Semax — wholesale 10-vial kits

Research context

Semax is a synthetic heptapeptide, Met-Glu-His-Phe-Pro-Gly-Pro, developed in Russia from structure–activity work on the adrenocorticotropic hormone fragment ACTH(4–10). It keeps the ACTH(4–7) core, Met-Glu-His-Phe, which carries the fragment's neurotropic activity without the corticotropic activity of the full hormone, and replaces the remaining residues with Pro-Gly-Pro. The same stabilizing motif appears in Selank.

The design solves a stability problem. ACTH(4–10) is cleaved quickly at its C-terminal end in biological matrices; the Pro-Gly-Pro tail places proline on either side of a glycine, and proline-flanked bonds resist most exopeptidases, so the heptapeptide survives longer in tissue and plasma preparations than the parent fragment. The Pro-Gly-Pro tripeptide released on degradation is itself studied as an active fragment, and work in Cellular and Molecular Neurobiology compared Semax and Pro-Gly-Pro directly on neurotrophin and receptor gene transcription after experimental cerebral ischemia in rats. The sequence also contains histidine and methionine, which sets its metal-binding and oxidation behaviour.

Reported molecular pharmacology centres on transcription rather than on a single receptor. Rodent studies describe increased transcription of brain-derived neurotrophic factor and nerve growth factor and of their receptor genes after ischemic challenge, along with changes in monoamine-pathway transcripts; a 2021 study in Neuropeptides examined behavioural and neurochemical endpoints in rats after early-life fluvoxamine exposure. Because the core is an ACTH fragment, interaction with melanocortin receptors is a live question in the literature, but the fragment lacks the His-Phe-Arg-Trp arrangement that drives high-affinity melanocortin agonism, and the receptor profile is not settled.

As a research tool Semax is used as a stimulus in neurotrophin gene-expression and protein readouts (qRT-PCR, Western blot, ELISA) in rodent brain tissue and neuronal cultures, as a comparator in oxygen-glucose-deprivation and rodent ischemia models, and as an analytical reference standard. Methionine and histidine in the same short sequence also make it a useful test peptide when developing methods that must resolve oxidation products and metal adducts, since both species appear readily and shift the observed mass in predictable increments. It is also a documented forensic analyte: the 2020 Drug Testing and Analysis survey of seized preparations characterized Semax by LC-MS, so a defined reference lot is useful for method validation and confirmation.

Regulatory position, stated factually: Semax is registered as a medicine in Russia and is not FDA-approved in the United States. Semax-related bulk substances were discussed at the Pharmacy Compounding Advisory Committee meeting of July 23–24, 2026, and the HHS interim enforcement-discretion notice published in the Federal Register on October 30, 2026 addresses certain peptide bulk substances used in 503A compounding while the 503A bulks list is developed through rulemaking. That notice is directed at state-licensed pharmacies and physicians, is not an approval, and does not change the research-use status of the material sold here.

Semax contains methionine, which can oxidize to the sulfoxide (+16 Da) in solution. Prepare fresh aliquots, and check the LC-MS identity line on the lot COA if you see an unexpected mass.

Research areas

• BDNF and NGF gene expression
• rodent cerebral ischemia models
• ACTH fragment structure–activity
• melanocortin receptor pharmacology
• methionine oxidation in peptide analytics
• Pro-Gly-Pro fragment pharmacology
• rodent neurotrophin transcription assays

U.S. regulatory status of the compound (as an active ingredient): Not FDA-approved; approved in Russia. The material sold here is a research reference chemical, not a drug product.

Handling and storage

• Store lyophilized vials at −20 °C, sealed, protected from light and moisture.
• Let the vial equilibrate to room temperature before opening to limit condensation.
• Reconstitute in an appropriate sterile buffer or solvent according to your laboratory SOP.
• Methionine is oxidation-sensitive: minimize air exposure, aliquot promptly and avoid repeated freeze–thaw.