What it is
A synthetic heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) derived from a fragment of adrenocorticotropic hormone (ACTH 4-10), developed by the Russian Academy of Medical Sciences in the 1980s.
How it works
Modulates BDNF and nerve growth factor (NGF) expression, enhances monoaminergic neurotransmission (dopamine, serotonin) in cortical regions, and has been shown in preclinical work to potentiate the action of endogenous regulatory peptides — together giving it a nootropic + neuroprotective profile.
Where it's used
Approved in Russia for ischemic stroke, transient ischemic attack, and cognitive disorders; not approved elsewhere. ROUTES: most commonly intranasal (typically 100-600 mcg per dose, 1-3x/day depending on formulation strength). Subcutaneous injection has been used in clinical studies. The N-acetyl variant (NA-Semax / Semax NA) is a longer-acting analog also dosed intranasally.
Regulatory status
Not FDA-approved; research compound in the US.
Reconstitution
Lyophilized vials reconstitute with bacteriostatic water (typically 2-3 mL per 5 mg vial). For nasal use, transfer the reconstituted solution into a spray bottle or dose with a micropipette.
Tracking it
As a nasal spray, Semax is easy to lose count of — logging each administration keeps the daily total honest.
Source
Russian State Pharmacopoeia; published preclinical and clinical literature
Last reviewed 2026-06-11