DSIP: What the Delta Sleep-Inducing Peptide Research Shows

DSIP, delta sleep-inducing peptide, is a nine-amino-acid peptide that a Basel research group described in 1977 after reporting that it increased deep-sleep brain-wave patterns in rabbits, but its role in human sleep has never been established: no gene, precursor protein or receptor for it has been identified, and the small human studies disagree. It is not FDA-approved, and in July 2026 an FDA advisory committee voted 6 to 7 against allowing it in compounding.

The name describes what its discoverers were looking for. The research since then is a good example of how a name can outlast the hypothesis behind it.

Discovery

The Basel group of Monnier and Schoenenberger had been studying a sleep-promoting factor in rabbit cerebral venous blood since the 1960s, according to the FDA's 2026 review. In 1977 they published its identity. Schoenenberger and Monnier (PNAS, 1977) reported a peptide that enhanced slow-wave, or delta, and spindle patterns on the electroencephalogram after infusion into the brain's ventricles in rabbits, and gave its sequence as Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu. They synthesized it alongside fragments and altered versions and tested all nine under double-blind conditions in 58 rabbits including controls. Only synthetic DSIP produced the specific EEG effect. A companion paper (Monnier and colleagues, Experientia, 1977) compared the properties of the original and synthetic peptide.

Delta waves are the slow, high-amplitude brain waves of deep non-REM sleep. "Delta sleep-inducing" described an EEG effect in rabbits, not a demonstrated effect on human sleep.

What the animal work shows, and where it stops

Some later animal findings were consistent with a sleep role. Iyer and colleagues (PNAS, 1988) deprived rats of sleep for four hours, which increased slow-wave sleep and growth hormone release afterward. Delivering an antiserum against DSIP into the brain's third ventricle blocked both increases, which the authors interpreted as evidence that the rats' own DSIP contributes to sleep-related growth hormone release.

The larger problem is foundational. In a 2006 review titled "a still unresolved riddle" (Journal of Neurochemistry), Kovalzon and Strekalova wrote that the link between DSIP and sleep had never been further characterized, in part because no DSIP gene, protein or receptor had been isolated, and called the sleep-factor hypothesis "extremely poorly documented." They noted that in their own early experiments, certain synthetic analogs of DSIP, but not DSIP itself, significantly promoted slow-wave sleep in rabbits and rats, and proposed that a still-unidentified DSIP-like peptide might explain the findings.

The FDA's 2026 review describes DSIP's sleep-inducing properties in animals as conserved across species and mediated by opioid-dependent mechanisms. It reports that DSIP does not appear to bind opioid receptors directly but can stimulate calcium-dependent release of endorphins, and flags that the agency found no studies of whether that creates a potential for addiction. Those are summaries of nonclinical work, not findings in people.

The human studies

The human literature dates mostly from the 1980s and early 1990s, uses small groups, and points in different directions.

Positive reports. Kaeser (European Neurology, 1984) treated 7 patients with severe insomnia in an open study, with no control group, and reported normalized sleep in all but one for follow-up periods of three to seven months. Schneider-Helmert (European Neurology, 1987) studied 14 middle-aged chronic insomniacs under double-blind, placebo-controlled conditions over seven nights and reported improved night sleep and better daytime alertness and performance.

A negative one. Bes and colleagues at the University of Amsterdam (Neuropsychobiology, 1992) ran a double-blind, matched-pairs study in 16 chronic insomniacs over three treatment nights. Objective sleep efficiency and sleep latency were somewhat better with DSIP than placebo, but the authors judged the significant effects weak and partly due to a chance change in the placebo group, found no change in subjective sleep quality, and concluded that short-term treatment was not likely to be of major therapeutic benefit.

Withdrawal. Dick and colleagues (European Neurology, 1984) gave DSIP to 107 inpatients in alcohol or opiate withdrawal and, based on clinical evaluation by staff, reported that symptoms disappeared or improved rapidly in most. The study had no control group.

The FDA's 2026 review took this literature as a whole. It found the insomnia studies "inconclusive and at best preliminary," noting conflicting conclusions across authors, poor or absent control groups, small samples and unknown long-term benefit, and found the narcolepsy and withdrawal studies limited by case-report or unblinded designs. On safety, it reported that small insomnia studies described no significant adverse effects, while withdrawal studies reported transient headache, nausea and vertigo, and cases of hypotension described as progressive after a second administration. It concluded that safety is insufficiently characterized.

We found no modern randomized trial of DSIP for any sleep outcome.

Regulatory status

FDA approval. None. The FDA notes that DSIP, which it reviewed under the name emideltide, has no USP monograph and is not a component of any approved drug.

Compounding. DSIP had been nominated for the 503A bulks list for insomnia, narcolepsy and opioid withdrawal and is listed among substances whose nominations were withdrawn from Category 2. The FDA evaluated it on its own initiative and proposed against adding it, citing poor chemical characterization, lack of evidence of effectiveness, insufficient safety information and the existence of approved treatments for those conditions. On July 24, 2026 the Pharmacy Compounding Advisory Committee voted 6 to 7, with one abstention, against recommending it. It was the only one of seven peptides at that meeting that the committee did not recommend.

Sport. DSIP is not named on the World Anti-Doping Agency's 2026 Prohibited List. Section S0 covers substances with no current approval by any government health authority for human therapeutic use, so athletes should check with their own anti-doping organization.

For the other peptides in this group, see Semax vs Selank and our review of the cognitive peptides.

Frequently asked questions

What is DSIP?

Delta sleep-inducing peptide, a nine-amino-acid peptide described in 1977 by a Basel group that reported it increased deep-sleep EEG patterns in rabbits. The FDA reviews it under the name emideltide.

Does DSIP improve sleep in humans?

The evidence does not establish that. Small studies from the 1980s and 1990s reported mixed results, and the FDA called the insomnia studies inconclusive and at best preliminary.

Does DSIP have a known receptor?

No. A 2006 review noted that no DSIP gene, precursor protein or receptor had been isolated, and we found no later report that changes that.

Is DSIP FDA-approved?

No. An FDA advisory committee also voted 6 to 7 against adding it to the compounding bulks list in July 2026.

Sources:

No compound discussed in this review is FDA-approved. Nothing above is dosing guidance or a treatment claim. Research use only.

For research use only · Not for human or veterinary use · No research compound discussed here is FDA-approved for any indication