Semax

What is Semax?

Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro (MEHFPGP), molecular weight approximately 813.9 g/mol. Structurally it joins the Met-Glu-His-Phe core of the ACTH(4-10) fragment to a C-terminal Pro-Gly-Pro extension, a deliberate design choice made to protect the fragment from rapid aminopeptidase and carboxypeptidase degradation, which is what separates it from the short-lived native sequence. It was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences and is registered as a nasal preparation in the Russian Federation, but it holds no marketing authorisation from the MHRA, EMA or FDA. The mechanistic literature centres on upregulation of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF) and their receptors, principally trkB. An honest reading of the evidence base: the overwhelming majority of the published work, including the clinical studies behind the Russian registration, originates from Russian groups, and independent replication in Western randomised controlled trials has not been published. Supplied as lyophilised powder for in-vitro research use only.

Semax vs Adamax and Other ACTH-Derived Analogues

Semax belongs to a small family of regulatory peptides built on one design strategy: take a short biologically active fragment of a native peptide and stabilise it with a C-terminal Pro-Gly-Pro. Semax is the founding member, applying that strategy to the ACTH(4-10) message region via its Met-Glu-His-Phe core. Adamax is a later analogue from the same design lineage, reported in the Russian preclinical literature in the same neurotrophin-expression and neuroprotection models; peer-reviewed characterisation outside that literature remains minimal, so findings for the two should not be treated as interchangeable. The more instructive comparator is Selank, which applies the identical Pro-Gly-Pro stabilisation to a completely different parent, the immunoglobulin-derived tetrapeptide tuftsin. The pairing explains why the two are so often studied side by side: same stabilisation chemistry, different message fragment, largely non-overlapping endpoints, with Semax dominant in neurotrophin and cerebral ischaemia models and Selank in anxiety, GABAergic and immune models. Even the bare Pro-Gly-Pro tripeptide has its own literature as a control, since the stabilising tail is not biologically inert.

Semax Research Applications

Semax is studied across preclinical neuroscience and cognitive pharmacology. The most cited strand is neurotrophin work: upregulation of BDNF protein and trkB signalling in rat hippocampus, and mapping of neurotrophin gene expression across brain regions following administration. A second strand is cerebral ischaemia, where Semax has been examined in rat middle cerebral artery occlusion models and in transcriptome-wide expression studies of the ischaemic brain, with reported effects on neurotrophin, vascular and immune-response gene clusters. Further reported endpoints include modulation of dopaminergic and serotonergic transmission, inhibition of enkephalin-degrading enzymes, and attention and memory performance in rodent behavioural tasks. Researchers should note that effect sizes and endpoints vary considerably between laboratories and that essentially all primary data come from one national research tradition, which makes independent replication a genuinely useful experimental contribution.

Reconstitution Guide

Allow vials to reach room temperature, then sterilise the rubber stopper of both the peptide vial and the bacteriostatic water vial with an alcohol swab. Slowly draw your bacteriostatic water into a sterile insulin syringe, then inject it gently down the inner glass wall of the peptide vial, never directly onto the lyophilised powder. Once added, gently swirl the vial in a slow circular motion until fully dissolved. Never shake or vortex. The N-terminal methionine is the oxidation-sensitive residue in this sequence, so keep stopper-open time and headspace air to a minimum and reconstitute away from strong light. The solution should be clear and colourless. Label the vial with the reconstitution date and refrigerate immediately.

See our full peptide reconstitution guide and reconstitution calculator for step-by-step protocol.

Storage Instructions

Lyophilised vials should be stored at -20°C, protected from light and moisture, and remain stable for up to 24 months. Once reconstituted with bacteriostatic water, store the solution at 2-8°C and use within approximately 4 weeks. For longer storage, prepare single-use aliquots at -20°C. Methionine oxidation is the degradation route to watch in this sequence, and it is accelerated by dissolved oxygen, light and repeated freeze-thaw cycling, so minimise headspace, keep aliquots single-use, and handle under sterile laboratory conditions throughout.

Frequently Asked Questions

Research References

• Semax, an ACTH(4-10) analogue, regulates BDNF and trkB expression (Neurosci Lett, 2008)
• Neuroprotective effect of Semax in cerebral ischaemia models (Bull Exp Biol Med, 2003)
• Neurotrophin gene expression in rat brain under the action of Semax (2007)

Related Research Compounds

• → Selank 10mg
• → DSIP 5mg
• → Bacteriostatic Water 10ml