Semax: the basics
What is it?
A synthetic peptide derived from part of ACTH, a hormone signal. It is studied mainly for effects involving the nervous system.
Research paper 1 ↗Research paper 2 ↗What do people claim it helps with?
Memory, focus and recovery after stroke. Research in stroke patients does not prove a cognitive boost in healthy people.
What has research actually shown?
Animal work and some human stroke reports explore biological changes and recovery. These findings do not establish a dependable treatment for everyday focus or memory problems.
Research paper 1 ↗Research paper 2 ↗Has this been demonstrated in people?
Preclinical studies plus limited human studies in specific neurological settings. Broad cognitive-enhancement claims remain unproven.
Research paper 1 ↗Research paper 2 ↗What side effects, risks and unknowns should I understand?
Reliable long-term safety and interaction information is limited. FDA highlights insufficient safety information.
FDA safety information ↗Is it an approved medicine?
No FDA-approved medicine contains this peptide. Availability online or through a clinic does not mean it has been approved.
FDA safety information ↗Approval here means U.S. FDA approval and applies to a particular product, formulation and use. This is a starting overview, not a complete side-effect list. Sources checked 10 October 2026; independent scientific review pending.
How is it used or studied?
Studied using specific research preparations. There is no FDA-approved treatment formulation; an online vial, capsule or spray is not necessarily the product used in a study.
Different routes and formulations can have different effects. A study of one product does not validate every product with the same peptide name.
A common misunderstanding
This page describes U.S. approval; medical use in another country does not establish FDA approval.
What should I ask a clinician?
- What diagnosis or goal are we trying to address, and what established options are available?
- Was the expected benefit shown in people like me, using this exact product?
- How could my medicines, health conditions or pregnancy plans affect the risks?
- What monitoring is needed, and what would tell us the treatment is helping or should be stopped?
What do the research words mean?
- Peptide
- A short chain of amino acids, the building blocks of proteins.
- Preclinical
- Research in cells, tissues or animals before dependable treatment evidence in people.
- Controlled trial
- A study comparing a treatment with another treatment or a placebo to help separate its effects from other explanations.
- Biomarker
- A measurement, such as a hormone level. A change does not necessarily mean someone feels better or lives longer.
Semax Evidence & Clinical Profile
Human Study Limits
Semax has been investigated in clinical contexts. Patient outcomes must be evaluated against study size, design, and control cohorts.
Laboratory & In Vivo Assays
Cellular and animal disease models examine receptor binding affinities and signaling cascades, which require human confirmation.
What is Semax?
Heptapeptide Semax (ACTH 4-7 Pro-Gly-Pro) is A synthetic heptapeptide combining an ACTH(4–7) fragment with a C-terminal Pro-Gly-Pro tripeptide for enzymatic protection. Approved in Russia for acute ischemic stroke and cognitive rehabilitation, but unapproved by the FDA or EMA. Aliases include: ACTH(4-7)-PGP, Met-Glu-His-Phe-Pro-Gly-Pro.
- Sequence (one-letter)
- MEHFPGP
- Molecular formula
- C37H51N9O10S
- Molecular weight
- 813.9 g/mol
- CAS Number
- 80714-61-0
- UNII Code
- I5FAL2585H
- PubChem CID
- 122178
Identifiers checked against PubChem and FDA's Global Substance Registration System on 13 October 2026. FDA substance record ↗ · PubChem record ↗ See all names and codes in the peptide name index.
Clinical Trials & Human Cohorts
Human research can examine tolerability, symptoms or patient outcomes. The design and comparator determine what each result can establish.
Semax and Rehabilitation Timing After Ischemic Stroke [1]
What was reported
Semax was associated with increased plasma BDNF levels that stayed high through the study, and with faster and better Barthel index recovery.
What limits the conclusion
Russian-language study; the abstract does not describe randomization, blinding or placebo control.
Effects of Semax on the Default Mode Network of the Brain [2]
What was reported
A greater volume of the rostral (medial frontal cortex) subcomponent of the default mode network was seen in the semax group compared with controls.
What limits the conclusion
Small exploratory imaging study measured within minutes of a single dose, without cognitive or clinical endpoints.
How the compound may work
Mechanisms describe how Semax may affect biological processes. Laboratory findings and patient outcomes answer different questions.
BDNF & TrkB Neurotrophic Upregulation
A single application increased hippocampal BDNF protein, trkB phosphorylation, and BDNF and trkB mRNA levels in rats. [3]
Areas Being Studied
These research topics reflect active areas of scientific exploration, distinct from unverified commercial marketing claims.
Compare the study designs.
| Study | Design / sample | Outcome type | Key limitation |
|---|---|---|---|
| Post-Stroke Rehabilitation · 2018 [1] | Comparative clinical study (semax vs no semax subgroups) n = 110 |
Clinical endpoint evaluation | Russian-language study; the abstract does not describe randomization, blinding or placebo control. |
| Functional Brain Connectivity · 2018 [2] | Placebo-controlled resting-state fMRI study n = 24 |
Clinical endpoint evaluation | Small exploratory imaging study measured within minutes of a single dose, without cognitive or clinical endpoints. |
Regulatory Status & Clinical Safety
Regulatory Classification
Approved on Russian State Register of Medicines; unapproved by FDA or EMA.
Safety Realities & Impurities
Safety depends on the molecule, formulation, route and evidence. A laboratory purity measurement alone cannot establish safety for human use.
Clinical Trials Registry Records
Official registry records from ClinicalTrials.gov. Study registration does not imply government endorsement or guaranteed efficacy.
WADA & Anti-Doping Regulations
WADA Anti-Doping Status
Semax is not prohibited under current World Anti-Doping Agency (WADA) regulations. However, athletes must ensure unregulated preparations or unverified vendor products do not violate Section S0 (Non-approved substances). Last verified: October 2026.
Research Timeline
-
2026
Western Status
Remains an unapproved experimental compound in the US and EU. [5]
What Researchers Still Don't Know
Long-term safety profiles
Multi-year observational data in broader heterogeneous cohorts remains uncharacterized.
Optimal dose-response thresholds
Comparative trials optimizing minimal effective exposure versus adverse event rates.
Formulation bioavailability
Differences between oral, subcutaneous, and modified peptide delivery vehicles.
References
Primary sources verified against PubMed / NLM and regulatory databases.
- Clinical Trial
-
Neuroimaging
Effects of Semax on the Default Mode Network of the Brain ↗ (external website)
- Primary Study
- Clinical Series
-
Regulatory
Inside Peptides Neuropeptide Directory: Semax ↗ (external website)