Selank and Semax: Russian-Developed Neuropeptides in Cognition Research
Two heptapeptides built on the same Pro-Gly-Pro tail, studied for different reasons.
Semax and Selank are synthetic heptapeptides developed at the Institute of Molecular Genetics of the Russian Academy of Sciences. Both are built from a short natural peptide extended with a Pro-Gly-Pro (PGP) tail that slows breakdown by peptidases.
Semax (Met-Glu-His-Phe-Pro-Gly-Pro) is an analog of the ACTH(4-10) fragment. Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) is an analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide.
Semax research
Semax has been studied mainly in neuroprotection and cognition models. Rodent work reported increased expression of brain-derived neurotrophic factor (BDNF) and its receptor TrkB in the hippocampus, and changes in gene expression in cerebral-ischaemia models. It is not a melanocortin-receptor activator in the way full-length ACTH is.
Selank research
Selank has been studied for anxiolytic-type effects in animal models without the sedation typical of classical anxiolytics. Reported mechanisms include modulation of enkephalin-degrading enzymes, GABAergic transmission, and cytokine expression such as IL-6, reflecting its tuftsin-derived immune-signalling origin.
Limits of the literature
Both peptides have been developed and used as drug products in Russia, so a large share of the literature is in Russian-language journals, and independent replication elsewhere is limited. Protocols should be designed with that in mind.
Reconstitution and handling
QSC supplies Selank and Semax separately in 10-vial packs of 5 mg and 10 mg vials, plus a pre-mixed 10 mg + 10 mg blend. Both are supplied as lyophilized powder; reconstitution at 2-5 mg/mL in sterile water is typical. Refrigerate after reconstitution, and avoid repeated freeze-thaw cycles.
