Unlike erectile dysfunction drugs that affect blood flow, PT-141 works directly in the central nervous system. It’s an analog of the alpha-MSH (melanocyte-stimulating hormone) family, specifically acting as a melanocortin receptor agonist, primarily at MC-3 and MC-4 receptors in the hypothalamus. These melanocortin receptors are involved in the neural pathways of sexual arousal. By activating MC-4R in particular, PT-141 triggers a cascade of neurological events that heighten sexual desire and arousal. In men, this can lead to erections via central (brain) mechanisms rather than direct vasodilation – meaning even men who cannot get erections from Viagra (which requires intact vascular function) may respond to PT-141. In women, it increases sexual desire and satisfaction by a similar brain effect. PT-141’s metabolite is related to Melanotan II; notably, it does not significantly darken the skin at normal doses because it was developed to separate the libido effect from the tanning effect. It also transiently increases dopamine activity in the brain’s reward centers, which is why users often feel a sense of heightened mood, focus, and craving for social/sexual interaction. Essentially, PT-141 “flips the switch” in the brain that initiates the physiological sexual arousal process, independent of tactile stimulation. This makes it a unique therapeutic for sexual dysfunction, especially in cases where the issue is not purely vascular.