Introduction
Semax is a synthetic heptapeptide analogue of the adrenocorticotropic hormone (ACTH) fragment ACTH(4-7), with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Originally developed in Russia in the 1980s, it has been the subject of extensive preclinical and clinical research, particularly in the areas of cognitive function, neuroprotection, and neurotrophin regulation.
All Semax products supplied by Alpha Peptides are intended strictly for in vitro and laboratory research use only and are not approved for human or veterinary administration.
For a separate compound investigated in neurotrophic research, see our P-21 research overview. It explains the CNTF-derived compound and the limits of its cited mouse studies; these findings should be considered separately from the Semax literature.
Structure & Background
Semax is derived from the ACTH(4-7) core sequence (Met-Glu-His-Phe) with a Pro-Gly-Pro C-terminal extension that confers resistance to enzymatic degradation, significantly extending its half-life compared to the parent fragment. Unlike full-length ACTH, Semax does not exhibit adrenocortical activity, making it a useful research tool for isolating the central nervous system effects of ACTH-derived peptides.
Proposed Mechanisms of Action
Research into Semax has identified several potential mechanisms through which it may exert its observed effects:
- BDNF upregulation: Multiple studies have reported that Semax increases expression of brain-derived neurotrophic factor (BDNF) and its receptor TrkB in the hippocampus and frontal cortex. BDNF plays a central role in synaptic plasticity, neuronal survival, and long-term potentiation — processes closely associated with learning and memory.
- NGF modulation: Semax has been shown to influence nerve growth factor (NGF) expression, which is involved in the maintenance and survival of cholinergic neurons.
- Dopaminergic and serotonergic activity: Preclinical studies suggest Semax may modulate dopamine and serotonin turnover in key brain regions, which may contribute to its observed effects on attention and mood in animal models.
- Neuroprotection: Research in ischaemia models has indicated potential neuroprotective properties, with Semax appearing to reduce neuronal apoptosis and oxidative stress markers following hypoxic insult.
Key Research Findings
Cognitive Function
Animal studies have consistently demonstrated improvements in learning and memory tasks following Semax administration. In rodent models, Semax-treated subjects showed enhanced performance in maze navigation and passive avoidance tasks, with effects attributed to hippocampal BDNF upregulation and improved cholinergic transmission.
Neuroprotection & Stroke Research
A significant body of Russian clinical research has investigated Semax in the context of ischaemic stroke and transient ischaemic attack (TIA). Studies published in the 1990s and 2000s reported improvements in neurological recovery scores and reduced infarct progression in treated groups, though these studies are limited by small sample sizes and methodological constraints by modern standards.
Attention & Executive Function
Preclinical research has explored Semax’s effects on attention and executive function, with some studies reporting enhanced sustained attention and reduced impulsivity in animal models. These findings have generated interest in Semax as a research tool for studying attention-related neurological pathways.
Research Formulations
Semax is available in two primary research formulations:
- Lyophilised powder: our Semax 10mg vial contains freeze-dried powder for laboratory research.
- Atomised solution: our Semax 10mg Atomised Solution contains reconstituted Semax supplied in an atomiser. It is a different supplied format from the powder vial. Both products are for laboratory and in vitro research only, not human or veterinary use.
For researchers working with multiple cognitive research compounds, our Cognitive Research collection provides a curated selection of neuropeptides and nootropic compounds studied for their effects on cognition and neuroplasticity.
Reconstitution & Storage
For lyophilised Semax, confirm solvent compatibility, preparation conditions and storage limits from product-specific documentation and your laboratory’s validated protocol. No universal shelf life after reconstitution is established here. See our Peptide Reconstitution Guide for a preparation checklist.
Research Considerations
- Much of the published Semax literature originates from Russian institutions; independent replication in Western research settings remains limited.
- Semax has a short plasma half-life in its unmodified form; the Pro-Gly-Pro extension in the synthetic version improves stability but researchers should account for this in protocol design.
- Check which documentation is available for the specific product and batch. Where a Certificate of Analysis (COA) is available, review its batch identifier, methods and reported results; do not assume that a purity result also confirms identity or suitability for a particular study.
Disclaimer: All products sold by Alpha Peptides are intended strictly for in vitro research and laboratory use only. They are not approved for human or veterinary use, and this article does not constitute medical advice.