Research use only. The materials discussed on this page are sold exclusively for in vitro laboratory research. They are not for human or veterinary use, and nothing here is medical advice or a claim of benefit. Animal-model and clinical data are mentioned only as cited published literature.
Semax and Selank are two synthetic heptapeptides developed by the Russian Academy of Medical Sciences in the 1980s-1990s, both extensively studied in nootropic and behavioral neuroscience research. While both are short heptapeptides used in cognitive research, their mechanisms target distinct pathways: Semax acts on BDNF/NGF and dopaminergic systems, while Selank modulates GABA and anxiety circuits.
The two compounds
Comparison table
| Property | Semax | Selank |
|---|---|---|
| Class | ACTH(4-10) heptapeptide analog | Tuftsin heptapeptide analog |
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Thr-Lys-Pro-Arg-Pro-Gly-Pro |
| Molecular weight | 813.91 g/mol | 751.88 g/mol |
| CAS Number | 80714-61-0 | 129954-34-3 |
| Primary target | BDNF, NGF, dopamine/serotonin systems | GABA-A receptor, serotonin, BDNF |
| Research focus | Neuroprotection, cognitive performance, attention | Anxiolytic effects (no sedation), memory consolidation |
| Discovery | 1980s — Russian Academy of Medical Sciences | 1990s — Russian Academy of Medical Sciences |
| Combinable | Yes — frequently stacked with Selank | Yes — frequently stacked with Semax |
| Purity documentation | Batch CoA (HPLC) | Batch CoA (HPLC) |
Research contexts
Literature contexts for Semax
Studies on neuroprotection (in vitro ischemic models), BDNF/NGF expression research, cognitive performance and attention models, dopaminergic system modulation.
Literature contexts for Selank
Anxiolytic research without sedation (GABA-A modulation), stress-response models, memory consolidation studies, immunomodulatory cytokine balance.
Mechanisms of action
Semax
Semax is a synthetic peptide derived from ACTH (adrenocorticotropic hormone) fragment 4-10. It upregulates BDNF (Brain-Derived Neurotrophic Factor) and NGF (Nerve Growth Factor) expression, modulates dopaminergic and serotonergic systems, and shows neuroprotective effects in ischemic and oxidative stress models. Studied in over four decades of Russian neuroscience research.
Selank
Selank is a synthetic analog of the natural tetrapeptide tuftsin, with prolyl-glycyl-prolyl stabilizing modifications. It modulates GABA-A receptors producing anxiolytic effects without sedation or motor impairment in research models. Also shows BDNF expression upregulation and immune cytokine modulation.
Combined research context
Semax + Selank is a classic Russian nootropic research stack — their mechanisms are complementary (cognitive enhancement via BDNF/dopamine + anxiolytic via GABA), allowing study of combined effects on cognitive performance under stress. Neither is approved by the FDA, EMA, or MHRA for clinical use outside Russia/CIS states.
Related research products
Axion Research Peptides supplies research-grade peptides for in vitro use, with a batch certificate of analysis. Browse Semax, Selank or the full research catalog.
Frequently asked questions
What is the main difference between Semax and Selank?
Semax targets BDNF/NGF and dopaminergic systems (cognitive enhancement, neuroprotection). Selank targets GABA-A receptors (anxiolytic without sedation). Different pathways, often combined in research.
Can Semax and Selank be studied together?
Yes — they form a classic Russian nootropic research stack with complementary mechanisms. Frequently studied in combination for cognitive performance under stress.
Are Semax and Selank approved in the USA?
No — both are not approved by the FDA, EMA, or MHRA for any clinical use. They are approved as medicines only in Russia and some former Soviet states. Legal for in vitro research.
Which has stronger anxiolytic effects in research models?
Selank is specifically developed for anxiolytic research and shows direct GABA-A modulation without sedation. Semax has minor anxiolytic effects secondary to its primary cognitive enhancement profile.
Reconstitution recommendation?
Both: sterile bacteriostatic water at 2-5 mg/mL concentration. Store reconstituted at 2-8°C for up to 14 days. See the reconstitution guidance on the Axion blog for laboratory handling.
Scientific references
- Kaplan AJ et al., 1996 — Semax neurotropic effects
- Zozulia AA et al., 2008 — Selank in anxiety research
Regulatory disclaimer
The peptides discussed in this comparison are not approved by the FDA, EMA, MHRA, or any regulatory agency for human or veterinary clinical use, except where a specific approved product is named (for example, tesamorelin as Egrifta). They are sold by Axion Research Peptides exclusively for in vitro scientific research. This page summarizes published literature and is neither medical advice nor a recommendation for clinical use.
