Pinc PeptideThe girly peptide research blog

Brain & sleep · 6 compounds · updated 8 October 2026

Best peptides for focus and sleep, ranked by the human evidence

6 compounds are sold for focus, memory, mood and sleep. We rank them by how strong the evidence in people is, not by popularity. 1 of the 6 is FDA-approved for some use; the rest are not.

In 2026 reviews, FDA called DSIP’s insomnia evidence ‘inconclusive and at best preliminary’ and found ‘insufficient evidence’ for semax in the three uses it reviewed: poor blood flow to the brain, migraine and a facial nerve pain12. Many human studies of selank and semax were small and published in Russian, and as of 7 October 2026 neither had a trial registered on ClinicalTrials.gov, the main US trial registry2345678. A 2021 US review called selank one of the ‘poorly studied Russian drugs’ being sold to US consumers as dietary supplements9. Cerebrolysin, a drug made from pig brain and approved in nine EU countries, has the largest trials here, but the biggest, in 1,070 stroke patients, missed its main goal, and reviews rate its benefits in dementia as small or uncertain10111213. For dihexa, sold online as a memory booster, we found no study in people, and a key paper from its inventors was retracted for falsified data1415. Oxytocin, a hormone approved in the US as Pitocin for labor, is sold as nasal sprays for calm and bonding, but those trials are mostly small with mixed results, and a large registered repeat of a famous trust study found no effect161718.

US pharmacies may not make dihexa, DSIP, selank or semax, and by our reading they may not make cerebrolysin either192021. By our reading, they may make oxytocin sprays on prescription, though these are not FDA-approved2223. In July 2026, FDA’s advisers voted 8 to 5, with 1 abstention, to let pharmacies make semax, and 6 for and 7 against, with 1 abstention, on DSIP; FDA staff had advised against both, the votes are only advice, and FDA had not acted on them by 8 October 2026720242526. Independent tests are few: Finnrick, a testing service, had logged 4 DSIP tests and 1 selank test by 3 August 2026 and 5 semax tests by 9 September 2026; 1 DSIP and 1 semax sample failed, and the selank test was incomplete272829. People choose which samples to send, so the results are not a random survey30. Finnrick listed no tests of cerebrolysin as of 25 September 2026, or of dihexa as of 7 October 20263132. FDA found that one DSIP lab certificate listed a formula matching no form of DSIP, and it warns that products sold as semax may be different salts or modified molecules12.

  1. Oxytocin

    AMixed resultsApproved as Pitocin; sprays and vials are not

    Oxytocin is a pituitary hormone approved in the US as Pitocin, a hospital injection for labor and bleeding after birth16. Nasal sprays sold for bonding, calm and libido rest on mostly small trials with mixed results171833.

    Does it work for bonding, mood, anxiety and libido? Trials disagree: one dose eased anxiety in a lab stress test, but sprays did not beat placebo for women’s sexual problems or social anxiety, and a large repeat study found no rise in trust18333435.

  2. Cerebrolysin

    BMixed resultsApproved in 9 EU countries; not in the US

    Cerebrolysin is an injectable drug made from digested pig brain: a mixture of small peptides and amino acids36. It is approved in parts of Europe but not the US, and reviews of its trials find small or uncertain benefits10121337.

    Does it work for memory, thinking and recovery after stroke? The largest randomized stroke trial missed its main goal, and dementia trials found small gains on weak evidence1112. The one healthy-volunteer trial we found, from 1998, mainly measured brain waves38.

  3. DSIP (emideltide)

    BMixed resultsApproved in Russia as nose drops; not in US

    DSIP is a lab-made copy of a 9-amino-acid peptide first found in rabbits, sold online for sleep139. Small trials from 1981 to 1992 disagreed, and two independent placebo-controlled trials found little or no benefit14041.

