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Peptide Atlas
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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

284 findings extracted from the 31 sources cited below, strongest evidence first within each group. Every one links to the source it came from.

What human studies found

Based on 8 human trial findings, 11 human study findings, 26 animal findings, 1 in vitro finding and 12 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 trialA follow-up double-blind study showed statistically measurable but weak effects24

  • human trialThe strongest human evidence comes from small placebo-controlled studies in chronic insomniacs from 1981-1987, with sample sizes of 6-14 and mixed results across studies27

  • human trialThe only available human RCT found no significant improvement in sleep in chronic insomniac patients28

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  • human studyIntravenous DSIP at 25 µg/kg produced measurable changes in sleep EEG architecture — specifically increases in delta-wave (slow-wave) sleep — that persisted across multiple nights following a short administration course2

  • human studyDelta sleep-inducing-peptide (DSIP) has been reported to increase sleep in subjects with insomnia3

  • human studySome studies in healthy volunteers and in patients with sleep disorders showed modest improvements in sleep onset latency, total sleep time, or subjective sleep quality with intravenous or subcutaneous DSIP20

  • human studyMultiple attempts to replicate positive findings produced neutral or contradictory results20

  • human studyadministration increases delta wave amplitude during EEG recordings22

  • human studyreduces stress-induced cortisol elevation22

  • human studydemonstrates anxiolytic effects in rodent and human trials without the tolerance or dependence profile of conventional sleep medications22

  • human studysubjective sleep quality improvements last 6–8 hours22

  • human studyIn a 1984 study, 10 DSIP injections normalized sleep in 6 of 7 severe insomniacs for 3-7 months24

  • human studyA narcolepsy case report showed reduced sleep attacks24

  • human studyDSIP alters sleep architecture in humans (small human studies Scherschlicht et al., 1983; Schneider-Helmert 1985), mixed design26

  • animalStudies have examined DSIP's effects on slow-wave sleep and REM cycles in rodents4

  • animalSome research investigates DSIP's neuroprotective potential in models of oxidative stress4

  • animalDSIP induces mainly delta-sleep in rabbits, rats, mice, and humans5

  • animalIn cats, the effect on REM sleep was more pronounced5

  • animalIn addition to sleep, the peptide also has been observed to affect electrophysiological activity, neurotransmitter levels in the brain, circadian and locomotor patterns, hormonal levels, psychological performance, and the activity of neuropharmacological drugs including their withdrawal5

  • animalCertain artificial DSIP structural analogues (but not DSIP itself!) showed significant slow-wave sleep promoting activity in rabbits and rats8

  • animalDelta sleep inducing peptide (DSIP) has been shown to increase sleep in various animals12

  • animalIntraventricular administration of DSIP (2 or 10 micrograms) failed to affect LH release in ovariectomized rats12

  • animalDSIP (2 or 10; 15 or 30 micrograms) promptly stimulated LH release in ovariectomized estrogen, progesterone-primed rats in two separate experiments12

  • animalSingle injection of synthetic DSIP (7 nmol/kg) into lateral ventricle of cats produces significant decrease in sleep latency13

  • animalDSIP administration produces significant increase in total sleep13

  • animalDSIP administration produces significant increase in total slow wave sleep (SWS)13

  • animalDSIP increases deep slow wave sleep (S2) while significantly decreasing light slow wave sleep (S1)13

  • animalDSIP does not affect total amount of REM sleep or hourly values of REM sleep13

  • animalDSIP does not affect REM sleep latency, mean episode number, or mean episode length13

  • animalDSIP induces sleep in animals14

  • animalDSIP has sleep-supporting effects in animals14

  • animalIntravenous administration of DSIP produces sleep lasting for hours in different animals15

  • animalDSIP induces mainly delta-sleep in rabbits, rats, mice, and humans16

  • animalIn cats, DSIP effect on REM sleep was more pronounced16

  • animalDSIP affects psychological performance16

  • animalOnly the delta-sleep-inducing peptide (synthetic) showed significant and specific enhancement/induction of delta and spindle electroencephalogram patterns in rabbits18

  • animalDSIP pretreatment completely prevented hypoxia-induced damage to mitochondrial respiration in rats19

  • animalWhen injected into other rabbits, DSIP appeared to increase delta-wave (slow-wave) sleep duration20

  • animalDSIP promotes slow-wave sleep in rabbits (original isolation experiment)26

  • animalDSIP was first isolated in 1977 by Schoenenberger and Monnier through an elegant cross-circulation experiment where cerebral venous blood of electrically induced sleeping rabbits was dialyzed and infused into awake recipient rabbits, which subsequently exhibited enhanced delta and spindle EEG activity characteristic of slow-wave sleep29

  • 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 rats12

  • expert opinionPreclinical studies on therapeutic peptides including DSIP are promising, but there is a current lack of clinical trials6

  • expert opinionThe hypothesis regarding DSIP as a sleep factor is extremely poorly documented and still weak8

  • expert opinionA physiological sleep regulatory role has not been determined for DSIP despite its identification in transfer experiments9

