Delta Sleep-Inducing Peptide (DSIP) is a naturally occurring neuropeptide first isolated from the thalamus of rabbits during slow-wave sleep. It has since been identified in numerous brain regions, peripheral tissues, and body fluids. Research has explored DSIP across a wide range of physiological contexts including sleep architecture modulation, stress hormone regulation (particularly cortisol and LH), antioxidant activity, and neuroendocrine function. Some studies have examined potential applications in research models of stress, pain, and circadian disruption. Its broad distribution and pleiotropic activity make it a compound of sustained scientific interest.