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What it is
A synthetic heptapeptide based on a fragment of adrenocorticotropic hormone, modified so it carries none of the hormone's corticotropic activity. Developed in the Soviet Union and in continuing clinical use in Russia.
How it is proposed to work
Proposed effects on brain-derived neurotrophic factor and nerve growth factor expression, and on monoaminergic signalling. Administered intranasally, which is central to its rationale and unusual among the compounds in this library.
Approved medical uses
Used in Russia for cerebrovascular and cognitive indications. Not approved in the US, EU or India, where no regulator has evaluated it.
Human research
Each entry states what the study found and, separately, what it cannot show.
- Controlled human trial2018n = 110
Semax alongside post-stroke rehabilitation: plasma BDNF, motor performance and Barthel index
Finding. A single Russian-language clinical study in patients already some months into rehabilitation after ischaemic stroke — roughly three months in one group and seven in the other, so this is subacute-to-chronic recovery rather than acute stroke treatment. It set out to evaluate "the efficacy of semax and timing of rehabilitation on the dynamics of plasma BDNF levels, motor performance, and Barthel index score", with patients divided into early and late rehabilitation groups, each of which "was subdivided into semax+ and semax- subgroups". The abstract designates no primary endpoint. Movement, the outcome that matters most to a patient, is where the result is weakest: the Russian-language abstract states that semax and high BDNF levels influenced the reduction of pareses to a lesser degree, and in the English abstract the motor gain is attributed to "a correlation between early rehabilitation and motor performance improvement" — to the timing of rehabilitation rather than to the compound. What the study reports most firmly is a blood marker rather than a clinical one: "Administration of semax, regardless of the timing of rehabilitation, increased BDNF plasma levels which remained high during the whole study period." On function, the report states that "Administration of semax and high BDNF levels accelerated the improvement and ameliorated the final outcome of Barthel score index" — a composite of an administered drug and an observed biomarker stratum rather than a clean between-group comparison — alongside "a positive correlation between BDNF plasma levels and Barthel score". The authors conclude that "Early rehabilitation and administration of semax increase BDNF plasma level, speed functional recovery, and improve motor performance", a conclusion that bundles the compound together with rehabilitation timing throughout.
Limitation. This is one Russian-language study, not the body of literature the dossier gestures at, and we read only its abstract. One hundred and ten patients were enrolled in total, but the abstract gives no size for the semax-treated subgroups, so the number of people who actually received the compound is unknown and is well below that headline figure. The abstract does not state how patients were allocated to the semax and non-semax subgroups, nor whether any placebo or blinding was used, so it cannot be described as randomised; it describes patients as examined and observed over five months rather than assigned, so even "controlled trial" is our characterisation of a design the source does not name. Semax was given on top of rehabilitation whose timing was itself a study variable, which entangles the two influences, and several of the reported results are correlations rather than group comparisons. Plasma BDNF is a blood measure whose relation to brain BDNF this study does not establish, so its firmest finding bears on the dossier's proposed mechanism more than on clinical benefit. The abstract reports no adverse events either way. We state no effect sizes from it, for the reason that governs this entry: an adversarial check found an entirely fabricated semax stroke trial circulating with complete fake figures, and we will not risk repeating invented numbers. We located no independent replication outside the Russian tradition, and the first author here also led the 1997 semax stroke study the earlier pass found.
Preclinical research
Animal and laboratory work. Useful for generating hypotheses; it cannot establish that something works in people.
No preclinical studies catalogued.
Potential safety concerns
- WatchPreliminary
Decades of clinical use in one country is a meaningful safety signal in itself, and better than most compounds here can claim. It is not equivalent to systematic pharmacovigilance data we can inspect.
- CautionEstablished
Grey-market material is not the registered Russian product. A registration elsewhere provides no assurance whatsoever about a vial bought outside that supply chain.
Known interactions and contraindication considerations
- Not well characterised in accessible literature.
This list is not exhaustive and is not a substitute for a clinician reviewing your full medication history.
Regulatory status
Status is shown per jurisdiction and is accurate only as of the date stated. Where a compound is approved, the approval is bound to a specific formulation, manufacturer and indication — shown in the detail column.
| Jurisdiction | Standing | Detail |
|---|---|---|
Russian Federation Ministry of Health / Roszdravnadzor | Approved as of 11 Aug 2026 | Marketed in Russia. Our check could not confirm current status against the state register itself — the certificate details in circulation come from commercial drug references, which retain entries after registrations lapse. Verify directly before relying on this. Reported indications centre on ischaemic stroke, transient ischaemic attack, cognitive disorders and optic nerve conditions. |
United States FDA | Unapproved / investigational as of 11 Aug 2026 | No marketing authorisation. The FDA has not evaluated this compound — that is an absence of any opinion, not a negative finding. |
European Union EMA | Unapproved / investigational as of 11 Aug 2026 | No marketing authorisation. |
India CDSCO | Unapproved / investigational as of 11 Aug 2026 | Not approved for human use. A first-time synthetically manufactured peptide falls under the new-drug pathway. |
How it is being used
What the grey community actually runs, the reasoning they give, and our read on whether it follows from known biology. This is observation, not evidence, and not a recommendation.
No community use documented for this compound yet. Absence here means our editorial team has not reviewed and verified a pattern — not that none exists.
Active clinical trials
No registered trials currently tracked for Semax.
What remains unknown
The questions that would change our assessment if they were answered.
- Do the Russian trial results replicate under independent, blinded, adequately powered conditions?
- How much of the intranasal dose reaches the central nervous system in humans?
- Why has no Western group attempted replication of a compound in routine clinical use elsewhere?
References
Editorial change history
When we change a grade or a regulatory note, we log it here rather than editing quietly.
Dossier created. A fabricated stroke trial with full fake figures was found circulating in our research sources and excluded. All registration certificate details were excluded pending state-register verification.
Spotted something wrong? Tell us — we publish corrections.