Delta sleep-inducing peptide (DSIP)
DSIP, emideltide, Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu, WAGGDASGE
DSIP is a nonapeptide isolated in the 1970s from the cerebral venous blood of rabbits in whom sleep had been induced by electrical stimulation of the thalamus. It was named for what its discoverers believed it did. Half a century later its endogenous gene has never been identified, no receptor has been found, and the human sleep trials divide sharply along the line of who ran them.
Mechanism
DSIP's mechanism is, candidly, unresolved after fifty years of work. No DSIP receptor has ever been cloned or characterised, and no gene encoding a DSIP precursor has been identified in any genome, an extraordinary situation for a peptide that has been studied since 1977 and that many sources still describe as an endogenous neuromodulator. Immunoreactive DSIP-like material has been detected in brain, plasma and peripheral tissues, but immunoreactivity is not proof that the exact nonapeptide is produced endogenously, and the failure to find a gene after decades of sequencing is a serious problem for that claim.
What is documented is a set of reproducible physiological effects without an identified molecular route. DSIP crosses the blood-brain barrier, which is unusual for a peptide of its size and charge. It reduces corticotropin-releasing-factor-induced corticosterone release, indicating an action somewhere on the hypothalamic-pituitary-adrenal axis, and much of the sustained interest in it as a stress-modulating rather than a strictly hypnotic agent derives from this. Various groups have reported effects on sleep architecture in cats and rodents, modulation of epileptic activity, and effects in spontaneously hypertensive rats. Proposed involvement of GABAergic and serotonergic systems is widely cited but rests on indirect evidence. It is more accurate to describe DSIP as a peptide with physiological effects and no known mechanism than as a sleep-regulating neuromodulator.
What the research shows
The human sleep literature is the crux, and it splits cleanly. Beginning with a 1981 Lancet report (indexed by PubMed as a letter that is also flagged as a randomised controlled trial), Schneider-Helmert, Graf and Schoenenberger published a sequence of studies reporting that synthetic DSIP improved sleep in insomniacs. A 1986 sleep-laboratory study by Schneider-Helmert in 18 chronic psychophysiological insomniacs, split into middle-aged (29-59 years) and elderly (60-83 years) groups and given six doses of 30 nmol/kg intravenously over a week with a week of follow-up, reported that the whole sample showed normal sleep patterns by the end of the investigation, with the elderly group taking longer to normalise. That 1986 study describes no placebo or control condition in its abstract, which is a material limitation: it is a within-subject improvement over a week, not a controlled comparison. Related work described effects on phase-shifted insomnia and on disturbed sleep more generally.
It was not confirmed independently. In 1987 Monti and colleagues ran a double-blind crossover polysomnographic study, giving 25 nmol/kg intravenously over four nights to chronic insomniacs, and reported that although awakenings, NREM sleep latency and waking time fell under DSIP, none of these reached significance against baseline or against double-blind placebo nights; the differences that were significant already existed at baseline. Their stated conclusion was that sleep improvement under DSIP treatment is of little clinical significance. That is the pattern that should shape any honest reading: the positive findings cluster in the work of the group most invested in the compound, and the independent double-blind replication was negative. Interest subsequently shifted to other applications (a 1997 case-report letter on DSIP in opioid detoxification, work on epileptic activity, and various stress-axis effects), but no application progressed to a modern registered trial, and a ClinicalTrials.gov search on 7 August 2026 returned no genuine DSIP study. Almost the entire human literature dates from 1981 to 1990, predating current standards for trial registration, powering and reporting.
Evidence assessment
Limited evidence
Human sleep data exist but come overwhelmingly from a single group in the 1980s, with the key 1986 study lacking any described control condition, and the principal independent double-blind crossover study concluded the sleep improvement was of little clinical significance.
Tiers are applied consistently across the library and re-checked when new trials read out. Read the grading method.
Key studies
Synthetic delta-sleep-inducing peptide improves sleep in insomniacs Limited evidence
Reported improved sleep in insomniac patients following synthetic DSIP administration, the report that established clinical interest in the peptide.
