NA Semax Amidate

The starting point is Semax, the Russian heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. In the variant listed here, the N-terminus carries an acetyl group and the C-terminus an amide. The purpose of these two protecting groups is pharmacokinetic: they delay enzymatic breakdown and noticeably extend the half-life compared with unmodified Semax.

What is not supposed to change is the pharmacology. For the parent peptide, the literature describes:

• a rise in BDNF in the hippocampus, in the 2006 rat study together with stronger phosphorylation of the receptor TrkB
• neuroprotective effects in models of cerebral ischemia, traced at the transcriptome and at the proteome level
• a shift in cholinergic and dopaminergic signalling that is linked to cognitive gains

Semax itself is a product of the Moscow Institute of Molecular Genetics; Russia has approved it for rehabilitation after stroke and for cognitive disorders. Studies deliver the peptide nasally; the stabilized form can also be given under the skin. Two more recent papers, from 2020 and 2021, confirmed the protective effect in the rat ischemia-reperfusion model at the level of gene expression and of protein patterns in the brain.

The data situation deserves an honest framing: robust head-to-head comparisons between the N-acetyl amidate form and the original barely exist. The longer duration of action is chemically plausible and explained by the protecting groups, but the actual evidence of effect rests on decades of Semax research, most of it from Russian groups.

Tolerability is inherited from Semax, which decades of Russian research rate as low in side effects. Whether the two protecting groups change anything about that has not been examined on its own, so the points below refer to the parent peptide. What you should keep in mind:

• Nasal dosing: burning, dryness or an irritated mucosa is the most common observation.
• Stimulation: as a cognitively activating peptide it can bring restlessness, pressure in the head or a shifted sleep pattern, in reports mostly when dosing happened late in the day.
• Subcutaneous dosing: isolated reports of redness or a feeling of pressure around the injection site.
• Origin of the evidence: the bulk of the Semax literature comes from Russia, and independent replications from elsewhere are rare.
• Missing comparisons: for the acetylated and amidated form there are neither clean comparative studies against the original nor robust long-term human data.

The points above describe what is known about Semax; for the stabilized form, observations of its own are lacking.

This summary is no substitute for medical advice.

• Semax, an analog of ACTH(4-10) with cognitive effects, regulates BDNF and trkB expression in the rat hippocampus - rat study: nasally given Semax lifts BDNF protein and strengthens TrkB phosphorylation in the hippocampus.
• Novel Insights into the Protective Properties of ACTH(4-7)PGP (Semax) Peptide at the Transcriptome Level Following Cerebral Ischaemia-Reperfusion in Rats - gene expression analysis tracing the protective effect after ischemia and reperfusion in the rat brain.
• Brain Protein Expression Profile Confirms the Protective Effect of the ACTH(4-7)PGP Peptide (Semax) in a Rat Model of Cerebral Ischemia-Reperfusion - proteome data confirming the same protective effect at the level of proteins.