What it is
Delta sleep-inducing peptide (DSIP) is a nine amino acid peptide, Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu. The Schoenenberger and Monnier group in Basel isolated it in 1977 from the blood draining the brains of rabbits in an induced state of sleep. It was named for its apparent ability to promote delta waves on EEG, the slow brain waves of deep sleep.
Almost fifty years later, the name is more confident than the science. DSIP's structure does not match any known peptide family, and no one has found the gene that makes it, the larger protein it might be cut from, or a receptor it acts on.
How it works
Nobody knows. The most useful summary comes from Kovalzon and Strekalova, two researchers who had studied DSIP and its analogues themselves. Their 2006 review, titled "a still unresolved riddle", made several points:
- The link between DSIP and sleep "has never been further characterized", partly because the gene, protein and receptor were never found.
- The hypothesis of DSIP as a sleep factor is "extremely poorly documented and still weak".
- DSIP-like material shows up in hypothalamic areas that are not especially relevant to sleep.
- In their own animal studies, certain synthetic DSIP analogues promoted slow-wave sleep, but DSIP itself did not.
They proposed that a still-unidentified DSIP-like natural peptide may explain the measurements. That remains a hypothesis.
Beyond sleep, DSIP has been studied in the lab for effects on stress hormones, pain and oxidative stress, mostly in Russian and European work from the 1980s and 1990s.
What the research found
Human studies
The human evidence is a handful of small trials in chronic insomnia, and they disagree:
- Schneider-Helmert (1987) gave 14 middle-aged people with chronic insomnia DSIP or placebo under double-blind conditions for 7 nights. He reported substantial improvement in night sleep, better daytime alertness and performance, and sleep efficiency reaching that of normal sleepers. The same author had published earlier positive reports.
- Bes and colleagues (1992) ran a double-blind trial in 16 patients with chronic insomnia, giving DSIP or a glucose placebo intravenously on three consecutive afternoons. Sleep efficiency and time to fall asleep looked slightly better with DSIP, but the authors judged the effects weak and possibly due to a chance change in the placebo group. Subjective sleep quality did not change. Their conclusion: short-term DSIP is "not likely to be of major therapeutic benefit" for chronic insomnia.
Both trials used intravenous infusion in a sleep laboratory, not the subcutaneous injections that research-chemical buyers use. No trial since the early 1990s has tested DSIP for sleep, and none has been large.
Animal studies
Rabbit and rat studies from the 1970s and 1980s gave mixed results on sleep, which is part of why the field stalled. Some groups reported more sleep after injecting DSIP directly into the brain; others, including Kovalzon's, found effects only with modified analogues.
Side effects reported in studies
The small insomnia trials did not report serious adverse events, but they were short and involved a few dozen people in total. There is no long-term safety data, and because the body's own DSIP system is not understood, there is no clear way to predict what repeated dosing does.
DSIP vs other sleep-linked peptides
| Compound | Link to sleep | Best human evidence |
|---|---|---|
| DSIP | Named for delta sleep; mechanism unknown | Small conflicting insomnia trials, 1980s to 1992 |
| Epitalon | Pineal gland and melatonin rhythm | Small reports from one group |
| Selank | Anxiety, which often disrupts sleep | Small Russian anxiety trials |
For a ranked overview see best peptides for sleep.
Status in the Philippines
No DSIP product is registered with FDA Philippines, and it is not an approved medicine anywhere. It is not a controlled substance under RA 9165. It is sold locally through research-chemical suppliers and gets attention from BPO night-shift workers and returning OFWs dealing with jet lag, groups for whom sleep problems are real. None of the published trials studied shift work or jet lag. Persistent insomnia is worth taking to a licensed physician, since conditions like sleep apnoea, depression and thyroid disease are common, treatable causes.
Local stock DSIP 10mg at Primara Labs, delivered in Metro Manila and nationwide. Research use only.
Storage
Lyophilised DSIP is best kept refrigerated and away from light. Once reconstituted, keep it at 2 to 8°C in the main body of the fridge, not the door. Brownouts can take a household fridge out of range within hours, so plan around them. See the beginner guide for handling basics.