    Does it work for better sleep in chronic insomnia? Small trials disagree. One research group reported longer, less broken sleep4243; two other placebo-controlled trials found little or no benefit4041. All gave it into a vein1.

  4. Selank

    BMixed resultsApproved in Russia as nose drops; not in US

    Selank is a lab-made chain of 7 amino acids built from tuftsin, a small immune peptide, and sold in Russia as nose drops for anxiety4445. Its anxiety evidence comes from small Russian trials without a placebo group34.

    Does it work for anxiety relief? In one Russian trial without placebo, anxiety eased about as much as with medazepam, a Valium-like drug3. Added to a similar drug, it did not clearly help at 2 weeks (40% vs 23% responders)4.

  5. Semax

    BUntestedApproved in Russia as nose drops; not in US

    Semax is a lab-made chain of 7 amino acids: part of the stress hormone ACTH plus a 3-amino-acid tail244. Russia sells it as nose drops for stroke and memory problems4647. Its human evidence is small and mostly Russian27.

    Does it work for focus and memory in healthy people? No placebo-controlled test of focus or memory in healthy people could be found. A 1996 study of 19 healthy men reported better work performance, but its summary mentions no placebo group248.

  6. Dihexa

    DUntestedNot approved for any use

    Dihexa is a lab-made compound designed to help brain cells form new connections4950. We found no study that gave dihexa itself to people, and a key paper behind it was retracted for falsified data1415.

    Does it work for memory, focus and learning? We found no study of dihexa itself in people1451. Rat and mouse studies, mostly in animals given drugs, injuries or disease to impair memory, gave mixed results495253.

How we ranked them

Compounds that trials show work for this goal come first, then those with mixed results, then those with no controlled human trial for this goal that has public results, and last those that trials found do not work. Within each group, the stronger the human evidence (tier A to E), the higher the place. Ties go to compounds FDA has approved as a medicine, then to those approved only in other countries, then to those whose US approval was withdrawn, then to peptides over non-peptide drugs, then to the winner of a trial that compared the two directly. Popularity, price and how a product is marketed play no part. A high place is not a recommendation to use anything.

How we grade evidence →

Head-to-head

Doses used in studies

Questions people ask

What peptide helps with sleep?

DSIP, which is sold for sleep, has not been shown to help: its small trials disagreed, and FDA found no human study of it injected under the skin, the form sold in the US14041. Ipamorelin is also sold for sleep, but we found no study testing it for sleep in people, and in older adults, months of nightly sermorelin did not improve sleep; an early analysis found slightly worse self-rated sleep54555657.

What is the best peptide for anxiety?

Selank is sold in Russia for anxiety, but we found no placebo-controlled anxiety trial of it34645. One of its main trials, which added it to a Valium-like drug, was part-funded by Peptogen, the company that holds its Russian registration445. When FDA looked in December 2025, US clinics and online sellers were also marketing semax for anxiety, but its Russian labels rule out use in people with anxiety disorders24647.

Do nootropic peptides improve focus or memory?

We found no placebo-controlled test in healthy people showing that any of them does. The placebo-controlled studies of semax and selank in healthy volunteers, of 24 and 52 people, measured only brain-scan patterns at rest, not thinking or memory5859. Cerebrolysin’s one trial in healthy men, from 1998, mainly measured brain waves, with only a trend on word recall38, and we found no study that gave dihexa itself to people1451. Much of semax’s other human evidence comes from its developers’ circle444860.

Are sleep and focus peptides safe?

For DSIP, selank and semax, little is known. In studies, 209 people got DSIP into a vein for 1 to 15 days, mostly without serious problems, but in a study of 107 patients in alcohol or opioid withdrawal, 3 had serious reactions, 2 of them low blood pressure1. FDA found no safety data for semax injections and too little to judge its nose drops, and it says it lacks important information on selank’s safety in people214. Cerebrolysin can cause severe allergic reactions, and stroke trials point to more non-fatal serious side effects than placebo3661. Dihexa has no human safety data, and it is meant to boost a growth signal that many cancers use1462.

