All compounds discussed are intended strictly for in vitro research and laboratory use. Not for human or animal consumption.
DSIP, delta sleep-inducing peptide, is one of the more unusual compounds in neuropeptide research: it has been studied for fifty years and its receptor has still never been identified. This profile sets out what DSIP is at the molecular level, what the literature does and does not establish about its mechanism, and the handling standards that matter when sourcing it. It is written for qualified researchers working in in vitro and controlled animal-model settings, and it describes molecular and research characteristics only, not outcomes in people.
The short version
- DSIP is a linear nonapeptide, sequence Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu, with no cysteine and therefore no disulfide bond.
- It was isolated in 1974 from the cerebral venous blood of rabbits in induced sleep, not from brain tissue.
- No receptor has ever been conclusively identified, which is the defining feature of its literature rather than a footnote to it.
- It crosses the blood-brain barrier, which is one of the few settled facts about it.
- Its INN is emideltide. For research use only. Not for human or veterinary use or consumption.
Molecular profile
| Research criterion | Value |
|---|---|
| Class | Naturally occurring linear nonapeptide |
| Sequence | Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu (WAGGDASGE) |
| Residues | 9 |
| Molecular formula | C35H48N10O15 |
| Molecular weight | 848.8 g/mol |
| CAS number | 62568-57-4 |
| PubChem CID | 68816 |
| UNII | YN28Z5YZ73 |
| INN | Emideltide |
| Disulfide bonds | None, no cysteine residue |
| Termini | Free N- and C-termini, not acetylated or amidated |
| Form supplied | Lyophilized powder |
Three structural points follow from that table and are worth drawing out, because they have practical consequences in the laboratory.
There is no cysteine, so there is no disulfide bond and no cyclization. DSIP is a single linear chain. Unlike a folded or cyclized peptide it has no tertiary structure to lose, which makes it considerably more forgiving to handle than a structured protein.
There is exactly one tryptophan, at the N-terminus. Tryptophan is the strongest natural ultraviolet chromophore among the amino acids, so a single Trp in a nine-residue peptide gives a clean spectroscopic handle for detection and concentration measurement without needing a label.
Two of the nine residues are acidic, the aspartate at position 5 and the glutamate at position 9, sitting on an otherwise glycine-rich and largely uncharged backbone. That distribution governs its solubility and its behavior in ion-exchange separation.
Discovery: where it actually came from
DSIP was isolated in 1974 by the Schoenenberger and Monnier group in Basel. The source material was the cerebral venous blood of rabbits in induced sleep, not brain tissue, and the naming follows directly from those experimental conditions rather than from any established mechanism.
That distinction matters more than it looks. The name describes the circumstances of discovery. It has been attached to the molecule ever since, and a great deal of subsequent writing has treated the name as though it were a finding. It is not.
The receptor question: the defining gap
No receptor for DSIP has ever been conclusively identified. This is not an obscure technicality; it is the central fact of the compound’s literature and it has been openly described as such by researchers in the field. Kovalzon and Strekalova titled their 2006 review in the Journal of Neurochemistry “Delta sleep-inducing peptide (DSIP): a still unresolved riddle” (PMID 16539679), which remains an accurate summary two decades later.
What exists instead of a receptor mechanism is a body of observed associations across several neuromodulatory and neuroendocrine systems, accumulated over decades and never resolved into a single pathway. For a researcher this has two consequences.
It makes DSIP a genuinely open question rather than a characterized tool, which is a reason it remains an active subject. And it means any mechanistic claim about DSIP should be read carefully, because the literature does not support the clean receptor story that is often asserted for it.
An earlier broad review by Graf and Kastin (PMID 6145137) surveys the mechanism literature as it stood, and is a reasonable entry point into the older work.
Blood-brain barrier transport
One of the few well-established properties is that DSIP crosses the blood-brain barrier. Banks, Kastin and Coy demonstrated saturable transport in a dog model and correlated it with protein binding (PMID 6897451).
This is a transport property rather than a mechanism of action, but it is the fact that makes the compound interesting to central nervous system researchers at all: a peptide that does not reach the central compartment is of limited use as a CNS probe regardless of what it binds. It is also one of the few DSIP findings that consumer-facing pages assert without ever citing.
What the literature does not establish
A profile of this compound is incomplete without stating the limits, and there is one specific case worth recording because it is frequently overstated.
DSIP is often described as modulating the hypothalamic-pituitary-adrenal axis, with associations to ACTH and cortisol. Associations of that kind do appear in the preclinical literature. However, a human study by Spath-Schwalbe and colleagues concluded that their data did not support an inhibitory role for DSIP on ACTH and cortisol secretion (PMID 7777652).
The honest position is therefore that the neuroendocrine association is reported but contested, and that at least one negative result exists. Stating that is more useful to a researcher designing a study than repeating the association unqualified.
Where DSIP sits among CNS research peptides
DSIP is commonly studied alongside other short CNS-targeted peptides. Selank and Semax are the closest comparators in a research catalog: both are short synthetic neuropeptides, both are used as neuromodulatory tool compounds, and unlike DSIP both have considerably better-characterized mechanisms. That contrast is itself useful, since DSIP’s value as a subject lies partly in what remains unknown about it.
Our nootropic and CNS-targeted peptide research overview sets the wider context, and DSIP sits within the broader neuropeptide research category.
