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DSIP

Tier 2 · Preclinical
Also known as Delta sleep-inducing peptide

The strongest evidence present is Tier 1: several small double-blind, placebo-controlled human crossover RCTs from the 1980s (e.g., Schneider-Helmert, Scherschlicht), including a 6-subject study reporting a 59% increase in total sleep time and delayed next-night effects. However, human data are small (n=6-14), dated, and contradictory: one RCT found no significant improvement in chronic insomniacs. Much mechanistic and pharmacokinetic understanding rests on animal, in-vitro, observational, and expert-opinion sources. No large-scale Phase II/III trials and no regulatory approval exist.

Half-life
~0.25 h
Routes
Intravenous (only validated human route) · Subcutaneous (researcher convention / extrapolated, not validated) · Intracerebroventricular (i.c.v., animal research) · Oral (negligible bioavailability; some absorption of analogues in animals)
Goals
healing · cognitive · longevity
Cost / mg
Not recorded

How it works

DSIP (delta sleep-inducing peptide) is a small 9-amino-acid peptide first isolated from the blood of sleeping rabbits in the 1970s. It was named for its ability to increase deep, slow-wave (delta) sleep in animals. Despite decades of study, no specific DSIP receptor, gene, or precursor protein has ever been identified, so how it works remains unresolved. Rather than sedating like a sleeping pill, it appears to support natural sleep — increasing sleep depth and efficiency and creating a subjective feeling of sleep pressure without suppressing REM sleep or causing next-day grogginess. It seems to influence sleep indirectly through several brain systems (GABA, glutamate/NMDA, and opioid/enkephalin pathways), circadian rhythms, melatonin, and stress hormones, and it turns up in many tissues and body fluids. Its human sleep effects are strongest in people with disrupted sleep and modest in healthy sleepers.

Overview

Overview

DSIP (Delta Sleep-Inducing Peptide) is a nonapeptide (sequence Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu, molecular weight ~849 Da, CAS 62568-57-4). It was first isolated from the cerebral venous blood of sleeping rabbits — sources date this to either 1974 or 1977 — in work attributed to Monnier and Schoenenberger at the University of Basel. In the defining experiment, dialyzed cerebral venous blood from electrically-induced sleeping rabbits was infused into awake recipient rabbits, which then displayed enhanced delta and spindle EEG activity.

What it was named for

DSIP was characterized by its ability to increase slow-wave (delta) sleep in animal models. In rabbits, rats, mice, and humans the effect is mainly on delta sleep; in cats the effect on REM sleep is more pronounced. In one cat study, a single 7 nmol/kg intraventricular injection reduced sleep latency, increased total and slow-wave sleep (raising deep S2 while reducing light S1), left REM unaffected, and lasted ~7 hours.

The core unresolved problem

Despite decades of research, no specific DSIP receptor, precursor gene, or precursor protein has ever been identified in mammals. A 2006 review in the Journal of Neurochemistry called DSIP "a still unresolved riddle" and concluded the sleep hypothesis was "extremely poorly documented and still weak." Notably, some artificial structural analogues — but not native DSIP itself — showed the strongest slow-wave sleep-promoting activity in rabbits and rats, and a phosphorylated derivative (DSIP-P, Ser-7 phosphorylation) is manyfold more potent. This undercuts a simple direct sleep-factor role for native DSIP.

Human sleep evidence

Human data are small, dated, and contradictory:

  • A double-blind crossover RCT in six normal volunteers (25 nmol/kg slow IV infusion) reported a 59% increase in median total sleep time within 130 minutes, plus delayed next-night benefits (shorter sleep onset, less stage 1, better efficiency) and an immediate subjective feeling of sleep pressure.
  • IV DSIP at 25 µg/kg produced measurable delta-wave EEG increases that persisted across multiple nights, suggesting biological effects outlast plasma clearance.
  • A 1984 study reported 10 injections normalized sleep in 6 of 7 severe insomniacs for 3–7 months, with a weaker follow-up double-blind effect.
  • However, the only available human RCT cited found no significant improvement in chronic insomniacs, and the best sleep data come from small (n=6–14) 1981–1987 studies (Scherschlicht 1983; Schneider-Helmert 1985) with mixed results.

DSIP's sleep effects appear strongest in people with disrupted sleep and barely register in healthy sleepers, seeming to modify sleep depth rather than force sleep onset. It does not sedate in the classic pharmacologic sense and appears to sustain natural sleep functions.

Broader biology

DSIP-like immunoreactivity is found in brain (including neurosecretory hypothalamic nuclei), pituitary, gut, CSF, plasma, urine, and milk across many species. Beyond sleep, it has been observed to influence electrophysiological activity, neurotransmitter levels, circadian and locomotor patterns, hormones, psychological performance, and the actions and withdrawal of drugs (morphine, d-amphetamine, barbiturates). Proposed and studied roles include indirect analgesia (via enkephalin release), anxiolysis, circadian/melatonin modulation, LH release in hormone-primed animals, antioxidant/neuroprotective activity, and possible antiepileptic (excitability-stabilizing) properties. CSF DSIP-LI correlates with stage 3 and delta sleep, and plasma DSIP-LI drops at the wake-to-sleep transition and follows a diurnal rhythm peaking in late afternoon.

Regulatory and research status

DSIP has never progressed to large-scale clinical trials or regulatory approval in any jurisdiction. It has no FDA, EMA, or Health Canada approval, is not scheduled, and is on the FDA's Category 2 do-not-compound list (as of September 2023, with a PCAC review scheduled July 2026). Broad therapeutic claims (e.g., fibromyalgia, adrenal fatigue) trace to a single low-detail podcast source and are not corroborated by higher-tier literature. It remains a research compound whose legal status varies by jurisdiction.