Sources

  1. 1FDA Evaluation of Emideltide-Related Bulk Drug Substances (Emideltide (Free Base) and Emideltide Acetate), PCAC briefing document U.S. Food and Drug Administration, 11 May 2026. fda.gov
  2. 2FDA Evaluation of Semax-Related Bulk Drug Substances (Semax (Free Base) and Semax Acetate), PCAC briefing document U.S. Food and Drug Administration, 11 May 2026. fda.gov
  3. 3Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia (in Russian) Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova, 2008. pubmed.ncbi.nlm.nih.gov
  4. 4Optimization of the treatment of anxiety disorders with selank (in Russian) Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova, 2015. pubmed.ncbi.nlm.nih.gov
  5. 5ClinicalTrials.gov search for ‘selank’ (10 records, none mentioning selank) ClinicalTrials.gov, accessed 7 Oct 2026. clinicaltrials.gov
  6. 6A comparison of the anxiolytic effect and tolerability of selank and phenazepam in the treatment of anxiety disorders (in Russian) Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova, 2014. pubmed.ncbi.nlm.nih.gov
  7. 7The PEPTIDE-L Wave Rolls On! PCAC Adds Two More Bulk Drug Substances for the 503A List FDA Law Blog (Hyman, Phelps & McNamara), 28 Jul 2026. thefdalawblog.com
  8. 8ClinicalTrials.gov search for ‘semax’ (0 studies) ClinicalTrials.gov, accessed 7 Oct 2026. clinicaltrials.gov
  9. 9Sedative-Hypnotic Agents That Impact Gamma-Aminobutyric Acid Receptors: Focus on Flunitrazepam, Gamma-Hydroxybutyric Acid, Phenibut, and Selank Journal of Clinical Pharmacology, Aug 2021. pubmed.ncbi.nlm.nih.gov
  10. 10Article 57 product data (EMA/518502/2018, Rev.89; data as present in the Article 57 database on 21 September 2026) European Medicines Agency, 21 Sep 2026. ema.europa.eu
  11. 11Cerebrolysin in patients with acute ischemic stroke in Asia: results of a double-blind, placebo-controlled randomized trial Stroke, Mar 2012. pubmed.ncbi.nlm.nih.gov
  12. 12Cerebrolysin for vascular dementia Cochrane Database of Systematic Reviews, 11 Nov 2019. pubmed.ncbi.nlm.nih.gov
  13. 13The efficacy and safety of animal-derived nootropics in cognitive disorders: Systematic review and meta-analysis Cerebral Circulation - Cognition and Behavior, 2021. pmc.ncbi.nlm.nih.gov
  14. 14Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks U.S. Food and Drug Administration, 22 Apr 2026. fda.gov
  15. 15Retraction notice to ‘The Procognitive and Synaptogenic Effects of Angiotensin IV-Derived Peptides Are Dependent on Activation of the Hepatocyte Growth Factor/c-Met System’ Journal of Pharmacology and Experimental Therapeutics, 29 Apr 2025. pmc.ncbi.nlm.nih.gov
  16. 16PITOCIN (oxytocin injection, USP) prescribing information Par Health USA, LLC via DailyMed (U.S. National Library of Medicine), 21 May 2026. dailymed.nlm.nih.gov
  17. 17Statistical and Methodological Considerations for the Interpretation of Intranasal Oxytocin Studies Biological Psychiatry, 1 Feb 2016. pubmed.ncbi.nlm.nih.gov
  18. 18A registered replication study on oxytocin and trust Nature Human Behaviour, Jun 2020. pubmed.ncbi.nlm.nih.gov
  19. 19Warning letter to Advanced Nutriceuticals, LLC dba The Guyer Institute of Molecular Medicine (MARCS-CMS 615908) U.S. Food and Drug Administration, 10 Nov 2021. fda.gov
