopausal women (Vyleesi, 2019)

For researchers specifically studying sexual motivation pathways in isolation from pigmentation effects, PT-141 is more appropriate. MT-2 remains the compound of choice for researchers studying the full melanocortin receptor profile or specifically investigating MC1R-mediated melanogenesis alongside other melanocortin effects. See also: PT-141 research guide →

OzPeps stocks research-grade Melanotan II with fast AU shipping and discreet packaging. View Melanotan II stock and pricing →

Melanotan II is sold strictly for in-vitro laboratory research purposes only. Not TGA-approved. Not for human or animal consumption. Researchers are responsible for all applicable regulatory compliance.