Semax

Built from a fragment of the stress hormone ACTH with a Pro-Gly-Pro tail added for stability. Russia registered it as prescription nasal drops for stroke, cognitive problems and optic nerve disease, and lists it as an essential medicine.

FDA calls the mechanism poorly understood. Proposed pathways, almost all from rodents, include a rapid rise in hippocampal BDNF and its receptor, activation of serotonin and dopamine systems, action at melanocortin MC4/MC5 receptors, and inhibition of enkephalin-degrading enzymes. In rat stroke models it suppressed inflammatory genes and pushed ischemia-disrupted gene expression back toward normal.

FDA's 2026 review found no adequate controlled trials it could assess for stroke, migraine or facial pain, and excluded Russian-language studies without translation. Available human reports are small and largely uncontrolled; across all studies, a few hundred adults and children have received it, with adverse events rarely reported. In rat stroke models it reduced infarct size. Human pharmacokinetics, toxicology and abuse potential are unstudied.

The Russian label lists only mild nasal irritation with prolonged use, and trials rarely reported adverse events. FDA flagged possible immunogenicity, bleeding risk based on animal antithrombotic effects, a possible abuse signal, and one hospitalization for eye pain after drops bought online.

Not FDA-approved and not a component of any approved drug. In July 2026 FDA's Pharmacy Compounding Advisory Committee voted 8–5–1 to recommend adding it to the 503A bulks list; the vote is advisory, FDA had issued no final rule as of October 2026, and it concerns pharmacy compounding for patients, not research-grade material. Approved in Russia as nasal drops. Not named on the 2026 WADA list; whether the corticotropin category applies is unclear.