What the research shows

140 findings extracted from the 18 sources cited below, strongest evidence first within each group. Every one links to the source it came from.

What human studies found

Based on 5 human trial findings, 1 human study finding, 18 animal findings, 1 in vitro finding and 5 expert opinion findings.

  • human trialDSIP applied as slow intravenous infusions increased sleep by 59% (median of total sleep time) within a 130-min interval after treatment compared with placebo1

  • human trialDSIP produced delayed effects on subsequent night sleep including shorter sleep onset1

  • human trialDSIP reduced percentage of stage 1 sleep in subsequent night1

  • human trialDSIP improved sleep efficiency in subsequent night1

  • human trialSubjects immediately reported a feeling of sleep pressure after DSIP administration1

  • human studyDelta sleep-inducing-peptide (DSIP) has been reported to increase sleep in subjects with insomnia2

  • animalCertain artificial DSIP structural analogues (but not DSIP itself!) showed significant slow-wave sleep promoting activity in rabbits and rats5

  • animalDelta sleep inducing peptide (DSIP) has been shown to increase sleep in various animals9

Show 22 more findings

  • animalIntraventricular administration of DSIP (2 or 10 micrograms) failed to affect LH release in ovariectomized rats9

  • animalDSIP (2 or 10; 15 or 30 micrograms) promptly stimulated LH release in ovariectomized estrogen, progesterone-primed rats in two separate experiments9

  • animalSingle injection of synthetic DSIP (7 nmol/kg) into lateral ventricle of cats produces significant decrease in sleep latency10

  • animalDSIP administration produces significant increase in total sleep10

  • animalDSIP administration produces significant increase in total slow wave sleep (SWS)10

  • animalDSIP increases deep slow wave sleep (S2) while significantly decreasing light slow wave sleep (S1)10

  • animalDSIP does not affect total amount of REM sleep or hourly values of REM sleep10

  • animalDSIP does not affect REM sleep latency, mean episode number, or mean episode length10

  • animalDSIP induces sleep in animals11

  • animalDSIP has sleep-supporting effects in animals11

  • animalIntravenous administration of DSIP produces sleep lasting for hours in different animals12

  • animalDSIP induces mainly delta-sleep in rabbits, rats, mice, and humans13

  • animalIn cats, DSIP effect on REM sleep was more pronounced13

  • animalDSIP affects psychological performance13

  • animalOnly the delta-sleep-inducing peptide (synthetic) showed significant and specific enhancement/induction of delta and spindle electroencephalogram patterns in rabbits15

  • animalDSIP pretreatment completely prevented hypoxia-induced damage to mitochondrial respiration in rats16

  • in vitroDSIP (10(-8) or 10(-6)M) had no effect on either basal or luteinizing hormone-releasing hormone-induced in vitro LH release from the hemipituitaries of ovarian steroid-primed rats9

  • expert opinionPreclinical studies on therapeutic peptides including DSIP are promising, but there is a current lack of clinical trials3

  • expert opinionThe hypothesis regarding DSIP as a sleep factor is extremely poorly documented and still weak5

  • expert opinionA physiological sleep regulatory role has not been determined for DSIP despite its identification in transfer experiments6

  • expert opinionA 2006 review in the Journal of Neurochemistry called DSIP 'a still unresolved riddle' and concluded the sleep hypothesis is 'extremely poorly documented and still weak'16

  • expert opinionDSIP has clinical applications in treating chronic insomnia17

How it works

Based on 2 human trial findings, 4 human study findings, 36 animal findings, 4 in vitro findings, 8 expert opinion findings and 8 theoretical findings.

  • human trialDSIP does not produce sedation in the classic pharmacologic way despite sleep-promoting effects1

  • human trialDSIP sustains natural sleep functions1

  • human studyCSF DSIP-like immunoreactivity was significantly correlated with stage 3 sleep (p = 0.05)2

  • human studyCSF DSIP-LI was significantly correlated with stage 3 and delta (stages 3 + 4) sleep during the first nonrapid eye movement NREM period (p = 0.02 and p = 0.05, respectively)2

  • human studyCSF DSIP-LI was significantly correlated with the ratio of the first and second NREM period (p < 0.05)2

  • human studyCSF DSIP-LI was negatively correlated with stage 2% sleep (p < 0.05)2

  • animalDSIP-like immunoreactivity is highly specifically distributed in the neurosecretory hypothalamic nuclei of various vertebrate species that are not particularly relevant for sleep regulation5

  • animalA naturally occurring dermorphin-decapeptide structurally similar to DSIP (in five of the nine positions) showed significant SWS-promoting activity in rabbits, with sleep-suppressing effect of its optical isomer5

Show 54 more findings

  • animalDelta sleep-inducing peptide (DSIP) was identified as a sleep factor in transfer experiments where tissue fluids from sleepy or sleeping animals elicited sleep when injected into recipient animals6

  • animalDelta sleep-inducing peptide-like immunoreactive cell bodies were mainly observed in the nucleus lateralis tuberis of the hypothalamus8

  • animalDSIP-like immunoreactive fibers were localized in the basal telencephalon, within the regions of the nucleus interstitialis commissurae anterioris and the nucleus entopeduncularis8

  • animalA dense network of DSIP-positive fibers was seen throughout the midcaudal hypothalamus, the lateral lobes, and the posterior lobe8