  20. 20Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the Federal Food, Drug, and Cosmetic Act (categories list) U.S. Food and Drug Administration, 14 May 2026. fda.gov
  21. 21FDA to Remove 12 Popular Peptides from the Category 2 ‘Do Not Compound’ List Frier Levitt, 16 Apr 2026. frierlevitt.com
  22. 22Bulk Drug Substances Used in Compounding Under Section 503A of the FD&C Act U.S. Food and Drug Administration, 14 May 2026. fda.gov
  23. 23Compounding and the FDA: Questions and Answers U.S. Food and Drug Administration, 16 Sep 2025. fda.gov
  24. 24July 23-24, 2026: Meeting of the Pharmacy Compounding Advisory Committee U.S. Food and Drug Administration, 6 Aug 2026. fda.gov
  25. 25PEPTIDE-L WAVE! PCAC Approves Four Bulk Drug Substances for the 503A List FDA Law Blog (Hyman, Phelps & McNamara), 24 Jul 2026. thefdalawblog.com
  26. 26Federal Register search: FDA documents mentioning “503A” published since 1 July 2026 Federal Register, accessed 8 Oct 2026. federalregister.gov
  27. 27DSIP Safety Testing Results & Vendor Ratings Finnrick, 3 Aug 2026. finnrick.com
  28. 28Selank Safety Testing Results & Vendor Ratings Finnrick, 3 Aug 2026. finnrick.com
  29. 29Semax Safety Testing Results & Vendor Ratings Finnrick, 9 Sep 2026. finnrick.com
  30. 30We’d Rather Buy the Future Than Wait For It Finnrick, 10 Jun 2026. finnrick.com
  31. 31Finnrick public data summary (llms-full.txt, generated 25 September 2026) Finnrick, 25 Sep 2026. finnrick.com
  32. 32Dihexa: safety testing results and vendor ratings (no published tests) Finnrick, accessed 7 Oct 2026. finnrick.com
  33. 33Effect of long-term intranasal oxytocin on sexual dysfunction in premenopausal and postmenopausal women: a randomized trial Fertility and Sterility, Sep 2015. pubmed.ncbi.nlm.nih.gov
  34. 34A randomized controlled trial of intranasal oxytocin as an adjunct to exposure therapy for social anxiety disorder Psychoneuroendocrinology, Jul 2009. pubmed.ncbi.nlm.nih.gov
  35. 35Social support and oxytocin interact to suppress cortisol and subjective responses to psychosocial stress Biological Psychiatry, 15 Dec 2003. pubmed.ncbi.nlm.nih.gov
  36. 36Cerebrolysin for acute ischaemic stroke Cochrane Database of Systematic Reviews, 11 Oct 2023. pubmed.ncbi.nlm.nih.gov
  37. 37About Cerebrolysin (product page with prescribing information and notice to U.S. visitors) EVER Neuro Pharma GmbH (maker of Cerebrolysin), 25 Jan 2024. cerebrolysin.com
  38. 38Dose-dependent effects of Cerebrolysin on EEG and short-term memory of healthy volunteers during control and hyperventilation induced cerebral ischemia Journal of Neural Transmission. Supplementum, 1998. pubmed.ncbi.nlm.nih.gov
  39. 39Characterization of a delta-electroencephalogram (-sleep)-inducing peptide Proceedings of the National Academy of Sciences, Mar 1977. pubmed.ncbi.nlm.nih.gov
  40. 40Study of delta sleep-inducing peptide efficacy in improving sleep on short-term administration to chronic insomniacs International Journal of Clinical Pharmacology Research, 1987. pubmed.ncbi.nlm.nih.gov
  41. 41Effects of delta sleep-inducing peptide on sleep of chronic insomniac patients. A double-blind study Neuropsychobiology, 1992. pubmed.ncbi.nlm.nih.gov
