DSIP was isolated in 1977 from rabbits in induced slow-wave sleep. Nearly fifty years on, the name is still the strongest claim made about it, and the small human trials disagree.
DSIP · Sleep-associated nonapeptide
Sleep is regulated by many signals, and in the 1970s researchers looked for one in the blood of sleeping animals. DSIP came out of that search. The question it still raises is whether it is a sleep factor at all: no gene or receptor for it has been found. Evidence is animal EEG work and a handful of small intravenous studies in people from the 1980s and 1990s.
Delta sleep-inducing peptide, DSIP, is a nonapeptide, nine amino acids, with the sequence Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu. Schoenenberger and Monnier (1977) isolated it from the cerebral venous blood of rabbits in which slow-wave sleep had been induced, and named it for the test that identified it: infused into the brain ventricles of other rabbits, the synthetic peptide increased delta-wave and spindle activity on the electroencephalogram. The name records that experiment. It is not proof of a sleep treatment.
What is unusual is what has not been found. Most peptides are cut from a larger protein encoded by an identifiable gene, and act at an identifiable receptor. For DSIP neither has been established. Kovalzon and Strekalova (2006) concluded that the link between DSIP and sleep had never been properly characterised, that DSIP itself did not reliably promote slow-wave sleep in their own rabbit and rat work, and that the DSIP-like material detected in the hypothalamus may be a related but different peptide.
Animals. The 1977 rabbit study compared synthetic DSIP with fragments and analogues under double-blind conditions and reported that only the full nonapeptide increased delta EEG activity. A 1986 review by Graf and Kastin collected animal work on sleep, pain and withdrawal, and noted that its mechanism remained to be established.
People with insomnia. The human trials are small, intravenous and old. Schneider-Helmert (1987) gave DSIP or placebo for seven nights to 14 middle-aged patients with severe chronic insomnia under double-blind conditions and reported improved night sleep and daytime performance. Bes et al. (1992) ran a double-blind parallel-group study in 16 chronic insomnia patients over three nights; sleep efficiency and sleep latency were statistically better with DSIP, but the authors judged the effects weak, partly attributable to change in the placebo group, and concluded that short-term DSIP was unlikely to be of major benefit.
Healthy volunteers. Bjartell et al. (1989) gave a single intravenous dose to 11 healthy men in a randomised crossover design and found lower ACTH immunoreactivity in plasma for at least three hours, with cortisol unchanged. That is a hormone measurement, not a sleep outcome.
Whether DSIP is a naturally occurring sleep factor, or whether the activity attributed to it belongs to a related peptide, is unresolved. No receptor has been identified, so there is no mechanism to test. The human sleep data come from two small trials in chronic insomnia with opposite conclusions, both intravenous, and no modern replication was identified. Results obtained by infusion into the brain of rabbits, or by intravenous injection in a laboratory, say nothing about other routes. Stability of the peptide in blood is short, which complicates interpretation of every systemic study.
DSIP is not an approved medicine in Australia. No regulator-approved DSIP medicine was identified in any jurisdiction for this note.
Sources and status checked 2026-09-22
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