Semax

Semax comes out of Russian peptide research, where it has been studied for more than three decades. The molecule is a chain of seven amino acids (Met-Glu-His-Phe-Pro-Gly-Pro) built on positions 4 to 10 of the hormone ACTH. A Pro-Gly-Pro tail at the C-terminus slows enzymatic breakdown and gives the peptide a much longer duration of action than the bare fragment. Its origin is the Moscow Institute of Molecular Genetics (Russian Academy of Sciences).

What the literature reports:

• In animal models, a single nasal dose triples BDNF mRNA in the hippocampus and raises BDNF protein 1.4-fold; the matching receptor TrkB is upregulated at the same time, in the hippocampus as well as in the cortex.
• Preclinical and clinical work spanning more than thirty years describes effects on learning, memory, attention and neuroprotective signalling.
• Downstream, the peptide shifts activity in serotonergic, dopaminergic and cholinergic systems.
• Papers from 2025 report a marked drop in amyloid plaques in Alzheimer models.

Semax is approved in Russia and listed there as a vital essential medicine; since 2011 it has been used for stroke, for cognitive disorders and for other neurological conditions. Because of the molecule's size and polarity, studies almost always deliver it across the nasal mucosa. One point matters for interpretation: most publications come from Russian groups, and independent confirmation from elsewhere is scarce.

Across three decades of Russian studies, Semax is described as low in side effects. What you should still keep in mind:

• Nasal mucosa: burning, dryness or irritation are the observations named most often, since studies give the peptide nasally.
• Activation: because the peptide touches stimulating and cognitive pathways, occasional restlessness, pressure in the head or a shifted sleep rhythm are mentioned, in reports mostly when dosing happened late in the day.
• Origin of the data: nearly all studies come from Russia, which makes an independent check of the safety profile difficult.
• Long-term observations outside the Russian research landscape are scarce.

This summary is no substitute for medical advice.

• Semax regulates BDNF and trkB expression in the rat hippocampus - animal study measuring more BDNF and more TrkB receptor in the rat hippocampus after Semax.
• Semax binds specifically and increases BDNF protein in rat basal forebrain - shows specific binding of the peptide and a rise in BDNF protein in the basal forebrain.
• The peptide semax affects the expression of genes related to the immune and vascular systems in rat brain focal ischemia - transcriptome analysis in an ischemia model: Semax shifts the activity of immune and vascular genes.