Nootropic Peptides Australia: Semax and Selank Research Guide

Semax and Selank were developed at the Institute of Molecular Genetics of the Russian Academy of Sciences over several decades of neuropeptide research. Both are synthetic analogues of endogenous regulatory peptides — Semax from the ACTH(4-7) sequence, and Selank from the immunomodulatory peptide tuftsin. Both incorporate C-terminal Pro-Gly-Pro extensions that improve metabolic stability by protecting against N-terminal degradation.

Despite originating from the same research programme, Semax and Selank have distinct receptor mechanisms and primary research applications, making them complementary rather than interchangeable research tools.

Semax (Met-Glu-His-Phe-Pro-Gly-Pro) is derived from the ACTH(4-7) fragment — the part of adrenocorticotropin responsible for CNS cognitive effects without the adrenal-stimulating activity of the full ACTH molecule. The Met-Glu-His-Phe core corresponds to the MSH(4-7) sequence responsible for CNS melanocortin receptor interaction.

Key research findings for Semax:

• BDNF upregulation — Semax has been shown to increase brain-derived neurotrophic factor (BDNF) mRNA expression in the hippocampus and frontal cortex in rodent studies, with potential implications for synaptic plasticity research
• Dopamine and serotonin modulation — studies document altered monoamine metabolism in limbic structures after Semax administration, including changes in dopamine and serotonin turnover rates
• Neuroprotection in ischaemia — Semax has been investigated in stroke models, where it demonstrated reductions in infarct size and improvements in neurological function in rodent middle cerebral artery occlusion studies
• Cognitive enhancement — learning and memory task performance improvements have been documented in rodent behavioural models following Semax administration

Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) is a synthetic analogue of tuftsin (Thr-Lys-Pro-Arg) — a natural tetrapeptide derived from IgG that functions as an immunostimulatory agent. The Pro-Gly-Pro extension added by Soviet researchers significantly increases metabolic stability while retaining the parent compound's immunomodulatory properties.

Key research findings for Selank:

• Anxiolytic effects — Selank has demonstrated anxiolytic activity in multiple animal models (elevated plus maze, open field, Vogel conflict test) with a mechanism distinct from benzodiazepines — no GABAergic activity has been identified
• BDNF and serotonin — similar to Semax, Selank influences BDNF expression and serotonin metabolism, though with a more pronounced effect on the serotonergic system in some models
• Immunomodulation — as a tuftsin analogue, Selank retains effects on immune cell function, including modulation of IL-6, TNF-α, and interferon expression in stress models
• Cognitive properties — working memory improvements and enhanced information processing speed have been documented in rodent studies

The two peptides share some overlapping research applications (BDNF, cognitive function) but have distinct primary research strengths:

• Use Semax for research focused on dopaminergic/serotonergic modulation, neuroprotection, ACTH pathway effects, or CNS ischaemia models
• Use Selank for research focused on anxiolytic mechanisms, HPA axis stress responses, immune-CNS interaction (neuroimmunology), or non-GABAergic anxiety pathway studies

Combination studies using both peptides simultaneously have also been conducted in models examining synergistic effects on cognitive performance and stress response modulation.

RetaLABS supplies research-grade Semax 10mg and Selank 10mg as lyophilised powders. Reconstitute with bacteriostatic water; store lyophilised at −20°C and reconstituted at 2–8°C for up to 4 weeks. See the Peptide Reconstitution Guide for protocol details. COAs available on request. For laboratory research use only.