DSIP

01 · What it is

In 2006 a review in the Journal of Neurochemistry summarised delta sleep-inducing peptide in its title: “a still unresolved riddle” ¹⁵.

That was nineteen years after the last substantial human sleep trial, and nothing located here has resolved it since.

The human evidence is a cluster in the 1980s and then silence. Synthetic DSIP was reported to improve sleep in insomniacs in the Lancet in 1981 ², with two further human studies that same year on its influence on disturbed human sleep ³ and its acute and delayed effects on human sleep behaviour ⁴. Two more followed in 1987 — a study of efficacy on short-term administration to chronic insomniacs ⁷ and one on 24-hour sleep-wake behaviour in severe chronic insomnia ⁸ — and a double-blind study in chronic insomniac patients in 1992 ¹⁰.

After 1992, this guide located no further controlled human trial of DSIP for sleep. The compound is named for an effect whose clinical investigation stopped more than thirty years ago.

What it is. DSIP is a peptide first characterised in the 1970s ¹, reviewed comprehensively in 1984 ⁵ and updated in 1986 ⁶. Animal work supports a role in slow-wave sleep and sleep-related growth hormone release ⁹.

And the human observational data complicate even the name. DSIP-like immunoreactivity and delta sleep were studied in schizophrenic volunteers ¹¹; plasma DSIP was found decreased alongside decreased delta sleep in Cushing syndrome ¹²; and DSIP was measured in normal humans and in patients with sleep apnoea and narcolepsy ¹⁴. Meanwhile a controlled study found that DSIP does not affect CRH- and meal-induced ACTH and cortisol secretion ¹³.

A compound named for an effect, investigated in humans for barely a decade, abandoned, and described by its own literature as unresolved.

02 · Evidence at a glance

Evidence grade

Early Clinical — multiple published human trials, all from 1981–1992

What it is

Delta sleep-inducing peptide, characterised from the 1970s ^1,5,6

Human sleep trials located

Six, between 1981 and 1992 ^2,3,4,7,8,10

Human sleep trials after 1992

None located

Its own literature’s verdict

“A still unresolved riddle” ¹⁵

Animal mechanism support

Slow-wave sleep and sleep-related growth hormone release in rat ⁹

Human endocrine finding

Does not affect CRH- and meal-induced ACTH and cortisol secretion ¹³

Observational human data

Schizophrenia ¹¹, Cushing syndrome ¹², sleep apnoea and narcolepsy ¹⁴

Only modern human study located

Adjunct to isoflurane anaesthesia, altering bispectral index, EEG and heart rate variability ¹⁶

Modern research direction

Animal stroke recovery ²⁰, high-altitude sleep and memory in rats ¹⁹, restraint-stress hepatocytes ¹⁷, recombinant production ¹⁸

Approval status

None identified in any jurisdiction

Published toxicology

None located

Literature size

~518 records, heavily weighted to the 1980s

03 · Mechanism of action

Named for an effect, and the effect is the disputed part

The compound’s name asserts its function. The 1984 review ⁵ and its 1986 update ⁶ set out the case, and animal work provides evidence for a role in slow-wave sleep and in sleep-related growth hormone release in the rat ⁹.

Naming a molecule after a proposed action is a decision that shapes everything downstream. Two decades later the field’s own summary was that the riddle remained unresolved ¹⁵.

What it does not do

A controlled human study found that DSIP does not affect corticotropin-releasing-hormone-induced or meal-induced ACTH and cortisol secretion ¹³.

A clean negative, in humans, on a specific endocrine hypothesis. Negatives of this quality are rare in this project and they are the most informative thing a mechanism section can contain.

The endogenous-marker literature

Much of the human work measures DSIP rather than administering it. DSIP-like immunoreactivity was examined alongside delta sleep in schizophrenic volunteers ¹¹. Plasma DSIP was found decreased along with decreased delta sleep in Cushing syndrome ¹². DSIP was measured in normal humans and in patients with sleep apnoea and narcolepsy ¹⁴.

This is the pattern this project has now seen five times over: a compound whose apparently substantial human literature turns out to be observational measurement of the endogenous molecule rather than trials of administering it. Correlation between a peptide’s level and a sleep stage does not establish that supplying the peptide produces the sleep stage.

