Semax is a seven-amino-acid peptide developed in Russia from a fragment of ACTH, engineered to keep the neurotropic activity while dropping the hormonal activity. Rodent studies show it raising BDNF and trkB expression in the brain, and it is registered in Russia for stroke, transient ischemic attack and cognitive disorders. It has never been approved in the United States, the European Union or the United Kingdom, and the Russian trial base has not been replicated to Western regulatory standards. An FDA advisory committee recommended it for pharmacy compounding on 24 July 2026, which does not make it legal to compound. Across 43 third-party-tested vials we hold, median purity is 99.93%, but one vial contained 31% less peptide than its label claimed.
Research notes
Semax is what you get when you cut a stress hormone down to the part that acts on neurons and throw away the part that acts on the adrenal glands. It is seven amino acids long, built from residues 4 to 7 of ACTH with a Pro-Gly-Pro tail bolted on to slow enzymatic breakdown. Removing the first three ACTH residues removes the hormonal signalling, so Semax does not drive cortisol release, while the retained fragment keeps the neurotropic activity that the Russian research programme was after.
It has an unusual evidentiary position. Most research peptides have animal data and no clinical use. Semax has decades of Russian clinical use, registration as a medicine in Russia, and essentially no presence in Western regulatory science. That is not the same as strong evidence, and it is not the same as no evidence.
What is Semax and where did it come from?
Semax was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences, with the design work summarised in a 1997 review describing fifteen years of development. The sequence is Met-Glu-His-Phe-Pro-Gly-Pro.
The design logic is worth understanding because it explains the safety framing the Russian literature uses. ACTH is a 39-residue hormone whose job is to tell the adrenal cortex to release cortisol. Its neurotropic effects had been observed separately from its hormonal ones, and the fragment carrying them was narrowed to residues 4 through 10, then 4 through 7. Strip residues 1 to 3 and the corticotropic activity goes with them. Adding Pro-Gly-Pro at the C-terminus slowed degradation enough to make the fragment practically usable.
The standard Russian route is intranasal, chosen because a bare heptapeptide clears quickly from plasma.
What does the Semax research actually show?
The mechanistic work is the most solid part of the file, and it is rodent work.
A 2006 Brain Research paper reported Semax regulating BDNF and trkB expression in the rat hippocampus. A companion 2006 paper in the Journal of Neurochemistry found it binding specifically in rat basal forebrain and raising BDNF protein levels there. A 2009 study in the Journal of Molecular Neuroscience tracked the time course of NGF and BDNF gene expression across hippocampus, frontal cortex and retina under Semax. Those three results converge on the same mechanism: neurotrophin upregulation.
| Claim | Evidence level |
|---|---|
| Raises BDNF and trkB expression | rodent, replicated across labs |
| Raises NGF expression | rodent |
| No corticotropic activity | mechanistically established by design |
| Stroke and ischemia benefit | Russian clinical trials, not replicated to Western standards |
| Cognitive enhancement in healthy people | no controlled Western trial |
The gap is the last row, and it is where most consumer interest sits. Semax is marketed in the research market largely as a nootropic. The registered Russian indications are clinical ones, in stroke, transient ischemic attack, optic nerve conditions and cognitive disorders, studied in patients with pathology rather than in healthy adults seeking enhancement.
Did the July 2026 FDA vote make Semax legal?
Update, 29 October 2026: HHS filed an interim enforcement-discretion policy (Federal Register, 30 October). It says HHS does not intend to act against 503A pharmacies and physicians compounding semax free base for intranasal use. The conditions include a patient-specific prescription, a single ingredient and API from a registered manufacturer. The policy is not a rule and does not cover research-use-only vials. Our HHS policy explainer lists all ten conditions.
No. On 24 July 2026 the FDA Pharmacy Compounding Advisory Committee voted 8-5 with one abstention to recommend Semax for the 503A Bulks List, nominated for cerebral ischemia, migraine and trigeminal neuralgia. Semax had already been removed from the Category 2 do-not-compound list in April 2026.
Neither step legalises anything. Category 2 removal does not confer compounding eligibility, and an advisory recommendation is not a rule. FDA must complete notice-and-comment rulemaking or separately grant interim Category 1 status, and its own review scientists recommended against all seven peptides on the agenda. The full picture is in our FDA peptide vote explainer.
Nothing in that process touches research-grade Semax sold online, which remains in exactly the legal position it occupied before the meeting.
