Despite descending from a hormone fragment, Semax has no meaningful hormonal (ACTH-like) activity of its own — the melanocortin backbone was retained but the corticotropic function was engineered out. Instead, it's characterized as neurotrophic: it upregulates BDNF and TrkB signaling and influences dopaminergic pathways, effects studied for cognitive support, focus, and neuroprotection after ischemic injury.

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• Russia/Ukraine: registered prescription drug for ischemic stroke, encephalopathy, optic nerve atrophy
• US: available only through 503A compounding pharmacies by prescription, or sold as an unregulated "research chemical"
• Nootropic community: informal off-label use for focus and cognitive performance

• One of the few peptides in this atlas with decades of real clinical use — but almost entirely outside the US, under a different regulatory framework than the FDA's
• As of April 2026, removed from the FDA's restrictive Category 2 compounding list and scheduled for a Pharmacy Compounding Advisory Committee (PCAC) review in July 2026 — a step toward, not equivalent to, legal compounding status
• Not currently on the WADA Prohibited List, unlike some other peptides in this collection (e.g. MOTS-c)