RESEARCH MONOGRAPH · KDC-MN-011

Semax

May 9, 2026 Kodiac biolabs Research Revised May 30, 2026 2 min read

Our opinion on this compound

72/100

ACTH fragment turned nootropic. Real BDNF signal and a Russian clinical history most Western researchers ignore

Semax is the Russian sibling story to selank. Same research lineage (Ivanov and Myasoedov at the Russian Academy of Sciences), same Pro-Gly-Pro stabilization strategy, different parent peptide. Semax derives from ACTH(4-10) (MEHFPGP) with the C-terminal PGP tail added for protease resistance.

The interesting thing about semax is that ACTH(4-10) itself was studied as a cognitive enhancer by De Wied and colleagues in the Netherlands going back to the 1970s, well before the Russian work. The melanocortin behavioral effects on attention and learning were already documented. Semax basically took that parent fragment, made it metabolically stable enough to be a clinical compound, and ran with it.

BDNF upregulation in the hippocampus is the central mechanism story, demonstrated repeatedly in rat brain microdialysis studies from the Levitskaya and Ashmarin groups. The peptide doesn't bind melanocortin receptors with high affinity itself (the metabolites might, the parent compound less so), so the central effects are believed to work through neurotrophin pathways and possibly through dopaminergic modulation in striatum.

The Russian clinical literature is actually more substantial than most Western researchers realize. Approved indication in Russia for stroke recovery, and trials in cognitive impairment, optic neuropathy, and pediatric attention deficits have produced consistent (if modestly designed) positive results. Again, the methodology gap with modern Western RCTs is real, but the consistency across studies and decades of clinical use weights toward signal rather than noise.

The N-acetyl-amidated variant (NA-Semax-amidate) has emerged in research-supplier markets recently with stronger in-vitro stability than the parent, but the human data on the modified version is essentially nonexistent.

Intranasal route is standard. Half-life is short, sub-hour for the parent compound, with downstream BDNF effects persisting much longer. The fast PK and slow PD relationship is the same general pattern as selank.

Sourcing is fine. Seven residues, simple synthesis, reasonably stable lyophilized. HPLC validation is easy. Vendor variability is moderate, watch the COA for the exact sequence (PGP tail position matters).

Real signal, underrated tool, weak Western evidence base.

Evidence: 60
Mechanism: 68
Reliability: 70
Safety: 80
Sourcing: 78
Value: 78
Signal: 75
Staying power: 70

Plain-language summary Intrigue 73 / 100

Semax is a synthetic seven-amino-acid peptide derived from a fragment of ACTH (a stress hormone). It is approved in Russia as a nootropic and stroke recovery medication. Research suggests effects on BDNF, dopamine, and other neurotrophic systems. Stocked in the Kodiac catalog as a research-only powder for laboratory work; not a medicine, not for human consumption.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

Synthetic heptapeptide nootropic, ACTH(4-10) analog

A 7-residue peptide derived from ACTH(4-10), developed at the Russian Academy of Sciences and registered for clinical use in stroke recovery and cognitive indications.

Abstract

Semax (sequence Met-Glu-His-Phe-Pro-Gly-Pro; CAS 80714-61-0; molecular formula C37H51N9O10S; molecular weight 813.92) is a synthetic heptapeptide developed in the early 1980s at the Institute of Molecular Genetics of the Russian Academy of Sciences. The peptide is a stabilized analog of the N-terminal heptapeptide of adrenocorticotropic hormone (ACTH(4-10)), a fragment that retains many of the cognitive and neuroprotective effects of the parent hormone without the steroidogenic effects mediated by the C-terminal portion. Semax extends the ACTH(4-10) sequence with the C-terminal tripeptide Pro-Gly-Pro (the same stabilizing extension used in Selank) to confer protection against rapid peptidase degradation. The compound is registered as a prescription medicine in the Russian Federation for ischemic stroke recovery, transient ischemic attack, and several other neurological and cognitive indications. The published preclinical and clinical record includes work on neuroprotection in cerebral ischemia models, modulation of BDNF and NGF expression, melanocortin receptor signaling effects, and cognitive enhancement endpoints. The compound is not approved by any regulatory authority outside the Russian Federation. The principal limitations on the strength of the evidence are the dominance of the Russian-language literature, limited Western independent replication of the most-cited findings, and the relatively small clinical sample sizes by Western regulatory standards. The lot of record at Kodiac biolabs (lot 20260331) carries a vendor-reported HPLC purity of 99.75 percent.

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The full reference document covers compound identification, discovery and developmental history, mechanism of action, pharmacokinetics, reported research dose ranges, sourcing and quality verification, reconstitution and handling, stack interaction considerations, and a curated reference list. Available as a research-use-only PDF download.

KDC-MN-011

The full reference document is provided strictly for research use only. It reports research dose ranges from the published literature, not instructions for use in humans or animals.

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FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

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Semax

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