Semax vs Selank in Australia: Research Comparison

Semax and Selank are synthetic peptides developed at the Institute of Molecular Genetics of the Russian Academy of Sciences (IMG RAS) from the 1980s onwards. Both have been used in Russian clinical and research settings, and both have generated interest internationally for their neuroprotective and cognitive-modulating properties. Despite their shared origin, they target different biological pathways and have distinct research profiles.

Semax (Met-Glu-His-Phe-Pro-Gly-Pro) is a heptapeptide derived from the ACTH(4–7) sequence with a Pro-Gly-Pro C-terminal extension that confers metabolic stability. It was registered in Russia in 1994 for clinical use in stroke and transient ischaemic attack.

Primary mechanisms:

• BDNF and NGF upregulation, Semax increases brain-derived neurotrophic factor and nerve growth factor mRNA and protein expression in animal models; this is its most studied mechanism and the basis for neuroprotection research
• Dopaminergic and serotonergic modulation, Semax modulates dopamine and serotonin turnover in the prefrontal cortex and striatum in rodent models; associated with effects on working memory and attention
• Melanocortin receptor activity, as an ACTH fragment, Semax retains some melanocortin receptor (MC3R, MC4R) activity, which mediates CNS effects on attention and arousal
• Anti-inflammatory and neuroprotective, in ischaemia models, Semax reduces inflammation markers and neuronal apoptosis

Key research findings:

• Russian clinical studies report reduced cognitive deficits and improved outcomes in stroke patients
• Animal studies show improved performance in spatial memory, attention, and learning tasks
• BDNF upregulation persists after a single administration in rodents, suggesting lasting trophic effects
• Neuroprotection against hypoxia and excitotoxicity in cell culture models

Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) is a synthetic analogue of the endogenous immunopeptide tuftsin, with a Pro-Gly-Pro extension. It was registered in Russia in 2009 for the treatment of anxiety disorders.

Primary mechanisms:

• Benzodiazepine receptor modulation, Selank shows affinity for benzodiazepine binding sites and modulates GABA-A receptor activity, producing anxiolytic effects without the dependence risk associated with classical benzodiazepines in animal models
• Enkephalin stabilisation, Selank inhibits enzymes that degrade endogenous enkephalins (leucine and methionine enkephalin), enhancing endogenous opioid peptide activity
• Immune modulation, as a tuftsin analogue, Selank modulates cytokine expression (IL-6, IL-1β, TNF-α) and enhances phagocytic activity; tuftsin itself is an endogenous immunostimulating peptide
• BDNF modulation, Selank also affects BDNF, but through a different pathway and to a lesser degree than Semax

Key research findings:

• Anxiolytic effects in rodent models comparable to benzodiazepines without sedation or dependence
• Improved memory consolidation and retrieval in animal models
• Normalisation of cytokine profiles in stress models
• Russian clinical data in anxiety disorder patients reporting reduced anxiety scores

Despite their shared origin and overlapping research domains, Semax and Selank have distinct pharmacological profiles that make them suited to different research questions:

In Russian research and clinical contexts, Semax and Selank are sometimes administered together, their mechanisms are complementary rather than overlapping or antagonistic. Semax's activating/nootropic profile (BDNF, dopamine) and Selank's calming/anxiolytic profile (GABA-A, enkephalins) can theoretically balance each other, producing cognitive enhancement without the arousal/anxiety that Semax alone may produce in high doses in animal models.

This combination has been used in the context of studying stress-related cognitive impairment, where anxiolytic effects (Selank) and neurotrophic support (Semax) are both relevant. There is no direct published RCT data on the combination; this remains a research-grade application.

Both Semax and Selank are lyophilised peptides requiring reconstitution with bacteriostatic water prior to use. Research notes:

• Reconstitute with bacteriostatic water to extend post-reconstitution stability
• Store reconstituted solution at 2–8°C; protect from light
• Use the OzPeps reconstitution calculator to determine volumes for your target concentration

Both peptides are susceptible to oxidation; handle under clean conditions and avoid repeated freeze-thaw cycles.

Researchers studying Semax and Selank may also be interested in:

• DSIP (Delta Sleep-Inducing Peptide), another Russian-researched neuropeptide with sleep and stress modulation effects
• Longevity peptides in Australia, GHK-Cu, MOTS-c, Epitalon for broader neuroprotection and ageing research
• BPC-157, broad neuroprotective and regenerative compound with CNS research data

Semax and Selank are not individually scheduled under the Australian TGA Poisons Standard for research supply. OzPeps supplies both strictly for in-vitro laboratory and scientific research use only, not for human or animal administration. Products are sourced from suppliers with verified supplier Certificate of Analysis (COA).

See: Are Research Peptides Legal in Australia? →