Melanotan II at a glance
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Melanotan II is a synthetic cyclic analog of alpha-melanocyte stimulating hormone (α-MSH) that binds to and activates multiple melanocortin receptors: MC1R (melanin production and skin tanning), MC3R/MC4R (sexual arousal, libido, and energy balance), and MC5R (exocrine gland function). It was originally developed at the University of Arizona as a sunless tanning agent intended to reduce skin cancer risk.
Its potent activation of MC4R in the hypothalamus and limbic system produces central pro-sexual effects - increasing desire, arousal, and in men, penile erection through a pathway independent of PDE5. This mechanism led to the development of PT-141 (bremelanotide), a more selective analog. Because Melanotan II is non-selective, it also produces stronger appetite suppression and more pronounced autonomic effects than PT-141.
Melanotan II was never approved by any regulatory agency due to safety concerns identified in trials (primarily nausea/vomiting, spontaneous erections, and facial flushing). It is widely available through research chemical suppliers but is technically unapproved and its use is not without risk. Facial moles and nevi may darken with use, requiring dermatological monitoring.
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