  • animalNumerous DSIP-like immunoreactive cells were detected in the median lobe of the pars distalis8

  • animalDSIP and MCH-like immunoreactive cells are stored in the same cells of the median lobe of the pituitary8

  • animalDSIP may act as a neuromodulator and/or a hypophysiotropic factor8

  • animalDSIP-like immunoreactive cells in the pars distalis suggests that this peptide may exert autocrine or paracrine effect in the pituitary8

  • animalDSIP is found in various parts of the brain including the hypothalamus9

  • animalIncrease in S2 is caused by prolongation of S2 episodes rather than more frequent occurrence10

  • animalDSIP-like material is naturally distributed in the body11

  • animalDSIP may have relations to certain diseases11

  • animalDelta-sleep-inducing peptide (DSIP) is a nonapeptide isolated, characterized and synthesized from 1970 to 197712

  • animalDSIP acts upon circadian rhythmicity of locomotor activity and transmitter concentrations in the brain12

  • animalDSIP acts upon circadian rhythmicity of plasma proteins and cortisol levels12

  • animalA phosphorylated derivative (DSIP-P) created by phosphorylation of serine in position 7 is manyfold more powerful12

  • animalDSIP occurs immunohistochemically in different regions of the rat brain12

  • animalDSIP interacts with acute and chronic stress12

  • animalDSIP interacts with drug-effects such as morphine, d-amphetamine and barbiturates12

  • animalAn induction of MAO-A and RNA synthesis in the brain was observed12

  • animalBrain concentration of DSIP increased during progressed hibernation12

  • animalAlcohol addictism produced a substantial decrease of DSIP-concentration in rat brain12

  • animalAnalogs with exchanged amino acids or shortening the peptide by one or two amino acids decreased or abolished sleep-induction effect12

  • animalDSIP-like material was found by RIA and immunohistochemistry in brain and by RIA in peripheral organs of the rat13

  • animalDSIP-like material was found by RIA in plasma of several mammals13

  • animalDSIP affects electrophysiological activity13

  • animalDSIP affects neurotransmitter levels in the brain13

  • animalDSIP affects hormonal levels13

  • animalDSIP affects the activity of neuropharmacological drugs including their withdrawal13

  • animalA peptide that induces slow-wave (delta) and spindles electroencephalogram enhancement after intraventricular (brain) infusion has been isolated from rabbits15

  • animalFive possible metabolic products and nonapeptide analogues with amino acids exchanged did not show the same effect as DSIP15

  • animalDSIP dampens the HPA axis response by reducing CRF-stimulated cortisol release at the pituitary level16

  • animalNakamura et al. (1989) showed DSIP does not bind opioid receptors directly but triggers brainstem to release Met-enkephalin16

  • animalDSIP upregulates protective enzymes: SOD, catalase, glutathione peroxidase16

  • in vitroDSIP can be entrapped in macroporous polymer matrices based on copolymer of dimethylaminoethyl methacrylate and methylen-bis-acrylamide (Co-DMAEMA-MBAA)4

  • in vitroDSIP biological activity shows a large spectrum revealed by biochemical and physiological studies in vitro5

  • in vitroSpecific electrophysiological effect on isolated neurons of rats and rabbits was established12

  • in vitroDSIP is a nonapeptide of MW 84913

  • expert opinionThe link between DSIP and sleep has never been further characterized, in part because of the lack of isolation of the DSIP gene, protein and possible related receptor5

  • expert opinionDSIP's natural occurrence and biological activity still remains obscure5

  • expert opinionDSIP structure is different from any other known representative of the various peptide families5

  • expert opinionDSIP is a nine-amino-acid peptide (Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu)16

  • expert opinionDSIP has been found in the hypothalamus, pituitary, gut, plasma, cerebrospinal fluid, and breast milk at measurable concentrations16

  • expert opinionAfter almost 50 years of research, nobody has found DSIP's gene, its receptor, or its precursor protein16

  • expert opinionThere is no identified receptor for DSIP16

  • expert opinionDSIP interacts with the body to promote restful sleep and stress relief17

  • theoreticalDelta sleep-inducing peptide (DSIP) targets circadian and mitochondrial regulators3

  • theoreticalDSIP or DSIP-like peptide(s) may activate the hypothalamic neural circuitry responsible for stimulation of LH release reported to occur during sleep9

  • theoreticalDSIP mechanism of action may involve modulation of adrenergic transmission11

  • theoreticalPeptides and regulatory proteins can cross the blood-brain barrier (BBB)18

  • theoreticalIn crossing the BBB, peptides and regulatory proteins act as informational molecules, informing the brain of peripheral events18

  • theoreticalBrain-to-blood passage helps to control levels of peptides within the brain and can deliver information in the brain-to-blood direction18

  • theoreticalTransporters for peptides and proteins are not static, but respond to developmental and physiological changes and are affected by disease states18

  • theoreticalThe BBB is adaptive to the needs of the CNS, but when that adaption goes awry, the BBB can be a cause of disease18

Dosing

Based on 2 animal findings and 1 expert opinion finding.

  • animalDSIP shows parabolic dose-response curve with different effective optima via i.c.v., i.v. and s.c. administration, in contrast to pharmaceuticals12

  • animalA U-shaped activity curve was determined for the dose as well as for the time of infusion13

  • expert opinionEffective dosing strategies for DSIP can be established17

How the body handles it

Based on 2 human study findings, 15 animal findings, 5 in vitro findings and 1 expert opinion finding.

