Melanotan II is a synthetic analog of the α-melanocyte-stimulating hormone (α-MSH). It has been studied for its ability to stimulate melanogenesis, leading to increased skin pigmentation. Research also suggests it may influence appetite regulation, energy balance, and sexual function through melanocortin receptor activity. Because of these multifaceted effects, Melanotan II has become a compound of interest in tanning, metabolic, and performance-related studies.