DSIP (Delta SleepInducing Peptide) is a naturally occurring neuropeptide first isolated in 1974. Its best known for its potential role in regulating sleep, stress, and neuroendocrine function., DSIP (Delta SleepInducing Peptide) is a naturally occurring neuropeptide first isolated in 1974. It's best known for its potential role in regulating sleep, stress, and neuroendocrine function. Here's a clear breakdown of Sleep Peptides Melatonin & Peptide Support NutraBio Brands Buy DSIP (Delta Sleep Inducing Peptide) for Sale USA Made Amazon.com: Source Naturals Sleep Science Melatonin, Helps Promote Sleep* 10 mg 60 Vegan Tablets : Health & Household