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Brain & CognitionSynthetic heptapeptide analogue of ACTH(4-10) with a C-terminal Pro-Gly-Pro extension

Semax

A synthetic neuropeptide derived from ACTH researched in Eastern Europe for stroke recovery, memory, and nerve cell protection.

UnapprovedEarly Clinical / Pharmacology (Phase 1)Also known as: MEHFPGP, ACTH(4-10) analogueSkip to Human Evidence ↓
Neuropeptide Biology

Semax: BDNF & Neuroprotection

Eastern European Clinical Approval

Semax is an ACTH(4-10) fragment analogue engineered with a Pro-Gly-Pro cap to resist brain enzymes. It rapidly upregulates Brain-Derived Neurotrophic Factor (BDNF) without steroidogenic hormonal activity.

TrkB Receptor Activation

Dramatically increases BDNF and NGF expression in hippocampal and cortical neurons, supporting synaptogenesis and ischemic recovery.

Western Regulatory Status

Approved on the Russian Essential Pharmaceuticals list, but unapproved by the US FDA and EMA. Sold online in the West as an unverified research chemical.

1

What is Semax?

Semax is a synthetic heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) developed in Russia, derived from a shortened fragment of adrenocorticotropic hormone (ACTH 4-10) stabilized with a C-terminal Pro-Gly-Pro sequence.

2

Why are people interested in it?

Widely researched for neuroprotection, memory enhancement, focus, and recovery from ischemic stroke or traumatic brain injury. Significantly, it lacks any hormonal steroidogenic activity.

Primary Research Categories

  • Peptide fragments
  • Preclinical research compounds
3

How does it work in the body?

Semax stimulates the synthesis of nerve growth factors, protects brain cells from oxygen deprivation, and modulates dopamine and serotonin pathways.

In Everyday Language: Semax is a brain-nourishing peptide. It stimulates the production of natural growth factors that help brain cells survive oxygen deprivation and sprout new connections, without triggering adrenal hormones.
Cellular & Receptor Signaling: Heptapeptide that rapidly stimulates the synthesis and release of Brain-Derived Neurotrophic Factor (BDNF) and Nerve Growth Factor (NGF) in cortical and hippocampal neurons. It modulates dopamine and serotonin turnover and provides ischemic cytoprotection.

Neurochemical Modulation

BDNF Neurotrophic Support & Neurotransmitter Balance

Regulatory Heptapeptide

Neurotrophic Factor Expression

Upregulates Brain-Derived Neurotrophic Factor (BDNF) and nerve growth factor (NGF) mRNA in hippocampal and cortical neurons, supporting neuroplasticity.

GABAergic & Monoamine Balance

Modulates inhibitory GABA receptors to alleviate anxiety and stress without hypnotic sedation or physical dependency.

BDNF & NGF Upregulation

Dramatically increases expression of Brain-Derived Neurotrophic Factor and Nerve Growth Factor in cortical and hippocampal neurons.

Ischemic Neuroprotection

Prevents excitotoxic neuronal death during cerebral ischemia by stabilizing cellular mitochondrial function.

Monoaminergic Balance

Modulates central dopaminergic and serotonergic turnover to enhance focus, alertness, and mental clarity.

4

What has actually been demonstrated in humans?

Early Clinical / Pharmacology (Phase 1)

Approved in Russia and included on the Russian Essential Pharmaceuticals list for acute ischemic stroke, transient ischemic attacks, and optic nerve disease. Human clinical publications are primarily in Russian neurology literature.

Acute Stroke Clinical Trial (Gusev et al., 2018)

Duration: Acute post-stroke intervention · Population: Patients with acute ischemic stroke in Russian neurology centers

Published Finding: Reported accelerated functional neurological recovery and reduced disability scores compared to standard therapy alone.

Gusev et al., Zh Nevrol Psikhiatr Im S S Korsakova (2018)

Pharmaceutical Reality vs. Unregulated Research Chemicals

Semax is not approved by the US FDA. Any products sold outside licensed pharmacies in Eastern Europe are unapproved research chemicals without FDA safety verification.

5

What is still uncertain or unknown?

Human clinical data is restricted to Eastern European stroke protocols. Multi-center double-blind trials conforming to FDA or EMA standards have not been performed.

Regulatory Position: Approved pharmaceutical in Russia. Unapproved research chemical in the United States.

Companion Resources & Guides

Compare with Selank→

Compare nootropic Semax with anxiolytic Selank.

Research at a Glance

Open the full evidence file (3 records)

3 records in this file

  • ANIMAL1
  • REGULATORY2

Publication span: 2006–2026

What Has Actually Been Studied

  • FDA — bulk substances nominated for compounding and withdrawn: Semax (heptapeptide) (FDA compounding communications, 2026) — FDA compounding classification.
  • FDA PCAC briefing — Semax-related bulk drug substances (24 July 2026) (FDA PCAC briefing, 2026) — FDA advisory-committee briefing.
  • Semax, an analogue of adrenocorticotropin (4-10), binds specifically and increases levels of brain-derived neurotrophic factor protein in rat basal forebrain (Journal of Neurochemistry, 2006) — In vivo (rat) with supporting binding work.

What is Still Unknown

What we know

  • A rodent BDNF literature exists, including Dolotov et al. 2006 in Journal of Neurochemistry.
  • No United States approved product. FDA's withdrawn-nominations table lists Semax (heptapeptide).
  • PCAC discussed Semax-related bulk substances on 24 July 2026. FDA briefing materials proposed against inclusion. That is not a listing decision.

Editorial reading of the records below, labelled as Therapept analysis. How records are built

What remains uncertain

  • How non-US labelled use, if any, should be read against US compounding policy — they are different systems.
  • Independent Western interventional trials on the endpoints FDA evaluated (cerebral ischemia, migraine, trigeminal neuralgia).

Combinations and Stacks

  • Selank + Semax

    Two Russian-developed heptapeptides discussed together for cognition, anxiety and focus.

Preparation and Handling

Lyophilized peptides ship as freeze-dried powders; whatever happens next involves diluents, concentrations and storage conditions that are compound- and product-specific.

Preparation Resource HubWhat “lyophilized” meansConcentration calculator

United States Regulatory Status

No FDA-approved product

  • No record of United States approval in Drugs@FDA.
  • Listed on FDA's table of bulk substances nominated for compounding and subsequently withdrawn, as Semax (heptapeptide). Published concerns include immunogenicity risk and limited safety information for the proposed routes.
  • On 24 July 2026 PCAC discussed Semax (free base) and Semax acetate (uses evaluated: cerebral ischemia, migraine and trigeminal neuralgia). FDA briefing materials proposed that they NOT be included on the 503A Bulks List. Nominations had been withdrawn; FDA elected to proceed. Committee recommendations are non-binding; FDA has not published a listing decision as of this review.
Technical Chemical SpecificationsClick to view CAS, sequence, and molecular formulas
Molecular weight
813.9 g/mol
Sequence length
7 chars
CAS number
80714-61-0
PubChem CID
9811102
Compound class
Synthetic heptapeptide analogue of ACTH(4-10) with a C-terminal Pro-Gly-Pro extension
Sequence
MEHFPGP
Molecular formula
C37H51N9O10S
Molecular weight
813.9 g/mol
CAS number
80714-61-0
PubChem CID
9811102