Efficacy of DSIP to normalize sleep in middle-aged and elderly chronic insomniacs Limited evidence
Sleep improved to normal values by the end of dosing in the middle-aged group and by the end of follow-up in the elderly group, with the whole sample showing normal sleep patterns at the end of the investigation; effects correlated with baseline severity of sleep disturbance.
Study of delta sleep-inducing peptide efficacy in improving sleep on short-term administration to chronic insomniacs Limited evidence
Awakenings, NREM sleep latency, total waking time and waking after sleep onset all fell under DSIP, but no significant difference was found against baseline or against double-blind placebo nights; the authors concluded that sleep improvement under DSIP treatment is of little clinical significance.
The influence of synthetic DSIP (delta-sleep-inducing-peptide) on disturbed human sleep Limited evidence
Reported effects of synthetic DSIP on sleep parameters in patients with disturbed sleep.
Delta-sleep-inducing peptide (DSIP): a review Preclinical only
Summarises the rapid degradation, blood-brain barrier permeability and diverse non-sleep effects of DSIP, and the difficulty of establishing a coherent mechanism.
Delta-sleep-inducing peptide reduces CRF-induced corticosterone release Preclinical only
DSIP reduced corticotropin-releasing-factor-induced corticosterone release, indicating action on the hypothalamic-pituitary-adrenal axis.
Delta-sleep-inducing peptide (DSIP): an update Preclinical only
Documents the widening range of reported DSIP effects alongside the continuing absence of an identified receptor or endogenous precursor gene.
Delta sleep-inducing peptide in opioid detoxification Limited evidence
Reported observations on DSIP during opioid withdrawal in a case report; the application was never developed further in controlled trials.
Safety
The human studies from the 1980s reported intravenous administration without notable acute adverse effects, but these were very small samples over days to weeks, with no systematic safety monitoring by modern standards and no long-term follow-up. There is no contemporary toxicology package in the public domain, no reproductive safety data, and no characterisation of chronic exposure. The HPA-axis effects, specifically the reduction of CRF-induced corticosterone release, imply an interaction with stress hormone regulation that has never been studied over any meaningful duration in humans. Material sold online is synthetic peptide of unverified purity produced outside pharmaceutical GMP. The near-total absence of research activity since around 1990 means that whatever was not learned then has not been learned since.
Regulatory status
| Jurisdiction | Status |
|---|---|
| United Kingdom | No UK marketing authorisation. Not a controlled drug, but as an unlicensed medicinal product it may not lawfully be sold, supplied or advertised for human use under the Human Medicines Regulations 2012. |
| United States | Not FDA-approved for any indication. DSIP carries the international non-proprietary name emideltide, under which it has featured in the review of bulk drug substances nominated for pharmacy compounding under section 503A of the Federal Food, Drug and Cosmetic Act. This monograph could not verify the compound's precise current placement on FDA's published 503A lists from primary FDA sources at the time of writing; readers needing the authoritative position should consult those lists directly. In practice it is sold in the US only as an unapproved substance under a "research use only" label. |
| WADA (sport) | Not named on the WADA Prohibited List. As a non-approved pharmacological substance it would fall within the scope of category S0. |
Questions
That is the standard description but it is not established. No gene encoding a DSIP precursor has ever been identified in any genome, and no DSIP receptor has been cloned, despite nearly fifty years of investigation. DSIP-like immunoreactivity has been found in tissues, but immunoreactivity is not proof that the exact nonapeptide is made endogenously.
The evidence is contradictory in a revealing way. The group that developed and championed DSIP published a series of positive studies through the 1980s, but the most-cited of them, from 1986, had no control condition at all. When Monti and colleagues ran an independent double-blind crossover polysomnographic study in 1987, the changes under DSIP did not reach significance against baseline or placebo and the authors concluded the improvement was of little clinical significance. That divergence should carry a lot of weight.
The human literature is almost entirely from 1981 to 1990. The independent replication was negative, no receptor was ever found, and no endogenous gene emerged. Research interest moved elsewhere. Current online interest is not a continuation of the science. It is a revival of a compound the field largely set aside.
It has no UK marketing authorisation. It is not a controlled drug, but as an unlicensed medicinal product it may not lawfully be sold, supplied or advertised for human use under the Human Medicines Regulations 2012, which is why sellers use the "research use only" framing.