What is SEMAX?
Semax is a synthetic linear heptapeptide classified within the family of short regulatory peptides used as reference materials in neuroscience research. It is a laboratory-produced analog structurally related to the N-terminal fragment (residues 4–7) of the adrenocorticotropic hormone (ACTH) sequence, extended with a C-terminal Pro-Gly-Pro motif. Its formal amino acid sequence is Met-Glu-His-Phe-Pro-Gly-Pro, comprising seven residues.
The molecule is defined by the molecular formula C37H51N9O10S and a molecular weight of 813.93, and it is cataloged under CAS registry number 80714-61-0. The single sulfur atom reflected in the formula corresponds to the N-terminal methionine residue, while the C-terminal Pro-Gly-Pro tripeptide extension is a structural feature commonly associated with increased resistance to enzymatic degradation relative to the parent ACTH fragment in in-vitro studies. As a defined single-sequence peptide, it is well suited to analytical characterization and use as a comparison standard.
Semax is associated with the neurochemistry and neuropeptide research area, where short ACTH-derived peptides are examined in vitro and in preclinical model systems. This material is offered strictly as a research chemical for in-vitro and laboratory investigation. It is not a drug, dietary supplement, or article intended for human or veterinary use, and no physiological or therapeutic properties are represented here.
Reconstitution & handling
Semax is supplied as a lyophilized (freeze-dried) powder and is typically reconstituted in the laboratory prior to analytical work. Bacteriostatic or sterile water is a common solvent for dissolving short hydrophilic peptides of this type; the presence of the polar glutamate and histidine residues generally supports aqueous solubility. To reconstitute, the diluent is directed slowly down the inner wall of the vial rather than onto the peptide cake, then allowed to dissolve with gentle swirling. Vigorous shaking, vortexing, or sonication is avoided because mechanical shear and foaming can promote aggregation or degradation of peptide chains.
For handling, the solvent is added at ambient temperature and the resulting solution kept cold during use. Because the methionine residue is susceptible to oxidation, exposure to air, heat, and light is minimized during preparation. Working with clean, sterile technique and preparing solutions shortly before an assay helps preserve the integrity of the material. The concentration of the reconstituted stock is determined by the researcher's analytical protocol.
Storage & stability
In its lyophilized form, Semax is best stored sealed and protected from moisture and light, with cold storage extending shelf stability; short-term holding is commonly at refrigerated temperatures (2–8 °C) while long-term storage typically uses a freezer (−20 °C or colder). The dry powder is considerably more stable than solution. Once reconstituted, the peptide is less stable and should be kept refrigerated, protected from light, and used within a short working window; aliquoting before freezing minimizes damaging freeze-thaw cycles. Because the N-terminal methionine can oxidize, limiting air exposure and temperature excursions supports the material's analytical integrity over time.
How it's tested
Identity and purity of Semax are verified analytically and documented on a Certificate of Analysis (COA). Reverse-phase high-performance liquid chromatography (HPLC) is used to quantify chromatographic purity, with this material specified at ≥99% by HPLC. Mass spectrometry (MS) confirms molecular identity by matching the observed mass against the expected molecular weight of 813.93 for the C37H51N9O10S composition, consistent with the intended Met-Glu-His-Phe-Pro-Gly-Pro sequence. Together, HPLC and MS provide orthogonal confirmation of purity and identity, and the COA records the lot-specific results available to researchers for their records.