  • 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'19

  • expert opinionHuman studies had significant methodological limitations: small sample sizes (often fewer than 20 subjects), lack of blinded polysomnography, variable dosing, and inconsistent inclusion criteria20

  • expert opinionThere are essentially no randomized controlled trials published in the last two decades testing DSIP for sleep disorders in humans20

  • expert opinionDSIP has clinical applications in treating chronic insomnia21

  • expert opinionA 2023 systematic review published in Neuroscience & Biobehavioral Reviews identified that 40% of preclinical studies evaluating anxiolytic peptides incorrectly grouped DSIP with enkephalin derivatives like Selank23

  • expert opinionNo large randomized controlled trial has confirmed DSIP efficacy for sleep; the best available human data comes from small studies, mostly from the 1980s, with mixed results26

  • expert opinionDSIP is best known for early reports of promoting delta-wave EEG activity27

  • expert opinionHuman clinical evidence of efficacy remains sparse and conflicting28

  • expert opinionNo human Phase II/III RCTs support DSIP efficacy for any indication28

How it works

Based on 2 human trial findings, 9 human study findings, 46 animal findings, 15 in vitro findings, 25 expert opinion findings and 24 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)3

  • 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)3

  • human studyCSF DSIP-LI was significantly correlated with the ratio of the first and second NREM period (p < 0.05)3

  • human studyCSF DSIP-LI was negatively correlated with stage 2% sleep (p < 0.05)3

  • human studyDSIP modulates cortisol and LH in humans (small human studies Schneider-Helmert, 1985 era)26

  • human studyPlasma DSIP-like immunoreactivity (DSIP-LI) decreases significantly at the transition from wakefulness to sleep28

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  • human studyDSIP-LI exhibits a diurnal rhythm with a negative correlation with both rapid eye movement sleep and slow-wave sleep28

  • human studyReduced DSIP-LI and reduced delta sleep observed in Cushing syndrome or cortisol dysregulation populations28

  • human studyA controlled study by Polleri et al. found that ACTH and cortisol responses to CRH were identical during DSIP and placebo infusion, suggesting that DSIP does not directly modulate CRH-stimulated HPA axis responses29

  • animalDSIP-like immunoreactivity is highly specifically distributed in the neurosecretory hypothalamic nuclei of various vertebrate species that are not particularly relevant for sleep regulation8

  • 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 isomer8

  • 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 animals9

  • animalDelta sleep-inducing peptide-like immunoreactive cell bodies were mainly observed in the nucleus lateralis tuberis of the hypothalamus11

  • animalDSIP-like immunoreactive fibers were localized in the basal telencephalon, within the regions of the nucleus interstitialis commissurae anterioris and the nucleus entopeduncularis11

  • animalA dense network of DSIP-positive fibers was seen throughout the midcaudal hypothalamus, the lateral lobes, and the posterior lobe11

  • animalNumerous DSIP-like immunoreactive cells were detected in the median lobe of the pars distalis11

  • animalDSIP and MCH-like immunoreactive cells are stored in the same cells of the median lobe of the pituitary11

  • animalDSIP may act as a neuromodulator and/or a hypophysiotropic factor11

  • animalDSIP-like immunoreactive cells in the pars distalis suggests that this peptide may exert autocrine or paracrine effect in the pituitary11

  • animalDSIP is found in various parts of the brain including the hypothalamus12

  • animalIncrease in S2 is caused by prolongation of S2 episodes rather than more frequent occurrence13

  • animalDSIP-like material is naturally distributed in the body14

  • animalDSIP may have relations to certain diseases14

  • animalDelta-sleep-inducing peptide (DSIP) is a nonapeptide isolated, characterized and synthesized from 1970 to 197715

  • animalDSIP acts upon circadian rhythmicity of locomotor activity and transmitter concentrations in the brain15

  • animalDSIP acts upon circadian rhythmicity of plasma proteins and cortisol levels15

  • animalA phosphorylated derivative (DSIP-P) created by phosphorylation of serine in position 7 is manyfold more powerful15

  • animalDSIP occurs immunohistochemically in different regions of the rat brain15

  • animalDSIP interacts with acute and chronic stress15

  • animalDSIP interacts with drug-effects such as morphine, d-amphetamine and barbiturates15

  • animalAn induction of MAO-A and RNA synthesis in the brain was observed15

  • animalBrain concentration of DSIP increased during progressed hibernation15

  • animalAlcohol addictism produced a substantial decrease of DSIP-concentration in rat brain15

  • animalAnalogs with exchanged amino acids or shortening the peptide by one or two amino acids decreased or abolished sleep-induction effect15

  • animalDSIP-like material was found by RIA and immunohistochemistry in brain and by RIA in peripheral organs of the rat16

  • animalDSIP-like material was found by RIA in plasma of several mammals16

  • animalDSIP affects electrophysiological activity16

  • animalDSIP affects neurotransmitter levels in the brain16

  • animalDSIP affects hormonal levels16

  • animalDSIP affects the activity of neuropharmacological drugs including their withdrawal16

