DSIP

What is DSIP

DSIP (Delta Sleep-Inducing Peptide) is a nonapeptide with the sequence Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu. It was isolated in 1977 from the blood of sleeping rabbits, which is where its name comes from. Despite that name, the peptide's role as a sleep factor is only weakly documented in the literature, and no clear receptor or associated gene has ever been found (PMID 16539679).

DSIP is not an approved drug and is not patented. Under the name Emideltide (acetate or free base) it was on the FDA 503A Category 2 list, which flags significant safety concerns. The updated 503A document (published 15 April 2026) removed Emideltide/DSIP from Category 2 effective 22 April 2026, as part of 12 peptides removed. Important: removal from Category 2 is not, by itself, a compounding clearance. A PCAC review of DSIP (together with Epitalon and Semax) is scheduled for 24 July 2026. Only addition to the 503A bulks list would open a clear compounding path.

We supply it as research-grade lyophilized powder.

How it works

The mechanism of action of DSIP is unresolved. Although the peptide has been studied since 1977, no single DSIP receptor and no DSIP gene have been identified (PMID 16539679). Statements about its activity therefore rest on observed functional effects rather than on a defined molecular target.

At the level of the stress axis, DSIP dampens hypothalamic-pituitary-adrenal reactivity in animal models. In rats it lowered stress-induced ACTH and cortisol, raised substance P in the hypothalamus, and reduced adrenal hypertrophy and thymus involution, with the strongest effect seen at the lower dose (PMID 1382246).

A second line of findings is antioxidant. In rat studies of cold and oxidative stress, DSIP inhibited lipid peroxidation and raised antioxidant enzymes such as superoxide dismutase, catalase, and glutathione peroxidase (PMID 11421812). In an ageing study run over several months, with dosing on five consecutive days per month, it suppressed lipid peroxidation and raised SOD, catalase, and ceruloplasmin (PMID 21809625), which forms the discussed geroprotective research angle.

Pharmacokinetically, DSIP is very short-lived. After intravenous dosing, half-lives were dog 4.0 min, monkey 2.9 min, and rat 2.0 min, at a clearance of about 30.7 ml/kg/min (PMID 6379493). In the sleep research that gave the peptide its name, a study in six chronic insomniacs reported longer sleep, better sleep quality, and fewer interruptions without daytime sedation after a single intravenous dose (PMID 7028502).

Often studied alongside

DSIP is studied in the context of CNS and stress regulation, and is therefore often considered alongside other neuromodulatory peptides. Selank and Semax are short regulatory peptides researched in anxiety- and stress-related models. Epitalon is the fourth peptide on the PCAC agenda for 24 July 2026, together with DSIP and Semax, and is studied in the context of ageing and antioxidant mechanisms.

For reconstitution, the standard solvent in published protocols is bacteriostatic water.

Documentation