Comparison
Selank vs Semax
Both are nootropic & neuro, so the meaningful differences are in kinetics, evidence and regulatory status.
| Selank | Semax | |
|---|---|---|
| Class | Nootropic & neuro | Nootropic & neuro |
| Evidence | Preliminary human | Preliminary human |
| Human trials | ~6 | ~8 |
| Half-life | ~30 minutes (intranasal) | ~30 minutes (intranasal) |
| Reported range | 250-750 mcg | 300-900 mcg |
| Frequency | 1-3x daily intranasal | 1-3x daily intranasal |
| Routes | Intranasal, Subcutaneous | Intranasal, Subcutaneous |
| FDA approved | No | No |
| Research use only | Yes | Yes |
| Banned in sport | No | No |
| Studied for | Generalised anxiety research, Stress resilience, Cognitive support | Cognitive enhancement research, Stroke recovery, Optic nerve conditions |
| Reported side effects | Nasal irritation, Transient drowsiness, Headache | Nasal irritation, Headache, Overstimulation, Irritability |
Selank
Selank is a heptapeptide built from the immunomodulatory tetrapeptide tuftsin with a proline-glycine-proline extension added for stability. It appears to act by modulating the expression and metabolism of enkephalins and by influencing GABAergic and serotonergic signalling, producing anxiolysis without the sedation, motor impairment or withdrawal associated with benzodiazepines. It is registered as a medicine in Russia; Western trial evidence is limited.
Semax
Semax is an analog of adrenocorticotropic hormone fragment 4-10, extended with proline-glycine-proline to resist enzymatic degradation. The modification removes hormonal activity at the adrenal cortex while preserving central effects, which include increased expression of brain-derived neurotrophic factor and its receptor TrkB, and modulation of dopaminergic and serotonergic transmission. It is on the Russian essential medicines list for stroke and cognitive disorders.
Selank vs Semax: common questions
What is the difference between Selank and Semax?
Both are nootropic & neuro. Selank: A synthetic tuftsin analog developed in Russia as an anxiolytic without sedation or dependence. Semax: A heptapeptide ACTH fragment analog used in Russia for stroke and cognitive indications, with no corticotropic activity.
Which has stronger evidence, Selank or Semax?
They sit at the same evidence level: preliminary human. Selank has about 6 human studies and Semax about 8.
Are Selank and Semax FDA approved?
Neither is FDA approved for any indication.
References
Regulatory and primary sources
- PubChem compound record (CID 11765600) ↗ · structure, identifiers, synonyms
- FDA: Unapproved drugs and "research use only" products ↗ · regulatory status of non-approved products
- CAS Registry Number 129954-34-3 ↗ · chemical identity
- PubChem compound record (CID 9811102) ↗ · structure, identifiers, synonyms
- CAS Registry Number 80714-61-0 ↗ · chemical identity
Published literature
- Therapeutic Peptides in Orthopaedics: Applications, Challenges, and Future Directions.J Am Acad Orthop Surg Glob Res Rev 2026.PubMed 41490200 · doi:10.5435/JAAOSGlobal-D-25-00236
- Tuftsin - Properties and Analogs.Curr Med Chem 2017.PubMed 28745220 · doi:10.2174/0929867324666170725140826
- Anaesthesia and circulating blood volume.Eur J Anaesthesiol 2005.PubMed 15892402 · doi:10.1017/s0265021505000438
- [Optimization of the treatment of anxiety disorders with selank].Zh Nevrol Psikhiatr Im S S Korsakova 2015.PubMed 26356395 · doi:10.17116/jnevro20151156133-40
- [A comparison of the anxiolytic effect and tolerability of selank and phenazepam in the treatment of anxiety disorders].Zh Nevrol Psikhiatr Im S S Korsakova 2014.PubMed 25176261
- Low dosage lithium augmentation in venlafaxine resistant depression: an open-label study.Psychiatriki 2012.PubMed 22796912
- [Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia].Zh Nevrol Psikhiatr Im S S Korsakova 2008.PubMed 18454096
- [Comparison of anticoagulant effects of regulatory proline-containing oligopeptides. Specificity of glyprolines, semax, and selank and potential of their practical application].Izv Akad Nauk Ser Biol 2006.PubMed 16634437
- Pharmacological Aspects of Neuro-Immune Interactions.Curr Pharm Des 2018.PubMed 28875850 · doi:10.2174/1381612823666170829135115
- [Prospects for use of short peptides in pharmacotherapeutic correction of Alzheimer's disease.].Adv Gerontol 2024.PubMed 38944767
- [Evolution of the stress concept].Vestn Ross Akad Med Nauk 2008.PubMed 19140465
- [The efficacy of semax in the tretament of patients at different stages of ischemic stroke].Zh Nevrol Psikhiatr Im S S Korsakova 2018.PubMed 29798983 · doi:10.17116/jnevro20181183261-68
- [POSSIBLE ROLE OF TRANSTHYRETIN IN THE BIOLOGICAL MECHANISM OF THE REGULATORY PEPTIDE NEUROPROTECTION.].Mol Gen Mikrobiol Virusol 2016.PubMed 30383932
- Modulation of neuropathological pathways by bioactive peptides and proteins/polypeptides: Targeting oxidative stress in neurodegenerative diseases.Neuropeptides 2025.PubMed 41004910 · doi:10.1016/j.npep.2025.102563
- [Place of oligopeptide H-Met-Glu-His-Phe-Pro-Gly-Pro-OH in the therapy and rehabilitation of patients with ischemic stroke].Zh Nevrol Psikhiatr Im S S Korsakova 2024.PubMed 39166935 · doi:10.17116/jnevro202412408256
Literature retrieved from PubMed on October 16, 2026, favouring human studies and reviews. Numbered markers in the text show which paper supports which statement; uncited entries are background reading.