  • human studyBoth DSIP and DSIP-P occur in human CSF12

  • human studyImmunoreactive DSIP-like material found in plasma of several mammals and humans, in human urine, CSF and milk12

  • animalDSIP effect is immediate with S2 increasing to more than 50% in first postinjection hour10

  • animalIncrease in S2 is maintained over 7 hours and disappears by eighth hour10

  • animalDSIP penetrates the blood-brain barrier12

  • animalUnweaned rats are able to take up DSIP by the intestinal tract12

  • animalEndogenous immunoreactive DSIP-like material in plasma, urine and CSF is bound to a larger protein (carrier) and thus protected from proteolysis12

  • animalEntry of delta sleep-inducing peptide (DSIP) into the circulation from the gastrointestinal (GI) tract occurs in unweaned rat pups14

Show 15 more findings

  • animalSignificant increases in plasma DSIP-like immunoreactivity occurred after feeding 100 micrograms/animal of N-Tyr-DSIP14

  • animalNo significant increases in plasma DSIP-like immunoreactivity occurred after vehicle (normal saline) or 1 microgram/animal14

  • animalPlasma immunoreactivity coeluted with intact DSIP and des-Trp1-DSIP on column chromatography14

  • animalA small but statistically significant increase of immunoreactivity occurred in plasma of pups whose nursing mothers were injected with N-Tyr-DSIP14

  • animalRadioactivity appeared in both the brain and blood of 1-2 and 10 day old rat pups fed 125I-N-Tyr-DSIP14

  • animalAlmost all of the radioactivity in brain coeluted with intact 125I-N-Tyr-DSIP on column chromatography, suggesting blood-brain-barrier crossing by the peptide14

  • animalA DSIP peptide administered orally can be absorbed through the GI tract into the systemic circulation14

  • animalDSIP crosses the blood-brain barrier easily via passive diffusion16

  • animalBanks et al. (1984) confirmed DSIP crosses the blood-brain barrier using radiolabeled DSIP16

  • in vitroApproximately 100% of DSIP has been entrapped into positively charged Co-DMAEMA-MBAA matrix4

  • in vitroThe quantity of DSIP adsorbed on negatively charged Co-AA-MBAA was only 2-6%4

  • in vitroDSIP release from Co-DMAEMA-MBAA was observed in saline solutions (0.9% NaCl and PBS)4

  • in vitroThere was no DSIP release in water or 25% ethanol, thus ionic strength was a reason of this process4

  • in vitroHalf-life time for proteolytic split-off of tryptophan by brain slices and homogenates is 15 min12

  • expert opinionPlasma levels of DSIP follow a circadian rhythm with peaks in the late afternoon16

Safety and side effects

Based on 1 human trial finding and 1 expert opinion finding.

  • human trialDSIP was well-tolerated with no psychologic, physiologic, or biochemical side effects observed1

  • expert opinionDSIP has a safety profile suitable for therapeutic use17

What people use it for

Based on 7 animal findings, 7 expert opinion findings and 3 theoretical findings.

  • animalDelta sleep-inducing peptide (DSIP) was isolated from rabbit cerebral venous blood in 1977 and initially regarded as a candidate sleep-promoting factor5

  • animalDSIP has sleep-facilitating properties10

  • animalDSIP has potential use for therapeutic treatment of insomnia11

  • animalDSIP has potential use for therapeutic treatment of pain11

  • animalDSIP has potential use for therapeutic treatment of withdrawal11

  • animalIn cats, DSIP administration predominantly produced REM-sleep12

  • animalDSIP affects circadian and locomotor patterns13

  • expert opinionDSIP appears to modify how deeply you sleep rather than forcing you to fall asleep16

Show 9 more findings

  • expert opinionSleep effects are strongest in people whose sleep is already messed up and barely register in healthy sleepers16

  • expert opinionDSIP shows stress modulation, pain relief, and antioxidant protection16

  • expert opinionDSIP has clinical applications in treating adrenal fatigue17

  • expert opinionDSIP has clinical applications in treating fibromyalgia17

  • expert opinionDSIP can be used for pain management17

  • expert opinionDSIP supports recovery17

  • theoreticalDSIP is a recovery-enhancing agent for orthopaedic injury management3

  • theoreticalDelta-sleep inducing peptide (DSIP) possesses numerous beneficial properties, including its abilities in burn treatment and neuronal protection4

  • theoreticalMechanisms by which peptides and proteins cross the BBB offer opportunities for drug delivery of these substances or their analogs to the brain in the treatment of diseases of the central nervous system18

Other findings

Based on 2 animal findings and 1 expert opinion finding.

  • animalFirst evidence for the presence of a DSIP-related peptide in fish8

  • animalDSIP amino acid sequence is Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu15

  • expert opinionDSIP was first isolated from rabbit brains in 1977 by Schoenenberger and Monnier at the University of Basel in Switzerland16

Points of contention

Where the evidence is unsettled, thin, or says less than the popular claim — worth knowing before you draw conclusions.

Contested

Human sleep efficacy studies are small and give mixed, often contradictory results.

Acute and delayed effects of DSIP (delta sleep-inducing peptide) on ... reports a 59% increase in total sleep time in a 6-subject RCT and multiple sources describe positive early findings; however DSIP: Mechanism, Dosing & Evidence (Tier 2) | Pepteligence states the only available human RCT found no significant improvement in chronic insomniacs, DSIP Peptide: Does Delta Sleep-Inducing Peptide Work? notes multiple failed replications and no RCTs in the last two decades, and How to Take DSIP Peptide: Dosing, Timing, and Protocol | FormBlends/DSIP Peptide: Benefits, Sleep, Dosage & Risks (2026) characterize the human data as small (n=6-14, 1980s) with mixed results.

