Mechanism of Action
Melanocortin & BDNF Signaling
ACTH fragment analogs that modulate melanocortin pathways and upregulate brain-derived neurotrophic factor.
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Compounds
1
Total studies
84
Human studies
12
FDA approved
0
Overview
Semax and Selank are synthetic analogs of ACTH(4-7) and tuftsin fragments, respectively. They modulate melanocortin signaling in the CNS and upregulate BDNF and NGF, supporting synaptic plasticity, cognition, and anxiolysis. Both are used clinically in Russia for stroke recovery, anxiety, and cognitive decline.
Semax and selank are Russian-developed peptide pharmaceuticals derived respectively from ACTH(4-10) and tuftsin (a tetrapeptide fragment of IgG). They occupy a distinct therapeutic niche that has not been replicated in Western drug development. Both are intranasal, both modulate CNS monoamine metabolism, and both have been studied for cognitive enhancement and neuroprotection in Russian clinical contexts. BDNF upregulation is a convergent mechanism observed across multiple studies.
Receptor & signaling detail
Semax interacts with melanocortin receptors (particularly MC4R-linked signaling) and downstream BDNF/NGF expression. Selank's receptor mechanism is less clearly characterized — likely tuftsin-related immune targets and indirect monoaminergic modulation.
How it works
- 1Fragment-based binding at melanocortin and tuftsin-related CNS targets.
- 2Upregulates BDNF and NGF expression.
- 3Modulates monoamine (serotonin, dopamine) metabolism.
- 4Enhances synaptic plasticity and neuronal survival.
- 5Anxiolytic effects through GABAergic and noradrenergic modulation.
Downstream clinical effects
- Improved cognition and memory
- Neuroprotection in stroke models
- Reduced anxiety without sedation
- Accelerated stroke recovery
Documented clinical implications
- Improved cognition and memory in Russian trials
- Neuroprotection in stroke recovery models
- Anxiolytic effects (selank) without sedation
- Accelerated stroke-recovery outcomes in Russian clinical use
Limitations & mechanism-driven side effects
- Western replication of Russian clinical findings is minimal
- Not FDA approved; not legally available for human use in the US
- Quality and purity of research-chemical sources is variable
- Long-term safety data outside Russian pharmacovigilance is absent
Discovery & development
Both peptides emerged from Russian institutional research in the 1980s-90s (Institute of Molecular Genetics, Moscow). Both are registered medicines in Russia but not FDA-approved or commonly available in Western markets.
Peptides using this mechanism
Evidence status
Approved in Russia for stroke and cognitive indications. Western clinical trial data is limited.
Frequently asked questions
Are semax and selank legal in the US?
No. Neither peptide is FDA approved. Products sold "for research use only" are not authorized for human consumption.
How is semax administered?
Semax is typically administered intranasally. Intranasal delivery bypasses first-pass metabolism and may provide some direct CNS access via olfactory pathways.
Does selank cause sedation?
Russian clinical literature reports anxiolytic effects without the sedation typical of benzodiazepines. This would be consistent with a non-GABA-A mechanism.
Is there Western research on semax?
Limited. Most clinical literature is published in Russian medical journals and has not been extensively replicated in Western randomized controlled trials.
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