Semax
Semax (synthetic ACTH 4-10 analogue)
A synthetic heptapeptide approved in Russia for stroke and cognitive disorders, studied for BDNF-driven neuroprotection.
Overview
Semax is derived from an ACTH fragment with added residues for stability. It is approved in Russia and Ukraine for stroke recovery, traumatic brain injury, and cognitive disorders. Research points to increased BDNF and NGF expression and enhanced neuroplasticity. It is not approved by the FDA. Regulatory update, September 2026: the FDA removed this peptide from Category 2 of the 503A bulk-drug list in April 2026, and on July 23 to 24, 2026 the Pharmacy Compounding Advisory Committee voted to recommend it for compounding against the advice of FDA scientists, who found no adequate human data. The vote is advisory; nothing changes until FDA rulemaking, and vials sold 'for research' remain unapproved drugs.
Mechanism of action
Increases BDNF and NGF expression and modulates the melanocortin and dopaminergic systems, supporting neuroprotection and synaptic plasticity.
Key studies & citations
- Animal2006
Semax, an analog of ACTH(4-10) with cognitive effects, regulates BDNF and trkB expression in the rat hippocampus
A single 50 mcg/kg dose raised hippocampal BDNF protein 1.4-fold, trkB phosphorylation 1.6-fold and BDNF mRNA 3-fold in rats, alongside improved conditioned avoidance learning.
Brain Research - Animal2007
Neurotrophin gene expression in rat brain under the action of Semax, an analogue of ACTH 4-10
Follow-up work mapping Semax-driven changes in BDNF and NGF gene expression across rat brain regions.
Neuroscience Letters - Human2018
The efficacy of semax in the treatment of patients at different stages of ischemic stroke
Russian clinical study of 110 post-stroke patients: Semax courses raised plasma BDNF and were associated with faster Barthel index improvement; not a blinded placebo-controlled trial.
Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova - Review2026
July 23-24, 2026: Meeting of the Pharmacy Compounding Advisory Committee
Official FDA meeting record: Semax (free base and acetate) was discussed on July 24, 2026 for possible inclusion on the 503A bulk drug substances list.
U.S. Food and Drug Administration
Frequently asked questions
Is Semax approved anywhere?
Yes, in Russia and Ukraine for certain neurological and cognitive indications. It is not approved by the FDA or EMA.