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Semax

Studied for recovery after ischaemic stroke, optic nerve disease and motor neuron disease. A seven-residue analogue of the ACTH 4-10 fragment, developed in Russia and in Russian clinical use since the 1990s.

categorycognitive
clinical evidencehuman [ru]
community adoptionhigh
uses graded5
sources11
last reviewed24 Aug 2026
compound file

The answer, first. A seven-residue analogue of the ACTH 4-10 fragment, developed in Russia and in Russian clinical use since the 1990s. The strongest evidence is for recovery after ischaemic stroke, graded C — small or open-label human only. Russian open trials report faster recovery.

In 110 post-stroke patients, semax at 6000 mcg/day across two 10-day courses raised plasma BDNF and improved Barthel scores 1.

No blinding, no placebo. The rest of what it is sold for — attention and working memory, mood and stress resilience — grade D or E: animal or mechanism data with no controlled human outcome.

What it is used for

Every use graded on its own evidence, not the compound as a whole. 5 outcomes, ranked by what the human record supports.

#outcome · human · animal · gradewhat the best evidence actually shows
01Recovery after ischaemic stroke3 Russian trials, none blinded · broad rodent recordgrade CRussian open trials report faster recovery. In 110 post-stroke patients, semax at 6000 mcg/day across two 10-day courses raised plasma BDNF and improved Barthel scores 1. No blinding, no placebo.
02Optic nerve diseaseone Russian series · none for this outcomegrade CA Russian series added semax to standard therapy for optic neuropathy and reported better acuity and visual field against an untreated control group 8. Open-label, single centre, no randomisation reported.
03Motor neuron diseaseone open series, n=27 · rodent spinal cord modelsgrade CAn open-label study gave 27 patients 12 mg/day intranasally in two 10-day courses and tracked needle electromyography and quality of life 11. No control arm, no blinding.
04Attention and working memoryimaging endpoints only · rodent learning tasksgrade DOne placebo-controlled study in 24 healthy adults found a larger medial frontal default-mode component after intranasal semax 3. That is a brain measure. No controlled trial has measured cognition itself.
05Mood and stress resilienceno trial · rat chronic stress modelgrade DRodent only. Semax showed antidepressant-like and antistress effects in male rats under chronic unpredictable stress 7. No human trial has tested semax against placebo for mood.
gradewhat it means
ARegulatory approval, or multiple adequately-powered trials agreeing with each other
BAt least one well-powered human randomised trial, with the direction replicated
CSmall or open-label human trials only
DAnimal or mechanism data only, with no controlled human outcome
EA claim the human trials have already killed

How it works

The proposed mechanism, in three steps. A mechanism is a reason to run a trial, never a substitute for one.

1targetBinds saturable sites on rat basal forebrain membranes, Kd 2.4 nM. It carries no corticotropic activity, unlike full ACTH 5710.
2signalIntranasal semax at 50 and 250 mcg/kg raised BDNF protein in rat basal forebrain within 3 hours 5.
3effectIn rat brain ischaemia it shifts transcription of immune, vascular and neurotrophin genes toward the uninjured pattern 9.

What it does not do

Claims the current record does not support. Worth knowing before you set expectations.

not supported by the evidence

How it is used

What published protocols administered, and what the community reports doing. Descriptive on both counts, and never a recommendation.

routeIntranasal drops in every published protocol. Russian hospital use also gives it intranasally rather than by injection.
formatAqueous 0.1% and 1% nasal solution in Russian practice.
published dosesPublished human protocols vary. The developers' work used 0.015 to 0.050 mg/kg intranasally 6. Motor neuron disease used 12 mg/day in 10-day courses 11. Post-stroke work used 6000 mcg/day in two 10-day courses 1, and acute stroke 12 to 18 mg/day 2.
human pharmacokineticsNo human pharmacokinetic data published. Rat brain membrane work reports rapid degradation of the intact peptide 10.
reported conventionsAs reported on nootropics forums and vendor threads, 2015 to 2026: intranasal dosing of the 0.1% solution in the low hundreds of micrograms daily. Split morning and midday, run in blocks of two to four weeks. Acetylated and amidated variants are discussed as separate items. Convention, not guidance.
commonly paired withSelank

This site does not publish protocols to follow. The doses above are what studies administered or what users report, stated as facts about the literature and the market. How protocols are structured, mixing and storage and the reconstitution calculator cover the arithmetic.

What to expect

Where a trial measured it, the trial. Where only the community reports it, that is said out loud.

onsetThe stroke trial dosed for 10 days per course and measured across 5 months 1. The imaging study saw a network difference 5 to 20 minutes after a dose 3. No trial has measured a cognitive onset time.
most common reportAs reported: a same-day alertness or focus shift, and nasal stinging from the solution.
adverse effectsThe developers' review states no side effects or complications were recorded across their programme 6. That is an uncontrolled claim from the sponsor. As reported: nasal irritation, headache, irritability at higher volumes.
the stop signalPublished protocols end at a fixed course length rather than at a signal 111. As reported: users stop on headache or on a flat response after two to three weeks.