  • animalA peptide that induces slow-wave (delta) and spindles electroencephalogram enhancement after intraventricular (brain) infusion has been isolated from rabbits18

  • animalFive possible metabolic products and nonapeptide analogues with amino acids exchanged did not show the same effect as DSIP18

  • animalDSIP dampens the HPA axis response by reducing CRF-stimulated cortisol release at the pituitary level19

  • animalNakamura et al. (1989) showed DSIP does not bind opioid receptors directly but triggers brainstem to release Met-enkephalin19

  • animalDSIP upregulates protective enzymes: SOD, catalase, glutathione peroxidase19

  • animalDSIP was isolated in 1974 by Monnier and Schoenenberger from venous blood of rabbits whose brains were being electrically stimulated to produce slow-wave (delta) sleep20

  • animalSome studies in rodent models suggested DSIP or DSIP analogs might reduce lipid peroxidation and protect against oxidative damage in several tissues20

  • animalDSIP crosses the blood-brain barrier (animal studies, some human inference)26

  • animalDSIP was originally characterized by its ability to increase slow-wave (delta) sleep in animal models28

  • animalDSIP at 15 nmol/kg retarded the nighttime rise of pineal N-acetyltransferase activity and melatonin levels during the dark phase in rats28

  • animalDSIP produces circadian-dependent hypothermic effects in intact rats, with differing effects in pinealectomized and hypophysectomized animals28

  • animalDSIP analogues have detoxifying effects against cisplatin-induced toxicosis in rats28

  • animalDSIP has been found in peripheral blood, cerebrospinal fluid, various brain regions, pituitary gland and gastrointestinal tract29

  • animalBhargava (1989) demonstrated that DSIP at doses of 1 pM to 1 nM significantly stimulated the calcium-dependent release of immunoreactive Met-enkephalin from rat lower brainstem slices29

  • animalDSIP showed no direct binding activity to any opioid receptor subtype, indicating that its analgesic effects are mediated indirectly through stimulation of endogenous enkephalin release29

  • in vitroIn vitro data suggest possible interactions with GABAergic and glutamatergic pathways4

  • in vitroDSIP is a nonapeptide of MW 8495

  • in vitroDSIP-like material was found by RIA and immunohistochemistry in brain and by RIA in peripheral organs of the rat as well as in plasma of several mammals5

  • in vitroDSIP can be entrapped in macroporous polymer matrices based on copolymer of dimethylaminoethyl methacrylate and methylen-bis-acrylamide (Co-DMAEMA-MBAA)7

  • in vitroDSIP biological activity shows a large spectrum revealed by biochemical and physiological studies in vitro8

  • in vitroSpecific electrophysiological effect on isolated neurons of rats and rabbits was established15

  • in vitroDSIP is a nonapeptide of MW 84916

  • in vitronaloxone, a non-selective opioid antagonist, only partially blocks DSIP's sleep-promoting effects22

  • in vitroDSIP reducing glutamate-mediated excitatory transmission in hippocampal slices22

  • in vitroDSIP does not bind directly to GABA-A receptors, confirmed through radioligand binding assays22

  • in vitroDSIP stimulates melatonin, 5-methoxytryptophol, and serotonin secretion from perifused rat pineal glands in a dose-dependent manner28

  • in vitroDSIP stimulation of melatonin secretion requires tryptophan aminopeptidase activity28

  • in vitroDSIP analogues possess direct antioxidative activity comparable to vitamin C and β-carotene in vitro28

  • in vitroElectrophysiological studies by Sudakov et al. demonstrated that DSIP enhances GABA-activated currents in hippocampal and cerebellar neurons29

  • in vitroDSIP blocks NMDA-activated responses in cortical areas29

  • expert opinionDSIP was first isolated from the hypothalamus of rabbits in the 1970s and has since been detected in various tissues and biological fluids4

  • expert opinionResearch suggests that DSIP may modulate sleep architecture, impact stress adaptation, and interact with neuroendocrine pathways, though its precise mechanism remains under investigation4

  • 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 receptor8

  • expert opinionDSIP's natural occurrence and biological activity still remains obscure8

  • expert opinionDSIP structure is different from any other known representative of the various peptide families8

  • expert opinionDSIP is a nine-amino-acid peptide (Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu)19

  • expert opinionDSIP has been found in the hypothalamus, pituitary, gut, plasma, cerebrospinal fluid, and breast milk at measurable concentrations19

  • expert opinionAfter almost 50 years of research, nobody has found DSIP's gene, its receptor, or its precursor protein19

  • expert opinionThere is no identified receptor for DSIP19

  • expert opinionDSIP interacts with the body to promote restful sleep and stress relief21

  • expert opinionDSIP is a 9-amino-acid neuropeptide that normalizes sleep architecture by promoting deep delta-wave sleep without acting as a sedative24

  • expert opinionDSIP modulates the HPA stress axis and stimulates GH secretion24

  • expert opinionDSIP appears to initiate signaling cascades through multiple systems (possibly NMDA, GABA-A, glycine, and opioid pathways) without having a single known target24

