Semax is a synthetic seven-amino-acid peptide built from the ACTH(4-7) fragment Met-Glu-His-Phe with a Pro-Gly-Pro tail added to the C-terminus. That tail makes it far more resistant to peptidases than the parent ACTH fragments, and it is studied mainly for its effects on brain-derived neurotrophic factor (BDNF) and on the brain’s response to ischaemia.
Semax was developed by Russian researchers, including the Institute of Molecular Genetics group in Moscow, as a stabilised analogue of the ACTH(4-10) sequence (Ashmarin et al., Zhurnal Vysshei Nervnoi Deyatelnosti, 1997), and it is registered in Russia as aqueous nasal drops. This reference section gathers what the sequence means for storage, mixing and bench work with the Semax 10 mg research vial and the ready-mixed Semax Nasal Spray.
Molecular reference
| Name | Semax |
|---|---|
| Also known as | ACTH(4-7)-Pro-Gly-Pro; Pro-Gly-Pro-ACTH(4-7); MEHFPGP |
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro |
| Residues | 7 |
| Molecular formula | C37H51N9O10S |
| Molecular weight | 813.9 g/mol |
| CAS number | 80714-61-0 |
The single sulphur atom in the formula belongs to the N-terminal methionine, which is the residue that matters most for stability. The molecule has one acidic side chain (Glu), one histidine and no lysine or arginine, so it carries a small net negative charge at neutral pH. PubChem lists a computed XLogP of minus 2.8 (PubChem CID 9811102), which places it firmly on the water-loving side for a peptide.
What it is studied for
The best-known finding is the link to BDNF. In an animal study, a single intranasal application of Semax raised hippocampal BDNF protein about 1.4-fold, increased activation of its receptor TrkB about 1.6-fold, and lifted BDNF exon III messenger RNA about threefold, alongside better performance in a conditioned avoidance task (Dolotov et al., Brain Research, 2006). An earlier study from the same group showed Semax binds specifically to basal forebrain membranes in animal tissue and raises BDNF protein there (Dolotov et al., Journal of Neurochemistry, 2006).
The second major line of work is cerebral ischaemia. A genome-wide transcription study in an animal model of middle cerebral artery occlusion found that Semax shifted the expression of immune and vascular genes, including chemokine and immunoglobulin genes and genes tied to endothelial development, which the authors propose as a key part of its neuroprotective profile (Medvedeva et al., BMC Genomics, 2014). In 110 patients recovering from ischaemic stroke, the Semax subgroups showed higher plasma BDNF throughout the observation period and better Barthel index recovery (Gusev et al., Zhurnal Nevrologii i Psikhiatrii, 2018). Our summary of that work is in Semax and stroke recovery, and a broader overview is in what the Semax research covers.
Intranasal delivery has been studied directly with tritium-labelled Semax: in an animal study, labelled material reached the brain within two minutes, and about 80% of the brain radioactivity at that point was still intact Semax (Shevchenko et al., Bioorganicheskaya Khimiya, 2006). The route comparison is in intranasal vs subcutaneous research routes, and the closest companion compound is covered in Semax vs Selank.
The rest of this reference
Stability: why methionine oxidation is the main chemical route for this sequence, why the Pro-Gly-Pro tail protects it from enzymes, and how temperature, light and freezing affect the powder and the mixed solution.
Solubility: why Semax dissolves readily in bacteriostatic water, the concentration range that stays clear, and what cloudiness usually points to.
Handling: bench practice for a methionine-containing heptapeptide, from warming the vial before opening to labelling and aseptic access, with a list of common mistakes.
On arrival: what to look at when the parcel is opened, what a good lyophilised cake looks like, and where each item goes first.
FAQ: short answers to the questions researchers ask most about storing, mixing and keeping Semax.
Storage windows are set out in how long Semax lasts, and water volumes and concentrations for the 10 mg vial are in the Semax reconstitution guide. The pages in this section agree with both and link back to them rather than repeating the tables.
Where to find it
Vistara Labs supplies Semax 10 mg as a lyophilised vial, the Semax Nasal Spray as a ready-mixed metered spray, and the Selank + Semax Nasal Spray with both peptides in one bottle. Orders ship within Canada by Canada Post Xpresspost. The Semax buying guide for Canada compares the formats, and certificates for the catalogue are on the lab reports page.
All products supplied by Vistara Labs are intended for laboratory research use only. They are not drugs, are not approved for human or veterinary use, and are not intended to diagnose, treat, cure or prevent any condition. Nothing on this page constitutes medical advice or guidance for use in humans.
