Key Statistics
| Statistic | Value | Detail |
|---|---|---|
| BDNF Increase | 1.4× | Protein levels in hippocampus |
| mRNA Expression | 3× | Exon III BDNF mRNA increase |
| Effect Duration | 24h | Extended by Pro-Gly-Pro modification |
| TrkB Activation | 1.6× | TrkB phosphorylation increase |
| Heptapeptide | 7 AA | MEHFPGP sequence |
Mechanism of Action
Neurotrophic Enhancement
Semax is a synthetic analog of ACTH (4-10) extended with Pro-Gly-Pro at the C-terminus for enhanced stability and prolonged effects. It upregulates brain-derived neurotrophic factor (BDNF), activates the TrkB receptor pathway, and influences the expression of genes involved in neuroplasticity and vascular function. Unlike the parent ACTH hormone, Semax lacks hormonal activity but retains potent nootropic effects.
Biological Pathways
BDNF/TrkB Pathway (Primary)
Brain-Derived Neurotrophic Factor
- 1.4-fold increase in BDNF protein levels
- 1.6-fold increase in TrkB phosphorylation
- Enhanced synaptic plasticity and learning
Melanocortin System (Moderate)
Melanocortin Receptor Modulation
- Potential interaction with MC receptors
- Modulates stress response pathways
- May contribute to cognitive effects
Vascular Gene Expression (Moderate)
Vascular Endothelial Growth Factor Pathway
- Upregulates vascular system genes
- Promotes angiogenesis after ischemia
- Supports neurovascular function
Key Mechanism
BDNF Upregulation
A single intranasal application of Semax (50 mcg/kg) results in significant increases in BDNF protein and mRNA levels in the hippocampus, the brain region critical for memory and learning.
Source: Institute of Molecular Genetics, Russian Academy of Sciences
| Metric | Value |
|---|---|
| BDNF Protein | ↑ 1.4-fold |
| TrkB Activation | ↑ 1.6-fold |
| BDNF mRNA (exon III) | ↑ 3-fold |
| TrkB mRNA | ↑ 2-fold |
Clinical Findings
| Metric | Value | Context |
|---|---|---|
| BDNF mRNA (exon III) | 300% | Increase in hippocampus |
| TrkB mRNA | 200% | Receptor expression increase |
| BDNF Protein | 140% | Protein level increase |
Research conducted at the Institute of Molecular Genetics demonstrated that intranasal Semax (50 mcg/kg) produces rapid and significant increases in neurotrophic factor expression in the rat hippocampus.
Preclinical Effects
| Effect | Model | Value |
|---|---|---|
| BDNF Increase | Stroke recovery | +100% |
| Motor Recovery | Clinical stroke studies | +85% |
| Functional Recovery | Rehabilitation data | +80% |
| Effect Duration | PGP modification benefit | 20-24h |
Research Areas
Cognitive Enhancement — Nootropic Effects
Semax enhances learning, memory, and attention through BDNF upregulation and TrkB pathway activation in the hippocampus.
Source: Russian Academy of Sciences
Neuroprotection — Stroke Recovery Support
Semax is approved in Russia for stroke treatment, demonstrating clinical efficacy in improving motor function and functional recovery.
Source: Clinical use in Russia since 1990s
Vascular Health — Angiogenesis Support
Semax promotes the expression of genes involved in vascular formation and function, supporting brain blood supply after injury.
Stress Response — Adaptive Regulation
As an ACTH analog, Semax may modulate stress response pathways through melanocortin receptor interactions without hormonal side effects.
