Nootropic
Semax
Prepared by the ezGLP team. Sources last checked . Profile reviewed .
Routes represented in the knowledgebase: Intranasal.
Educational overview
Semax is listed in the ezGLP knowledgebase under Nootropic. Evidence and regulatory status can vary by formulation, route, and jurisdiction.
Semax is a synthetic heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) developed in the Soviet Union and Russia from the 1980s at the Institute of Molecular Genetics of the Russian Academy of Sciences and Moscow State University. Its N-terminal segment reproduces the ACTH(4-7) fragment shared by adrenocorticotropic hormone and alpha-melanocyte-stimulating hormone, and the C-terminal tripeptide Pro-Gly-Pro was added to resist enzymatic degradation. It is classed as a nootropic and neuroprotective peptide without hormonal corticotropic activity. Proposed mechanisms drawn from rodent work include increased hippocampal BDNF and TrkB expression, modulation of dopaminergic and serotonergic systems, and suppression of pro-inflammatory gene transcription after cerebral ischaemia. In Russia it is administered as intranasal drops.
Nearly all published research originates from Russian institutions, including the Institute of Molecular Genetics, the Kurchatov Institute, and Pirogov University. A 1997 review by Ashmarin and colleagues summarised fifteen years of development and described effects on memory, attention, and hypoxia tolerance in animals and humans. Mechanistic rodent studies from 2005 onward reported BDNF induction and transcriptomic changes after experimental stroke, with a 2024 analysis identifying thousands of differentially expressed genes influenced by the peptide. Clinical use in acute ischaemic stroke rests on Russian trials published mainly in Russian-language journals. No large randomised trial conducted or replicated outside Russia and Eastern Europe has been published.
Semax is registered as a medicine in Russia and several neighbouring countries, where it is marketed as an intranasal solution for cognitive complaints, stroke rehabilitation, and optic nerve conditions. It is not approved by the FDA, the EMA, the MHRA, or the TGA for any indication. In the United States it was reviewed under the FDA compounding bulk drug substances programme, where the agency described the heptapeptide as presenting a risk of immunogenicity from aggregation and peptide-related impurities. Outside Russia it circulates as a research chemical in nasal spray and lyophilised forms, sometimes alongside N-acetyl or amidated derivatives, without regulator-reviewed labelling or verified purity.
Storage depends on the product. The Russian nasal drops carry manufacturer instructions on refrigeration and shelf life after opening; research-chemical products depend on supplier statements that are not independently checked. Peptide solutions are sensitive to heat, light, and temperature cycling, and multi-dose nasal bottles carry contamination risk once opened, so the beyond-use time is formulation-specific and often unknown. A dose log that records product source, lot number, stated concentration, route, date first opened, and storage conditions, together with an inventory record of bottles or vials on hand, gives a person the traceability that a licensed product label would otherwise provide.
- Category
- Nootropic
- Routes represented
- Intranasal
- Storage context
- Follow the dispensed product or pharmacy label; storage and beyond-use time vary by formulation.
Published literature
Safety evidence
Serious or important: potential immunogenicity, aggregation, impurity, or product-quality risks.
A dependable route-specific human interaction and side-effect profile is not established; this is not evidence of no risk.
Safety evidence sourceCommon questions
What is Semax used for?
In Russia, Semax is registered for cognitive impairment, recovery after ischaemic stroke, and certain optic nerve disorders, and is promoted for attention and memory support. Outside Russia it has no approved indication. Online interest focuses on cognition, focus, and mood, but the clinical support consists of Russian trials and rodent mechanistic studies that have not been independently replicated in Western peer-reviewed journals.
What is the difference between Semax and Selank?
Both are Russian heptapeptides that share the C-terminal Pro-Gly-Pro tail and are formulated as nasal drops, but they come from different parent molecules. Semax is derived from the ACTH(4-7) fragment and is studied mainly for cognition and stroke recovery, with BDNF induction as a proposed mechanism. Selank is derived from the immunoglobulin fragment tuftsin and is studied mainly as an anxiolytic acting through GABA and enkephalin systems.
Is Semax FDA-approved or legal in the United States?
Semax is not FDA-approved and cannot lawfully be marketed as a drug for human use in the United States. The FDA compounding bulk substances review described it as carrying immunogenicity risk from aggregation and peptide impurities. It is not a scheduled controlled substance, so products are sold online as research chemicals. The EMA, MHRA, and TGA have likewise not authorised it.
Does Semax raise BDNF?
In rats, a 2006 study reported that a single administration increased hippocampal BDNF protein and TrkB receptor phosphorylation, with larger rises in the corresponding mRNAs. Later Russian transcriptomic studies described related changes after experimental stroke. These findings are from rodents; no published human study has measured brain BDNF changes after Semax, so the effect in people is inferred rather than demonstrated.
Does Semax affect cortisol or act like ACTH?
Semax retains only the ACTH(4-7) fragment and lacks the region of ACTH that activates adrenal melanocortin-2 receptors, so it does not stimulate cortisol release in the way corticotropin does. The Russian developers reported no hormonal side effects across their studies. Its overlap with alpha-MSH sequences has prompted study of melanocortin receptor binding, but it is not classed as a hormone.
Further reading
- Ashmarin et al., A nootropic adrenocorticotropin analog 4-10 Semax: 15 years of design and study, 1997
- Dolotov et al., Semax regulates BDNF and trkB expression in the rat hippocampus, 2006
- Eremin et al., Semax activates dopaminergic and serotoninergic brain systems in rodents, 2005
- Brain protein expression profile confirms the protective effect of Semax in a rat model of cerebral ischemia-reperfusion, 2021
- ACTH-like peptides compensate rat brain gene expression profile disrupted by ischemia, 2024
- FDA, Certain bulk drug substances for use in compounding may present significant safety risks
Tools for your existing schedule
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Summarised from published literature for reference only, with citations to the source. Evidence is graded as reported and is not a recommendation to combine, dose, or use any compound.
For personal tracking and education only. Not medical advice, diagnosis, or treatment, and not a medical device. Peptides may be prescription-only or unapproved where you live. Consult a licensed healthcare professional.