Semax is a synthetic heptapeptide composed of seven amino acids with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It was originally developed at the Institute of Molecular Genetics as a modified analogue of a fragment of adrenocorticotropic hormone (ACTH). In research settings, Semax is studied as a neuropeptide with potential nootropic, neuroprotective, and neuromodulatory properties, including effects on brain-derived neurotrophic factor (BDNF) expression, neurotransmitter systems (such as dopaminergic and serotonergic pathways), and mechanisms involved in stress response, learning, and memory.

Semax is typically supplied as a white lyophilized (freeze-dried) powder for laboratory research, which must be reconstituted with an appropriate sterile solvent before use. Its chemical composition is described by the molecular formula C₃₇H₅₁N₉O₁₀S and a molecular weight of approximately 813.93 Da.

For storage, Semax should be kept in a cool, dry environment. Lyophilized Semax is commonly stored at −20 °C or lower to maintain long-term stability. After reconstitution, peptide solutions are generally used promptly or stored under refrigeration as recommended, while avoiding repeated freeze/thaw cycles to preserve peptide integrity.

A Certificate of Analysis (COA) is typically provided by vendors and includes the batch or lot number, verification of compound identity, purity (commonly ≥97–99% as determined by analytical techniques such as HPLC), confirmation of molecular weight, physical description, and recommended storage conditions.

Semax is intended strictly for research purposes only and is not approved by the U.S. Food and Drug Administration for clinical use or human consumption. It is commonly used in preclinical research to investigate peptide-mediated modulation of neural signaling, neurotrophic activity, cognitive processes, and stress-related pathways.