Where the modern work has gone

Recent research is preclinical and largely unrelated to sleep: recovery of motor function after focal stroke in rats ²⁰; a phosphorylated analogue restoring spatial memory and p-CREB expression by improving sleep architecture at high altitude ¹⁹; hepatocyte function under restraint stress in rats ¹⁷; and recombinant expression and purification fused to a protein transduction domain and human serum albumin ¹⁸.

Note the 2018 study used a phosphorylated DSIP ¹⁹, and the 2017 production paper made a fusion construct ¹⁸. Neither is the plain peptide, which is a distinction that matters when reading modern citations as support for an unmodified compound.

04 · Key research findings

Origins, 1977–1986. Synthesis of a related tripeptide compared against DSIP for biological activity ¹; a comprehensive review ⁵; and an update two years later ⁶.

The 1981 human trials. Synthetic DSIP reported to improve sleep in insomniacs, in the Lancet ²; a study of synthetic DSIP’s influence on disturbed human sleep ³; and a study of acute and delayed effects on human sleep behaviour ⁴.

Three human studies in one year, from the same Basel research group. The Lancet paper carries no abstract in the indexed record, so its numbers are not available here.

Animal mechanism, 1988. Evidence for a role of DSIP in slow-wave sleep and sleep-related growth hormone release in the rat, published in PNAS ⁹.

The second wave of human trials, 1987 and 1992. Efficacy in improving sleep on short-term administration to chronic insomniacs ⁷; effects on 24-hour sleep-wake behaviour in severe chronic insomnia ⁸; and a double-blind study of effects on the sleep of chronic insomniac patients ¹⁰.

The 1992 study is the only one of the six explicitly described as double-blind in the record consulted, and it is the last of them.

The endocrine negative, 1995. DSIP does not affect CRH- and meal-induced ACTH and cortisol secretion ¹³.

Observational human studies, 1992–1995. DSIP-like immunoreactivity and delta sleep in schizophrenic volunteers ¹¹; decreased delta sleep and decreased plasma DSIP in Cushing syndrome ¹²; and DSIP levels in normal humans and in patients with sleep apnoea and narcolepsy ¹⁴.

The field’s own summary, 2006. A review in the Journal of Neurochemistry titled “Delta sleep-inducing peptide (DSIP): a still unresolved riddle” ¹⁵.

Twenty-five years after the first human trial, the review literature’s position was that the basic question was open.

The one modern human study, 2009. DSIP as an adjunct to isoflurane anaesthesia, altering bispectral index, the electroencephalogram and heart rate variability ¹⁶.

A measurable central effect in humans, in an anaesthetic context, and the most recent human administration study located here. It concerns depth-of-anaesthesia monitoring rather than sleep as ordinarily understood.

Preclinical work, 2016–2021. Effects on hepatocyte function in rats during restraint stress ¹⁷; expression and purification of a DSIP fusion construct ¹⁸; a phosphorylated DSIP restoring spatial memory and p-CREB expression by improving sleep architecture at high altitude ¹⁹; and recovery of motor function in rats after focal stroke ²⁰.

Its current commercial framing, 2026. DSIP appears in a review of therapeutic peptides in orthopaedics, grouped among recovery-enhancing agents alongside epithalon and pinealon ²¹.

The compound has largely left the sleep literature and re-entered circulation through a different door.

05 · Evidence overview

06 · Safety profile

Human data. Six sleep trials in insomniac patients between 1981 and 1992 ^2,3,4,7,8,10 and one anaesthesia adjunct study in 2009 ¹⁶ constitute the human exposure record located here. This guide read abstracts rather than full texts and does not report adverse-event data, because the abstracts available do not contain it and several of the oldest records carry no abstract at all.

Absence of reported harm across six small trials from the 1980s is close to no safety information. Reporting standards of that era, the small numbers involved, and the short durations studied mean this record cannot support a safety claim in either direction.

Animal data. No dedicated toxicology study appears in the material located. Recent rodent work concerns efficacy endpoints in stroke, stress and altitude models ^17,19,20.

What is genuinely unknown. Almost everything. No modern human pharmacokinetics, dose-finding, repeat-dose toxicology, genotoxicity, carcinogenicity or reproductive toxicity was located. No study addresses long-term use.