Approval and status

What regulators and sport bodies have actually said, separately from what the evidence shows.

approvalRegistered as a medicine in Russia. No approval in the US, EU or UK.
FDANot FDA-approved for any indication and not an approved US drug product. Sold on the research market.
sport [WADA]Not named on the Prohibited List. Russian registration bears on S0.
sold asresearch chemical

Covered in depth

These reports grade Semax at length and carry their own verified reference lists.

The State of Peptides, 2026: What They Are, Who Is Fighting Over Them, and What Each One Can Prove

Seventeen compounds, one ladder, no generosity. Two hold an FDA approval for what they are sold to do, seven grade D, and the thing everyone called a legalisation in April 2026 was the opposite.

Check the vial

The grade above describes a molecule studied under controlled conditions. It says nothing about the powder in a particular vial.

That gap is the one part of this market a reader can actually close. How to read a certificate of analysis covers the five measures in five minutes, and the 2026 audit grades vendors on the documents they publish against a rubric printed in full.

Questions we get

What is Semax used for?

In Russia it is prescribed for recovery after ischaemic stroke and for optic nerve disease, and the published trials sit there 128.

Outside that, it is bought as a nootropic for attention and working memory. That use has no controlled trial behind it. The one placebo-controlled study in healthy adults measured a brain network, not cognition 3.

How is Semax used?

Descriptively, and not as advice. Every published protocol gives it intranasally as a 0.1% or 1% aqueous solution. Russian trials used 0.015 to 0.050 mg/kg in the developers' work 6.

Others used 6000 mcg/day in two 10-day courses after stroke 1, and 12 mg/day in motor neuron disease 11. The research market sells the same solution without a protocol.

How long does Semax take to work?

No trial answers this for cognition. The imaging study detected a resting-network difference 5 to 20 minutes after a dose 3. That is a brain measure, not an effect anyone would notice.

The clinical trials ran fixed 10-day courses and read their endpoints weeks or months later 111. Anything faster than that is a report, not a measurement.

Is Semax an approved drug?

It is registered as a medicine in Russia and nowhere else. That matters less than it sounds. Registration in one jurisdiction is not the same as a replicated trial base.

No blinded, adequately powered semax trial has been published in any language. On our index it is graded human [ru] on clinical evidence and high on community adoption, rated separately on purpose.

How do I know what is actually in a vial of Semax?

You do not, unless a certificate of analysis for that specific lot says so. A certificate worth trusting covers five measures: identity, purity, measured net content, endotoxin and a microbial screen.

It names the lab that ran them and carries an accession number you can verify with that lab. Most certificates on this market cover one to three of the five. Purity alone is one number, not a quality programme.

References

  1. Gusev EI, Martynov MY, Kostenko EV, et al. [The efficacy of semax in the treatment of patients at different stages of ischemic stroke]. Zh Nevrol Psikhiatr Im S S Korsakova. 2018. PMID 29798983
  2. Gusev EI, Skvortsova VI, Miasoedov NF, et al. [Effectiveness of semax in acute period of hemispheric ischemic stroke]. Zh Nevrol Psikhiatr Im S S Korsakova. 1997. PMID 11517472
  3. Lebedeva IS, Panikratova YR, Sokolov OY, et al. Effects of Semax on the Default Mode Network of the Brain. Bull Exp Biol Med. 2018. PMID 30225715
  4. Panikratova YR, Lebedeva IS, Sokolov OY, et al. Functional Connectomic Approach to Studying Selank and Semax Effects. Dokl Biol Sci. 2020. PMID 32342318
  5. Dolotov OV, Karpenko EA, Seredenina TS, et al. Semax, an analogue of adrenocorticotropin 4-10, binds specifically and increases levels of brain-derived neurotrophic factor protein in rat basal forebrain. J Neurochem. 2006. PMID 16635254
  6. Asmarin IP, Nezavibat'ko VN, Miasoedov NF, et al. [A nootropic adrenocorticotropin analog 4-10-semax, 15 years experience in its design and study]. Zh Vyssh Nerv Deiat Im I P Pavlova. 1997. PMID 9173745
  7. Inozemtseva LS, Yatsenko KA, Glazova NY, et al. Antidepressant-like and antistress effects of the ACTH 4-10 synthetic analogs Semax and Melanotan II on male rats in a model of chronic unpredictable stress. Eur J Pharmacol. 2024. PMID 39442746
  8. Polunin GS, Nurieva SM, Baiandin DL, et al. [Evaluation of therapeutic effect of new Russian drug semax in optic nerve disease]. Vestn Oftalmol. 2000. PMID 10741256
  9. Filippenkov IB, Stavchansky VV, Denisova AE, et al. Novel Insights into the Protective Properties of ACTH 4-7 PGP, Semax, Peptide at the Transcriptome Level Following Cerebral Ischaemia-Reperfusion in Rats. Genes. 2020. PMID 32580520
  10. Dolotov OV, Zolotarev YA, Dorokhova EM, et al. [The binding of Semax, ACTH 4-10 heptapeptide, to plasma membranes of the rat forebrain basal nuclei and its biodegradation]. Bioorg Khim. 2004. PMID 15344653
  11. Serdiuk AV, Levitskii GN, Miasoedov NF, et al. [The study of chronic partial denervation and quality of life in patients with motor neuron disease treated with semax]. Zh Nevrol Psikhiatr Im S S Korsakova. 2007. PMID 18379501

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