Semax: FDA's Own Reviewers Said No, and the Advisory Committee Voted Yes Anyway

FDA's reviewers read every Semax study and concluded the evidence of effectiveness was insufficient. Its Pharmacy Compounding Advisory Committee then voted 8–5, with one abstention, to recommend listing Semax anyway. Neither outcome changed the compound's legal status. FDA published no minutes or transcript for that meeting, so the tally comes from published meeting coverage rather than an agency document.

That disagreement is the most useful fact about Semax and the one least visible in the marketing that followed it. The agency staff who read the full file said the evidence was not there. A committee of outside experts, hearing the same material in a day, went the other way. This article works outward from both documents, through the trials underneath them, and into what a buyer in the cognitive and neuroprotective peptides category can actually verify.

What did FDA decide about Semax?

FDA's staff decided against Semax and its advisory committee overruled them in a recommendation. A briefing document published in May 2026 concluded there is "insufficient evidence of effectiveness to support use of semax (free base) or semax acetate for cerebral ischemia, migraine, or trigeminal neuralgia," and that "the evaluation criteria weigh against placing both semax (free base) and semax acetate on the list of bulk drug substances." On 24 July 2026 the Pharmacy Compounding Advisory Committee voted 8–5, with one abstention, to recommend adding it.

An advisory vote is not an agency action. As one legal analysis of the meeting put it, "an advisory committee vote is not an agency action, and FDA officials will have to make an ultimate decision on whether to accept or reject those recommendations." Semax today is exactly what it was before the meeting.

The split matters for a different reason. It maps precisely onto what the evidence base looks like when you open it: enough material for experienced people to form a favourable impression, and not enough for a regulator to write down a finding of effectiveness. Both readings are defensible from the same file, which is itself a statement about the file.

Why did FDA's own reviewers recommend against Semax?

FDA's briefing document rested on four grounds, and only one of them was efficacy. Beyond the insufficient-evidence conclusion, the review found both Semax forms "not well-characterized," with missing impurity, aggregate, endotoxin and bioburden data, flagged an abuse-potential observation, and counted the entire documented human exposure as 33 to 47 healthy adults, 69 adults with medical conditions and 451 children with depression or tics. Three of the underlying references were conference abstracts whose full studies could not be located.

On product quality, the agency also flagged "inconsistent naming conventions that do not follow established chemical nomenclature standards" and raised "potential for immunogenicity associated with these impurities and peptide related aggregates." That is a manufacturing and characterisation objection rather than a pharmacological one, and it applies to the substance as supplied rather than to the molecule in principle.

On abuse potential, FDA noted that Semax "potentiated amphetamine-induced dopamine release in the striatum." That is a pharmacological observation, not a claim that Semax is a stimulant, but the agency thought it worth raising.

On safety surveillance, literature searches through 3 December 2025 "did not identify literature case reports of adverse events in humans." One FAERS report exists: a consumer report from May 2024 of ocular pain and eye burning after Semax 0.1% nasal drops, with hospitalisation, unresolved as of May 2025. A single report is not a safety signal. It is also, alongside that exposure denominator, most of what is known.

What did the human studies of Semax actually find?

Five human studies of Semax exist and zero randomised placebo-controlled trials in patients are among them. The foundational stroke work compared 30 Semax patients against 80 conventional-therapy controls without randomisation or blinding, and reported a qualitative result with no p-values. A 2018 follow-up in 110 patients again split by non-randomised subgroup. The only trial carrying a randomised tag, in 27 patients with motor neurone disease, was null on its primary endpoint.

Read the 1997 study carefully, because it is the foundation of the entire Semax stroke claim. Thirty patients received Semax and eighty received conventional therapy. Patients were not randomised between those groups and nobody was blinded. The reported outcome is a qualitative statement, "some influence," with no numbers and no p-values in the abstract. The 2018 follow-up is larger but shares the non-randomised subgroup design and again reports no effect sizes.

The 2007 motor neurone disease trial is the only Semax study carrying the randomised-controlled-trial tag, and its primary result is null: Semax did not affect the course of chronic partial denervation or the clinical estimates. The quality-of-life secondary improved. A null primary with a positive secondary is a hypothesis, not a finding.

The only placebo-controlled work on Semax is two small fMRI studies in healthy volunteers measuring resting-state connectivity. Those are surrogate imaging endpoints, in people with nothing wrong with them, and neither states whether it was randomised or blinded. Every patient trial was conducted in Russia and published in Russian. ClinicalTrials.gov returns zero Semax studies and the EU Clinical Trials Register returns zero. There is no Cochrane review of Semax for stroke: we searched and found none, and you should not claim one exists in either direction.

