Maple Side-by-side research comparison of Semax and Selank, two synthetic neuropeptides developed at the Institute of Molecular Genetics (Russian Academy of Sciences). Both are derived from endogenous regulatory peptides but target distinct neurotransmitter systems with different research applications.
Common Origins, Divergent Mechanisms
Semax and Selank share a development lineage (both emerged from Russian neuropeptide research programs in the 1980s-90s) and a structural strategy (both are short synthetic peptides derived from endogenous precursors with C-terminal Pro-Gly-Pro extensions for enzymatic stability). But they target fundamentally different neurotransmitter systems:
Head-to-Head Comparison
| Parameter | Semax | Selank |
|---|---|---|
| Full Sequence | Met-Glu-His-Phe-Pro-Gly-Pro (ACTH(4-10) + PGP) | Thr-Lys-Pro-Arg-Pro-Gly-Pro (Tuftsin + PGP) |
| Endogenous Precursor | ACTH (adrenocorticotropic hormone) | Tuftsin (IgG-derived immunopeptide) |
| Amino Acids | 7 | 7 |
| C-Terminal Extension | Pro-Gly-Pro (enzymatic stability) | Pro-Gly-Pro (enzymatic stability) |
| Primary Neurotransmitter Target | Neurotrophic (BDNF/NGF/TrkB) | GABAergic + enkephalinergic |
| Secondary Systems | Dopaminergic, serotonergic, copper binding | Serotonergic, immunomodulatory (IL-6, TNF-alpha) |
| BDNF Effect | Strong upregulation (2-4x in rodent models) | Moderate modulation |
| GABAergic Effect | Minimal direct effect | Allosteric modulation of GABA-A receptor |
| Immune Effects | Minimal | Significant (tuftsin heritage): phagocyte activation, cytokine modulation |
| Hormonal Activity | None (ACTH fragment lacks adrenal activity) | None |
| Russian Regulatory Status | Approved (nasal, 2011) | Approved (nasal, 2009) |
| Western Regulatory Status | Research compound only | Research compound only |
| Research Character | Neurotrophic/neuroprotective | Anxiolytic-like/immunomodulatory |
Semax: Neurotrophic Factor Modulation
Semax’s primary mechanism centers on modulation of brain-derived neurotrophic factor (BDNF) and its high-affinity receptor TrkB. Research has demonstrated that Semax increases BDNF mRNA and protein levels in multiple brain regions, with temporal dynamics that vary by region and dose. The BDNF/TrkB pathway is one of the most intensively studied systems in neuroscience, with roles in synaptic plasticity, neuronal survival, and circuit refinement.
Beyond neurotrophic signaling, Semax exhibits copper-binding capacity (KD ~2.4 nM at the His-Phe-Pro motif), which may modulate copper-dependent enzymatic processes in the central nervous system, including dopamine-beta-hydroxylase and peptidylglycine alpha-amidating monooxygenase.
Selank: GABAergic and Enkephalinergic Modulation
Selank’s anxiolytic-like effects in animal models are mediated through allosteric modulation of GABA-A receptors, potentiating GABAergic inhibitory tone without directly binding the benzodiazepine site. This mechanism is distinct from classical benzodiazepines and produces a different pharmacological profile in research settings.
Selank also modulates the enkephalinergic system by inhibiting enkephalin-degrading enzymes, increasing endogenous enkephalin availability at delta and mu opioid receptors. This provides a separate anxiolytic-like mechanism that operates independently of GABA modulation.
The immunomodulatory effects inherited from tuftsin include enhanced phagocyte function and modulation of pro-inflammatory cytokines (IL-6, TNF-alpha), creating a unique dual neuro-immune research profile not shared by most neuropeptides.
Research Selection Guide
| Research Focus | Recommended Compound | Rationale |
|---|---|---|
| Neurotrophic factor dynamics (BDNF/NGF) | Semax | Strongest published evidence for BDNF upregulation in CNS tissue |
| GABAergic modulation without benzodiazepine binding | Selank | Allosteric GABA-A modulation through a non-benzodiazepine mechanism |
| Neuro-immune crosstalk | Selank | Tuftsin-derived immunomodulation + neuropeptide activity |
| Copper-dependent neurochemistry | Semax | High-affinity copper binding at His-Phe-Pro motif |
| Enkephalin system research | Selank | Inhibits enkephalin degradation, increases endogenous opioid peptide availability |
| Serotonergic modulation | Either | Both modulate serotonergic transmission through different upstream mechanisms |
| Combination neuropeptide studies | Both | Non-overlapping primary mechanisms allow clean combination protocols |
Research Products
Available at Maple Research Labs
Third-party COA verification | Same-day Canadian shipping
Deep-Dive Research Pages
Semax Neuropeptide Research | Full BDNF/TrkB mechanism, copper binding, published study citations
Selank Neuropeptide Research | GABAergic modulation, enkephalin system, immunomodulatory profile
Frequently Asked Questions
What is the difference between Semax and Selank?
Semax is derived from ACTH(4-10) and primarily modulates neurotrophic factors (BDNF, NGF) via TrkB signaling, with secondary effects on dopaminergic systems and copper-dependent enzymes. Selank is derived from tuftsin and primarily modulates GABAergic and enkephalinergic neurotransmission, with secondary immunomodulatory effects inherited from its tuftsin precursor. They target fundamentally different neurotransmitter systems and serve different research purposes.
Can Semax and Selank be used together in research?
Yes, their non-overlapping primary mechanisms (neurotrophic for Semax, GABAergic/enkephalinergic for Selank) make them suitable for combination research protocols. Each compound’s effects can be attributed to its specific pathway without confounding from mechanism overlap. Both share the Pro-Gly-Pro C-terminal extension for enzymatic stability and have similar molecular sizes.
Where can I buy Semax and Selank for research in Canada?
Maple Research Labs supplies both Semax and Selank within Canada, with third-party purity verification via HPLC and mass spectrometry. All products include batch-specific COAs and ship same-day from Canadian facilities. Both compounds are supplied exclusively for in-vitro and preclinical research use.