DSIP
DSIP (delta sleep-inducing peptide) is a nonapeptide first isolated in the 1970s from the blood of rabbits in which sleep had been induced. Its physiological role and receptor remain unresolved, and human evidence is limited.
Overview
Delta sleep-inducing peptide was described by a Swiss research group in the 1970s, who isolated it from the cerebral venous blood of rabbits during electrically induced sleep and reported that it promoted slow-wave (delta) EEG activity when given to recipient animals. The international nonproprietary name for the synthetic peptide is emideltide. Its discovery prompted considerable interest in endogenous sleep factors during the following decades.
Despite that early interest, DSIP has remained poorly characterized. No gene encoding it has been clearly identified, no specific receptor has been confirmed, and later studies produced inconsistent effects on sleep in animals and people. Small human studies were conducted, mainly in the 1980s, with mixed results. In July 2026 the FDA's Pharmacy Compounding Advisory Committee did not support adding emideltide to the 503A bulk drug substances list. DSIP is not approved by the FDA for any use.
Structure
DSIP is a linear nonapeptide with the sequence Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu (WAGGDASGE). It carries a free N-terminus and a free C-terminal acid. The N-terminal tryptophan is susceptible to oxidation, and the Asp-Ala sequence can undergo slow aspartate-related degradation in solution. Phosphorylated forms have been described in the literature. Research material is typically supplied as an acetate or trifluoroacetate salt.
Mechanism
The mechanism of DSIP is not established. Because no dedicated receptor or precursor gene has been confirmed, proposed actions are based on indirect observations. Studies in animals and tissue preparations have reported interactions with GABAergic, glutamatergic and opioid signaling, effects on stress-hormone release, and changes in body temperature regulation. DSIP-like immunoreactivity has been reported in the brain and peripheral tissues, but the identity of the immunoreactive material has been debated. Overall, DSIP is best described as a peptide with reported biological effects whose molecular target remains unknown.
Research
Sleep and EEG studies in animals
The original studies reported increased delta-wave EEG activity in rabbits after infusion of the isolated peptide. Later animal work produced variable results: some groups observed changes in sleep architecture, while others found little or no effect. Differences in dosing conditions, species and peptide stability have been suggested as explanations. The inconsistency of these findings is a major reason DSIP did not progress as a drug candidate.
Small human studies
In the 1980s, small clinical studies examined synthetic DSIP in people with sleep complaints and in other settings. Results were mixed, and the studies were small and often uncontrolled by modern standards. No large randomized trial has established any clinical effect. Human evidence is therefore limited and of low quality. Interest in DSIP as a therapeutic candidate declined after these studies, and few new clinical investigations have been reported since. Much of the remaining research is mechanistic or historical.
Stress, endocrine and other effects
Animal and in-vitro studies have explored DSIP in relation to stress responses, hormone release, temperature regulation and oxidative stress. These reports are scattered across decades and models, with limited replication. They are preclinical findings and do not establish a consistent pharmacological profile. Many of these reports date from the 1980s and 1990s, used varied peptide preparations, and were not followed by systematic dose-response or mechanistic work. Their relevance to any physiological role of DSIP remains uncertain.
Regulatory status
DSIP (emideltide) is not approved by the FDA for any use. At its July 2026 meeting, the FDA's Pharmacy Compounding Advisory Committee did not support adding emideltide to the Section 503A bulk drug substances list, while voting to recommend several other peptides. The committee's votes are advisory and no final FDA action has been announced. For sport, check the current WADA Prohibited List.
Status changes often. See the regulatory tracker for dated updates.
Quality and identity testing
A DSIP certificate of analysis should confirm identity by mass spectrometry against the expected mass shown on this page and report HPLC purity with a chromatogram. Compound-specific concerns include oxidation of the N-terminal tryptophan, which produces mass-shifted species, and aspartate-related degradation products such as isoaspartate or succinimide forms, which can be difficult to separate from the parent peptide. The salt form, net peptide content and water content should be reported. The FDA committee's discussion highlighted that characterization of peptides in this class is an ongoing concern.
Open DSIP in the sequence analyzer to see the expected [M+H]+ and multiply charged ions for an MS identity check.
For a walkthrough of each section of a certificate, see how to read a COA.
Storage and stability
Store lyophilized DSIP sealed at -20 °C or below, protected from light and moisture. Light protection matters because tryptophan is photosensitive. Solutions are less stable than the dry powder because of possible aspartate-related degradation, so prepare them close to use, keep them cold, aliquot them and avoid repeated freeze-thaw cycles.
Download the DSIP data sheet (PDF): sequence, masses, expected MS ions and handling on one printable page.
Latest research
The newest PubMed-indexed papers that mention DSIP in their title or abstract, retrieved through Europe PMC and refreshed automatically. Inclusion is not an endorsement of a paper's findings.
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Frequently asked questions
Is DSIP FDA approved?
No. DSIP, whose nonproprietary name is emideltide, is not approved by the FDA for any use. At its July 2026 meeting, the FDA's Pharmacy Compounding Advisory Committee did not support adding emideltide to the 503A bulk drug substances list, even though it voted in favor of several other peptides at the same meeting. No final FDA action has been announced.
Does DSIP have a known receptor?
No specific receptor for DSIP has been confirmed, and no gene encoding it has been clearly identified. Proposed mechanisms rely on indirect evidence from animal and tissue studies, including interactions with GABA, glutamate and opioid signaling. This lack of a defined target is one reason the peptide's biology remains uncertain several decades after its discovery.
Is emideltide the same as DSIP?
Yes. Emideltide is the international nonproprietary name assigned to delta sleep-inducing peptide, the nonapeptide Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu. The name is used in regulatory contexts, such as the FDA Pharmacy Compounding Advisory Committee review, while DSIP remains the more common name in the research literature.
Related compounds
- Selank
Selank is a synthetic heptapeptide developed in Russia, built from the immunomodulatory tetrapeptide tuftsin extended with a Pro-Gly-Pro tail. It is studied mainly for effects on anxiety-related behavior and immune signaling.
- Semax
Semax is a synthetic heptapeptide developed in Russia as an analogue of the adrenocorticotropic hormone fragment ACTH(4-7), extended with a Pro-Gly-Pro tail. It is studied for neurotrophic signaling and in models of brain injury.
- Epitalon
Epitalon is a synthetic tetrapeptide (Ala-Glu-Asp-Gly) developed by Vladimir Khavinson's group in St. Petersburg, based on a pineal gland extract. It is studied in aging and telomere research, with evidence coming mostly from that group.
References
- PubMed: all indexed literature on DSIP
- ClinicalTrials.gov: registered studies mentioning DSIP
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