A synthetic analog of an ACTH fragment, registered as a nootropic in Russia and studied for neuroprotective and cognitive effects, mostly in animal models.
Reviewed for accuracy · Last reviewed July 7, 2026Semax is a synthetic heptapeptide based on the N-terminal ACTH(4-10) fragment, developed in Russia and registered there as a nootropic and neuroprotective drug, with uses that include acute ischemic stroke and cognitive recovery. In the West it has no FDA or EMA approval and is treated as a research compound. It is typically given intranasally.
Its proposed mechanism centers on neurotrophic signaling: in rat studies, Semax raised brain-derived neurotrophic factor (BDNF) and activated neurotrophin-related gene expression, and genome-wide analyses point to effects on immune and vascular genes after ischemia. The important caveat is that this evidence is overwhelmingly preclinical and largely Russian, so its cognitive effects in healthy people are not well established.
Semax is dosed intranasally by the specific Russian product where it is registered, so there is no single Western dosing guideline. Community nootropic figures are extrapolation rather than validated regimens.
Read the full Semax dosage guide →Western safety data is limited. As an intranasal peptide the most commonly mentioned effect is mild nasal irritation, and the honest caveat is that its adverse-effect profile is not well characterized outside its Russian registration.
Read the full Semax side effects guide →Keep the unmixed peptide refrigerated and away from light, and store any reconstituted intranasal solution refrigerated. See the full storage & safety guide for handling and disposal basics.
This page is an independent educational reference and is not medical advice, and does not indicate any approval status for any use. Talk to a doctor before starting any compound.