  • expert opinionNaloxone blocks some of its effects, suggesting opioid pathway involvement24

  • expert opinionThe exact receptor targets remain undefined as of now, which means the optimal subcutaneous dose of DSIP has not been scientifically established25

  • expert opinionDSIP is a 9-amino-acid neuropeptide with a molecular weight of approximately 848.9 Da26

  • expert opinionDSIP is an endogenous nonapeptide first isolated from rabbit cerebral venous blood in 1974 by Monnier and colleagues26

  • expert opinionIts sequence is Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu26

  • expert opinionDSIP is a nine-amino-acid peptide with sequence Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu27

  • expert opinionDSIP has a molecular weight of about 849 daltons27

  • expert opinionDSIP's exact receptor and mechanism are not fully established27

  • expert opinionReported pathways include possible interactions with NMDA receptors, alpha-adrenergic signaling, and the hypothalamic-pituitary-adrenal axis27

  • expert opinionDSIP has been studied as a possible cortisol or stress-hormone modulator27

  • expert opinionDSIP receptor has not been definitively identified, no DSIP-encoding gene has been found in mammals28

  • expert opinionDSIP and neuropeptide Y may represent endogenous stabilizing factors of brain excitability with potential antiepileptic properties28

  • theoreticalDSIP is a nonapeptide with sequence Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu2

  • theoreticalDSIP is an amphiphilic peptide with the amino acid sequence Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu4

  • theoreticalDelta sleep-inducing peptide (DSIP) targets circadian and mitochondrial regulators6

  • theoreticalDSIP or DSIP-like peptide(s) may activate the hypothalamic neural circuitry responsible for stimulation of LH release reported to occur during sleep12

  • theoreticalDSIP mechanism of action may involve modulation of adrenergic transmission14

  • theoreticalDSIP is a nonapeptide (Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu)22

  • theoreticalbinds to delta opioid receptors and potentially NMDA receptor sites in the central nervous system22

  • theoreticalmodulating sleep architecture by increasing slow-wave sleep duration and reducing sleep latency22

  • theoreticalDSIP binds with highest affinity to delta opioid receptors (DORs)22

  • theoreticalDelta opioid receptor activation inhibits adenylyl cyclase, reducing intracellular cyclic AMP (cAMP) levels and subsequently decreasing protein kinase A (PKA) activity22

  • theoreticalDSIP appears to act as a negative allosteric modulator rather than a competitive antagonist22

  • theoreticalincreases GABAergic tone in the ventrolateral preoptic nucleus (VLPO)22

  • theoreticalDSIP primarily acts on delta opioid receptors and GABA-A receptor complexes to modulate circadian rhythm and sleep architecture23

  • theoreticalSelank Amidate functions as an enkephalin analog that enhances GABA transmission and upregulates brain-derived neurotrophic factor (BDNF) expression for anxiolytic and nootropic effects23

  • theoreticalDSIP's action on delta opioid receptors produces downstream effects on melatonin secretion and slow-wave sleep duration23

  • theoreticalSelank Amidate's tuftsin-derived sequence modulates immune-brain axis signaling through IL-6 and TNF-alpha pathways that DSIP does not influence23

  • theoreticalSelank Amidate derives from tuftsin (Thr-Lys-Pro-Arg), a naturally occurring tetrapeptide produced by enzymatic cleavage of IgG heavy chains, with three additional amino acids and a C-terminal amidation23

  • theoreticalDSIP is a naturally occurring nonapeptide with the amino acid sequence Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu29

  • theoreticalNo specific DSIP receptor, precursor gene, or precursor protein has been identified29

  • theoreticalPeptides and regulatory proteins can cross the blood-brain barrier (BBB)31

  • theoreticalIn crossing the BBB, peptides and regulatory proteins act as informational molecules, informing the brain of peripheral events31

  • theoreticalBrain-to-blood passage helps to control levels of peptides within the brain and can deliver information in the brain-to-blood direction31

  • theoreticalTransporters for peptides and proteins are not static, but respond to developmental and physiological changes and are affected by disease states31

  • theoreticalThe BBB is adaptive to the needs of the CNS, but when that adaption goes awry, the BBB can be a cause of disease31

Dosing

Based on 2 human trial findings, 3 animal findings, 8 expert opinion findings and 1 anecdotal finding.

  • human trialHuman trials testing DSIP for various applications used doses ranging from 25–100 nmol/kg intravenously, with no doses exceeding 21.4 mcg/kg daily25

  • human trialSchneider-Helmert trials used 25 nmol/kg of DSIP intravenously across short courses of four to seven nights27

  • animalA U-shaped activity curve was determined for the dose as well as for the time of infusion5

  • animalDSIP shows parabolic dose-response curve with different effective optima via i.c.v., i.v. and s.c. administration, in contrast to pharmaceuticals15

  • animalA U-shaped activity curve was determined for the dose as well as for the time of infusion16

  • expert opinionEffective dosing strategies for DSIP can be established21

  • expert opinionDSIP typically requires continuous infusion or multiple daily administrations in preclinical studies, while Selank Amidate demonstrates sustained activity with single-dose administration23

