Semax is a synthetic heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) derived from the N-terminal fragment of adrenocorticotropic hormone (ACTH 4-10), developed at the Institute of Molecular Genetics of the Russian Academy of Sciences. Unlike its parent molecule ACTH, Semax has no hormonal (corticosteroid-stimulating) activity — the modifications eliminate adrenal receptor binding while preserving and enhancing the nootropic and neuroprotective properties of the ACTH fragment. Semax has been approved as a pharmaceutical nootropic in Russia since 2001, giving it an unusually robust clinical history for a research peptide.

Semax's primary mechanism of action involves the upregulation of brain-derived neurotrophic factor (BDNF) and its receptor TrkB in the hippocampus and prefrontal cortex. BDNF is the master regulator of neuroplasticity — the brain's ability to form new synaptic connections, strengthen existing ones, and adapt to new information. By increasing BDNF expression, Semax enhances long-term potentiation (LTP), the electrophysiological basis of learning and memory. Additionally, Semax modulates serotonergic and dopaminergic neurotransmission, enhances the expression of nerve growth factor (NGF) and glial cell line-derived neurotrophic factor (GDNF), and inhibits the enzymatic degradation of endogenous enkephalins, providing anxiolytic effects without sedation or cognitive impairment.

The research literature on Semax documents improvements in attention, working memory, verbal fluency, and cognitive processing speed in both healthy subjects and those with cognitive impairment. Studies demonstrate neuroprotective effects in models of ischemic stroke (reduced infarct volume, improved neurological outcomes), traumatic brain injury, and neurodegenerative conditions. The anxiolytic effects are particularly notable: Semax reduces anxiety-related behaviors without the sedation, cognitive dulling, or dependence risk associated with benzodiazepines or similar compounds.

Semax is suited for researchers investigating cognitive enhancement, neuroprotection, BDNF-mediated neuroplasticity, anxiety modulation, and post-injury neural recovery. It is the premier nootropic peptide for researchers who want cognitive benefits without CNS depression.

Reconstitute with 1ml bacteriostatic water (yielding 5mg/ml). Semax is most commonly administered intranasally — the nasal mucosa provides rapid access to the CNS, bypassing the blood-brain barrier. Typical intranasal dosing is 200-600mcg per dose, 1-3 times daily. It can also be administered subcutaneously at similar doses. Semax has a relatively short effective half-life of 1-2 hours when delivered intranasally, but its neurotrophin-upregulating effects persist for hours beyond clearance. Store reconstituted solution at 2-8C. No known tolerance, dependence, or withdrawal effects have been documented.