--- title: "Semax" canonical_url: https://bestpeptidecalculator.app/library/semax description: "Synthetic analog of the ACTH(4-10) fragment with a stabilising tail added, developed in Russia and used there as an intranasal nootropic and neuroprotective agent for stroke and cognitive indications. It has no corticotropic activity despite its ACTH origin. Reported activity centres on brain-derived neurotrophic factor expression and monoamine modulation. Not FDA-approved, and the clinical literature is almost entirely Russian-language with limited independent replication." updated: 2026-11-07 publisher: Peptide Library notice: "Research and educational use only. Not medical advice." --- # Semax Semax (also called ACTH(4-10) analog or Met-Glu-His-Phe-Pro-Gly-Pro) is an ACTH fragment nootropic. Semax is a synthetic analog of ACTH(4-10) with a Pro-Gly-Pro tail added to the C-terminus, a modification that markedly slows enzymatic degradation while removing the corticotropic activity of the parent hormone. Synthetic analog of the ACTH(4-10) fragment with a stabilising tail added, developed in Russia and used there as an intranasal nootropic and neuroprotective agent for stroke and cognitive indications. It has no corticotropic activity despite its ACTH origin. Reported activity centres on brain-derived neurotrophic factor expression and monoamine modulation. Not FDA-approved, and the clinical literature is almost entirely Russian-language with limited independent replication. Also known as: ACTH(4-10) analog, Met-Glu-His-Phe-Pro-Gly-Pro. Categories: Cognitive, Experimental. ## Classification - Type: ACTH fragment nootropic / research - Mechanism class: ACTH Analog - Development stage: Research only - Regulatory class: Research compound, not FDA-approved ## Mechanism Semax is a synthetic analog of ACTH(4-10) with a Pro-Gly-Pro tail added to the C-terminus, a modification that markedly slows enzymatic degradation while removing the corticotropic activity of the parent hormone. It does not stimulate the adrenal cortex. Reported activity centres on the neurotrophin system: animal and small human studies describe increased expression of brain-derived neurotrophic factor and nerve growth factor in the hippocampus and cortex, alongside modulation of dopaminergic and serotonergic transmission. Most of the clinical literature is Russian-language, where it is used for stroke and cognitive indications; it has no FDA-approved use, and independent replication outside Russia is limited. Targets: Melanocortin-related CNS pathways, BDNF. Origin: Synthetic Met-Glu-His-Phe-Pro-Gly-Pro. ## Properties - Sequence: Met-Glu-His-Phe-Pro-Gly-Pro - Length: 7 - Molecular formula: C37H51N9O10S - Molecular weight: 813.92 g/mol - CAS number: 80714-61-0 - Half-life: ~20-30 minutes (nasal) - Studied routes: Intranasal ## Evidence - Evidence level: Limited Human Evidence - Highest documented: Early or uncontrolled human studies - Human trials: 3 - Controlled human trials: 0 - Preclinical sources: 0 - Latest source: 2018 No human dose is established for this compound. Each step shows whether the sources Peptide Library has reviewed include that kind of research. Counts are reviewed sources, not every study ever published. Reviews and programme summaries that describe human use are shown as "reported", not as trials, and registered trials without published results are listed but not counted. A higher step means research has progressed further; it does not mean a compound works better or is safer. Compounds whose evidence has not been reviewed yet show "Not reviewed" instead of a guess. ### Studies 1. The efficacy of semax in the treatment of patients at different stages of ischemic stroke. Zh Nevrol Psikhiatr Im S S Korsakova. 2018. 2018. Human study (early or uncontrolled). Population: Patients at different stages of ischaemic stroke. Neurological recovery [Source](https://pubmed.ncbi.nlm.nih.gov/29798983/) 2. Effectiveness of semax in acute period of hemispheric ischemic stroke (a clinical and electrophysiological study). Zh Nevrol Psikhiatr Im S S Korsakova. 1997. 