Contested

Sources disagree widely on DSIP's plasma half-life.

Estimates range from ~15 minutes (DSIP (Delta Sleep-Inducing Peptide): Research Evidence & Safety Profile | PeptideInsight), 15-20 min (DSIP Science Explained — Peptide Mechanisms | Real Peptides), 7-15 min (DSIP: Benefits, Dosage & Safety | FormBlends), 'minutes' (DSIP Peptide: Does Delta Sleep-Inducing Peptide Work?), ~30 min (How to Take DSIP Peptide: Dosing, Timing, and Protocol | FormBlends), 30-40 min (DSIP Half-Life: ~30–40 Min IV — Pharmacokinetics & Sleep Data | Halflife Labs), to 2-4 hours in animal models (DSIP 5mg Half-Life | Pharmacokinetics Data). No formal human subcutaneous PK study exists per DSIP Half-Life: ~30–40 Min IV — Pharmacokinetics & Sleep Data | Halflife Labs.

Contested

DSIP's effect on the HPA/cortisol axis is inconsistent across studies.

DSIP (Delta Sleep-Inducing Peptide): Research Evidence & Safety Profile | PeptideInsight (Polleri et al.) found ACTH and cortisol responses to CRH were identical during DSIP and placebo infusion, suggesting no direct HPA modulation, whereas DSIP Peptide: Benefits, Dosing, Side Effects & What to Know [2026] - Brainflow reports animal data showing DSIP dampens the HPA axis by reducing CRF-stimulated cortisol at the pituitary, and DSIP Science Explained — Peptide Mechanisms | Real Peptides reports reduced stress-induced cortisol in humans.

Limited evidence

No identified receptor, gene, or precursor, and no regulatory approval for DSIP.

Multiple sources (DSIP: Mechanism, Dosing & Evidence (Tier 2) | Pepteligence, DSIP (Delta Sleep-Inducing Peptide): Research Evidence & Safety Profile | PeptideInsight, DSIP Peptide: Benefits, Dosing, Side Effects & What to Know [2026] - Brainflow, Delta sleep-inducing peptide (DSIP): a still unresolved riddle.) note no DSIP receptor, gene or precursor protein has ever been found after decades of research; a 2006 review called it 'a still unresolved riddle.' DSIP is not FDA/EMA/Health Canada approved and is on FDA's Category 2 do-not-compound list (DSIP Peptide: Benefits, Sleep, Dosage & Risks (2026)).

Limited evidence

Subcutaneous and at-home dosing is not validated by controlled human trials.

How to Take DSIP Peptide: Dosing, Timing, and Protocol | FormBlends and How to Take DSIP (Delta Sleep-Inducing Peptide) for Better Sleep: Dosage Chart emphasize that clinical trials used intravenous administration only; the commonly cited 100-250 mcg subcutaneous doses derive from case reports, observational studies and researcher convention, not controlled trials, and the optimal SC dose is not scientifically established.

Limited evidence

A key finding is that DSIP analogues, not DSIP itself, promote sleep.

Delta sleep-inducing peptide (DSIP): a still unresolved riddle. explicitly notes that certain artificial DSIP structural analogues (but not DSIP itself) showed significant slow-wave sleep promoting activity in rabbits and rats, undercutting the direct sleep-factor hypothesis for native DSIP.

Inconsistency

"No human doses exceeded ~21.4 mcg/kg daily" contradicts the stated 25–100 nmol/kg range and the "25 µg/kg IV" study.

25 nmol/kg × ~849 Da ≈ 21.2 µg/kg, so 21.4 µg/kg reflects only the low end of the range. 100 nmol/kg ≈ 85 µg/kg, and the separately cited 25 µg/kg both exceed 21.4 µg/kg. The ceiling claim is arithmetically inconsistent with the same section's dose range.

What you may have heard

The evidence that DSIP reliably improves human sleep is weaker and more contradictory than its reputation suggests.

DSIP is often presented as a proven sleep aid, but its human sleep reputation rests almost entirely on small studies from the 1980s, typically 6 to 14 subjects, that produced mixed results. A frequently cited 6-person infusion study reported a 59% jump in total sleep time, yet the one controlled trial in chronic insomniacs found no significant improvement. After roughly 50 years of research, no DSIP receptor, gene, or precursor protein has been identified in mammals, and a 2006 review in the Journal of Neurochemistry called the sleep hypothesis 'extremely poorly documented and still weak,' describing DSIP as 'a still unresolved riddle.' Some of the pharmacokinetic figures circulated for DSIP, such as the ~30–40 minute intravenous half-life, trace back to commercial vendor pages rather than primary clinical measurement, so certainty should be treated as limited rather than established.

Inconsistency

Two human intravenous studies report DSIP doses written as "25 nmol/kg" and "25 µg/kg" — units easy to confuse with one another.

The double-blind crossover described in "Acute and delayed effects of DSIP (delta sleep-inducing peptide) on human sleep behavior" gave DSIP as a slow intravenous infusion at 25 nmol/kg. A separate figure of 25 µg/kg IV (attributed to Schneider-Helmert 1985) appears in the Halflife Labs pharmacokinetic summary. Because DSIP is a nonapeptide of roughly 850 Da, 25 nmol/kg works out to about 21 µg/kg — numerically close to the 25 µg/kg figure. The matching "25" with different units is worth checking against primary sources before treating the two as independent doses.