Two specific points. The endocrine interface is only partly characterised — DSIP does not affect ACTH or cortisol responses ¹³, and separate work links it to growth hormone release in the rat ⁹ and to altered levels in Cushing syndrome ¹², so its relationship with the hypothalamic-pituitary-adrenal and growth hormone axes is neither absent nor mapped. And the anaesthesia finding is the one hard modern human result: a compound that measurably alters bispectral index, EEG and heart rate variability alongside an anaesthetic ¹⁶ is doing something centrally, and nothing located here characterises interactions with sedatives, hypnotics or alcohol.

Nothing is published on the identity or purity of any material sold under this name.

07 · US regulatory status

Current as of 7 September 2026. DSIP is not an approved drug in the United States, is not a controlled substance, and is not a lawful dietary supplement ingredient. No marketing authorisation in any jurisdiction was identified for this guide.

Under the World Anti-Doping Code, DSIP does not appear as a named prohibited substance in the classes reviewed for this guide. Competitors should consult the current Prohibited List directly rather than rely on secondary summaries, including this one.

08 · Limitations of the evidence

1. The human sleep evidence is more than thirty years old. Six trials between 1981 and 1992 ^2,3,4,7,8,10, and none located since. Trial methodology, reporting standards and sleep measurement have all changed substantially in that time, and none of these studies would satisfy contemporary expectations for reporting.
2. The research concentration is severe and geographically narrow. The 1981 human studies and the 1987 work share authorship from one Basel group ^2,3,4,8. Independent replication of the sleep claim is thin.
3. Much of the human literature measures rather than administers. Studies in schizophrenia ¹¹, Cushing syndrome ¹², sleep apnoea and narcolepsy ¹⁴ observe endogenous DSIP. Association between peptide level and sleep stage does not establish that administration produces the effect.
4. The field’s own verdict is that the question is open ¹⁵, published in a mainstream neurochemistry journal two decades after the trials.
5. The clearest human result is a negative ¹³.
6. Some modern work does not use the plain peptide. A phosphorylated analogue ¹⁹ and a fusion construct ¹⁸ are different molecules, and results obtained with them should not be read as support for unmodified DSIP.
7. No adverse-event data are reported here, and the underlying record is too old and too small to supply them.
8. Several key records carry no abstract, including the 1981 Lancet paper ², so their numbers and designs are not available in what was consulted.
9. No toxicology of any kind was located.
10. This guide has read abstracts, not full texts, for every source cited, and fewer than twenty-five of roughly 518 records were examined.
11. Nothing is known about material sold under this name. No published analysis has examined the identity or purity of any DSIP-labelled product.

09 · References

1. Monnier VM. Synthesis of the tripeptide L-Trp-L-Ser-L-Glu: comparison of its biological activity with that of the delta-sleep-inducing-peptide (DSIP). Experientia Suppl. 1977;29:3–27.

   PMID 891716 ↗

2. Schneider-Helmert D, Graf M, Schoenenberger GA. Synthetic delta-sleep-inducing peptide improves sleep in insomniacs. Lancet. 1981 Jun 6;1(8232):1256–1257. No abstract available..

   PMID 6112579 ↗

3. Schneider-Helmert D, Schoenenberger GA. The influence of synthetic DSIP (delta-sleep-inducing-peptide) on disturbed human sleep. Experientia. 1981;37(9):913–917.

   PMID 7028502 ↗

4. Schneider-Helmert D, Gnirss F, Monnier M, Schenker J, Schoenenberger GA. Acute and delayed effects of DSIP (delta sleep-inducing peptide) on human sleep behavior. Int J Clin Pharmacol Ther Toxicol. 1981 Aug;19(8):341–345.

   PMID 6895513 ↗

5. Graf MV, Kastin AJ. Delta-sleep-inducing peptide (DSIP): a review. Neurosci Biobehav Rev. 1984 Spring;8(1):83–93. Review.

   PMID 6145137 ↗

6. Graf MV, Kastin AJ. Delta sleep-inducing peptide (DSIP): an update. Peptides. 1986 Nov–Dec;7(6):1165–1187. Review.

   PMID 3550726 ↗

7. Monti JM, Debellis J, Alterwain P, Pellejero T, Monti D. Study of delta sleep-inducing peptide efficacy in improving sleep on short-term administration to chronic insomniacs. Int J Clin Pharmacol Res. 1987;7(2):105–110.

