Article

DSIP (delta sleep-inducing peptide): fifty years of an unresolved peptide

Published 21 October 2026 · CognitivePepti Research Desk

Abstract chain of nine linked spheres drifting across a dark blue field with faint wave-like lines

Prepared by: Research Desk. Sources are linked for verification.

Published 21 October 2026

At a glance

Type: a nonapeptide (nine amino acids) with the sequence Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu (WAGGDASGE).
Origin: reported in 1977 by Schoenenberger, Monnier and colleagues, who isolated it from rabbit brain.
Research stage: early primary work consisted mainly of rabbit electroencephalography (EEG) experiments. No specific receptor or settled molecular mechanism has been established.
Regulatory status: not an FDA-approved drug. FDA's page of bulk drug substances that may present significant safety risks lists it as Emideltide (DSIP). Under the name emideltide, it was on the agenda of FDA's Pharmacy Compounding Advisory Committee on 24 July 2026.

For background on the field, see the cognition peptide research guide.

Discovery in 1977

Delta sleep-inducing peptide (DSIP) takes its name from the experiments in which it was first described. Schoenenberger et al. (1977) characterised the peptide, reported its sequence and described EEG experiments in rabbits.

Two further papers from the same year extended this work. Monnier et al. (1977) reported EEG and motor-activity observations after DSIP administration in rabbits. A separate study by Monnier et al. (1977) examined transport of synthetic DSIP across the blood–brain barrier in rabbits.

The name reflects how the authors interpreted their rabbit recordings. It is a historical label, not an established description of function, and the early sleep-associated observations are not proof of a defined mechanism.

Sequence and structure

DSIP is a linear nonapeptide:

Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu (WAGGDASGE)

The sequence is rich in glycine and alanine, with an N-terminal tryptophan and acidic residues (aspartate and glutamate). The full sequence was reported in the 1977 characterisation paper, and the blood–brain barrier study from the same year used synthetic DSIP.

In US regulatory records the substance appears as emideltide. The FDA advisory committee agenda describes emideltide as "also referred to as delta sleeping inducing peptide (DSIP)" and lists a free base and an acetate form.

The unresolved receptor and mechanism

Almost fifty years after DSIP was first described, basic questions about its biology remain open. Its receptor and a definitive molecular mechanism have not been identified. The sources assembled for this page also do not identify a confirmed gene or precursor protein.

The source list names several reviews. As described in that list:

Graf (1980) reviewed research on DSIP and its reported sleep-related effects.
Schoenenberger (1982) reviewed DSIP research and the questions surrounding its physiological role.
Iyer (1987) examined DSIP-related findings and the challenge of identifying a specific receptor or mechanism.
D'Aguanno (1990) reviewed the biological and pharmacological literature on DSIP.

Individual PubMed records for these four reviews could not be confirmed, so they are named here without links, and their content is summarised only at the level given in the source list. Readers checking the history should locate the original publications directly.

The problem these reviews describe is straightforward. Without a known receptor, an observed effect cannot easily be linked to a molecular pathway. Without a confirmed gene or precursor in the sources assembled here, it is also hard to say how, or whether, the peptide is produced endogenously.

The research landscape

A concentrated founding period. The core primary data summarised here come from a few 1977 papers by Schoenenberger, Monnier and colleagues, using rabbits and EEG.
Review-based follow-up. The later work named on this page consists of reviews published between 1980 and 1990, which discussed the earlier findings and the open questions around them. They are named but not linked, for the reasons given above.
Slow progress on mechanism. The receptor question examined in the 1987 review by Iyer remains open in the sources assembled for this page.

For a comparable summary of another peptide studied in neuroscience laboratories, see the Selank research overview.

Regulatory status

FDA approval. DSIP (emideltide) is not an FDA-approved drug.

Compounding framework. FDA documents on the section 503A bulks list (FDA framework document; FDA framework document) separate substances included on the list from those that are not. Inclusion is not FDA approval of a drug.

FDA safety-risk page. FDA's page of bulk drug substances that may present significant safety risks covers substances placed in category 2 under its interim policies, as well as nominations that were withdrawn. That page lists Emideltide (DSIP).

July 2026 advisory committee. FDA's calendar recorded a Pharmacy Compounding Advisory Committee meeting on 23–24 July 2026. The agenda for 24 July listed emideltide free base and emideltide acetate among substances "being considered for inclusion on the 503A Bulks List", alongside Semax and Epitalon. The uses FDA reviewed for emideltide were listed as opioid withdrawal, chronic insomnia and narcolepsy.

These entries described the scope of FDA's review, not findings that the peptide works for any condition. The agenda stated that nominators would be invited to present, and the public docket, FDA-2025-N-6895, closed on 22 July 2026. The sources assembled for this page do not report the outcome of the meeting. An agenda listing does not mean a substance was added to the list or approved.

Open research questions

Receptor. Which receptor, if any, mediates the effects reported in the rabbit studies?
Endogenous origin. Is there a confirmed gene or precursor, and does the isolated form occur naturally?
Mechanism. Can the EEG observations be tied to a defined molecular pathway?
Replication. How well do the 1977 findings hold up in independent laboratories using modern methods?
Material identity. Comparisons across studies depend on documented identity and purity of the peptide used.

Limitations of the evidence

The founding data summarised here come from a small set of 1977 rabbit studies by Schoenenberger, Monnier and colleagues.
The only primary studies linked on this page are those three 1977 papers. The later reviews are named without links because individual records could not be confirmed.
No receptor has been established, and the sources assembled here do not identify a confirmed gene.
The name reflects early interpretation, not an established function.
Animal EEG and behavioural observations do not show what the peptide does in people.
Regulatory records describe review scope and listing decisions, not effects.

Where researchers source it

Purita is a store that lists DSIP for laboratory research use only. Its product page labels the item for research use only and not for human or animal administration.

Purita product page

Affiliate disclosure: this is a paid link. CognitivePepti earns a commission if a purchase is made through it, at no extra cost to the buyer. A listing is not an endorsement or a statement about product quality. See the affiliate disclosure.