Category: Cognitive Research | Reading time: 6 min | For research use only
Selank and Semax are synthetic neuropeptides developed in Russia by the Institute of Molecular Genetics of the Russian Academy of Sciences. Both have undergone clinical investigation and received approval in Russia for specific neurological and psychiatric applications — a regulatory status that provides an unusually detailed human pharmacology and safety profile compared to most research peptides. Outside Russia and some CIS countries, both remain investigational compounds studied in research contexts.
Their distinct but complementary mechanisms — Selank primarily modulating anxiolytic and immunomodulatory pathways, Semax primarily addressing neurotrophic and cognitive function pathways — have made them subjects of growing research interest in cognitive neuroscience, stress response biology, and neuroprotection research globally.
This article summarizes published research on both compounds for scientific and educational purposes. All compounds discussed are strictly for laboratory and research use only.
Selank
Molecular Profile
- Full name: Selank (TP-7)
- Sequence: Thr-Lys-Pro-Arg-Pro-Gly-Pro (heptapeptide) with additional stabilizing sequence
- Origin: Synthetic analogue of the endogenous tetrapeptide Tuftsin (Thr-Lys-Pro-Arg) with a Pro-Gly-Pro extension
- Molecular weight: ~751.9 g/mol
- Regulatory status: Approved in Russia (2009) as an anxiolytic agent; investigational elsewhere
- Form: Lyophilized powder (research grade); also studied as intranasal formulation
- Half-life: ~2 minutes (parent peptide); metabolites show longer activity profiles
- Stability: Store at −20°C
Tuftsin Connection
Selank's design as a Tuftsin analogue is significant for understanding its mechanism. Tuftsin is a naturally occurring tetrapeptide fragment of immunoglobulin G, produced by the spleen, and known to stimulate phagocytic activity and immune function. Selank retains Tuftsin's sequence but adds the Pro-Gly-Pro tripeptide extension, which dramatically increases metabolic stability from seconds (Tuftsin half-life) to approximately 2 minutes while preserving and extending biological activity.
Mechanisms Studied in Research
GABAergic modulation Research has identified interaction between Selank and the GABAergic system — the primary inhibitory neurotransmitter system in the brain. Studies have examined Selank's effect on GABA-A receptor function, benzodiazepine binding sites, and the expression of GABA-related genes in treated animal models. This mechanism is proposed as one basis for the anxiolytic effects documented in preclinical and clinical research.
BDNF and serotonin system interactions Published research has documented Selank's association with increased BDNF (brain-derived neurotrophic factor) expression in rat brain tissue and modulation of serotonin metabolism — specifically increased serotonin levels and altered serotonin turnover in various brain regions including hippocampus and hypothalamus.
Enkephalin stability Research has examined Selank's ability to inhibit enkephalin-degrading enzymes, potentially extending the activity of endogenous enkephalins — opioid peptides involved in mood and stress regulation.
Immune modulation Consistent with its Tuftsin origin, Selank has documented immunomodulatory effects in preclinical research. Studies have examined its effects on T-cell populations, cytokine production, and natural killer cell activity, with several publications reporting normalization of immune parameters in stressed animal models.
Anxiety and stress response models The most developed preclinical literature for Selank concerns anxiolytic-like effects in rodent behavioral models including elevated plus maze, open field test, and forced swim test. Selank has been compared to classical benzodiazepines in some studies, with researchers reporting anxiolytic effects without sedation or impaired motor coordination — a selectivity profile that has motivated research into its GABAergic mechanism specificity.
Clinical Research (Russia/CIS)
Selank was approved in Russia as an anxiolytic with nootropic properties. Clinical studies have examined it in generalized anxiety disorder, neurasthenia, and cognitive impairment contexts. Published clinical data documents tolerability, anxiolytic effects, and cognitive function improvements in treated populations, providing a human pharmacology basis for ongoing research.
Semax
Molecular Profile
- Full name: Semax (ACTH(4-7)-Pro-Gly-Pro)
- Sequence: Met-Glu-His-Phe-Pro-Gly-Pro (heptapeptide)
- Origin: Synthetic analogue of ACTH(4-7) — a fragment of adrenocorticotropic hormone — with Pro-Gly-Pro extension
- Molecular weight: ~813.9 g/mol
- Regulatory status: Approved in Russia (1996) for stroke recovery, cognitive impairment, and optic nerve pathology; investigational elsewhere
- Form: Lyophilized powder (research grade); primarily studied as intranasal formulation
- Half-life: ~7 minutes (parent peptide); active metabolites persist longer
- Stability: Store at −20°C; protect from light
ACTH Fragment Origin
Semax derives from ACTH(4-7) — the four amino acid sequence Met-Glu-His-Phe within adrenocorticotropic hormone. This fragment is responsible for ACTH's cognitive and neurotropic effects but lacks the corticotropic (cortisol-stimulating) activity of the full ACTH molecule, making it a research tool for studying ACTH-related neurobiology without HPA axis activation. The Pro-Gly-Pro extension, identical to Selank's stabilizing addition, increases metabolic stability.