  • expert opinionThe commonly cited research-use only dosages of 100–250 mcg subcutaneously once daily for sleep optimization are based on case reports and observational studies, not on controlled trials25

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  • expert opinionSome individuals who are highly sensitive to neuroactive peptides may prefer to begin slightly lower (100–150 mcg) for the first few doses to assess tolerance25

  • expert opinionThe only validated administration route in human research is intravenous; subcutaneous use is extrapolated from general peptide pharmacology and researcher convention, not a controlled human trial26

  • expert opinionReconstitution at 1 mg/mL in bacteriostatic water is a common working concentration26

  • expert opiniona 200 mcg dose from that solution requires drawing 0.2 mL in a U-100 insulin syringe26

  • expert opinionA U-shaped activity curve exists where small or short doses produced the strongest reported effect, while higher or longer infusions did not27

  • anecdotalSubcutaneous dosing in 100-500 mcg range produces sleep effects (researcher convention, no controlled human trial)26

How the body handles it

Based on 8 human study findings, 18 animal findings, 5 in vitro findings, 7 expert opinion findings and 2 theoretical findings.

  • human studyDSIP has an elimination half-life of approximately 30–40 minutes following intravenous administration in humans2

  • human studyDSIP is cleared primarily by proteolytic degradation across multiple tissues2

  • human studyDSIP's biological sleep effects may persist well beyond plasma clearance2

  • human studyBoth DSIP and DSIP-P occur in human CSF15

  • human studyImmunoreactive DSIP-like material found in plasma of several mammals and humans, in human urine, CSF and milk15

  • human studyhalf-life is approximately 15–20 minutes in circulation, yet effects persist for hours22

  • human studyplasma half-life of roughly 30 minutes after intravenous administration in early human studies26

  • human studyIV plasma half-life approximately 30 minutes (Graf and Kastin, 1984 review)26

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  • animalPublished preclinical studies indicate that DSIP has a relatively short plasma half life, typically ranging from 2 to 4 hours in animal models4

  • animalRapid enzymatic degradation is believed to limit its duration in circulation4

  • animalDSIP effect is immediate with S2 increasing to more than 50% in first postinjection hour13

  • animalIncrease in S2 is maintained over 7 hours and disappears by eighth hour13

  • animalDSIP penetrates the blood-brain barrier15

  • animalUnweaned rats are able to take up DSIP by the intestinal tract15

  • animalEndogenous immunoreactive DSIP-like material in plasma, urine and CSF is bound to a larger protein (carrier) and thus protected from proteolysis15

  • animalEntry of delta sleep-inducing peptide (DSIP) into the circulation from the gastrointestinal (GI) tract occurs in unweaned rat pups17

  • animalSignificant increases in plasma DSIP-like immunoreactivity occurred after feeding 100 micrograms/animal of N-Tyr-DSIP17

  • animalNo significant increases in plasma DSIP-like immunoreactivity occurred after vehicle (normal saline) or 1 microgram/animal17

  • animalPlasma immunoreactivity coeluted with intact DSIP and des-Trp1-DSIP on column chromatography17

  • animalA small but statistically significant increase of immunoreactivity occurred in plasma of pups whose nursing mothers were injected with N-Tyr-DSIP17

  • animalRadioactivity appeared in both the brain and blood of 1-2 and 10 day old rat pups fed 125I-N-Tyr-DSIP17

  • animalAlmost all of the radioactivity in brain coeluted with intact 125I-N-Tyr-DSIP on column chromatography, suggesting blood-brain-barrier crossing by the peptide17

  • animalA DSIP peptide administered orally can be absorbed through the GI tract into the systemic circulation17

  • animalDSIP crosses the blood-brain barrier easily via passive diffusion19

  • animalBanks et al. (1984) confirmed DSIP crosses the blood-brain barrier using radiolabeled DSIP19

  • animalDSIP is found in the brain, cerebrospinal fluid, plasma, and peripheral organs20

  • in vitroApproximately 100% of DSIP has been entrapped into positively charged Co-DMAEMA-MBAA matrix7

  • in vitroThe quantity of DSIP adsorbed on negatively charged Co-AA-MBAA was only 2-6%7

  • in vitroDSIP release from Co-DMAEMA-MBAA was observed in saline solutions (0.9% NaCl and PBS)7

  • in vitroThere was no DSIP release in water or 25% ethanol, thus ionic strength was a reason of this process7

  • in vitroHalf-life time for proteolytic split-off of tryptophan by brain slices and homogenates is 15 min15

  • expert opinionNo formal subcutaneous pharmacokinetic study in humans has been published in peer-reviewed English-language literature2

  • expert opinionPlasma levels of DSIP follow a circadian rhythm with peaks in the late afternoon19

  • expert opinionDSIP appears to cross the blood-brain barrier poorly20

  • expert opinionDSIP has a half-life of minutes in plasma20

  • expert opinionOral dosing has no meaningful bioavailability26

  • expert opinionDSIP can cross the blood-cerebrospinal fluid barrier27

  • expert opinionNo human pharmacokinetic data (half-life, bioavailability) are available28

  • theoreticalSelank Amidate's C-terminal amidation extends plasma half-life from under 5 minutes to approximately 20–30 minutes23

  • theoreticalDSIP has a short plasma half-life of approximately 15 minutes due to rapid degradation by aminopeptidases29

Safety and side effects

Based on 1 human trial finding, 1 human study finding, 4 animal findings, 6 expert opinion findings and 4 anecdotal findings.

