NPY(Neuropeptide Y) also known as PYY4 is a neuropeptide that is widely expressed in the central nervous system and influences many physiological processes, including cortical excitability, stress response, food intake, circadian rhythms, and cardiovascular function. NPY plays a crucial role in regulating energy balance and appetite control, making NPY significant in understanding metabolic disorders and obesity. NPY is primarily located in the central and peripheral nervous systems, particularly in deep layers of the cortex and smaller cell bodies in white matter, where NPY is involved in modulating various physiological processes. NPY′s structure features a polyproline stretch followed by an amphipathic α-helix, which is essential for interaction with Y-receptor family of G protein-coupled receptors. NPY interacts with Y1 receptor to influence corticotropin levels and noradrenaline release in hypothalamus, thereby playing a vital role in stimulating food intake and promoting energy storage through increased lipoprotein lipase activity in white adipose tissue.