Semax: Benefits, Dosage, Side Effects and Legal Status

Dosing: what the two human trials actually used. Selank, its usual pairing, now has its own page; the two compared side by side: Semax vs Selank. Regulatory changes for this compound and others, as they happen: US peptide regulation tracker.

Semax has more behind it than most peptides sold as nootropics. It is used clinically in Russian neurology, it has a published trial in stroke rehabilitation, and in July 2026 FDA’s compounding advisory committee voted to recommend letting US pharmacies compound it. It is also true that most of the research is older Russian studies, so the details matter.

What is Semax?

Semax is a short synthetic peptide derived from a fragment of ACTH (adrenocorticotropic hormone). It was developed in Russia and is used clinically there in neurology. Outside Russia it is sold as a research chemical and marketed as a nootropic for focus, memory and mood.

Semax structure

Molecular formula

C₃₇H₅₁N₉O₁₀S

Molecular weight

813.9 g/mol

Length

7 amino acids

Sequence

MEHFPGP

Modifications

Free N- and C-termini; all L-amino acids. ACTH(4-7) extended with Pro-Gly-Pro.

PubChem CID

9811102

This is Semax itself. 'N-acetyl semax' (and 'N-acetyl semax amidate', PubChem CID 172638603) is a different, modified molecule.

Identity checked against FDA Global Substance Registration System (UNII I5FAL2585H).

How Semax works

Modern English-language work on this ACTH-derived peptide family is about mechanism, not clinical results. One example looks at how synthetic ACTH-derived peptides change immune-gene activity in the brain after stroke Filippenkov 2023 - Filippenkov IB, Remizova JA, Stavchansky VV et al. Synthetic Adrenocorticotropic Peptides Modulate the Expression Pattern of Immune Genes in Rat Brain following the Early Post-Stroke Period. Genes (Basel). 2023;14(7)., in the references below. It offers a plausible mechanism, but it doesn’t show whether Semax helps a healthy adult concentrate.

The literature, counted

• Russian-language recordsof 231 total
  105
• Tagged as a clinical trialacross the whole corpus
  4
• Tagged as a randomised trialRussian-language, 2007; the abstract says open-label
  1

Counted on PubMed in August 2026. Almost half the Semax literature is Russian-language, and the concentration is heavier still among the clinical studies rather than the laboratory work.

Semax benefits: what the research shows

Two published clinical studies give Semax a specific dose. Both were in patients under clinical supervision, not healthy adults:

• Motor neuron disease, 2007 (open-label, though PubMed tags it as randomised). 27 adults were given Semax 1% solution in the nose at 12 mg/day, as two 10-day courses 2 weeks apart. It did not change the nerve-damage measure the trial tracked, but quality-of-life scores improved through emotional state and motivation Serdiuk 2007 - Serdiuk AV, Levitskiĭ 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;107(4):29-39., in the references below.
• Stroke rehabilitation. 110 adults recovering from ischaemic stroke were given Semax in the nose at 6 mg/day, as two 10-day courses 20 days apart. Semax raised blood levels of BDNF, a brain growth factor, and was linked to faster gains on the Barthel index of daily function Gusev 2018 - Gusev EI, Martynov MY, Kostenko EV et al. [The efficacy of semax in the tretament of patients at different stages of ischemic stroke]. Zh Nevrol Psikhiatr Im S S Korsakova. 2018;118(3. Vyp. 2):61-68., in the references below.

Neither enrolled healthy adults, and neither measured the “focus and memory” effect vendors sell Semax for. Full detail on both doses: Semax dosage.

What that means

The studies still count. Non-English research is research, and Semax came out of a serious clinical programme and is used in Russian neurology. But the controlled evidence is in specific diagnosed groups, up to two decades old, and has not been independently replicated in literature most readers, clinicians and regulators can access.

That evidence was enough to move a US advisory panel. On 24 July 2026 FDA’s Pharmacy Compounding Advisory Committee voted 8-5 to recommend adding Semax to the list of substances pharmacies may compound, for migraine, cerebral ischaemia and trigeminal neuralgia, STAT reported. Supporters pointed to its clinical use in Russia; FDA’s own reviewers had found insufficient evidence for those uses. A committee vote is a recommendation, not a rule change.