Inconsistency

Two sources report different figures for how fast DSIP clears — roughly 15 minutes versus 30–40 minutes.

PeptideInsight gives a plasma half-life of approximately 15 minutes, attributing it to rapid degradation by aminopeptidases. Halflife Labs instead reports an elimination half-life of about 30–40 minutes following intravenous administration in humans, based on the Graf and Kastin 1986 pharmacokinetic review, while explicitly cautioning that this figure should not be treated as an established human half-life given the limited underlying data. Neither source reconciles the two values.

What you may have heard

Claim that DSIP binds delta opioid receptors "with highest affinity" conflicts with claim that it releases Met-enkephali…

These two mechanistic statements are contradictory: one asserts direct DOR binding (theoretical, DSIP Science Explained — Peptide Mechanisms | Real Peptides/DSIP vs Selank Amidate — Mechanism & Use Comparison), the other asserts analgesia is enkephalin-mediated because DSIP shows no direct opioid receptor binding (DSIP (Delta Sleep-Inducing Peptide): Research Evidence & Safety Profile | PeptideInsight/DSIP Peptide: Benefits, Dosing, Side Effects & What to Know [2026] - Brainflow). The technical section presents both, creating an internal inconsistency about whether DSIP is an opioid receptor ligand at all.

What you may have heard

"Anxiolytic effects in rodent and human trials" and "reduces stress-induced cortisol" asserted from a single tier-3 vend…

DSIP Science Explained — Peptide Mechanisms | Real Peptides is a peptide-vendor page (tier 3). Claiming demonstrated human anxiolytic and cortisol-lowering effects goes beyond what the cited evidence tier supports, especially given the contested HPA-axis data elsewhere in the profile.

What you may have heard

"Well-tolerated with no observed psychological, physiological, or biochemical side effects" generalized from a 6-subject…

A single-dose n=6 crossover cannot support a general tolerability claim; the absence of side effects in 6 subjects is weak evidence. The no-long-term-data caveat exists but the headline framing still overstates safety.

What you may have heard

The claim that DSIP "completely prevented" hypoxia-induced mitochondrial damage comes from a single vendor guide and is stated far more cautiously everywhere else.

The absolute wording — "DSIP pretreatment completely prevented hypoxia-induced damage to mitochondrial respiration in rats" — appears in the Brainflow guide (DSIP Peptide: Benefits, Dosing, Side Effects & What to Know [2026]). Other write-ups describe the same antioxidant line of work in much weaker terms: the DSIP Peptide sleep-evidence review notes only that rodent studies "suggested DSIP or DSIP analogs might reduce lipid peroxidation and protect against oxidative damage in several tissues." The preclinical record summarized in DSIP: Mechanism, Dosing & Evidence goes no further than DSIP analogues showing in vitro antioxidative activity comparable to vitamin C and β-carotene, plus detoxifying effects against cisplatin toxicity in rats — a modest characterization that the "completely prevented" phrasing overstates.

Other

Profile presents DSIP as both stimulating melatonin secretion and retarding the nighttime melatonin/NAT rise without rec…

Claims 16 (in vitro pineal stimulation) and 17 (in vivo retardation of nighttime melatonin rise) point in opposite directions; a reader needs a note that these are context-dependent (in vitro vs in vivo) rather than a settled effect.

Contested

Sources disagree on whether any human pharmacokinetic data for DSIP exist at all.

One review (DSIP: Mechanism, Dosing & Evidence, Pepteligence) states flatly that no human pharmacokinetic data on half-life or bioavailability are available. A second source (DSIP Half-Life: ~30–40 Min IV, Halflife Labs) does report a human figure — an intravenous elimination half-life of approximately 30–40 minutes — but attributes it to a single 1986 review by Graf and Kastin and explicitly cautions that this limited reference should not be treated as an established human half-life. That same source notes that no formal subcutaneous pharmacokinetic study in humans has been published and that no human bioavailability value is available. So the disagreement is real but narrow: the only human half-life figure in circulation comes from one older review, is flagged as low quality by the source reporting it, and is confined to the intravenous route.

Contested

The link between spinal-fluid DSIP levels and slow-wave sleep was seen only in men with schizophrenia, and it is unknown whether it holds in anyone else.

In the study "Delta sleep-inducing-peptide-like immunoreactivity (DSIP-LI) and delta sleep in schizophrenic volunteers," cerebrospinal fluid DSIP-like immunoreactivity was measured in 15 drug-free male subjects who all carried a DSM-III-R diagnosis of schizophrenia. In this group, CSF DSIP-LI correlated with stage 3 sleep (p=0.05), with stage 3 and delta (stages 3+4) sleep during the first NREM period (p=0.02 and p=0.05), and with the ratio of the first to second NREM period (p<0.05), and was negatively correlated with stage 2% sleep (p<0.05). The authors describe this as a first report and state explicitly that whether it can be generalized to sleep in non-psychiatric subjects awaits further study.

Contested

Sources disagree on when DSIP was first isolated, giving either 1974 or 1977.

The isolation year is reported inconsistently across the literature. The Basel group's own account, "Characterization, properties and multivariate functions of delta-sleep-inducing peptide (DSIP)," describes the peptide as having been isolated, characterized and synthesized over the span 1970 to 1977 rather than in a single year. The review "Delta sleep-inducing peptide (DSIP): a still unresolved riddle" states it was isolated from rabbit cerebral venous blood by the Schoenenberger–Monnier group in 1977, and the Halflife Labs pharmacokinetics reference likewise attributes the isolation to Schoenenberger & Monnier 1977. Several commercial secondary sources, however, give 1974 as the isolation year — the FormBlends "How to Take DSIP Peptide" guide and the PeptideAdvisors "DSIP Peptide: Benefits, Sleep, Dosage & Risks" guide both date it to 1974, with one noting the underlying paper (Pflügers Archiv) was published in 1977.

