Melanotan (MT)-II is a potent non-selective melanocortin receptor agonist with high affinity for MC1, MC3, MC4, and MC5 receptor subtypes which are involved in the regulation of a number of physiological systems such as the pigmentary system, energy homoeostasis, sexual functioning, the immune system, inflammation, and the cardiovascular system.

Melanotan (MT)-II exerts a dose-dependent inducer activity on erection by eliciting erectile events and shortening latency of the first erectile event to occur. Erectile responses elicited by cavernous nerve stimulation are increased after i.v. melanotan (MT)-II (1 mg/kg), thereby exerting facilitator effect on erection. Melanotan (MT)-II promotes peripheral nerve regeneration and has neuroprotective properties in the rat. Melanotan (MT)-II significantly enhances the recovery of sensory function following a crush lesion of the sciatic nerve in the rat at a dose of 20 μg/kg per 48 h, s.c., but not at a dose of 2 or 50 μg/kg. Melanotan (MT)-II is a potent initiator of penile erection in men with erectile dysfunction. Melanotan (MT)-II reduces food intake and body weight and invokes thermogenic responses in a mouse model.