DSIP (Delta Sleep-Inducing Peptide)

Research-Grade

DSIP (delta sleep-inducing peptide) is a nine-amino-acid peptide (Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu). In 1977 experiments in freely moving rabbits, an intravenous injection of synthetic DSIP increased cortical delta-wave activity and reduced motor activity for about 5 hours, which the authors took as evidence that it crosses the blood-brain barrier. Human studies were small and mostly European, from the 1980s and early 1990s, and all used intravenous injection. A 1983 summary of five double-blind studies reported good tolerability, sleep induction after a latency of about an hour, and normalized sleep in insomniacs after four consecutive injections. A 1987 placebo-controlled study in 14 chronic insomniacs reported better night sleep and daytime performance over 7 nights. A 1992 double-blind trial in 16 chronic insomniacs, however, found only weak effects on sleep efficiency and latency that could partly reflect chance changes in the placebo group, and no change in subjective sleep quality; the authors concluded that short-term DSIP treatment is unlikely to be of major therapeutic benefit. Open studies also reported benefits in alcohol and opiate withdrawal (107 inpatients) and in chronic pain episodes (7 patients), but without control groups. An early idea that DSIP inhibits the stress axis was not borne out in healthy men: intravenous DSIP did not change CRH-stimulated or meal-related ACTH and cortisol release. No modern polysomnographic trial has been published. DSIP is not an FDA-approved drug; in the US it is a research-only compound.