Mechanisms Studied in Research
BDNF and NGF upregulation The most extensively documented mechanism of Semax is its association with increased expression of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in neural tissue. Research has reported upregulation of these neurotrophins in hippocampal and cortical tissue of Semax-treated animals, with proposed downstream effects on neuronal survival, synaptic plasticity, and neurogenesis.
Dopaminergic and serotonergic modulation Published studies have examined Semax's effects on dopamine and serotonin systems in rodent brain models, reporting changes in neurotransmitter levels and receptor expression in prefrontal cortex, striatum, and hippocampus. These findings have been examined in the context of attention, motivation, and memory consolidation research.
Neuroprotection models A substantial body of research has examined Semax in models of neurological injury — ischemic stroke, traumatic brain injury, and excitotoxicity. Studies have examined infarct volume, neurological deficit scores, and cellular survival markers in Semax-treated animals following experimental brain injury. The clinical approval in Russia for stroke recovery reflects this research base.
HIF-1α and oxidative stress Research has examined Semax's interaction with hypoxia-inducible factor 1-alpha (HIF-1α) — a transcription factor activated by low oxygen conditions. Studies in hypoxic brain models have reported Semax-associated upregulation of HIF-1α target genes involved in cellular oxygen sensing and metabolic adaptation.
Attention and memory models Behavioral pharmacology research has examined Semax in rodent models of attention, learning, and memory. Published studies using Morris water maze, radial arm maze, and passive avoidance paradigms have reported improved performance in Semax-treated animals across multiple research groups.
Optic nerve and retinal research The Russian clinical approval for optic nerve pathology reflects a specific area of Semax research. Published studies have examined Semax in models of optic nerve compression, retinal ischemia, and glaucoma, with investigators documenting neuroprotective effects on retinal ganglion cells and optic nerve fiber preservation.
Clinical Research (Russia/CIS)
Semax has been in clinical use in Russia since 1996 for ischemic stroke recovery, cognitive impairment, and optic nerve disease. Published clinical data from Russian studies provides human pharmacokinetic data, tolerability profiles, and efficacy endpoints across these approved indications, representing a more developed human evidence base than most research peptides.
Selank vs Semax: Comparative Research Profile
| Parameter | Selank | Semax |
|---|---|---|
| Primary mechanism | GABAergic / anxiolytic | Neurotrophic (BDNF/NGF) |
| Secondary mechanism | Immune modulation, serotonin | Dopaminergic / neuroprotective |
| Primary research domain | Anxiety, stress response | Cognitive function, neuroprotection |
| Clinical approval (Russia) | Anxiolytic (2009) | Stroke, cognition, optic nerve (1996) |
| Behavioral model literature | Anxiety models (EPM, OFT) | Memory models (MWM, passive avoidance) |
| Complementarity | Stress/anxiety regulation | Cognitive enhancement / protection |
The complementary profiles have motivated research examining both compounds together in models where anxiety-related impairment of cognitive function is a key variable — given that Selank's anxiolytic mechanism and Semax's neurotrophic mechanism could theoretically address different limiting factors in the same cognitive performance outcome.
Key Published Research
Selank:
- Semenova TP, et al. (2010). Selank and short peptides of the tuftsin family in the regulation of adaptive behavior in stress. Russian Journal of Bioorganic Chemistry, 36(3), 281–290.
- Zozulya AA, et al. (2001). Tuftsin controls anxiety-related behavior in rats. Peptides, 22(12), 1949–1957.
- Uchakina ON, et al. (2008). Immunomodulatory effects of selank in patients with anxiety-asthenic disorders.Russian Journal of Immunology, 5(1), 111–115.
Semax:
- Agapova TY, et al. (2007). Effects of ACTH(4-7)PGP (Semax) on the expression of BDNF and its receptor TrkB in the hippocampus of rats. Bulletin of Experimental Biology and Medicine, 144(6), 925–928.
- Dmitrieva VG, et al. (2010). Semax and Pro-Gly-Pro activate the transcription of neurotrophins and their receptor genes after cerebral ischemia. Cellular and Molecular Neurobiology, 30(1), 71–79.
- Limborska SA, et al. (2003). Analysis of Semax activity using ACTH(4-7) and Pro-Gly-Pro analogs. Molecular Genetics and Genomics, 269(4), 587–591.
Research Considerations
Both Selank and Semax have their primary research base in Russian-language literature, with the most comprehensive published data from Russian institutions. International replication of key findings has been limited, and researchers should evaluate the evidence base with appropriate consideration of publication concentration from a single geographic research community.
The Pro-Gly-Pro extension present in both compounds is itself biologically active — published research has documented independent effects of the Pro-Gly-Pro tripeptide on enkephalin metabolism. Researchers designing mechanistic studies should consider including Pro-Gly-Pro controls to isolate the contribution of the functional peptide sequences.
Both compounds are studied primarily via intranasal administration in clinical contexts. Researchers using alternative administration routes should consult the pharmacokinetic literature for route-specific bioavailability data.
NordBioLab supplies Selank and Semax as research-grade lyophilized peptides with ≥98% purity (HPLC verified) and full COA documentation per batch.
View Selank in our catalog → View Semax in our catalog →
All products and information provided by NordBioLab are strictly for scientific research and laboratory use only. Not for human or veterinary consumption. This article does not constitute medical advice.