Research Cluster
Cognitive & Neuroprotective Peptides
Cognitive peptides attract a different research audience than most clusters on this site—one that skews toward nootropic self-experimentation, often with a higher tolerance for acting on preclinical data. That tolerance is understandable given the limited pharmacological options for cognitive enhancement and the urgency of neurodegenerative disease. It does not change what the evidence shows.
This cluster contains two compounds with Phase II or Phase III Western clinical data, two Russia-approved compounds with meaningful but geographically limited clinical records, a polypeptide mixture with more human data than its obscurity in Western literature would suggest, and several preclinical-only compounds where the mouse data is genuinely interesting and the human evidence is absent. The tier system here is doing the most important work on the site.
Cluster at a Glance
10 compounds • 0 FDA-approved • 2 with Phase II/III Western trials • 4 pilot/limited human data • 4 preclinical only
Clinical Trials
Pilot / Human Data
Preclinical Only
Editorial note: Russia-approved status is noted where applicable but does not substitute for FDA or EMA approval. The Russian regulatory framework and clinical trial standards differ from Western ones. Compounds approved in Russia are documented accurately—their approval status is not treated as equivalent to a Western Phase III program, nor is it dismissed as meaningless.
Cerebrolysin: Brain-Derived Neuropeptides for Neurological Injury
Porcine brain-derived peptide mixture (EVER Neuro Pharma). CASTA Phase III stroke trial (n=1,070) failed primary endpoint. Approved in 30+ countries, not FDA-approved.
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Cortexin: Neuropeptide Complex for Brain Injury and Cognitive Decline
Bovine/porcine cerebral cortex-derived polypeptide complex. Approved in Russia for stroke, TBI, epilepsy. Cochrane review: insufficient evidence. No Western clinical trials.
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Dihexa: HGF/c-Met Agonist and the Synaptogenesis Hypothesis
Hexapeptide analog activating HGF/c-Met synaptogenesis. WSU research showed potent cognitive enhancement in rodents. Zero human pharmacokinetic or safety data.
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NAP (Davunetide): The NAPVSIPQ Neuroprotective Octapeptide
NAPVSIPQ octapeptide from activity-dependent neuroprotective protein (ADNP). Phase II/III PSP trial failed. Intranasal CNS delivery validated in humans.
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P21: The CNTF-Derived Peptide and Adult Neurogenesis Research
CNTF-derived tetrapeptide (Ac-DGGL-AG-NH2) promoting adult hippocampal neurogenesis in rodent models. No human pharmacokinetic, safety, or efficacy data.
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Selank: The Russian Anxiolytic Peptide—Evidence and Mechanism
Tuftsin analog (TP-7) approved in Russia for generalized anxiety. GABA-A receptor modulation confirmed in multiple studies. No Western clinical trials.
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Semax: The ACTH 4-10 Analog for Cognition and Neuroprotection
ACTH 4-10 analog with Pro-Gly-Pro extension. Approved in Russia for stroke and cognitive disorders. BDNF upregulation documented. No Western Phase II data.
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How These Compounds Relate
The ten compounds in this cluster operate through distinct mechanisms that address different aspects of cognitive and neurological function. Cerebrolysin and NAP/Davunetide are the most clinically studied—both have Phase II or Phase III Western trial data, both have failed primary endpoints in at least one major trial, and both remain scientifically credible despite those failures. A compound that completes rigorous Phase II/III trials and does not meet its primary endpoint is providing more useful information than a compound that has never been tested in humans at all.
Selank and Semax are the most widely self-experimented peptides in this cluster in Western communities, despite their evidence base being primarily Russian. Both are Russia-approved, both have intranasal delivery that achieves CNS bioavailability without injection, and both have plausible and well-characterized mechanisms. The absence of Western Phase II trials does not mean the Russian clinical data is fabricated—it means it has not been independently replicated in a Western regulatory context.
Cerebrolysin and Cortexin are both complex polypeptide mixtures derived from animal brain tissue rather than single defined peptides. This places them in a different category from everything else in this cluster and introduces composition variability that single-peptide compounds do not have. Their mechanism is diffuse rather than targeted—neurotrophic support across multiple pathways rather than a specific molecular target.
Dihexa and P21 represent the high-excitement end of this cluster—compounds with compelling preclinical findings and zero human data. Dihexa’s HGF/c-Met mechanism and the synaptogenesis findings from the Washington State University group generated genuine scientific interest. P21’s adult neurogenesis mechanism touches one of the more active areas of neuroscience research. Neither has a human pharmacokinetic study, let alone an efficacy trial.
DSIP sits in a unique position—an endogenous peptide with a well-characterized biological role in sleep architecture, a human evidence base that is real but inconsistent, and a mechanism (sleep quality and stress-axis modulation) that is relevant to cognitive function without being a direct nootropic. Its community use often conflates sleep optimization with cognitive enhancement—a distinction worth maintaining.