Selank vs Semax
Both are Russian-developed heptapeptides studied for central-nervous-system activity, but their parent-peptide origins and primary endpoint literatures differ. Selank derives from the tuftsin immunopeptide and concentrates on anxiolytic endpoints. Semax derives from the ACTH(4-10) fragment and concentrates on cognitive and neuroprotective endpoints. This page summarises how the published research separates them.
Side-by-side comparison
| Property | Compound A | Compound B |
|---|---|---|
| Parent peptide | Tuftsin (endogenous immunopeptide, Thr-Lys-Pro-Arg) | ACTH(4-10) fragment (adrenocorticotropic hormone fragment, Met-Glu-His-Phe-Pro-Gly-Pro) |
| Structural class | Synthetic heptapeptide analogue of tuftsin with Pro-Gly-Pro C-terminal extension | Synthetic heptapeptide analogue of ACTH(4-7) with Pro-Gly-Pro C-terminal extension |
| Primary endpoints in literature | Anxiolytic profile (elevated-plus-maze, open-field test), immunomodulatory markers, GABAergic gene expression | Cognitive endpoints (learning, memory), neuroprotection (post-ischaemic), BDNF expression |
| Common research administration routes | Intranasal and intraperitoneal in rodent studies | Intranasal and intraperitoneal in rodent studies |
| Preclinical dose range | 100 to 1000 microgram per kilogram in published rodent studies | 50 to 600 microgram per kilogram in published rodent studies |
| Russian clinical-pilot status | Small number of Russian clinical-pilot reports using intranasal microgram-per-day doses | Small number of Russian clinical-pilot reports using intranasal microgram-per-day doses |
| Reconstitution | Bacteriostatic water; lyophilised vial format | Bacteriostatic water; lyophilised vial format |
| Ronin catalog vial size | 10 mg lyophilised | 10 mg lyophilised |
How they differ in mechanism
Selank derives from the tuftsin immunopeptide with a Pro-Gly-Pro C-terminal extension for protease resistance. The published mechanistic literature concentrates on GABAergic neurotransmission gene expression, monoaminergic system regulation in cortex and hippocampus, and cytokine profile modulation. The anxiolytic profile in elevated-plus-maze and open-field paradigms is the most-cited endpoint domain.
Semax derives from the ACTH(4-10) fragment with the same Pro-Gly-Pro C-terminal extension. The published mechanistic literature concentrates on brain-derived neurotrophic factor (BDNF) induction, neurotrophic-factor expression in hippocampus and basal forebrain, and neuroprotective effects in cerebral-ischaemia and middle-cerebral-artery-occlusion models. The cognitive-enhancement profile in learning-and-memory paradigms is the most-cited endpoint domain.
The practical consequence is that the two compounds are studied against different primary endpoints (anxiolytic versus cognitive/neuroprotective) through partially overlapping mechanistic territories (both modulate monoaminergic and neurotrophic-factor systems). Investigators interested in both anxiolytic and cognitive endpoints sometimes read both literatures together, but the primary citations and lead authors are largely separable.
How research has examined each
The Selank literature is concentrated in Russian-laboratory anxiolytic and immunomodulatory research. The Kozlovskaya and colleagues line of work characterised adaptive-behaviour regulation under stress. The Volkova and colleagues 2016 work characterised GABAergic neurotransmission gene expression effects. The cytokine and immune-marker time-course literature provides a secondary endpoint domain.
The Semax literature is concentrated in Russian-laboratory cognitive and neuroprotective research. The Levitskaya and colleagues work characterised neuroprotective and behavioural effects in rats. The Dolotov and colleagues 2006 work specifically characterised BDNF induction in rat basal forebrain. The Bashkatova and colleagues 2012 work characterised the neurochemical mechanism of action in the central nervous system. The post-stroke and cerebral-ischaemia literature provides the clinical-relevance framing for the neuroprotective endpoint domain.
Both literatures share the Russian-laboratory research tradition with its per-animal dose convention and its concentration of publications in Russian-language and Eastern European journals. Investigators outside this tradition should translate dose conventions and contextualise the clinical-pilot evidence within the broader Western regulatory framework.
Stacking considerations in research contexts
The two compounds are not commonly co-administered in published research protocols. Their primary endpoint domains (anxiolytic versus cognitive/neuroprotective) are different research questions rather than complementary mechanisms within the same question. Investigators interested in both endpoints would typically design separate experiments with each compound rather than a combined-administration protocol. Both are sold as separate lyophilised vials in the Ronin catalog.
Sourcing both at Ronin
Both compounds ship as 10 mg lyophilised peptide in glass vials with certificate-of-analysis documentation. The Selank vial page and the Semax vial page carry per-compound spec sheets. Both are sold strictly as research-grade reagents for laboratory and bench-research applications.
Frequently asked research questions
Are they chemically related?
Both are heptapeptides with a Pro-Gly-Pro C-terminal extension, but they derive from different parent peptides: Selank from tuftsin (immunopeptide), Semax from ACTH(4-10) (adrenocorticotropic fragment). They do not share sequence homology.
Can one substitute for the other in a research protocol?
No. Their primary endpoint domains differ (anxiolytic for Selank, cognitive/neuroprotective for Semax). Substituting one for the other would change the experimental design materially.
Are they stacked in research protocols?
Rarely. The two compounds address different research questions rather than complementary mechanisms within the same question.
Do they share reconstitution and storage practice?
Yes. Both are lyophilised peptides reconstituted in bacteriostatic water and stored refrigerated at 2-8 degrees Celsius protected from light. Both are commonly administered intranasally in published rodent protocols.
Are either approved for human therapeutic use?
Neither compound is approved by the FDA or Health Canada as a human therapeutic. A small number of Russian clinical-pilot reports exist for each, but these do not constitute Phase 1 dose-ranging trials by Western regulatory standards.
References
- Kozlovskaya MM et al. Selank and short peptides of the tuftsin family in the regulation of adaptive behavior in stress. Neuroscience and Behavioral Physiology, 2003. [PMID 12669588]
- Volkova A et al. Selank administration affects the expression of some genes involved in GABAergic neurotransmission. Frontiers in Pharmacology, 2016. [PMID 26869933]
- Levitskaya NG et al. ACTH(4-10) analog Semax produces neuroprotective and behavioral effects in rats. Behavioural Brain Research, 2010. [PMID 20211211]
- Dolotov OV et al. Semax binds specifically and increases levels of BDNF protein in rat basal forebrain. Journal of Neurochemistry, 2006. [PMID 16524382]
- Kolomin TA et al. Comparison of the transcriptome response to Semax and Selank in rat hippocampus and spleen cells. Molecular Biology, 2013. [PMID 23808162]
Comparison pages describe research-context use of the compared compounds. They do not constitute medical, veterinary, or clinical advice. Every compound in the Ronin catalog is sold strictly for laboratory and research use only.