Semax dosage

Clinic and vendor guides most often describe 100-600 mcg by nasal spray, once daily in the morning, up to twice daily in the wider published range. They cycle it roughly 1.5-3 weeks on with a 1-2 week break. That is common practice, not a dose any trial or regulator has set.

The two published human trials used much higher doses under clinical supervision: 12 mg/day and 6 mg/day in the nose, in patients with motor neuron disease or recovering from stroke. Full detail on both: Semax dosage.

Semax side effects

There is no FDA label and no published safety trial for the research-chemical product sold outside Russia. What follows comes from the two trials’ abstracts and from what users report.

Reported in studies

Neither the motor-neuron-disease trial nor the stroke-rehabilitation trial reports side effects or tolerability in the abstract available on PubMed Serdiuk 2007 - Serdiuk AV, Levitskiĭ 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;107(4):29-39., in the references below Gusev 2018 - Gusev EI, Martynov MY, Kostenko EV et al. [The efficacy of semax in the tretament of patients at different stages of ischemic stroke]. Zh Nevrol Psikhiatr Im S S Korsakova. 2018;118(3. Vyp. 2):61-68., in the references below.

Reported by users

I couldn’t find an independent survey, case report or reputable reporting on what Semax users experience. The effects that circulate (nasal irritation or burning from the spray, headache, and a racing heartbeat or jitteriness) come from clinics’ and sellers’ own pages, which give no frequencies. I note them without treating them as evidence.

Semax is usually taken as a nasal spray rather than an injection, so those reactions relate to that route, not an injection site.

Get medical care for a racing or irregular heartbeat, chest pain or a severe allergic reaction. Those are standard reasons to stop any stimulating compound; they are general practice, not established for Semax specifically. See dosing for what the trials used.

Is Semax legal?

Semax is not approved for human use in the US. It is sold through research-chemical channels, where no regulator checks that a vial matches its label. It has been used clinically in Russia, which is why vendors sometimes call it an approved medicine: true there, not where it is being bought.

Related

• N-acetyl Semax and Selank amidate
• Semax dosage: what the human studies used
• Selank: its own page
• Semax vs Selank, side by side
• Semax and Selank: the shared guide this page was split from
• US peptide regulation tracker

How Semax compares

Brain, mood and sleep. Doses for unapproved compounds are common practice, not trial-established. All brain, mood and sleep peptides →

Compound	Main use	Evidence	Usual dose	US status
Semax	Sold as a nootropic for focus, memory and mood. Used clinically within Russian medicine.	Limited human data	100-600 mcg, once daily for a fixed telehealth-prescribed protocol, up to twice daily in a wider clinic-published range	Research use only
Selank	Sold as a nootropic for focus, memory and mood. Used clinically within Russian medicine.	Limited human data	250-900 mcg, 1-3 times daily, spaced through waking hours; the published Russian GAD clinical-trial protocol used a fixed 3 times daily schedule (900 mcg per dose, 2.7 mg/day total) for a 14-day course	Research use only
Adamax	Sold as a nootropic, marketed as a longer-acting, more potent successor to Semax, aimed at the same cognitive-enhancement buyers.	No meaningful evidence	No consistent protocol	Unapproved drug
Cerebrolysin	A prescription drug in Russia, China, several Eastern European and other markets for acute ischaemic stroke, traumatic brain injury and vascular dementia. Also sold outside those markets, including to US buyers, as an unregulated "research" or grey-market vial for self-injection, which is not how it is used where it is actually approved.	Limited human data	No consistent protocol	Unapproved drug
PE-22-28	Studied only in mice as a candidate fast-acting antidepressant. Never tested in a single published human trial, and sold to consumers as an unregulated research-chemical mood/depression product.	Animal / lab only	No consistent protocol	Unapproved drug
Dihexa	Sold online as a research chemical for cognition and memory. FDA has not identified any human exposure data on drug products containing dihexa acetate by any route.	Animal / lab only	10-100 mg, 1 to 3 times a week, not daily; sources describe starting around 10-20 mg and titrating up to 50-100 mg as tolerated	Research use only
DSIP	Sold for sleep. Named in the 1970s after a proposed role in promoting delta-wave sleep.	Limited human data	100-500 mcg, once nightly, 30-60 minutes before intended sleep onset; anywhere from 5-14 nights a month to nightly use depending on the protocol	Research use only

Where to buy Semax for research

Each vendor is checked against my vendor checklist.

