SEM
Synthetic peptide derived from ACTH, developed in Russia and approved there for stroke and cognitive disorders. In a clinical study of 110 post-stroke patients, semax raised plasma BDNF and accelerated functional recovery.
Regulatory status (as of Sept 2026)
Not FDA-approved. Removed from 503A Category 2 on April 15, 2026. PCAC recommended for the 503A Bulks List (advisory); awaiting FDA rulemaking; not lawfully compoundable under 503A as of Sept 17, 2026. PCAC vote: 8–5–1 (yes–no–abstain), July 24, 2026.
See the FDA peptide regulatory tracker · Read our July 27, 2026 dispatch on the FDA PCAC peptide vote2 studies referenced · Last reviewed Oct 1, 2026 · Reviewed by The Peptide Dispatch Editorial Team · How we research & label content
Semax is approved as a medicine in some countries outside the US, but not by the FDA. Synthetic peptide derived from ACTH, developed in Russia and approved there for stroke and cognitive disorders.
| Half-life | Not established in published research |
|---|---|
| How it's given in studies | Intranasal |
| Research stage | Approved outside US |
| Dosing | Published research: 6000 micrograms/day intranasally for 10 days, repeated after a 20-day interval, in a clinical study of 110… details6000 micrograms/day intranasally for 10 days, repeated after a 20-day interval, in a clinical study of 110 post-ischaemic-stroke patients; rodent neuroprotection work uses the transient middle cerebral artery occlusion model in ratsCommunity-reportedCommunity-reported: 200–600 mcg, intranasal |
Published-research dosing is what was given in the cited studies (species and units as reported). Community-reported dosing is what users describe, not from clinical studies. Neither is a recommendation. Not medical advice.
Where each point comes from: Clinicalhuman trials and FDA labels Lab / animalrodent, cell and ex vivo studies Community-reporteduser experience and commonly used protocols, not from clinical studies
In plain terms: It is a peptide studied mainly in rats after stroke, where it changed the activity of inflammation- and nerve-related genes. Proposed mechanism, from rodent studies: in a rat ischaemia-reperfusion stroke model, semax suppressed inflammatory gene expression and increased expression of neurotransmission-related genes (Filippenkov 2020). Claims that semax raises brain BDNF or modulates dopamine and serotonin come from rodent work, not human studies; in humans, a clinical study of 110 post-stroke patients reported higher plasma BDNF (Gusev 2018).
How to read this: Each item below is an effect observed in research subjects in the cited studies — think of Dexter, our stand-in research subject. These are findings from the literature, not results you should expect, and not medical advice.
Community-reportedUsers have reported doses of 200–600 mcg (intranasal). This is not a recommendation.
Side effects reported in studies are listed separately below.
Community reports are anecdotal, vary widely in product quality and purity, and are not medical advice. Talk to a licensed provider.
N-acetyl Semax is marketed as a more stable Semax derivative. No published literature was found for the N-acetyl form (or its amidate); all dosing and study data on this page are for Semax. N-acetyl Semax was not part of the July 2026 PCAC vote, and Semax’s status does not transfer to the derivative.
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| Peptide | Half-Life | Route | Research Status |
|---|---|---|---|
| Semax | No published PK data found | Intranasal | Approved outside US |
| Dihexa | Unknown | Oral or intraperitoneal (rodent studies only); no human administration published | Preclinical (animal) |
| FGL (L) | Unknown | Subcutaneous injection | Preclinical (animal) |
| P21 | Unknown | Oral (mice) | Preclinical (animal) |
| PE-22-28 | No published PK data found | Subcutaneous injection, Intranasal | Preclinical (animal) |
Values reflect figures reported in published research. Compare any peptides side-by-side →
This peptide belongs to the Cognitive category. View All Cognitive Peptides
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Dosing, half-life figures, and mechanism descriptions on this page are compiled from peer-reviewed published research, with the species and study type stated where reported. Figures labeled “Dosing used in published research” describe what was given in those studies and do not constitute dosing recommendations for any human use. Each cited paper is listed with DOI and PubMed links in the References section above. Found an error? Contact us.