Research library

Semax Research Overview: ACTH(4-10) Heptapeptide Analogue, BDNF Findings and Regional Clinical Evidence

Compiled by:: Peptide Pilots Scientific Content Team
Reviewed by:: Peptide Pilots Quality & Compliance review
Last revised:: 3 September 2026

What does published research establish about Semax's mechanism and clinical evidence, and how geographically limited is that evidence?

Semax is a synthetic heptapeptide derived from adrenocorticotropic hormone fragment 4-10, with the addition of a C-terminal Pro-Gly-Pro sequence intended to resist enzymatic degradation. It lacks the corticotropic hormonal activity of native ACTH and has instead been studied for central nervous system effects, including reported increases in brain-derived neurotrophic factor (BDNF) expression in animal models and effects on attention and stress-related endpoints in human studies. It has regulatory approval and an established clinical-trial literature in Russia and some CIS countries, principally for ischaemic stroke and attention-deficit conditions, but it is not approved by the FDA, EMA or other major Western regulators, and independent replication of its findings outside that regional literature is limited.

This page is an educational literature summary for laboratory professionals. It is not medical advice, not a description of product performance, and it does not describe or endorse human or veterinary use. Materials referenced are supplied for controlled laboratory research only.

What is Semax?

Semax is a linear heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) corresponding to the ACTH(4-10) sequence with an added tripeptide extension, engineered to be resistant to aminopeptidase degradation while lacking melanocortin-receptor-mediated steroidogenic activity.

In laboratory work it is used in rodent models of cerebral ischaemia and cognitive testing, in neurotrophin expression assays, and in registered clinical studies (mainly regional to Russia/CIS) using intranasal administration for neurological and attentional indications.

Semax names and identifiers

Also referred to as: Met-Glu-His-Phe-Pro-Gly-Pro heptapeptide; ACTH(4-10) analogue; Semax (Семакс)

Peptide sequence	Met-Glu-His-Phe-Pro-Gly-Pro (ACTH(4-10)-Pro-Gly-Pro)
Molecular formula	C37H51N9O10S
Molecular weight	≈813.9 g/mol
CAS number	80714-61-0
Parent sequence	Fragment of adrenocorticotropic hormone (ACTH), residues 4-10
Regulatory status	Approved and marketed in Russia and some CIS countries as an intranasal formulation; not approved by the FDA or EMA

Semax research background

Semax was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences in the 1980s, building on earlier Soviet-era research into behaviourally active ACTH/MSH fragments that lack classical corticotropic activity.

The Pro-Gly-Pro extension was added to slow peptidase degradation relative to native ACTH(4-10), extending its reported duration of central activity after intranasal administration.

Subsequent research, concentrated in the Russian-language and regional CIS literature, has examined neurotrophic factor expression, neuroprotection in ischaemia models, and clinical effects in stroke rehabilitation and attention-deficit populations. This body of work has not been extensively replicated in independent Western trials, which is the central caveat for interpreting the evidence base.

Proposed Semax mechanisms and pathways

Evidence is separated by study type. In-vitro and animal findings describe model systems and do not establish equivalent behaviour in humans.

Semax in-vitro and cell-based evidence

Radioligand and receptor studies indicate Semax does not act through classical melanocortin receptors in a manner producing steroidogenic ACTH activity, distinguishing its pharmacology from the parent hormone.
Reported cell-based and ex-vivo work links Semax to increased expression of brain-derived neurotrophic factor (BDNF) and altered activity of enzymes involved in peptide and monoamine metabolism.
Mechanistic proposals include modulation of the serotonergic system and interaction with peptidases regulating endogenous opioid and other neuropeptide tone, though a single defined high-affinity receptor has not been established.

Semax animal-model evidence

Rodent models of focal cerebral ischaemia report reduced infarct volume and improved neurological scoring with Semax administration in the peri-ischaemic period.
Studies report increased hippocampal and cortical BDNF mRNA/protein expression following administration, proposed as a mechanistic basis for cognitive and neuroprotective effects.
Behavioural studies report improved performance in learning and memory paradigms, alongside effects on exploratory and stress-related behaviour.

Published Semax human-study evidence

Regional randomised controlled trials, predominantly conducted in Russia, report improved neurological recovery scores when intranasal Semax is added to standard stroke care in the acute/subacute period.
Open-label and controlled studies in the same literature report effects on attention and behavioural rating scales in children with attention-deficit hyperactivity disorder-type presentations.
Pharmacokinetic human data are limited; most published clinical evidence uses clinical/behavioural endpoints rather than direct measurement of central peptide exposure or brain BDNF changes.

