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 6–7, with one abstention, against recommending it for the section 503A list — the only molecule the panel rejected at that meeting. 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.

Related molecules

The index files DSIP with the neuropeptides alongside Semax, which the same July 2026 meeting recommended 8–5 — 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.