NA-Semax: ACTH(4-10) Heptapeptide Analog Research Overview

NA-Semax is derived from the heptapeptide fragment of adrenocorticotropic hormone (ACTH) consisting of residues 4-10 (Met-Glu-His-Phe-Pro-Gly-Pro), extended at the C-terminus to enhance enzymatic stability. The parent fragment was identified through studies of which ACTH residues retain the neurotropic and behavioral activities separate from the hormone's classical corticotropic activity at the adrenal cortex.^[1]

NA-Semax was developed at the Russian Institute of Molecular Genetics in the 1980s as part of the same research program that produced NA-Selank. The 'NA' prefix indicates the Russian original designation. The compound has been studied extensively in the Russian neuropharmacology literature as a tool for nootropic-related research.^[2]

NA-Semax is studied as a research reference compound. It has not been approved by the FDA for any human therapeutic or medical purpose.

NA-Semax structural features:

• Sequence: Met-Glu-His-Phe-Pro-Gly-Pro-NH₂ (7 residues with C-terminal amidation)

• Parent: ACTH(4-10) fragment with extension

• Length: 7 amino acids

• Molecular formula: approximately C₃₇H₅₁N₉O₁₀S

• Molecular weight: approximately 813 Da

The C-terminal Pro-Gly-Pro extension provides enzymatic stability through proline-induced backbone rigidity and the natural resistance of Pro-Pro motifs to proteolytic cleavage. C-terminal amidation further reduces carboxypeptidase susceptibility. The N-terminal methionine is preserved from native ACTH and is the locus of some research focus due to methionine oxidation chemistry under storage.^[2]

NA-Semax's research-characterized mechanisms span several neuropeptide signaling pathways.

Cell culture and rodent brain tissue studies have examined NA-Semax effects on brain-derived neurotrophic factor (BDNF) expression. BDNF is a key neurotrophic factor with roles in neuronal survival, synaptic plasticity, and learning-related signaling.^[3]

Because NA-Semax is derived from ACTH (which engages melanocortin receptors), the peptide has been examined for melanocortin receptor pharmacology. The specific selectivity profile across the five MC receptor subtypes differs from full ACTH due to the truncation and modifications.^[4]

Russian research has examined NA-Semax effects on monoamine systems in rodent brain, with attention to dopamine and serotonin pathway markers in regions involved in cognition and stress response.^[5]

NA-Semax research is concentrated in the Russian neuropharmacology literature.

Rodent learning and memory assays (Morris water maze, novel object recognition, passive avoidance) have been used to characterize NA-Semax in preclinical settings.^[5]

Animal models of ischemic injury have included NA-Semax in experimental arms examining neurological recovery endpoints. These studies are conducted in standard rodent stroke models.^[6]

NA-Semax is used as a comparator in studies of NA-Selank and other Russian-class neuropeptides, helping to dissect distinct vs overlapping signaling contributions across the family.^[2]

NA-Semax requires standard peptide handling. The N-terminal methionine should be protected from oxidative conditions during storage.

Lyophilized material is stored at minus 20 degrees Celsius for long-term preservation. Brief refrigerated storage is acceptable for active material.

Bacteriostatic water is the standard reconstitution solvent.

HPLC for purity, mass spectrometry for identity confirmation, and verification that the N-terminal methionine is not oxidized in the active batch. Each batch of Instant Peptides NA-Semax ships with a full Certificate of Analysis.

Instant Peptides supplies NA-Semax as a synthetic lyophilized reference compound. Material is supplied to qualified research professionals. Not for human or animal consumption.

View the product page for current pricing and the Certificate of Analysis for the active batch.