How much Semax reaches the brain?

Semax brain uptake has been measured in rats and never in humans. Shevchenko et al. 2006 gave tritium-labelled Semax intranasally at 50 µg/kg and found "0.093% of the total introduced radioactivity per gram can be found in the rat brain 2 min after the administration, 80% of this radioactivity belonged to Semax." FDA's own summary puts rodent intranasal brain uptake at approximately 0.072% of the administered dose with a brain-to-blood ratio of 0.67, against 0.005% and a ratio of 0.24 for intravenous dosing.

FDA states the human position without hedging: "We were not able to find pharmacokinetic studies in humans following exposure to semax (free base) or semax acetate via any route of administration." No human half-life. No human bioavailability. No human measurement of brain penetration by any route. Every number in vendor copy describing how much Semax reaches your brain is extrapolated from rats or fabricated.

The rodent comparison does support one narrow claim. Intranasal genuinely beats intravenous here, by roughly thirteen-fold on the brain-to-blood ratio, which is the pharmacological reason the intranasal peptide guide exists for this compound. Both numbers are still a fraction of one per cent, in a rodent, and the peptide degrades fast: "the tripeptide proline-glycine-proline was the main metabolite identified in the blood and brain."

Is Semax an approved medicine, and at what dose?

Semax is a registered medicine in Russia and nowhere else, at doses far below those used in its own trials. FDA says so in its own document: "Semax is a registered drug in Russia and is available as 0.1% and 1% nasal drops." The current certificate for Semax 0.1% is ЛП-№(009449)-(РГ-RU), dated 26 March 2025, indefinite term, held by JSC INPC "Peptogen" of Moscow, ATC code N06BX. Registered dosing is 2–3 drops per nostril, two to four times daily, for 7–30 days.

It sits on Russia's ЖНВЛП list of Vital and Essential Medicines, and the registered indications are broad: intellectual-mnestic disorders in cerebrovascular disease, post-stroke recovery, dyscirculatory encephalopathy, transient ischaemic attack, recovery after head trauma or neurosurgery, neurotic disorders, adaptation in extreme conditions, optic nerve atrophy and neuritis, and minimal brain dysfunction in children aged seven and up.

Note the gap between the label and the literature. The 1997 stroke study used 12 mg/day in moderate stroke and 18 mg/day in severe; the 2018 study used 6000 µg/day. Those are hospital protocols, not the over-the-counter drop regimen, and the two are routinely conflated in dosing guidance written for the research market. Converting between a percentage solution and a vial labelled in milligrams depends entirely on the volume you reconstitute into, which the peptide dosing calculator and the reconstitution calculator will do arithmetically, without supplying the pharmacokinetics that would make the answer meaningful.

We could not verify the original year of first registration from any primary source, and the years circulating online are not traceable. The register shows only the current re-issued certificate. A national registration is a real regulatory fact; it is not the same as the evidence base behind it.

What is Semax chemically, and is it an ACTH analogue?

Semax is a synthetic heptapeptide, Met-Glu-His-Phe-Pro-Gly-Pro (MEHFPGP), molecular weight 813.93 g/mol by FDA's own figure, CAS 80714-61-0. It is built from ACTH(4-7) — the first four residues are amino acids 4 through 7 of adrenocorticotropic hormone — with a Pro-Gly-Pro tail attached. It is not an ACTH analogue in any functional sense: the fragment has no corticotropic activity and does not stimulate cortisol. Content describing it as a form of ACTH is wrong.

The Pro-Gly-Pro extension is the same stabilising motif this research group attached to tuftsin to make Selank. One design idea, two parent peptides, two registered Russian drugs.

One identity note. PubChem's record title for CID 9811102 is not "Semax" — it reads "ACTH (4-7), Pro-Gly-Pro-". Anyone verifying a certificate of analysis against PubChem should expect that rather than treat it as a mismatch. Sigma-Aldrich supplies the research material as a TFA salt, quoting molecular weight on a free-base basis; the salt form changes the mass on your scale without changing the peptide, which is why net peptide content matters here. See TFA versus acetate versus amidate salt forms.

Which Semax claims survive the evidence?

