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BigPeptideList

Semax

Compoundable (Rx)

Nootropic Peptides · Cognitive Enhancement

Semax is a synthetic peptide derived from ACTH (adrenocorticotropic hormone, fragment 4-10) developed by the Russian Institute of Molecular Genetics.

What is Semax?

Semax is a synthetic peptide derived from ACTH (adrenocorticotropic hormone, fragment 4-10) developed by the Russian Institute of Molecular Genetics. It is approved in Russia and Ukraine for treating stroke, cognitive disorders, and peptic ulcers. It has gained popularity in the biohacking community as a nootropic for focus, memory, and neuroprotection.

Also known as: MEHFPGP, Semax acetate

How Does Semax Work?

Increases brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) expression. Modulates dopaminergic and serotonergic neurotransmission. Enhances neuroplasticity and protects against oxidative stress. Unlike ACTH, it does not stimulate adrenal cortisol production.

What is Semax Used For?

  • Cognitive enhancement
  • Neuroprotection
  • Focus & attention
  • Stroke recovery
  • Anxiety reduction

Potential Side Effects

  • Nasal irritation
  • Headache (rare)
  • Dizziness (uncommon)

Contraindications

  • Pregnancy
  • Seizure disorders
  • Children

FDA Legal Status

United States — FDA

Compoundable (Rx)

Category 1 (restored 2026)

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Head-to-head comparisons:

Semax vs Selank

Frequently Asked Questions

How does Semax work as a nootropic?
Semax increases BDNF (brain-derived neurotrophic factor) levels by up to 8x in some studies, promoting neuroplasticity and neurogenesis. It also modulates dopamine and serotonin, improving focus, mood, and cognitive processing speed without the jitteriness of stimulants.
Is Semax addictive?
Semax has not shown addictive potential in studies. It does not produce tolerance, dependence, or withdrawal effects. It can be used cyclically or continuously, though many practitioners recommend periodic cycling.

Quick Facts

Legal Status (USA)
Compoundable (Rx)
FDA Category
Category 1 (restored 2026)
Evidence Rating
BModerate Evidence (Some Human Data)
Class / Subclass
Nootropic Peptides / Cognitive Enhancement
Administration
nasal, subcutaneous
Typical Dosage
200-600mcg nasal, 1-2x daily
Half-Life
~3-5 minutes (rapid onset, sustained effects)
Year Discovered
1982

Sources

PubMed 17369778

Last updated: 2026-04-01

Sources & references

Primary sources used for the dosing, mechanism, side-effect, and regulatory claims on this page. Verify time-sensitive information (regulatory status, prescribing details) on the source before relying on it for medical decisions. See our disclaimer.

  1. PubMed PMID 17369778 — peer-reviewed primary literature on Semax.
  2. FDA Federal Register — official notice record for FDA regulatory actions and Category 1 / 503A bulk-substance updates.