Evidence review
Why was DSIP the only peptide the July 2026 committee refused to recommend?
The answer
The panel voted 6–7, with one abstention, against listing, and the record it was reading contains no identified gene, precursor protein, or receptor after nearly fifty years, alongside a human literature of a few small studies whose most recent entry dates from 1992.
On July 23 and 24, 2026, the Pharmacy Compounding Advisory Committee reviewed seven of the twelve peptides the FDA had removed from Category 2 of its interim 503A bulks list three months earlier [5]. It recommended six of them for the section 503A list. It refused the seventh.
Delta sleep-inducing peptide was that seventh, rejected 6–7 with one abstention. The margin is worth reading precisely: this was not a panel that found the dossier obviously deficient and dispatched it, but a panel that split almost evenly and landed one vote short. The full arithmetic of the meeting, molecule by molecule, is in the vote ledger.
The vote is advisory in either direction. A recommendation does not make a substance lawful to compound, and a rejection does not add a prohibition that was not already there; DSIP left Category 2 in April 2026 and sits on no list, which is where it sat before the meeting and where it sits now.
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 its discoverers formed, not a function anyone has since established: nearly fifty years on, the DSIP gene, precursor protein, and receptor have never been identified.
That is an unusual position for a substance nominated for pharmacy compounding. A review published in 2006 from within the field's own literature describes the sleep-factor hypothesis as "extremely poorly documented and still weak" [2] — a judgment from a friendly source, not a skeptical outsider, and one that has not been overtaken since.
The human literature 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 that the study's 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. Sixteen patients across three nights, reported by authors who declined to claim much for the result, is the strongest controlled entry in the file, and it is thirty-four years old. A committee weighing whether pharmacies should be permitted to compound the substance was weighing that.
DSIP has no lawful United States supply route, none is pending, and the compound is sold for sleep and stress on the strength of a four-decade-old hypothesis its own field has not confirmed. Material offered under the name is research-use-only supply, outside pharmacy oversight; the research-only page explains why removal from a list is not permission.
The contrast within the meeting itself is the clearest way to read the outcome. The same panel recommended Semax 8–5 on the same days, and this index files both molecules as neuropeptides — one recommendation, one rejection, one class, one meeting. The committee read each dossier on its own terms, and the monograph carries the dated ledger for this one.
Monographs
Reference tables
Every source below is inherited from a monograph in this index, where it was verified at writing time; this review introduces none of its own. The pointer beside each entry names the monograph and the reference number it came from.