What you may have heard

DSIP is often presented as a proven sleep aid, but the human evidence for that is small, old, and inconsistent.

The best human data come from a handful of small double-blind crossover trials in the 1980s (typically six to fourteen subjects), and they did not agree — the only randomized controlled trial in chronic insomniacs found no significant sleep improvement. No large modern trials have been run, and despite roughly 50 years of research no DSIP receptor, gene, or precursor protein has ever been identified; a 2006 Journal of Neurochemistry review called the sleep hypothesis 'extremely poorly documented and still weak.' Some confident-sounding summaries online trace back to commercial vendor pages rather than primary clinical data.

Using it with other compounds

Check a stack
  • EpithalonSame downstream effect

    May be complementary

    Both peptides converge on restoring normal melatonin secretion and circadian rhythm, but by different upstream mechanisms: DSIP influences pineal melatonin synthesis and delta sleep, while Epithalon reportedly upregulates the pineal melatonin (AANAT) axis and circadian clock genes. Used together they could reinforce circadian normalization and sleep timing.

    Tier 4Theoretical — not established

    Timing Take in the evening to reinforce the natural nighttime melatonin rise and consolidate circadian effects.

    Shares melatonin pathway

  • SermorelinComplementary

    May be complementary

    Sermorelin stimulates the pituitary's own GH pulse, which independently increases slow-wave (deep) sleep duration, while DSIP promotes delta sleep through GABAergic and enkephalin/opioid mechanisms. Because the upstream mechanisms are entirely different but both converge on deeper sleep, they can complement each other for sleep-focused protocols.

    Tier 4Theoretical — not established

    Timing Both work best dosed at night, since GH release and slow-wave sleep both peak early in the sleep cycle.

    Shares sleep architecture

  • MK-677Complementary

    May be complementary

    Both are used to improve sleep quality but through completely different routes: DSIP deepens slow-wave (delta) sleep via GABA-A enhancement and opioid/enkephalin signaling, while MK-677 raises GH/IGF-1 and has been reported to increase REM and deep sleep. Stacking them targets sleep architecture from two angles, which can be additive. Note that MK-677 also raises appetite and can cause vivid dreams or morning grogginess in some users, so evaluate how the combination affects your own sleep.

    Tier 4Theoretical — not established

    Timing Both are typically taken in the evening/before bed to align with the natural nighttime GH pulse and sleep onset.

    Shares sleep architecture

  • SelankComplementary

    Worth caution

    Both peptides calm the nervous system through overlapping routes: DSIP enhances GABA-A currents and releases enkephalins, while Selank is an anxiolytic that positively modulates GABA-A signaling and boosts enkephalins by inhibiting enkephalinase (neprilysin). Their shared GABA and enkephalin actions make this a plausible anxiolytic/sleep-support pairing, though the combined sedative/calming effect should be monitored.

    Tier 4Theoretical — not established

    Timing DSIP is best taken before bed for sleep; Selank is often used earlier in the day for daytime anxiety, so consider separating them to avoid excess sedation.

    Shares GABA signaling

  • SemaxComplementary

    Worth caution

    Both peptides engage the endogenous enkephalin/opioid system — DSIP releases Met-enkephalin while Semax inhibits enkephalin-degrading enzymes and acts at the μ-opioid receptor — and both report neuroprotective/antioxidant effects. Their upstream mechanisms differ, so together they could reinforce enkephalinergic and neuroprotective signaling, though Semax is stimulating/nootropic and DSIP is sedating.

    Tier 4Theoretical — not established
    What the research doesn't establish
    Although DSIP and Semax both touch enkephalinergic signaling, they do so by mechanistically distinct routes — DSIP releasing Met-enkephalin, Semax inhibiting enkephalin-degrading enzymes — and no evidence shows these separate actions reinforce one another. Their neuroprotective effects likewise arise from different pathways, and DSIP's sedating profile versus Semax's stimulating one has not been shown to be complementary rather than opposing.

    Timing Semax is activating and best used earlier in the day; DSIP is sleep-promoting and used at night, minimizing functional conflict.

  • CortexinComplementary

    Worth caution

    Both enhance GABAergic tone and dampen glutamate/NMDA excitatory signaling, giving overlapping anti-excitotoxic and calming effects — DSIP primarily to deepen slow-wave sleep, Cortexin to protect neurons. Their converging effects on the excitation/inhibition balance make them a reasonable complementary pairing, though additive sedation should be monitored.

    Tier 4Theoretical — not established

    Timing DSIP is best dosed in the evening for sleep; watch for additive calming/sedative effects.

    Shares GABA signaling

Safety and side effects

Safety & Tolerability

Human trial data: In the double-blind RCT of six volunteers, DSIP was well-tolerated with no observed psychological, physiological, or biochemical side effects. Human observations report that DSIP does not suppress REM sleep and does not cause next-day cognitive impairment, and it lacks the tolerance/dependence profile of conventional sleep medications. Subjective sleep-quality improvements have been reported to last roughly 6–8 hours.

Anecdotal / reported adverse effects: These include dose-dependent fatigue or morning lethargy, injection-site reactions, and rare headache or dizziness. One experienced source reports never having encountered significant adverse effects and considers DSIP a benign compound.

