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Evidence-rated reference Updated August 2026
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Limited Approval Cognitive & Neurological Evidence 2/5 · Limited

Semax

Also known as ACTH (4-10) Pro-Gly-Pro · N-acetyl semax

Synthetic heptapeptide analog of ACTH (4-10) with no corticotropic activity

Overview

A well-established medicine in Russia with essentially no Western trial replication. The pharmacology is plausible and the domestic clinical literature is substantial; the problem is that almost none of it meets the methodological standards Western regulators require.

Limited or non-US approvalPrescription medicine in Russia. Unapproved elsewhere; import for personal use occupies a legal grey area.

At a glance
Regulatory statusRegistered in Russia for stroke, cognitive disorders and optic nerve conditions. Not approved in the US, EU or UK.
Drug classSynthetic heptapeptide analog of ACTH (4-10) with no corticotropic activity
RouteIntranasal (primary), subcutaneous
Half-lifeMinutes systemically; central effects outlast plasma levels
Evidence rating
2/5 Limited Evidence rating 2 out of 5: Limited
Preclinical work plus scattered human reports, uncontrolled use, or negative trials.
Studied inRussian clinical trials in ischemic stroke, cognitive impairment, optic nerve atrophy and ADHD; extensive Russian preclinical neuroprotection work.

How it works

Modified ACTH fragment stripped of hormonal activity. Increases BDNF and NGF expression in the hippocampus, modulates monoaminergic and cholinergic transmission, and shows antioxidant and anti-apoptotic effects in ischemia models. The Pro-Gly-Pro tail confers resistance to peptidase degradation.

Evidence base

Rated 2 of 5 — Limited. Preclinical work plus scattered human reports, uncontrolled use, or negative trials.

  • Large domestic literature, negligible international replication — treat both facts as real.

Benefits & potential uses

Bars indicate how well each claim is supported: three = strong human evidence, two = moderate, one = preliminary or preclinical.

  • Neuroprotection in stroke models Preliminary

    Consistent reduction in infarct volume and improved functional recovery in animal ischemia models, supported by Russian clinical use.

  • BDNF upregulation Preliminary

    Documented increases in brain-derived neurotrophic factor expression, a plausible substrate for cognitive effects.

  • Reported attention and memory effects Preliminary

    Russian studies and extensive user reports describe improved focus and working memory; not replicated under Western trial conditions.

  • No corticotropic activity Moderate evidence

    Unlike ACTH itself, it does not stimulate cortisol release — an important safety feature.

  • Good short-term tolerability Preliminary

    Decades of Russian clinical use without major safety signals reported.

Risks, cons & cautions

Bars indicate seriousness: three = serious or common, two = moderate, one = minor.

  • No Western regulatory review Serious

    Not evaluated by FDA or EMA. The evidence base has not been independently audited.

  • Trial methodology concerns Serious

    Much of the supporting literature lacks blinding, adequate power, or placebo control by contemporary standards.

  • Unknown long-term neurological effects Moderate evidence

    Chronically manipulating neurotrophin expression has no long-term human safety characterisation.

  • Grey-market supply in the West Serious

    Purity and concentration of imported product are unverified.

  • Overstimulation and irritability Minor

    Commonly reported at higher doses, along with headache and sleep disruption.

Who should avoid it

  • Pregnancy
  • Uncontrolled anxiety disorders
  • Concurrent stimulant use without medical supervision

If used under medical supervision, monitor

  • Blood pressure
  • Sleep and mood tracking

Commonly confused with

These mix-ups cause real harm — two products sold under one name, or two molecules whose effects run in opposite directions.

Selank Limited Approval Evidence 2/5

Developed at the same Russian institute and usually sold together. Semax targets cognition and neuroprotection; Selank targets anxiety. Both are registered in Russia and nowhere else.

Compare side by side
Noopept Limited Approval Evidence 2/5

Both Russian nootropics sold as Western supplements. Semax is an intranasal ACTH fragment; noopept is an orally active dipeptide ester that FDA has ruled is not a lawful dietary ingredient.

Compare side by side

Prescription medicine in Russia. Unapproved elsewhere; import for personal use occupies a legal grey area.

Infographic

Semax — benefits & risks at a glance Download SVG
Infographic summarising the benefits and risks of Semax, from pepteyes.com

Where to read further

We link to live literature searches rather than a frozen citation list, so you always see current results — including anything published after our last review.

nootropicBDNFstrokeintranasalRussia-approved

Related peptides in Cognitive & Neurological

Terms used on this page

Enzymatic Degradation
Enzymatic degradation is the breakdown of a peptide by proteases and peptidases in gut, blood, tissue and kidney, and it is the main reason unmodified peptides act only briefly.
Nerve Growth Factor (NGF)
Nerve growth factor is the founding neurotrophin, supporting sympathetic and sensory neurons and basal forebrain cholinergic neurons while also acting as a potent peripheral pain mediator.
Cholinergic Signalling
Cholinergic signalling is neurotransmission by acetylcholine at nicotinic and muscarinic receptors, the system that sets cortical attention and encoding and degenerates early in Alzheimer's disease.
Tissue Perfusion
Tissue perfusion is the volume of blood delivered through the capillary bed per unit of tissue mass per minute, the quantity that determines local oxygen and drug delivery.
Adrenocorticotropic Hormone (ACTH)
Adrenocorticotropic hormone is a 39-amino-acid pituitary peptide, cleaved from proopiomelanocortin, that drives cortisol synthesis in the adrenal cortex through the melanocortin-2 receptor.
Brain-Derived Neurotrophic Factor (BDNF)
BDNF is a neurotrophin that signals through the TrkB receptor to support neuronal survival, dendritic growth and the late, protein-synthesis-dependent phase of synaptic potentiation.

This page is educational information, not medical advice. It cannot account for your medical history, medications, or risk factors. Do not start, stop or change any treatment based on it. Speak to a qualified healthcare professional who knows your case.