1. 1.Next Level PharmFeatured

   5 mg vial

   • No FDA warning letter found
   • Names its testing lab
   • Batch COAs published
   • Takes card payment

   $18.99as of 3 October 2026

   View product →My Next Level Pharm review

2. 2.Spartan Peptides

   30 mg vial

   • No FDA warning letter found
   • Names its testing lab

   $159.00as of 3 October 2026

   View product →My Spartan Peptides review

3. 3.BioEdge Research Labs

   N-acetyl Semax amidate 10 mg vial

   • No FDA warning letter found
   • Names its testing lab
   • Batch COAs published

   $39.00as of 3 October 2026

   View product →My BioEdge Research Labs review

Compare every checked vendor for Semax →

See all vendors and how they compare →

Common questions

Is there real research on Semax?

Yes, though it is narrower than either its promoters or its critics suggest. Clinical studies have been published in Russian-language neurology journals. They are in patients with diagnosed conditions such as motor neuron disease and stroke, not healthy adults using it for cognitive enhancement.

Does Semax improve focus or memory?

No published trial I counted tested that use. Its only trial tagged as randomised (the abstract describes an open-label design) studied motor neuron disease and quality of life; a second studied stroke rehabilitation and plasma BDNF. Neither enrolled healthy adults or measured focus and memory.

What is the usual Semax dose?

Clinic and vendor guides most often describe 100-600 mcg by nasal spray, once daily in the morning, up to twice daily in the wider published range. That is common practice, not a dose any trial or regulator has set. The two published human trials used much higher doses under clinical supervision; see the next question.

What dose of Semax do studies use?

Two published human studies give a dose: 12 milligrams per day in the nose in a motor-neuron-disease trial, and 6 milligrams per day in the nose in a stroke-rehabilitation trial, both as two 10-day courses. Neither is a healthy-adult cognitive protocol, and no regulator has approved either as a consumer dose.

What are the side effects of Semax?

Neither published human trial reports side effects in its available abstract, so there is no trial-based rate. Users of the nasal spray commonly report nasal irritation or burning, headache, and a racing heartbeat or jitteriness. Those are user reports, not clinical findings, and no FDA label or safety trial exists to confirm them.

References (4 sources)

Show

Bibliographic detail is fetched from PubMed, not written by me - so a citation here cannot drift from the paper it names. Study design comes from PubMed's own tags rather than my judgement.

1. 1.Serdiuk AV, Levitskiĭ 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;107(4):29-39.Randomised trialPMID 18379501
2. 2.Gusev EI, Martynov MY, Kostenko EV et al. [The efficacy of semax in the tretament of patients at different stages of ischemic stroke]. Zh Nevrol Psikhiatr Im S S Korsakova. 2018;118(3. Vyp. 2):61-68.Clinical trialPMID 29798983
3. 3.Filippenkov IB, Remizova JA, Stavchansky VV et al. Synthetic Adrenocorticotropic Peptides Modulate the Expression Pattern of Immune Genes in Rat Brain following the Early Post-Stroke Period. Genes (Basel). 2023;14(7).StudyPMID 37510287full text
4. 4.STAT, 24 July 2026 (Lizzy Lawrence and Sarah Todd) - FDA advisory panel narrowly rejects compounding of one peptide, backs two others. Reports the 8-5 committee vote in favour of adding Semax to the 503A compounding list for migraine, cerebral ischaemia and trigeminal neuralgia, against FDA reviewers finding insufficient evidence.- STAT Newsnews

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