Semax vs Selank: Nootropic Peptide Research Comparison
Published: 2026-03-19Updated: 2026-03-19Category: Comparisons
Semax and Selank are the two most studied nootropic peptides in preclinical and clinical literature. Both were developed at the Institute of Molecular Genetics of the Russian Academy of Sciences, but they derive from different parent molecules and act through distinct receptor pathways. This guide compares the published research on each.
Structural Overview
| Property | Semax | Selank |
|---|
| Full Name | ACTH(4-10) analogue with Pro-Gly-Pro extension | Tuftsin analogue with Pro-Gly-Pro extension |
| Amino Acids | 7 (Met-Glu-His-Phe-Pro-Gly-Pro) | 7 (Thr-Lys-Pro-Arg-Pro-Gly-Pro) |
| Parent Molecule | ACTH (adrenocorticotropic hormone) | Tuftsin (Thr-Lys-Pro-Arg) |
| CAS Number | 80714-61-0 | 129954-34-3 |
| Primary Research Area | Neurotrophic signaling / cognitive models | Anxiolytic / immunomodulatory models |
| Regulatory Status (Russia) | Approved pharmaceutical (nasal spray) | Approved pharmaceutical (nasal spray) |
| FDA Status (US) | Not approved — available as RUO reference material | Not approved — available as RUO reference material |
Mechanism of Action (Published Research)
Semax
Semax has been studied primarily for its effects on neurotrophic factor expression. In preclinical models, it has been observed to upregulate BDNF (brain-derived neurotrophic factor) and NGF (nerve growth factor) expression. The Pro-Gly-Pro C-terminal extension stabilizes the peptide against enzymatic degradation, extending its half-life compared to the native ACTH(4-10) fragment. Published research includes studies on cerebral ischemia models, cognitive function in animal models, and neurotransmitter signaling pathways including dopamine and serotonin systems.
Selank
Selank is derived from tuftsin, an endogenous immunomodulatory tetrapeptide. In preclinical research, Selank has been studied for its influence on GABA signaling, with observations suggesting modulation of GABA-A receptor subunit expression. Published studies have examined its effects on anxiety-like behavior in animal models, enkephalin metabolism, and IL-6 cytokine modulation. The anxiolytic research profile distinguishes it from Semax's primarily cognitive/neurotrophic profile.
Key Research Differences
| Research Focus | Semax | Selank |
|---|
| Neurotrophic factors | BDNF and NGF upregulation observed in multiple models | Some BDNF data, but not the primary research focus |
| Anxiety/stress models | Secondary research area | Primary research area — GABA modulation observed |
| Immune function | Limited data | IL-6 modulation, tuftsin-derived immunomodulatory effects |
| Ischemia models | Extensive — neuroprotective observations in stroke models | Limited ischemia-specific data |
| Enkephalin system | Not a primary focus | Observed inhibition of enkephalin-degrading enzymes |
Published Study Highlights
Semax: Dolotov et al. (2006) demonstrated BDNF mRNA upregulation in rat hippocampus and cortex. Shadrina et al. (2010) reported gene expression changes in neurotrophic pathways. Multiple Russian clinical studies have been published on cerebrovascular applications, though these are primarily available in Russian-language journals.
Selank: Seredenin et al. (2008) reported anxiolytic effects comparable to benzodiazepines in animal models without sedation or dependence observations. Uchakina et al. (2008) published on immunomodulatory effects including cytokine modulation. Zozulya et al. (2001) studied effects on enkephalin metabolism.
Research context: Both peptides are approved pharmaceuticals in Russia but remain unapproved in the US. They are available as research chemical reference materials for in-vitro laboratory use. All published references here are from peer-reviewed preclinical or clinical studies.
Availability
Both Semax and Selank are available at Pepta Labs with ≥99% HPLC purity and third-party COA: Semax 25mg | Selank 10mg. See our purity testing guide for details on HPLC methodology.
All information is sourced from published peer-reviewed literature and provided for educational purposes only. This content does not represent claims about products sold by Pepta Labs. All products are chemical reference materials for in-vitro laboratory research only. Not for human or animal consumption. See
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