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

  • human studydoes not suppress REM sleep or cause next-day cognitive impairment22

  • animalPreclinical studies have reported that DSIP is generally well-tolerated in animal models when used within standard research concentrations4

  • animalKnown side effects in animal models include mild sedation and changes in activity4

  • animalDocumented adverse effects include transient alterations in locomotor activity, mild changes in blood pressure, and rare behavioral changes4

  • animalNo confirmed long-term toxicity in preclinical studies4

  • expert opinionDSIP is not approved by the FDA or any major regulatory body and has no approved clinical indication2

  • expert opinionLong-term safety data in humans are not available, and DSIP is not approved for clinical use4

Show the remaining 8

  • expert opinionDSIP has a safety profile suitable for therapeutic use21

  • expert opinionDSIP is not FDA-approved and not scheduled; it is a research compound, and its legal and safety status varies by jurisdiction26

  • expert opinionDSIP is not FDA-approved and is on the FDA's Category 2 do-not-compound list as of September 202327

  • expert opinionDSIP has no FDA, EMA, or Health Canada approval for any indication28

  • anecdotalFatigue or morning lethargy (dose-dependent) is a reported adverse effect24

  • anecdotalInjection site reactions are a reported adverse effect24

  • anecdotalHeadache or dizziness (rare) are reported adverse effects24

  • anecdotalI've personally never experienced significant adverse effects from DSIP, and in my decades of working with therapeutic peptides, it stands out as a benign compound in terms of safety profile25

What people use it for

Based on 1 human study finding, 7 animal findings, 14 expert opinion findings and 3 theoretical findings.

  • human studyDSIP promotes slow-wave (delta) sleep2

  • animalDelta sleep-inducing peptide (DSIP) was isolated from rabbit cerebral venous blood in 1977 and initially regarded as a candidate sleep-promoting factor8

  • animalDSIP has sleep-facilitating properties13

  • animalDSIP has potential use for therapeutic treatment of insomnia14

  • animalDSIP has potential use for therapeutic treatment of pain14

  • animalDSIP has potential use for therapeutic treatment of withdrawal14

  • animalIn cats, DSIP administration predominantly produced REM-sleep15

  • animalDSIP affects circadian and locomotor patterns16

Show the remaining 17

  • expert opinionDSIP is a naturally occurring neuropeptide that has attracted significant attention in sleep and cognitive research4

  • expert opinionDSIP is primarily studied for its potential influence on sleep regulation, neuroprotection, and stress response in experimental models4

  • expert opinionProtocols may use DSIP as a tool to study the neurobiology of circadian rhythms4

  • expert opinionDSIP is not approved by the FDA for use as a drug, supplement, or for human consumption4

  • expert opinionDSIP appears to modify how deeply you sleep rather than forcing you to fall asleep19

  • expert opinionSleep effects are strongest in people whose sleep is already messed up and barely register in healthy sleepers19

  • expert opinionDSIP shows stress modulation, pain relief, and antioxidant protection19

  • expert opinionDSIP has clinical applications in treating adrenal fatigue21

  • expert opinionDSIP has clinical applications in treating fibromyalgia21

  • expert opinionDSIP can be used for pain management21

  • expert opinionDSIP supports recovery21

  • expert opinionClinical trials demonstrating DSIP's sleep effects used intravenous administration, and NOT the subcutaneous injections people are doing at home25

  • expert opinionDSIP appears to influence sleep architecture and circadian signaling, injecting 1–3 hours before your target sleep time tends to produce the best results25

  • expert opinionDSIP has been studied in opioid and alcohol withdrawal research contexts27

  • theoreticalDSIP is a recovery-enhancing agent for orthopaedic injury management6

  • theoreticalDelta-sleep inducing peptide (DSIP) possesses numerous beneficial properties, including its abilities in burn treatment and neuronal protection7

  • 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 system31

Other findings

Based on 2 animal findings, 5 expert opinion findings and 3 theoretical findings.

