DSIP

Definition

Delta sleep-inducing peptide is a nonapeptide isolated in 1977 from the cerebral venous blood of rabbits in induced sleep ^[1]. The name records the hypothesis of its discoverers, not an established function: nearly fifty years on, the DSIP gene, precursor protein, and receptor have never been identified.

That unresolved biology is the molecule's defining feature. A 2006 review from within the field's own literature calls the sleep-factor hypothesis “extremely poorly documented and still weak” ^[2].

Evidence

The human record is small, old, and equivocal. A 1981 report described improved sleep in insomniacs given the synthetic peptide ^[3]; a 1992 double-blind study of sixteen chronic insomniac patients found higher objective sleep efficiency and shorter sleep latency against placebo across three nights of intravenous dosing — effects its own authors judged weak, possibly an artifact of change in the placebo group, and unlikely to carry major therapeutic benefit ^[4].

The literature then largely stopped. No modern trial exists, and the compound is sold today for sleep and stress on the strength of a four-decade-old hypothesis its own field has not confirmed.

Lawful access

DSIP was removed from Category 2 of the interim 503A bulks list in April 2026 without Category 1 listing, and in July 2026 the Pharmacy Compounding Advisory Committee voted against recommending it for the section 503A list — the only molecule the panel rejected at that meeting. The margin is reported as 6–7 with one abstention by McDermott Will & Schulte and by LumaLex Law, whose separate accounts agree substance by substance ^{[5, 6]}; the FDA has published no minutes, transcript or vote summary for the meeting, so that figure is secondary and this page says so wherever it appears. The committee's stated concerns tracked the record above: no established mechanism, no adequate human evidence.

No lawful US supply route exists, none is pending, and material sold online is research-use-only supply outside pharmacy oversight. The research-only page explains why removal from a list is not permission.

The substance also appears in a criminal case. In October 2020 Tailor Made Compounding, a Kentucky pharmacy, pleaded guilty in federal court to distributing unapproved new drugs between October 2018 and April 2020; the Justice Department's account of the plea agreement names DSIP among them, and the company agreed to forfeit $1,788,906.82, its 2019 sales of those products ^[7].

Related molecules

The index files DSIP with the neuropeptides alongside Semax, which the same July 2026 meeting recommended on a reported 8–5 ^{[5, 6]} — the clearest single illustration in this index that the committee read each dossier on its own terms. The pending page holds the six recommendations still awaiting FDA action.

Elsewhere in this index