DSIP

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Snapshot

Chemistry and make-up

DSIP is a nine-residue linear peptide first isolated from rabbit brain in 1974 during work on humorally-transmitted sleep signals [A]. The sequence is acidic (two aspartate/glutamate carboxyls, plus a C-terminal glutamate) with a single tryptophan at the N-terminus, no cysteine and no metal-binding motif, so no disulfide bridges. It is small, unmodified and unremarkable chemically, which is part of the puzzle: despite fifty years of study, no gene encoding DSIP and no specific DSIP receptor have been definitively identified, and it is not clear the peptide exists as a discrete signalling molecule in the way the name implies (Kovalzon, *J Neurochem* 2006, “a still unresolved riddle”) [A]. Usually supplied as the acetate salt; CoA should state the salt form and the observed 848.8 mass.

What it is studied for (evidence)

• Mechanism (preclinical, proposed and unsettled [A]): candidate mechanisms include enhancement of GABA-activated currents and blockade of NMDA responses, partial agonism at mu/delta opioid receptors (it shares some structural similarity with dermorphin), modulation of GABA-B signalling and voltage-gated calcium channels, and a reported antioxidant effect via activation of endogenous antioxidant defences. It has also been reported to lower basal ACTH/corticotropin and blunt stress-induced release, and to influence somatotropin/somatostatin balance [A/D — proposed, not settled]. None of these is an agreed primary mechanism.
• Established (good evidence): essentially none by modern standards. There is no indication for which DSIP has robust, replicated, adequately-powered human evidence.
• Emerging / thin / contested: the human sleep literature is a cluster of small placebo-controlled studies in chronic insomniacs from roughly 1981 to 1987, with sample sizes around 6 to 14 and openly conflicting results (PubMed 1299794, PubMed 3583493, PubMed 7028502, PubMed 6391925). Some reported better sleep efficiency, shorter latency and improved daytime alertness; others found the differences from placebo did not reach clinical significance and concluded any benefit was of little clinical value [A]. The broader non-sleep claims (stress protection, addiction/withdrawal, antioxidant, anti-tumour in aged mice) are almost entirely preclinical and old [A/D].
• Marketing claims vs data: vendors market DSIP as a sleep and recovery peptide with dosing protocols. The actual human evidence is weak, contradictory, forty-plus years old and never confirmed in a modern trial, so any “improves sleep” claim is unsupported by current standards. No dosing is published here.
• Human clinical status: not approved anywhere for any indication; no modern registration trial. As of 2026 not FDA-approved. Reviewed under the name emideltide at the FDA PCAC on 24 July 2026 (proposed for insomnia and opioid withdrawal), it was the only one of the seven peptides the committee declined to recommend, on a 6-in-favour to 7-against vote (1 abstention); panelists cited low-quality efficacy evidence, poor characterisation of the substance, and the existence of approved therapies for its proposed uses [B].

Handling, format and stability

Supplied lyophilised; research handling reconstitutes with bacteriostatic water (no dosing here). As a small acidic peptide it follows the usual pattern: most stable as lyophilised powder stored cold (around minus 20 C) and protected from light, less stable and cold-chain dependent once reconstituted [D — vendor stability claims, verify]. The tryptophan residue is light-sensitive, which is a further reason to protect solutions from light. No cartridge/pen format is standard; it circulates as research vials.

Regulatory and trade status

• UK/EU RUO: legal to sell and possess as a research chemical; not a licensed medicine. Sleep or recovery treatment claims trigger the Human Medicines Regulations 2012 and MHRA scrutiny, so any listing must stay research use only [B].
• US: not FDA-approved. DSIP was removed from 503A Category 2 in April 2026 and referred to the Pharmacy Compounding Advisory Committee under the name emideltide. On 24 July 2026 the PCAC voted against recommending it for the 503A bulks list (6 in favour, 7 against, 1 abstention), making it the only rejection of the seven peptides heard that week [B] (FDA PCAC July 2026). The vote is advisory only, but here it points the other way: the committee’s own panel judged the evidence too weak.
• WADA (sport): not an approved human drug, so it falls under S0 (non-approved substances) and should be treated as prohibited in sport. WADA does not list DSIP by name [B — verify current wording].
• Customs: low profile; the main issues are marketing language and the weak evidence base rather than trade controls.

Sources

• [A] Kovalzon, “Delta sleep-inducing peptide (DSIP): a still unresolved riddle”, *J Neurochem* 2006 — https://onlinelibrary.wiley.com/doi/10.1111/j.1471-4159.2006.03693.x
• [A] “Effects of delta sleep-inducing peptide on sleep of chronic insomniac patients. A double-blind study”, *PubMed 1299794* — https://pubmed.ncbi.nlm.nih.gov/1299794/
• [A] “Study of DSIP efficacy in improving sleep on short-term administration to chronic insomniacs”, *PubMed 3583493* — https://pubmed.ncbi.nlm.nih.gov/3583493/
• [A] “The influence of synthetic DSIP on disturbed human sleep”, *PubMed 7028502* — https://pubmed.ncbi.nlm.nih.gov/7028502/
• [A] “DSIP in insomnia”, *PubMed 6391925* — https://pubmed.ncbi.nlm.nih.gov/6391925/
• [B] FDA, Bulk Drug Substances Used in Compounding under 503A (DSIP removed from Category 2 April 2026; reviewed as “emideltide” and rejected 6-7 at the 24 July 2026 PCAC, the only rejection of seven) — https://www.fda.gov/drugs/human-drug-compounding/bulk-drug-substances-used-compounding-under-section-503a-fdc-act
• [B] WADA Prohibited List (S0 non-approved substances) — https://www.wada-ama.org/en/prohibited-list
• [B] PubChem CID 68816 (C35H48N10O15, MW 848.8)
• [D] Vendor/clinic pages (Innerbody, PeptideJournal, biolongevitylabs) — commercial; publish dosing and human-use claims we do not use; treated as leads only.

Plain summary

DSIP is a nine-amino-acid peptide isolated from rabbit brain in 1974 and named for early reports that it promoted delta-wave sleep, but after fifty years there is still no confirmed gene, no confirmed receptor and no agreed mechanism, and the human sleep evidence is a handful of tiny 1980s studies that flatly contradict one another. It is not approved anywhere, the “improves sleep and recovery” marketing is not supported by current evidence, and when the FDA advisory committee looked at it (as “emideltide”) in July 2026 it was the one peptide of seven they declined to recommend for compounding. On the strength of the data this is best treated as a landscape/education entry rather than a product to promote.

For laboratory and research use only (RUO). Not for human or veterinary use, not for consumption, and not a medicine. Information is a research summary, not medical advice, and contains no dosing guidance.

For laboratory research use only. Not for human or veterinary use, not for consumption, and not a medicine. This is a research summary, not medical advice, and contains no dosing guidance.