  • animalFirst evidence for the presence of a DSIP-related peptide in fish11

  • animalDSIP amino acid sequence is Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu18

  • expert opinionDSIP was first isolated from rabbit brains in 1977 by Schoenenberger and Monnier at the University of Basel in Switzerland19

  • expert opinionDSIP (Delta Sleep-Inducing Peptide) was first isolated from rabbit cerebral venous blood during slow-wave sleep experiments in 197722

  • expert opinionDSIP was first isolated from rabbit brain in 197427

  • expert opinionDelta sleep-inducing peptide (DSIP) is a nine-amino-acid neuropeptide first isolated from rabbit cerebral venous blood in 197728

  • expert opinionDSIP has never progressed to large-scale clinical trials or regulatory approval in any jurisdiction29

  • theoreticalDSIP was isolated, characterized, and synthesized more than 6 years ago5

Show the remaining 2

  • theoreticalAbout 100 publications have dealt with this peptide5

  • theoreticalDSIP is a nonapeptide with the sequence Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu20

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

"Pretreatment completely prevented hypoxia-induced damage to mitochondrial respiration" is an absolute claim from tier-3…

"Completely prevented" is an unusually strong efficacy statement for animal oxidative-stress models cited to vendor-tier sources (DSIP Peptide: Does Delta Sleep-Inducing Peptide Work?/DSIP Peptide: Benefits, Dosing, Side Effects & What to Know [2026] - Brainflow); should be softened or verified against primary literature.

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

DSIP was first isolated from rabbit cerebral venous blood and characterized by Monnier and Schoenenberger at the Univers…

The statement claims that 'higher-tier sources dating the isolation to 1977 (work spanning 1970–1977)' but the source material contradicts this timeline. The PubMed tier 2 source (https://pubmed.ncbi.nlm.nih.gov/6548966/) explicitly states that DSIP was 'isolated, characterized and synthesized from 1970 to 1977,' indicating the isolation work began in 1970, not that it was completed in 1977 as a single date. More critically, multiple tier 3 sources (FormBlends, PeptideAdvisors, NewOnlineProducts, and BrainFlow) cite 1974 as the isolation year, not 1977. The statement acknowledges that 'some secondary sources cite 1974' but claims higher-tier sources date it to 1977. However, the tier 2 PubMed source only confirms the work spanned 1970-1977 without specifying 1977 as the isolation date. The preponderance of evidence in the provided sources actually supports 1974 as the isolation year, contradicting the statement's assertion that higher-tier sources support 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
  • 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

    What the research doesn't fully establish

    Both peptides' mechanisms clearly establish independent pathways to increased slow-wave/delta sleep: DSIP via GABAergic tone enhancement, NMDA blockade, and enkephalin release; Sermorelin via GH/IGF-1 axis stimulation. The mechanisms are mechanistically distinct (opioid/GABA/glutamate modulation vs. somatotroph GH secretion), both explicitly produce the shared dimension of sleep_architecture (slow-wave sleep increase), and convergence on a common endpoint (deeper sleep) from different upstream mechanisms is the definition of complementarity. The explanation accurately reflects the provided mechanism material without contradiction.

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

    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

    What the research doesn't fully establish

    Both peptides' mechanisms clearly establish GABA_signaling as a shared dimension. DSIP is described as enhancing GABA-A receptor functional currents (without direct binding) and increasing GABAergic tone in the ventrolateral preoptic nucleus. Selank is explicitly described as producing allosteric modulation of GABA-A receptors (positive modulation). Both also converge on enkephalin system enhancement—DSIP via direct Met-enkephalin release, Selank via enkephalinase inhibition. The proposed 'complementary' relationship type is justified: the mechanisms show overlapping anxiolytic and GABAergic pathways that would plausibly combine without direct antagonism. The explanation accurately reflects the provided mechanism material.

    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 fully establish

    While both peptides have documented effects on enkephalinergic signaling and neuroprotection, the proposed relationship claims they are 'complementary' but provides no mechanistic basis for how their different enkephalin-system actions would synergize. DSIP releases Met-enkephalin via calcium-dependent mechanisms (proposed via DOR activation), while Semax inhibits enkephalinase degradation—these are mechanistically distinct pathways that do not clearly establish complementarity. The explanation acknowledges their 'upstream mechanisms differ' but offers only a speculative assertion ('could reinforce') without mechanistic justification from the provided descriptions. The contrast between DSIP's sedating and Semax's stimulating profiles actually suggests potential opposition rather than complementarity. The shared neuroprotective/antioxidant effects are both documented but are attributed to different pathways (DSIP: antioxidant enzyme upregulation; Semax: BDNF/TrkB/CREB signaling, MMP-9/JNK modulation) and do not constitute a clear shared dimension. The proposed relationship lacks sufficient mechanistic grounding in the provided material.

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

  • 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

    What the research doesn't fully establish

    Both peptides' mechanisms explicitly converge on the melatonin pathway and circadian rhythm restoration via distinct upstream mechanisms. DSIP's mechanism includes 'Circadian/melatonin (pineal NAT, melatonin, serotonin, 5-methoxytryptophol)' and effects on sleep architecture. Epithalon's mechanism explicitly includes 'Melatonin biosynthesis (AANAT / pineal axis)' and 'Circadian gene regulation (Clock, Csnk1e, Cry2)' with restoration of melatonin secretion and circadian rhythms as documented effects. Both are tagged with 'melatonin_pathway'. The proposed relationship correctly identifies that they target the same downstream outcome (melatonin/circadian restoration) through different upstream pathways (DSIP via GABAergic/sleep-promoting mechanisms; Epithalon via telomerase/epigenetic mechanisms), which is precisely what 'same_downstream' describes.

