Pep IQ
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DSIP (Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu) was first isolated in 1974 from rabbit cerebral venous blood during induced sleep states. Animal work shows it increases delta-wave (slow-wave) sleep, modulates substance P in the hypothalamus, and produces antinociceptive effects when administered intracerebroventricularly. A 2021 rat study suggested motor function recovery after focal stroke. The animal evidence base is modest and old.
Community protocols converge on 100–500 mcg SubQ or intranasal pre-bed, either nightly for 2–4 week cycles or as-needed. Most users start at 100 mcg and assess. Intranasal delivery works well for sleep applications and is often preferred — convenient, fast onset, and avoids injections. Some run short cycles (2–4 weeks) to avoid theoretical adaptation; others use PRN for travel or shift-work disruption. Effects are described as subtle — improved sleep depth and quality without next-day grogginess — and individual response varies widely. Continuous nightly use is not well-studied.
Small early human trials, mostly from the 1980s and 1990s. A 1981 placebo-controlled trial in 14 insomnia patients reported improved sleep and daytime performance after 25 nmol/kg IV DSIP. A 1984 pilot trial in chronic pain patients reported therapeutic effects. A 1995 trial found DSIP at 3–4 mg IV did not affect ACTH or cortisol response to CRH stimulation, suggesting earlier claims of HPA axis modulation were over-stated. No modern RCTs. Older opioid and alcohol withdrawal trials reported symptom alleviation in 87–97% of patients but were small and uncontrolled.
Not FDA-approved. Not a prescription medicine. Sold via research-peptide vendors. A preparation called Deltaran was used in Russia for paediatric CNS recovery after antiblastic therapy. WADA does not list DSIP.
DSIP research spans 50 years. Animal work consistently shows delta-sleep enhancement, substance P modulation, and analgesia. Small early human studies were directionally supportive. No modern RCT has been completed. Community protocols run 100–500 mcg SubQ or intranasal pre-bed in 2–4 week cycles, or as-needed. Individual response varies widely.
DSIP has one of the most evocative origin stories in peptide science. In 1974, Swiss researchers in Basel were studying sleep by electrically stimulating the thalami of rabbits and then collecting venous blood from the sleeping animals. From this blood they isolated a small peptide that, when injected into other rabbits, induced deep delta-wave sleep. They called it Delta Sleep-Inducing Peptide.
The discovery attracted significant interest — here was a molecule that appeared to regulate the deepest stage of sleep from within the body's own chemistry. DSIP was subsequently found in human cerebrospinal fluid, hypothalamus, limbic system, pituitary, and peripheral organs. It is found in human breast milk — a striking location suggesting possible roles in infant sleep regulation. It co-localises in the pituitary with ACTH, melatonin-stimulating hormone, and thyroid-stimulating hormone, hinting at broad neuroendocrine roles beyond sleep.
The mystery deepened over subsequent decades. Despite extensive research, scientists have never been able to identify the gene that encodes DSIP, its biosynthetic pathway, or its receptor. Its natural half-life in vitro is only 15 minutes due to a specific enzyme, yet it appears to have lasting effects in vivo — suggesting it either binds to carrier proteins or forms part of a larger precursor molecule not yet characterised.
Research over 50 years has revealed that DSIP has a far wider range of biological effects than its name implies. It appears to function as a broad neuroendocrine regulator rather than a narrow sleep inducer — which may explain why its effects are so inconsistent when studied purely in the context of sleep.
The 2024 development of a DSIP-brain-penetrating peptide fusion (DSIP-CBBBP) is worth noting. By attaching a blood-brain barrier crossing peptide to DSIP, researchers were able to significantly improve delivery and demonstrate meaningful correction of neurotransmitter imbalances (5-HT, dopamine, melatonin) in sleep-deprived mice. This suggests the delivery limitation — not the mechanism — may have been responsible for some of the inconsistency in earlier research.