PT-141

What it is

PT-141 is a cyclic heptapeptide (cyclo-[Nle4, D-Phe7]-α-MSH) and metabolite of Melanotan II. At 1025.2 g/mol, it is a mid-range compound by molecular weight. It is an agonist at MC3R (melanocortin receptor 3) and MC4R (melanocortin receptor 4) — two of the five melanocortin receptor subtypes. These receptors are expressed primarily in the brain and central nervous system, distinguishing PT-141 from peripherally acting compounds studied in similar contexts. The MC3R and MC4R subtypes are particularly concentrated in the hypothalamus, where they play roles in energy homeostasis, autonomic function, and CNS signalling.

How it works

By selectively activating MC3R and MC4R in the hypothalamus and other CNS structures, PT-141 engages central signalling pathways without the peripheral vascular effects associated with earlier melanocortin agonists. Research has focused on understanding the downstream consequences of MC3R and MC4R activation in the brain, including their roles in autonomic nervous system regulation, neuroinflammation, and behavioural modulation. PT-141's central mechanism makes it a valuable research tool for dissecting melanocortin receptor function in the CNS independently of peripheral effects.

Research context

PT-141 has been extensively studied in melanocortin receptor research, CNS pathway modelling, and behavioural pharmacology. It was developed from Melanotan II by researchers at the University of Arizona, initially as part of a programme investigating melanocortin agonists for pigmentation research. Its CNS activity was identified during this research and subsequently became the primary focus of published literature. Research has investigated MC3R and MC4R activation in models of autonomic function, neuroinflammation, and energy regulation.