One Semax claim is true, one is outright false, one is misleading about mechanism, and one holds only in rodents. The Russian registration is real. The claim that FDA approved Semax for compounding is false: a committee recommended, and the agency has not acted. The ACTH-analogue framing is misleading because the fragment has no corticotropic activity. Stroke benefit, neuroprotection and nootropic effect in healthy people are unestablished, preclinical-only and unshown respectively.

Is Semax legal in the United States, and is it banned in sport?

Semax is not legally compoundable in the United States and is not named on the WADA Prohibited List. The FDA page current 22 April 2026 lists fourteen substances in the active Category 2 group and Semax is not one of them; it appears instead under "Bulk drug substances nominated but withdrawn." Semax remains an unapproved new drug, with no USP monograph, no European or Japanese pharmacopoeial monograph, and no status as a component of any FDA-approved product.

Both nominations, from Wells Pharmacy Network and LDT Health Solutions, were withdrawn by the nominators. FDA's note reads: "The nominations were withdrawn and FDA is evaluating the substances at its discretion." Being off the Category 2 list is a procedural fact about who withdrew what, not a safety clearance. Our FDA peptide regulation timeline tracks where this goes next, and compounding pharmacy versus research peptide explains why the distinction changes what a buyer is actually purchasing.

On WADA, do not overstate. Semax does not appear anywhere in the 2026 Prohibited List. Neither does "ACTH" as a standalone entry: S2.2.2 covers "corticotrophins and their releasing factors, e.g. corticorelin and tetracosactide," and Semax is neither, having no corticotropic activity. The catch-all S0 clause captures substances with "no current approval by any governmental regulatory health authority," and Semax holds a Russian approval, which on the literal wording puts it outside S0. No anti-doping authority has published a determination. The honest position is that the status is ambiguous and an athlete should get a ruling rather than a forum opinion.

How do you verify Semax before you buy it?

The specific risk with Semax is not contamination but substitution: it is sold alongside N-Acetyl Semax Amidate, a modified derivative with a different mass, and an HPLC purity figure cannot tell you which molecule is in the vial. The Purity Index records Semax at 99.44% average HPLC purity across 269 independent tests (verified August 2026) across 227 verified shops, with recent tests running 99.00–99.90%. Quantity variance is the weaker number, running −2.1% to +22.3%.

HPLC measures homogeneity. A pure sample of the wrong compound produces a beautiful chromatogram, which is why mass spectrometry against 813.93 Da for the free base is the only check that establishes identity here. A 22% overage, meanwhile, means the filling process is not controlled at that vendor.

Endotoxin, where reported at all, comes in at 0.05 to 0.096 EU/mL, but it is reported on a minority of listings, and FDA specifically flagged missing endotoxin and bioburden data as a characterisation gap for this substance. See endotoxin testing and LAL assay interpretation for how to read the result you do get.

Semax price data shows 72 shops in stock, median $4.09/mg and a lowest tracked price of $1.75/mg on a 10 mg vial (verified August 2026), across 84 comparable offers from 179 known sellers, ranging to $18.00/mg. Small 5–8 mg vials run a median $6.71/mg; 10 mg and larger run $3.60/mg. Those figures exclude shipping, taxes and customs, coupon codes, bulk tiers, multi-vial kits and account-gated pricing. Compare vendors on the Semax compound page, and see where to buy Selank and Semax for the identity checks specific to this pair.

How does Semax compare with Selank and Epithalon?

Semax, Selank and Epithalon come out of the same Soviet and post-Soviet peptide research tradition and share the same shape of evidence base. Semax weighs 813.93 g/mol, Selank 751.9 and Epithalon 390.3. Semax and Selank hold Russian registrations and Epithalon does not. All three have substantial preclinical work, none has any human pharmacokinetic data, and none has a randomised placebo-controlled trial in patients anywhere. Two of the three were voted on by the same FDA advisory committee.

Our bioregulators and the Khavinson peptides article covers the wider group, and the Semax versus Selank comparison covers the two nasal peptides side by side.

Who made Semax, and one name to delete

Content on Semax and Selank routinely quotes "Elena Yaroslavtseva" of the Institute of Molecular Genetics, and no such researcher exists. A PubMed author search under that surname returns five records, covering an HIV cohort in St Petersburg, insect pathogenic fungi and 1976 bacteriophage genetics, none related to peptides or this institute. Any article citing that name should be treated as unreliable throughout. The real programme is easy to trace, and one name runs through all of it.

