DSIP

DSIP (delta sleep-inducing peptide) is a nine-residue neuropeptide first isolated from rabbit blood in 1977 and named for its capacity to shift the electroencephalogram toward slow-wave and spindle activity. It occurs naturally in human biology — measurable concentrations have been detected in breast milk.

The published literature is sparse and dated, concentrated between the late 1970s and early 1990s, with no substantial research activity since 1993. Human data is limited to small open-label studies and a single case report from the mid-1980s, two of which were published by the same investigator in the same journal issue. No receptor has been definitively identified.