Semax

Overview

Semax is a synthetic heptapeptide analog of ACTH (adrenocorticotropic hormone), specifically derived from the ACTH(4-10) fragment with a C-terminal Pro-Gly-Pro modification that extends its biological half-life. Developed in Russia, it has been used clinically there for cognitive and neurological applications since the 1990s.

Mechanism of Action

Semax increases brain-derived neurotrophic factor (BDNF) expression in the hippocampus and cortex, supporting neuroplasticity and neuronal survival. It modulates serotonergic and dopaminergic neurotransmission without the adrenal-stimulating effects of full-length ACTH. Additional mechanisms include enhancement of enkephalin processing and modulation of immune-related gene expression in the brain.

Research Context

Clinical use in Russia includes treatment of stroke, cognitive impairment, and optic nerve disease. Research studies have documented improvements in attention, memory consolidation, and cognitive flexibility. Unlike many nootropic compounds, Semax has a substantial clinical evidence base, though primarily from Russian-language publications.

Key Research Areas

Considerations for Researchers

Semax is typically administered intranasally for CNS delivery, though injectable forms are also available. Store lyophilized at -20C. The peptide has good intranasal bioavailability. Several modified versions exist (N-Acetyl Semax, Adamax) with potentially different potency profiles.