Regulatory status
DSIP is not an approved medicine in the United States or elsewhere, and it has no marketed pharmaceutical product. Its INN, emideltide, was assigned but no approval followed.
Its entire status is as a research compound. Peptides Source supplies it for in vitro and laboratory research only, and it is not approved for human or veterinary use.
Verification: what a certificate should tell you
Reproducibility depends on knowing exactly what is in the vial:
- Purity verified by HPLC, with the figure recorded on a batch-specific certificate of analysis tied to your lot number
- Identity confirmed by mass spectrometry against the expected mass of 848.8 g/mol
- Third-party testing, independent of the supplier
- Documented sourcing, US-based, for traceability
At 848.8 g/mol DSIP sits in a mass range where a routine mass spectrometry run is decisive, and because the peptide is short and linear there are fewer ways for a synthesis to go subtly wrong than with a folded or cyclized sequence.
Peptides Source supplies DSIP at 98 percent or higher purity by HPLC with third-party batch documentation. For the criteria to apply to any supplier, see our guide to choosing a reliable peptide source.
Handling in the laboratory
DSIP is supplied as a lyophilized powder and reconstituted before study. For step-by-step technique see our research peptide reconstitution protocol.
- Reconstitution: use a diluent appropriate to the assay, commonly a suitable research diluent. Confirm solubility in the intended vehicle before preparing working solutions.
- Storage, lyophilized: sealed vial frozen at approximately -20 degrees Celsius, protected from light.
- Storage, reconstituted: refrigerated at 2 to 8 degrees Celsius, aliquoted to avoid repeated freeze-thaw cycles, used within a short window.
Because there is no disulfide bond to scramble and no fold to lose, the failure modes are the ordinary ones for a short linear peptide: hydrolysis over time in solution, and adsorption losses to container surfaces at low concentrations.
Frequently asked questions
What is DSIP peptide?
DSIP, delta sleep-inducing peptide, is a naturally occurring linear nonapeptide with the sequence Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu. It was isolated in 1974 from the cerebral venous blood of rabbits in induced sleep. Its INN is emideltide. It is supplied strictly for in vitro and laboratory research and is not approved for human or veterinary use.
What receptor does DSIP act on?
No receptor has ever been conclusively identified, despite five decades of study. Its literature consists of observed associations across several neuromodulatory and neuroendocrine systems rather than one defined receptor mechanism. A 2006 review in the Journal of Neurochemistry described it as “a still unresolved riddle”, and that remains accurate.
What is the molecular weight of DSIP?
848.8 g/mol, with the molecular formula C35H48N10O15 and CAS number 62568-57-4. It is nine residues long with free N- and C-termini and no disulfide bond.
What is the sequence of DSIP?
Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu, or WAGGDASGE in single-letter code. It contains no cysteine, so it is a single linear chain with no cyclization, and its single N-terminal tryptophan provides a useful ultraviolet chromophore for detection.
Does DSIP cross the blood-brain barrier?
Yes. Saturable transport across the blood-brain barrier was demonstrated in a dog model by Banks, Kastin and Coy, with correlations to protein binding. This is one of the few well-established properties of the compound and it is what makes it usable as a central nervous system research probe.
Where was DSIP discovered?
It was isolated in 1974 by the Schoenenberger and Monnier group in Basel, from the cerebral venous blood of rabbits in induced sleep. It is frequently reported as having come from brain tissue, which is incorrect. The name reflects the conditions of the experiment rather than an established mechanism.
What purity should research-grade DSIP meet?
It should be verified by HPLC at 98 percent or higher on a batch-specific certificate of analysis, with identity confirmed by mass spectrometry against the expected 848.8 g/mol, and tested by an independent third-party laboratory.
How is DSIP stored and handled?
It is supplied as a lyophilized powder and reconstituted in the laboratory, typically in a suitable research diluent. Sealed lyophilized vials are stored frozen at approximately -20 degrees Celsius and protected from light. Reconstituted material is refrigerated at 2 to 8 degrees Celsius, aliquoted to avoid repeated freeze-thaw cycles, and used within a short window.
References
- US National Library of Medicine, PubChem. Compound record: Emideltide (DSIP), CID 68816.
- Kovalzon VM, Strekalova TV. Delta sleep-inducing peptide (DSIP): a still unresolved riddle. J Neurochem. 2006;97(2):303-309. PMID 16539679.
- Graf MV, Kastin AJ. Delta-sleep-inducing peptide (DSIP): a review. Neurosci Biobehav Rev. 1984;8(1):83-93. PMID 6145137.
- Banks WA, Kastin AJ, Coy DH. Delta sleep-inducing peptide crosses the blood-brain-barrier in dogs: some correlations with protein binding. Pharmacol Biochem Behav. 1982;17(5):1009-1014. PMID 6897451.
- Spath-Schwalbe E, Schafer A, Uthgenannt D, Born J. Delta-sleep-inducing peptide does not affect CRH and meal-induced ACTH and cortisol secretion. Psychoneuroendocrinology. 1995;20(3):231-237. PMID 7777652.
Peptides Source supplies research compounds for in vitro and laboratory research only. Nothing on this page is a recommendation for human or veterinary use. All products are sold strictly for research purposes and are not for human or animal consumption. Must be 21+ to purchase.
