Kisspeptin is a neuropeptide encoded by the KISS1 gene and is recognized as a master upstream regulator of the hypothalamic-pituitary-gonadal (HPG) axis. By binding to its receptor (KISS1R, also known as GPR54) in the hypothalamus, kisspeptin triggers pulsatile release of gonadotropin-releasing hormone (GnRH), which in turn drives LH and FSH secretion from the pituitary. Research into kisspeptin spans reproductive endocrinology, fertility biology, and neuroendocrine function. It has also been studied for potential roles in sexual motivation and reward pathways through central nervous system mechanisms.