Dosing Protocols
Standard Nootropic Protocol
Dose: 200-600 mcg | Frequency: 2-3x daily intranasal | Duration: 10-14 day cycles
- 0.1% solution (2-3 drops per nostril)
- Total daily dose: 400-1,800 mcg
- Cycles may be repeated after 2-4 week break
- Russian approved formulation for cognitive enhancement
Stroke Recovery Protocol
Dose: 2,000-6,000 mcg | Frequency: 3-4x daily intranasal | Duration: 1-10 days
- 1% solution for stroke and severe cognitive impairment
- Higher doses for acute neuroprotection
- Combined with rehabilitation therapy
- Medical supervision required
Pharmacokinetics
| Parameter | Value |
|---|---|
| Half-Life | 1-2 hours (plasma) |
| Peak Concentration | Within hours of administration |
| Bioavailability | Intranasal or subcutaneous |
| Stability | Pro-Gly-Pro extends duration to 20-24h |
| Excretion | Breaks down into natural amino acids |
| Metabolism | Crosses BBB readily (intranasal) |
Safety Profile
| Issue | Incidence | Severity |
|---|---|---|
| Nasal Irritation | 10% | mild |
| Mild Headache | 8% | mild |
| Dizziness | 5% | mild |
| Taste Disturbance | 3% | mild |
- No hormonal effects — does not affect cortisol levels or HPA axis
- No adrenal stimulation unlike parent ACTH
- No dependence observed in clinical use
- No withdrawal symptoms reported
- Breaks down into natural amino acids
Compound Information
| Property | Value |
|---|---|
| Type | Synthetic heptapeptide |
| CAS Number | 80714-61-0 |
| Molecular Weight | 813.9 g/mol |
| Amino Acids | 7 residues |
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro |
| Formula | C37H51N9O10S |
Frequently Asked Questions
Q: What is Semax and where does it come from?
A: Semax is a synthetic heptapeptide (7 amino acids: Met-Glu-His-Phe-Pro-Gly-Pro) developed at the Institute of Molecular Genetics of the Russian Academy of Sciences. It is an analog of ACTH (4-10), extended with Pro-Gly-Pro at the C-terminus for enhanced metabolic stability and prolonged duration of action from minutes to 20-24 hours.
Q: How does Semax differ from ACTH?
A: While Semax is derived from ACTH (4-10), it lacks the hormonal activity of the parent hormone. ACTH stimulates the adrenal cortex to produce cortisol, but Semax does not affect the hypothalamic-pituitary-adrenal (HPA) axis. Semax retains the nootropic and neuroprotective properties without causing hormonal side effects.
Q: What does the research show about Semax?
A: Research demonstrates that Semax increases BDNF protein levels by 1.4-fold and BDNF mRNA by 3-fold in the hippocampus. It also increases TrkB receptor phosphorylation by 1.6-fold. In clinical use in Russia, Semax has shown efficacy in stroke recovery, improving motor function and functional recovery.
Q: Is Semax approved for medical use?
A: Semax has been approved in Russia since the 1990s for treating ischemic stroke, traumatic brain injury, and cognitive impairment. It is available as 0.1% nasal drops for cognitive enhancement and 1% solution for stroke treatment. It is not approved by the FDA in the United States.
Q: How does Semax compare to Selank?
A: Semax and Selank are both Russian-developed peptides but have different origins and mechanisms. Semax is an ACTH (4-10) analog targeting BDNF/TrkB pathways for cognitive enhancement. Selank is a tuftsin analog that modulates the GABAergic system for anxiolytic effects. Both are approved in Russia and can be used together.
Q: Is Semax safe?
A: Semax has been used clinically in Russia for over 30 years with a favorable safety profile. Unlike ACTH, it does not affect cortisol levels or the HPA axis. Reported side effects are generally mild: nasal irritation, mild headache, and transient dizziness. No dependence, tolerance, or withdrawal symptoms have been reported.
References
- Dolotov OV, Karpenko EA, Inozemtseva LS, et al. (2006) “Semax, an analog of ACTH(4-10) with cognitive effects, regulates BDNF and trkB expression in the rat hippocampus” Brain Research DOI: 10.1016/j.brainres.2006.07.108 PMID: 16996037
- Medvedeva EV, Dmitrieva VG, Povarova OV, et al. (2014) “The peptide semax affects the expression of genes related to the immune and vascular systems in rat brain focal ischemia” BMC Genomics DOI: 10.1186/1471-2164-15-228 PMID: 24661656
- Multiple authors (2018) “The efficacy of semax in the treatment of patients at different stages of ischemic stroke” Zhurnal Nevrologii i Psikhiatrii PMID: 29798983
- Shadrina M, Kolomin T, Agapova T, et al. (2010) “Comparison of the temporary dynamics of NGF and BDNF gene expression in rat hippocampus, frontal cortex, and retina under Semax action” Journal of Molecular Neuroscience DOI: 10.1007/s12031-009-9270-z PMID: 19662538
- Multiple authors (2020) “Novel Insights into the Protective Properties of ACTH(4-7)PGP (Semax) Peptide at the Molecular Level” International Journal of Molecular Sciences PMID: 32575851