DSIP, or Delta Sleep-Inducing Peptide, is a naturally occurring neuropeptide that plays a significant role in regulating sleep. It was first isolated from the brains of rabbits during sleep and is known for its ability to promote sleep and restore circadian rhythms. DSIP has been studied for its various benefits, including improving sleep quality, enhancing mood, and potentially reducing chronic pain. Its amino acid sequence is Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu, and it functions as a neuromodulator in the central nervous system.