Animal data: In animal models DSIP is generally well-tolerated within standard research concentrations. Known effects include mild sedation, transient alterations in locomotor activity, mild changes in blood pressure, and rare behavioral changes. No confirmed long-term toxicity has been reported preclinically.

Important limitations

  • No long-term human safety data exist.
  • No FDA/EMA/Health Canada approval for any indication; DSIP is a research compound, is not scheduled, and is on the FDA's Category 2 do-not-compound list (Sept 2023, PCAC review July 2026). Legal and safety status varies by jurisdiction.
  • Because no receptor, gene, or precursor has been identified, and human efficacy data are small and conflicting, safety cannot be characterized with the confidence of an approved drug.
  • HPA/cortisol effects are inconsistent across studies (no CRH-response change in one human study; dampening in animal data), so hormonal effects are not well established.

Reconstitution and handling

Reconstitution & Preparation

No dose has been established for this compound. No regulatory label exists for it, so the figures below are what sources report — not guidance.

Note: DSIP is a research compound. The only validated human administration route in published trials is intravenous. Subcutaneous, oral, and at-home dosing are extrapolated from general peptide pharmacology and researcher convention, not from controlled human trials. Oral dosing has no meaningful bioavailability in humans. Because the receptor target is undefined, the optimal subcutaneous dose has not been scientifically established.

Commonly cited research reconstitution

  • A typical research reconstitution is 1 mg/mL in bacteriostatic water.
  • At that concentration, a 200 mcg dose corresponds to 0.2 mL measured in a U-100 insulin syringe.

Doses reported in the literature

Human trials (intravenous):

  • Doses ranged from 25–100 nmol/kg IV; Schneider-Helmert trials used 25 nmol/kg across short courses of four to seven nights.
  • In mass units this range is roughly 21–85 mcg/kg (25 nmol/kg ≈ 21 mcg/kg; 100 nmol/kg ≈ 85 mcg/kg); the separately reported IV study used 25 µg/kg.
  • The 6-subject sleep RCT used 25 nmol/kg slow IV infusion; another study used 25 µg/kg IV.

Anecdotal / researcher-convention subcutaneous use:

  • Commonly cited 100–500 mcg (often 100–250 or 100–300 mcg) once daily, taken roughly 30–60 minutes (some sources 1–3 hours) before sleep, based on case reports and convention rather than controlled trials.

Pharmacokinetic considerations for dosing

  • Plasma half-life estimates vary widely (from ~7–15 minutes up to 30–40 minutes IV, and 2–4 hours in animal models); DSIP is cleared primarily by proteolytic degradation (aminopeptidase split-off of tryptophan, ~15 min half-life in brain tissue).
  • Preclinical work often required continuous infusion or multiple daily administrations, and the dose-response is U-shaped (parabolic) rather than linear, with different optima by route (i.c.v., i.v., s.c.) — an important departure from conventional pharmaceuticals.
  • Despite short plasma persistence, EEG sleep effects have been reported to persist across multiple nights beyond plasma clearance; endogenous DSIP-like material is protected from proteolysis by binding to a larger carrier protein.

Sources

Ordered by evidence quality — the strongest first.

  1. Acute and delayed effects of DSIP (delta sleep-inducing peptide) on ...(opens in a new tab)
    Tier 1Web · pubmed.ncbi.nlm.nih.gov
  2. Delta sleep-inducing-peptide-like immunoreactivity (DSIP-LI) and delta sleep in schizophrenic volunteers.(opens in a new tab)
    Tier 1PubMed · pubmed.ncbi.nlm.nih.gov · 1992
  3. Therapeutic Peptides in Orthopaedics: Applications, Challenges, and Future Directions.(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov · 2026
  4. Delta-sleep inducing peptide entrapment in the charged macroporous matrices.(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov · 2014
  5. Delta sleep-inducing peptide (DSIP): a still unresolved riddle.(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov · 2006
  6. Biochemical regulation of non-rapid-eye-movement sleep.(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov · 2003
  7. Delta sleep-inducing peptide.(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov · 2001
  8. Immunohistochemical localization of delta sleep-inducing peptide (DSIP) in the brain and pituitary of the cartilaginous fish Scyliorhinus canicula.(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov · 1992
  9. Delta sleep-inducing peptide (DSIP) stimulates LH release in steroid-primed ovariectomized rats.(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov · 1987
  10. The effects of delta-sleep-inducing peptide (DSIP) on wakefulness and sleep patterns in the cat.(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov · 1987
  11. Delta-sleep-inducing peptide (DSIP): an update.(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov · 1986
  12. Characterization, properties and multivariate functions of delta-sleep-inducing peptide (DSIP).(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov · 1984
  13. Delta-sleep-inducing peptide (DSIP): a review.(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov · 1984
  14. Delta sleep-inducing peptide (DSIP)-like material is absorbed by the gastrointestinal tract of the neonatal rat.(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov · 1983
  15. Characterization of a delta-electroencephalogram (-sleep)-inducing peptide.(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov · 1977
  16. DSIP Peptide: Benefits, Dosing, Side Effects & What to Know [2026] - Brainflow(opens in a new tab)
    Tier 3Web · brainflow.co
  17. DSIP Peptide: Revolutionizing Sleep, Stress, and Pain Management in Clinical Practice(opens in a new tab)
    Tier 3Web · youtube.com
  18. Peptides and the blood-brain barrier.(opens in a new tab)
    Tier 4PubMed · pubmed.ncbi.nlm.nih.gov · 2015

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