Delta Sleep-Inducing Peptide (DSIP) is a nonapeptide that promotes sleep, especially deep, restorative sleep. It's found naturally in the brain, hypothalamus, and other tissues, and has been studied for its role in sleep regulation, stress adaptation, and neuroprotection. While it's not currently approved as a medication by the FDA, it's a research peptide with potential benefits for sleep disorders and other conditions. 
Key aspects of DSIP:
Discovery and Function:
DSIP was first isolated from rabbit blood and found to induce sleep, particularly deep slow-wave sleep. It's believed to influence sleep by modulating the balance between sleep-wake cycles and impacting the brain's electrical activity during sleep. 
Potential Benefits:
Research suggests DSIP may help with:
Restoring disturbed sleep patterns. 
Promoting the release of hormones like luteinizing hormone (LH) and growth hormone (GH). 
Reducing chronic pain. 
Modulating cortisol levels. 
Potentially aiding in the treatment of alcohol and opioid withdrawal, and even having antimetastatic activity.