1997. Human study (early or uncontrolled). Population: Patients in the acute period of hemispheric ischaemic stroke. Clinical outcome in acute stroke [Source](https://pubmed.ncbi.nlm.nih.gov/11517472/) 3. Evaluation of therapeutic effect of new Russian drug semax in optic nerve disease. Vestn Oftalmol. 2000. 2000. Human study (early or uncontrolled). Population: Patients with optic nerve disease. Therapeutic effect in optic nerve disease [Source](https://pubmed.ncbi.nlm.nih.gov/10741256/) ## Safety Side effects: Nasal irritation; Headache. Risks: Overstimulation; Limited data. Contraindications: Epilepsy. Human safety basis: Limited human reports Key limitations: No established human dosage.; No controlled human trial results in the reviewed sources.; Not approved by the FDA for any use.. ## Regulatory status Semax is not an FDA-approved product. It is sold for laboratory research and has no approved medical use. - FDA status: Not Approved - Availability: Research-Only ## Frequently asked questions ### What is Semax? Synthetic analog of the ACTH(4-10) fragment with a stabilising tail added, developed in Russia and used there as an intranasal nootropic and neuroprotective agent for stroke and cognitive indications. It has no corticotropic activity despite its ACTH origin. Reported activity centres on brain-derived neurotrophic factor expression and monoamine modulation. Not FDA-approved, and the clinical literature is almost entirely Russian-language with limited independent replication. ### What are the side effects of Semax? Semax has only limited human data, so its side-effect profile is not well established. Effects recorded on this profile include nasal irritation and headache. Cautions recorded on this profile: epilepsy. This is reference information, not medical advice. ### How does Semax work? Semax is a synthetic analog of ACTH(4-10) with a Pro-Gly-Pro tail added to the C-terminus, a modification that markedly slows enzymatic degradation while removing the corticotropic activity of the parent hormone. It does not stimulate the adrenal cortex. ### Is Semax FDA approved? No. Semax is not approved by the FDA for any indication and is categorised as research-only. It has not been reviewed for safety or efficacy as a medicine, and published research should be read as investigation rather than established use. FDA's compounding lists show 503A nomination: Previously in Category 2; nomination withdrawn by the nominators. ### What is the half-life of Semax? Reported half-life for Semax is ~20-30 minutes (nasal). Half-life describes how long the compound persists in circulation, not how long any effect lasts, and published figures vary with route of administration, formulation and the population studied. ### What is the amino acid sequence of Semax? Semax has the sequence Met-Glu-His-Phe-Pro-Gly-Pro, giving a chain of 7 amino acids. Its molecular formula is C37H51N9O10S. ### What peptides are similar to Semax? Compounds most often compared with Semax include N-Acetyl Semax Amidate, Adamax, Selank and Cerebrolysin. They are grouped by shared mechanism or research area rather than by equivalence, and their regulatory status and evidence base differ. ## References - [\[Place of oligopeptide H-Met-Glu-His-Phe-Pro-Gly-Pro-OH in the therapy and rehabilitation of patients with ischemic stroke\] — Zh Nevrol Psikhiatr Im S S Korsakova, 2024](https://pubmed.ncbi.nlm.nih.gov/39166935/) - [\[Prospects for use of short peptides in pharmacotherapeutic correction of Alzheimer's disease.\] — Adv Gerontol, 2024](https://pubmed.ncbi.nlm.nih.gov/38944767/) - [\[Effectiveness of semax in acute period of hemispheric ischemic stroke (a clinical and electrophysiological study)\] — Zh Nevrol Psikhiatr Im S S Korsakova, 1997](https://pubmed.ncbi.nlm.nih.gov/11517472/) - [\[The Peptide Drug ACTH(4-7)PGP (Semax) Suppresses mRNA Transcripts Encoding Proinflammatory Mediators Induced by Reversible Ischemia of the Rat Brain\] — Mol Biol (Mosk), 2021](https://pubmed.ncbi.nlm.nih.gov/34097675/) - [\[Nootropic and analgesic effects of Semax following different routes of administration\] — Ross Fiziol Zh Im I M Sechenova, 2010](https://pubmed.ncbi.nlm.nih.gov/21268834/) Note: Dose figures are left out of this Markdown version. See the cited sources.