How pure is the Semax being sold, and does the vial contain what it says?
These are two different questions and Semax is a good illustration of why that matters.
Across 43 Semax certificates issued by Kovera Labs, covering 36 vendors, certified between 20 February and 29 May 2026 and retrieved from Kovera's verifier on 2 August 2026:
| Measure | Value |
|---|---|
| Records | 43 |
| Distinct vendors | 36 |
| Median purity | 99.93% |
| Lowest purity | 98.73% |
| Records below 98% | 0 |
| Identity confirmation failures | 0 |
| Vials more than 10% under labelled content | 1 |
On purity alone this looks excellent. The single content failure is the instructive one. Certificate KVR-2026-1AF8EF, issued to Peptide Partners on 24 March 2026, records a vial labelled 30 mg that measured 20.62 mg. Its purity was 99.933%.
That vial was 99.9% pure Semax and roughly a third short. Purity answers "is what is in here the right molecule and how much of it is contamination." Content answers "how much molecule is in here at all." A vendor quoting a purity figure and staying silent about measured content is answering the easier question. Check both fields on any certificate, and run it through our COA verifier rather than trusting the vendor's copy.
What this means
Semax is unusual in this market for having real clinical history behind it, and that history is entirely inside one national regulatory system that Western agencies have not evaluated. Treat "registered in Russia" as meaningful context rather than as a substitute for FDA or EMA review, and treat the nootropic framing as an extrapolation from clinical populations to healthy ones that nobody has actually tested.
The material itself tests clean. The thing to verify is not whether it is Semax but how much of it is in the vial.
Related reading
- FDA peptide vote 2026 - the July PCAC recommendation and the gates still standing between it and legal compounding.
- Selank - the other short Russian regulatory peptide, from tuftsin rather than ACTH, studied for anxiety.
- Epitalon - a third compound from the same Russian peptide-bioregulator tradition, also recommended by the committee.
- KPV and MOTS-c - the other compounds voted on in July, with their own third-party purity records.
- What 1,828 Kovera COAs show - the corpus behind the purity figures on this page.
- Is tianeptine legal? and is phenibut legal? - two non-peptide nootropics sold in the same gray market, and where their legal status now stands.
What it's researched for
- cognitive and neuroprotection research
- stroke and cerebral ischemia research
- attention and memory research
Where to source it
ALL 3 VENDORS →3 audited vendors stock Semax, but the price walk hasn't captured a current listing for it. See all 3 vendors →
Frequently asked about Semax
What is Semax?
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro, built from residues 4 to 7 of adrenocorticotropic hormone with a Pro-Gly-Pro tail added for stability. It was developed at the Institute of Molecular Genetics in Russia and is studied for cognition, neuroprotection and stroke recovery.
Is Semax FDA approved?
No. Semax has never been approved by the FDA, the EMA or the MHRA. It is registered as a medicine in Russia for indications including stroke and cognitive disorders. On 24 July 2026 an FDA advisory committee voted 8-5 with one abstention to recommend Semax for the 503A Bulks List, but that recommendation requires rulemaking before compounding becomes lawful.
How does Semax work?
The most-cited mechanism is neurotrophin regulation. Rodent studies from 2006 onward report Semax increasing BDNF and trkB expression in the hippocampus and BDNF protein in the basal forebrain, alongside changes in NGF expression. Because the first three ACTH residues are absent, it does not stimulate corticosteroid release the way the parent hormone does.
What is the Semax dosage?
There is no established Western dose. Russian clinical practice uses intranasal solution at 0.1% or 1% concentration in short daily courses, with more intensive courses in acute stroke care. Research-market vials are typically 5 mg, 10 mg or 30 mg of powder. Dosing charts on vendor sites are converted from Russian intranasal practice, not from controlled trials.
Is Semax the same as Selank?
No, though they share an origin. Both were developed by the same Russian research tradition as short regulatory peptides, but Selank derives from tuftsin and is studied for anxiety, while Semax derives from ACTH and is studied for cognition and neuroprotection. They are frequently sold and discussed together, which is where the confusion comes from.
How pure is research-grade Semax?
In our third-party lab data, Semax purity is consistently high but vial content is not. Across 43 Kovera-certified vials from 36 vendors, certified between February and May 2026, median purity was 99.93% with a floor of 98.73% and no identity failures. One vial labelled 30 mg measured 20.62 mg, a 31% shortfall, while still testing at 99.93% pure.