  42. 42The influence of synthetic DSIP (delta-sleep-inducing-peptide) on disturbed human sleep Experientia, 1981. pubmed.ncbi.nlm.nih.gov
  43. 43Effects of delta-sleep-inducing peptide on 24-hour sleep-wake behaviour in severe chronic insomnia European Neurology, 1987. pubmed.ncbi.nlm.nih.gov
  44. 44A New Generation of Drugs: Synthetic Peptides Based on Natural Regulatory Peptides Neuroscience & Medicine (Scientific Research Publishing), Dec 2013. scirp.org
  45. 45Селанк (Selank) 0.15% nasal drops: instructions for use Vidal Russia drug reference, 22 Oct 2018. vidal.ru
  46. 46Семакс (Semax) 1% nasal drops: instructions for use Vidal Russia drug reference, 18 Mar 2021. vidal.ru
  47. 47Семакс (Semax) 0.1% nasal drops: instructions for use Vidal Russia drug reference, 17 Mar 2021. vidal.ru
  48. 48Synthetic ACTH analogue Semax displays nootropic-like activity in humans Neuroscience Research Communications, Sep 1996. doi.org
  49. 49Evaluation of metabolically stabilized angiotensin IV analogs as procognitive/antidementia agents Journal of Pharmacology and Experimental Therapeutics, Jan 2013. pmc.ncbi.nlm.nih.gov
  50. 50Prospective Alzheimer’s drug builds new brain cell connections Washington State University, 11 Oct 2012. archive.news.wsu.edu
  51. 51ClinicalTrials.gov search for ‘dihexa’ or ‘PNB-0408’ (no records) ClinicalTrials.gov, U.S. National Library of Medicine, accessed 7 Oct 2026. clinicaltrials.gov
  52. 52Effects of an Angiotensin IV Analog on 3-Nitropropionic Acid-Induced Huntington’s Disease-Like Symptoms in Rats Journal of Huntington’s Disease, 2024. pubmed.ncbi.nlm.nih.gov
  53. 53Hepatocyte Growth Factor/MET Activator Rescues Working Memory Deficits after Repeated Mild Traumatic Brain Injury Neurotrauma Reports, 2025. pmc.ncbi.nlm.nih.gov
  54. 54FDA Briefing Document, Pharmacy Compounding Advisory Committee meeting of October 29, 2024: ipamorelin-related bulk drug substances (FDA evaluation dated 19 August 2024) U.S. Food and Drug Administration, 19 Aug 2024. fda.gov
  55. 55PubMed search: ipamorelin (54 results) National Library of Medicine (PubMed), accessed 8 Oct 2026. pubmed.ncbi.nlm.nih.gov
  56. 56Growth hormone-releasing hormone and growth hormone secretagogues in normal aging Endocrine, Oct 2003. pubmed.ncbi.nlm.nih.gov
  57. 57Treating age-related changes in somatotrophic hormones, sleep, and cognition Dialogues in Clinical Neuroscience, Sep 2001. pmc.ncbi.nlm.nih.gov
  58. 58Functional Connectomic Approach to Studying Selank and Semax Effects Doklady Biological Sciences, Jan 2020. pubmed.ncbi.nlm.nih.gov
  59. 59Effects of Semax on the Default Mode Network of the Brain Bulletin of Experimental Biology and Medicine, Sep 2018. pubmed.ncbi.nlm.nih.gov
  60. 60Effectiveness of semax in acute period of hemispheric ischemic stroke (a clinical and electrophysiological study) (in Russian) Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova, 1997. pubmed.ncbi.nlm.nih.gov
  61. 61Life-Threatening Anaphylaxis due to Cerebrolysin® Case Reports in Neurological Medicine, 2024. pmc.ncbi.nlm.nih.gov
  62. 62Dihexa (Cognitive Vitality report) Alzheimer’s Drug Discovery Foundation, 13 Aug 2021. alzdiscovery.org

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