Nikolay F. Myasoedov, of the Department of Chemistry of Physiologically Active Compounds at the Institute of Molecular Genetics RAS, is a named author on the 1997 stroke trial, the 2007 motor neurone disease trial, the 2018 stroke study, the intranasal pharmacokinetic work and both fMRI papers. Lyudmila A. Andreeva is his long-standing collaborator. Konstantin V. Shevchenko and Igor A. Grivennikov did the pharmacokinetics. On the clinical side, Evgeny I. Gusev and Veronika I. Skvortsova, later Russia's Minister of Health, ran the stroke studies. FDA traces the original synthesis to Ponomareva-Stepnaya et al., 1984.

The frequently repeated claim that Igor P. Ashmarin co-created Semax is not something we could verify. He is a real and prolific author in the adjacent glyproline literature. We found no source attributing Semax's creation to him, so we are not printing it.

Frequently Asked Questions

Did FDA approve Semax?

No. FDA's Pharmacy Compounding Advisory Committee voted 8–5, with one abstention, to recommend adding Semax to the 503A bulk substances list. That is a non-binding recommendation from an outside committee. FDA's own reviewers had recommended against it, and the agency has not issued a decision. Semax remains an unapproved new drug in the United States.

Is Semax on FDA's banned list?

Not currently. It was in Category 2 of FDA's interim compounding policy, but the page current 22 April 2026 moves it to a table of nominations withdrawn by the nominators. That is a procedural move, not a safety clearance.

Does Semax work for stroke?

The evidence is two non-randomised, unblinded Russian studies reporting qualitative benefit with no published effect sizes or p-values, plus a randomised trial in motor neurone disease whose primary endpoint was null. FDA reviewed all of it and concluded the evidence of effectiveness was insufficient. There is no Cochrane review either way.

How much Semax reaches the brain?

In rats, roughly 0.07–0.09% of an intranasal dose per gram of brain tissue at two minutes — about thirteen times better than intravenous on a brain-to-blood basis, but still a fraction of one per cent. FDA searched for human pharmacokinetic data and reported finding none, for any route.

Is Semax the same as N-Acetyl Semax Amidate?

No. They are different molecules with different masses, sold side by side. An HPLC purity figure cannot distinguish them. Only mass spectrometry against 813.93 Da for the Semax free base establishes which one you have.

Is Semax banned in sport?

It is not named on the WADA 2026 Prohibited List, and it is not a corticotrophin, so S2.2.2 does not fit. Whether the catch-all S0 clause applies is unclear, because S0 turns on having no approval from any governmental health authority and Semax holds a Russian one. No anti-doping body has ruled. Get a determination before competing.

The trial that would settle this

Six elements would settle the Semax question and no study contains them: a randomised, blinded placebo arm, an acute ischaemic stroke population outside Russia, modified Rankin at 90 days as the endpoint rather than EEG and evoked potentials, a published effect size with a confidence interval, any human pharmacokinetic study at all, and pre-registration on a public registry. FDA's reviewers reached their conclusion because this package does not exist. The advisory committee voted the other way on the same absence.

Until someone runs that study, both positions are defensible and neither is knowledge.

Where this leaves Semax

Semax has more behind it than most compounds sold on this market: a genuine institutional origin, a real national registration, forty years of published work, and, unusually, an FDA review that read all of it. That review is the most valuable document in the file, and what it found is that the human evidence does not carry the claims. Two unblinded stroke studies with no numbers, one randomised trial that missed its primary, two fMRI studies in healthy people, and no human pharmacokinetics of any kind.

An advisory committee looked at the same material and recommended listing it anyway, 8–5, against the agency's written assessment. You can read that vote as expert judgement filling a gap in the data, or as a committee going beyond it. What you cannot read it as is new evidence. Nothing about Semax's effectiveness changed in July 2026 — only the opinion of thirteen people about what to do while the evidence is missing.

Browse the cognitive and neuroprotective peptides category, or our complete peptide guide with 118 compounds (verified August 2026). For per-dose volume when reconstituting a vial, use the peptide dosing calculator alongside the reconstitution calculator. Compare shops through independent lab tests and community-verified shop reviews.

This article is for educational and informational purposes only and does not constitute medical advice. Peptides discussed may be investigational compounds not approved by the FDA (or equivalent regulators in your jurisdiction) for human use. Always consult a qualified healthcare provider before using any peptide or research compound. Peptigrity is an independent review platform and does not sell, endorse, or recommend specific products or vendors.