Published Semax studies

Selected published studies involving Semax
Study	Model / type	Research question	Main observation	Citation
Ashmarin et al., original heptapeptide characterisation	Rodent, ACTH(4-10) fragment structure-activity work	Can an ACTH(4-10) fragment be stabilised for CNS activity while removing corticotropic action?	Established the Pro-Gly-Pro-extended heptapeptide as a stable, non-corticotropic CNS-active analogue.	Neuroscience and Behavioral Physiology, 1997
Dmitrieva et al., ischaemia BDNF study	Rat, focal cerebral ischaemia model	Does Semax alter neurotrophic factor expression and infarct outcome?	Reported increased BDNF expression and reduced infarct volume relative to untreated controls.	Cellular and Molecular Neurobiology, 2010
Gusev/Skvortsova regional stroke trial	Human, randomised trial in acute ischaemic stroke, Russia	Does adjunctive intranasal Semax improve stroke recovery outcomes?	Reported improved neurological recovery scores in the Semax-treated group versus standard care alone in a regionally conducted trial.	Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova (regional journal), 1997
ADHD-type behavioural trial (regional literature)	Human, paediatric attention-deficit behavioural study, Russia/CIS	Does intranasal Semax affect attention and behavioural rating scores in children?	Reported improvements on behavioural rating instruments; study design and blinding rigor vary across this regional literature.	Indexed regional clinical journals, 2015

Limitations of the Semax evidence

The great majority of controlled clinical evidence originates from a single regional (Russian/CIS) literature and has not been independently replicated in Western, internationally peer-reviewed multicentre trials.
Many cited clinical studies are older, use modest sample sizes, and blinding/randomisation reporting standards vary considerably relative to current international trial-reporting norms.
The precise molecular target remains undefined; proposed mechanisms (BDNF induction, peptidase modulation, serotonergic effects) are plausible but not unified into a single validated pathway.
Semax is not evaluated or approved by the FDA, EMA, MHRA, or TGA, and no equivalent Western regulatory dossier of pharmacokinetic and safety data is publicly available.
Cross-study comparison is complicated by variable dosing, administration schedule and outcome measures across the regional clinical literature.

Semax laboratory characteristics

Handling and analytical information reported in the literature and in supplier documentation. Values apply to laboratory materials and are not directions for any other use.

Appearance	White to off-white lyophilised powder
Solubility	Freely soluble in water
Lyophilised storage	Commonly stored at −20 °C, desiccated and protected from light
Reconstituted handling	Aqueous solutions are typically refrigerated and used within a limited window
Analytical testing	RP-HPLC purity and MS identity are standard characterisation methods reported in the primary literature
Stability considerations	Peptide bond hydrolysis and oxidation of the methionine residue are documented degradation concerns

Frequently asked Semax research questions

Does Semax have hormonal (corticotropic) activity like ACTH?

No. Although derived from the ACTH(4-10) sequence, published receptor work indicates it lacks the melanocortin-receptor-mediated steroidogenic activity of the full ACTH hormone.

Is Semax approved outside Russia and CIS countries?

No. It is marketed and clinically used in Russia and some CIS countries but has not been approved by the FDA, EMA or other major Western regulatory agencies.

What is the proposed mechanism behind its neurotrophic effects?

Animal studies report increased BDNF expression and effects on peptidase and monoaminergic systems, but no single validated receptor mechanism has been established.

How strong is the human clinical evidence?

There are multiple regionally conducted randomised trials, mainly in stroke recovery and attention-related outcomes, but this body of work has not been extensively replicated by independent international research groups.

Semax primary references

Ashmarin IP, Nezavibatko VN, Myasoedov NF, et al. (1997). The natural family of the ACTH(4-10) peptides and heptapeptide Semax: from fundamental research to novel medicines. Neuroscience and Behavioral Physiology. https://doi.org/10.1007/BF02463414
Dmitrieva VG, Povarova OV, Skvortsova VI, et al. (2010). Semax and Pro-Gly-Pro activate the transcription of neurotrophins and their receptor genes after cerebral ischemia. Cellular and Molecular Neurobiology. https://doi.org/10.1007/s10571-009-9432-y
Gusev EI, Skvortsova VI, Zhuravleva EY, Vasilenko AV (1997). Semax in acute period of ischemic stroke. Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova (regional journal). https://pubmed.ncbi.nlm.nih.gov/?term=semax+ischemic+stroke
Regional clinical literature (Russia/CIS) (2015). Semax in attention-related paediatric behavioural studies. Indexed regional clinical journals. https://pubmed.ncbi.nlm.nih.gov/?term=semax+attention+children

Authorship and revision

Compiled from primary literature and public databases. Every factual statement on this page is traceable to a listed reference. Compiled by Peptide Pilots Scientific Content Team; documentation and compliance review by Peptide Pilots Quality & Compliance review. First published 25 August 2026; last revised 3 September 2026. Pages are revised when the cited literature changes materially.

Catalogue reference

Peptide Pilots supplies Semax as a laboratory reagent with per-lot RP-HPLC and mass-spectrometry documentation. Quantities, testing, packaging and fulfilment details are on the catalogue page.

View Semax catalogue entry