Semax
Russian nootropic; intranasal neuroprotective peptide fragment of ACTH.
- Primary research area
- Cognitive / neuroprotection
- Last updated
- Apr 21, 2026
- Reviewed by
- Peptide Examiner editorial team
What it is
Semax (N-acetyl Semax Amidate, or simpler forms) is a synthetic heptapeptide developed in Russia in the 1980s-90s at the Institute of Molecular Genetics of the Russian Academy of Sciences. It is a modified fragment of adrenocorticotropic hormone (ACTH 4-10). Approved in Russia for cerebrovascular indications, cognitive recovery, and optic nerve atrophy. Not FDA approved. Typically administered as an intranasal spray.
Mechanism of action
Semax is thought to act through multiple central-nervous-system pathways, including upregulation of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF), modulation of monoamine systems (dopamine, serotonin), and effects on melanocortin receptors. Animal models show neuroprotective effects in ischemic and toxic insult contexts. The intranasal delivery route exploits direct nose-to-brain transport, bypassing first-pass metabolism.
Research history
Russian clinical literature supports use in cerebrovascular disease, post-stroke recovery, cognitive impairment, and optic-nerve disease. Published research is largely in Russian-language journals with limited independent Western replication. Animal research is more broadly available and consistently shows BDNF/NGF effects and neuroprotection in stress and injury models.
Current trial status
Approved and clinically used in Russia. US: no FDA-track development. Research-use-only sales.
Regulatory status
Not FDA approved. FDA Category 2 (September 2023). Feb 2026 HHS proposed removal. Russian pharmacy approved for specific cerebrovascular and cognitive indications. Full regulatory timeline →
Controversies and open questions
US nootropic marketing of Semax is substantially broader than its Russian clinical indications. The evidence base for general cognitive enhancement in healthy adults is far thinner than biohacker claims suggest. Purity variability across research-peptide sources is also a concern — Russian approved products meet specific pharmacopoeia standards that research-peptide vendors may or may not replicate.
Further reading
Frequently asked
What is Semax approved for?
In Russia, Semax is approved for cerebrovascular disorders, post-stroke cognitive recovery, and optic nerve atrophy. Not FDA approved in the US.
Is it useful for general cognitive enhancement?
The marketing claims for general nootropic use outrun the Russian approved indications. BDNF/NGF modulation in animal models and small Russian clinical studies are reasonable support for neuroprotective effects in specific disease contexts, not broad cognitive enhancement in healthy adults.
Why intranasal?
Intranasal delivery exploits direct nose-to-brain transport, bypassing first-pass metabolism and delivering peptide to the CNS more effectively than subcutaneous injection would for a short peptide.
Is the 'Semax' I can buy quality-controlled?
US research-peptide vendor products aren't held to Russian pharmacopoeia standards. Purity and identity vary by source. Russian pharmacy-approved Semax is a different product from what most US biohackers are buying.