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

    Shares melatonin pathway

  • 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

    What the research doesn't fully establish

    Both peptides' mechanisms explicitly target sleep architecture through distinct pathways. DSIP increases slow-wave (delta) sleep via GABAergic tone, NMDA inhibition, and enkephalin release. MK-677 modulates sleep architecture through GH/IGF-1 axis elevation and hypothalamic signaling. The mechanisms confirm they operate on different neurobiological systems affecting sleep, supporting the 'complementary' relationship claim with 'sleep_architecture' as a shared dimension. The explanation accurately reflects the distinct routes (GABA/opioid vs. GH/IGF-1) described in both mechanism profiles.

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

    Shares sleep architecture

  • 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

    What the research doesn't fully establish

    Both peptides' mechanisms clearly support GABAergic signaling as a shared dimension. Cortexin targets GABA-A receptor and produces GABAergic/neurotransmitter-balancing effects with neuroprotection against excitotoxicity. DSIP functionally enhances GABA-A receptor current (though without direct binding) and increases GABAergic tone in the ventrolateral preoptic nucleus. Both also modulate glutamatergic transmission (Cortexin via AMPA/kainate/mGluR; DSIP via NMDA blockade and negative allosteric modulation). The proposed complementary relationship is justified: they converge on excitation/inhibition balance through overlapping GABAergic and anti-glutamatergic mechanisms, with distinct primary endpoints (neuroprotection vs. sleep architecture). The explanation accurately reflects the mechanism material provided.

    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. DSIP Half-Life: ~30–40 Min IV — Pharmacokinetics & Sleep Data | Halflife Labs(opens in a new tab)
    Tier 1Web · halflife-labs.com · 2026
  3. 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
  4. DSIP 5mg Half-Life | Pharmacokinetics Data(opens in a new tab)
    Tier 2Web · precisionpeptidemd.com
  5. PII: 0149-7634(84)90022-8(opens in a new tab)
    Tier 2Web · paulinamedicalclinic.com
  6. Therapeutic Peptides in Orthopaedics: Applications, Challenges, and Future Directions.(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov · 2026
  7. Delta-sleep inducing peptide entrapment in the charged macroporous matrices.(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov · 2014
  8. Delta sleep-inducing peptide (DSIP): a still unresolved riddle.(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov · 2006
  9. Biochemical regulation of non-rapid-eye-movement sleep.(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov · 2003
  10. Delta sleep-inducing peptide.(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov · 2001
  11. 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
  12. 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
  13. 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
  14. Delta-sleep-inducing peptide (DSIP): an update.(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov · 1986
  15. Characterization, properties and multivariate functions of delta-sleep-inducing peptide (DSIP).(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov · 1984
  16. Delta-sleep-inducing peptide (DSIP): a review.(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov · 1984
  17. 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
  18. Characterization of a delta-electroencephalogram (-sleep)-inducing peptide.(opens in a new tab)
    Tier 2PubMed · pubmed.ncbi.nlm.nih.gov · 1977
  19. DSIP Peptide: Benefits, Dosing, Side Effects & What to Know [2026] - Brainflow(opens in a new tab)
    Tier 3Web · brainflow.co
  20. DSIP Peptide: Does Delta Sleep-Inducing Peptide Work?(opens in a new tab)
    Tier 3Web · newonlineproducts.com
  21. DSIP Peptide: Revolutionizing Sleep, Stress, and Pain Management in Clinical Practice(opens in a new tab)
    Tier 3Web · youtube.com
  22. DSIP Science Explained — Peptide Mechanisms | Real Peptides(opens in a new tab)
    Tier 3Web · realpeptides.co
  23. DSIP vs Selank Amidate — Mechanism & Use Comparison(opens in a new tab)
    Tier 3Web · realpeptides.co
  24. DSIP: Benefits, Dosage & Safety | FormBlends(opens in a new tab)
    Tier 3Web · formblends.com
  25. How to Take DSIP (Delta Sleep-Inducing Peptide) for Better Sleep: Dosage Chart(opens in a new tab)
    Tier 3Web · jaycampbell.com
  26. How to Take DSIP Peptide: Dosing, Timing, and Protocol | FormBlends(opens in a new tab)
    Tier 3Web · formblends.com · 2026
  27. DSIP Peptide: Benefits, Sleep, Dosage & Risks (2026)(opens in a new tab)
    Tier 3Web · peptideadvisors.org · 2026
  28. DSIP: Mechanism, Dosing & Evidence (Tier 2) | Pepteligence(opens in a new tab)
    Tier 3Web · pepteligence.com · 2026
  29. DSIP (Delta Sleep-Inducing Peptide): Research Evidence & Safety Profile | PeptideInsight(opens in a new tab)
    Tier 3Web · peptideinsight.com · 2026
  30. Member Access - The Peptide Report(opens in a new tab)
    Tier 4Web · thepeptidereport.com
  31. Peptides and the blood-brain barrier.(opens in a new tab)
    Tier 4PubMed · pubmed.ncbi.nlm.nih.gov · 2015