   PMID 3583493 ↗

8. Schneider-Helmert D. Effects of delta-sleep-inducing peptide on 24-hour sleep-wake behaviour in severe chronic insomnia. Eur Neurol. 1987;27(2):120–129.

   PMID 3622582 ↗

9. Iyer KS, Marks GA, Kastin AJ, McCann SM. Evidence for a role of delta sleep-inducing peptide in slow-wave sleep and sleep-related growth hormone release in the rat. Proc Natl Acad Sci U S A. 1988 May;85(10):3653–3656.

   PMID 3368469 ↗

10. Bes F, Hofman W, Schuur J, Van Boxtel C. Effects of delta sleep-inducing peptide on sleep of chronic insomniac patients: a double-blind study. Neuropsychobiology. 1992;26(4):193–197.

    PMID 1299794 ↗

11. van Kammen DP, Widerlöv E, Neylan TC, Ekman R, Kelley ME, Mouton A, Peters JL. Delta sleep-inducing-peptide-like immunoreactivity (DSIP-LI) and delta sleep in schizophrenic volunteers. Sleep. 1992 Dec;15(6):519–525.

    PMID 1475566 ↗

12. Friedman TC, García-Borreguero D, Hardwick D, Akuete CN, Doppman JL, Dorn LD, Barker CN, Yanovski JA, Chrousos GP. Decreased delta-sleep and plasma delta-sleep-inducing peptide in patients with Cushing syndrome. Neuroendocrinology. 1994 Dec;60(6):626–634.

    PMID 7700506 ↗

13. Späth-Schwalbe E, Schäfer A, Uthgenannt D, Born J, Fehm HL. Delta-sleep-inducing peptide does not affect CRH and meal-induced ACTH and cortisol secretion. Psychoneuroendocrinology. 1995;20(3):231–237.

    PMID 7777652 ↗

14. Vgontzas AN, Friedman TC, Chrousos GP, Bixler EO, Vela-Bueno A, Kales A. Delta sleep-inducing peptide in normal humans and in patients with sleep apnea and narcolepsy. Peptides. 1995;16(6):1153–1156.

    PMID 8532601 ↗

15. Kovalzon VM, Strekalova TV. Delta sleep-inducing peptide (DSIP): a still unresolved riddle. J Neurochem. 2006 Apr;97(2):303–309. Review.

    PMID 16539679 ↗

16. Pomfrett CJ, Dolling S, Anders NR, Glover DG, Bryan A, Pollard BJ. Delta sleep-inducing peptide alters bispectral index, the electroencephalogram and heart rate variability when used as an adjunct to isoflurane anaesthesia. Eur J Anaesthesiol. 2009 Feb;26(2):128–134.

    PMID 19142086 ↗

17. Bobyntsev II, Kryukov AA, Belykh AE, Dudka VT. Effect of delta sleep-inducing peptide on functional state of hepatocytes in rats during restraint stress. Bull Exp Biol Med. 2016 Feb;160(4):421–424.

    PMID 26902351 ↗

18. Zhang XG, Wang WN, Zhang CS, Li K, Ma GD, Li JY. Expression and purification of delta sleep-inducing peptide fused with protein transduction domain and human serum albumin in Pichia pastoris. Protein Pept Lett. 2017;24(7):668–675.

    PMID 28462721 ↗

19. Roy K, Chauhan G, Kumari P, Wadhwa M, Alam S, Ray K, Panjwani U, Kishore K. Phosphorylated delta sleep inducing peptide restores spatial memory and p-CREB expression by improving sleep architecture at high altitude. Life Sci. 2018 Sep 15;209:282–290.

    PMID 30107169 ↗

20. Tukhovskaya EA, Ismailova AM, Shaykhutdinova ER, Slashcheva GA, Prudchenko IA, Mikhaleva II, Khokhlova ON, Murashev AN, Ivanov VT. Delta sleep-inducing peptide recovers motor function in SD rats after focal stroke. Molecules. 2021 Aug 26;26(17):5173.

    PMID 34500605 ↗

21. Rahman OF, Lee SJ, Seeds WA. Therapeutic peptides in orthopaedics: applications, challenges, and future directions. J Am Acad Orthop Surg Glob Res Rev. 2026 Jan 2;10(1):e25.00236. Review.

    PMID 41490200 ↗