One of the most interesting areas of research on Selank is its potential impact on brain-derived neurotrophic factor (BDNF). BDNF is a protein that plays a crucial role in neuronal survival, neuroplasticity, memory formation, learning processes, and cognitive adaptation. It is often considered one of the most important neurotrophic factors in the brain, as it supports the formation of new neural connections and helps maintain the proper function and integrity of existing neurons.
Evidence linking Selank to BDNF regulation primarily comes from preclinical studies. In a study conducted by Levitskaya et al., intranasal administration of Selank altered BDNF expression in the rat hippocampus, a brain region closely associated with memory, emotional regulation, and stress responses [1]. The findings indicated that Selank could influence neurotrophic signaling pathways upon administration, providing direct evidence of the peptide's interaction with BDNF regulation mechanisms in vivo.
These observations are particularly relevant because reduced BDNF activity is associated with chronic stress, anxiety disorders, depression, and impaired cognitive function. By influencing neurotrophic signaling, Selank may contribute to some of the cognitive, emotional, and neuroprotective effects observed in experimental and clinical studies.
Despite promising results, it should be noted that current evidence primarily comes from animal studies. Large-scale human clinical trials, directly assessing changes in BDNF levels after Selank administration, have not yet been conducted. Therefore, while available data suggest an interaction between Selank and BDNF-related pathways, it cannot be definitively stated at this time that Selank consistently increases BDNF levels in humans.
What BDNF Research Suggests About Selank?
Available research indicates that Selank's action extends beyond simple neurotransmitter modulation. Experimental studies suggest that the peptide may influence gene expression, neuronal adaptation, and neuroplasticity-related pathways, including those involving BDNF [1,2].
This broader mechanism of action distinguishes Selank from many conventional anxiolytic drugs, which exert their effects mainly through interactions with neurotransmitter receptors, without directly influencing neurotrophic signaling. Researchers suggest that Selank's ability to interact with both neurotransmitter systems and processes related to neuroplasticity may account for its unique pharmacological profile [2].
Does Selank affect dopamine?
Dopamine is a neurotransmitter involved in motivation, reward processing, attention, executive functions, and learning. As some users report improvements in focus and mental clarity, the question often arises whether Selank directly increases dopamine levels.
Current data suggest that Selank affects several neurotransmitter systems, however, evidence for a direct increase in dopamine remains limited. Most mechanistic studies have focused on its effects on GABAergic signaling, endogenous opioid peptides such as enkephalins, and neuroimmune pathways, rather than on direct dopaminergic activity stimulation [2,3].
Researchers suggest that Selank may indirectly influence neurotransmitter balance through its broad regulatory effects on brain function. By reducing anxiety and modulating stress-related pathways, the peptide may secondarily interact with dopamine-associated neural circuits, particularly those responsible for cognitive processes and emotional regulation [2].
Does Selank Increase Dopamine?
Currently, there is no strong clinical evidence to confirm that Selank directly increases dopamine levels in humans.
Unlike substances designed specifically to interact with dopamine receptors or transporters, Selank appears to function primarily as a regulatory neuropeptide. Its reported effects on mood, cognitive function, and mental performance are therefore likely related to overall neurochemical balance rather than direct dopaminergic stimulation.
This is an important distinction, as substances that rapidly increase dopamine levels are often associated with overstimulation, tolerance development, or addiction. Selank exhibits a distinctly different profile – studies indicate it has anxiolytic and cognitive-enhancing effects without the stimulating or euphoric properties typical of potent dopaminergic compounds [3,4].
Based on current evidence, it is more accurate to describe Selank as a peptide that may indirectly affect systems related to dopamine regulation, rather than as a direct dopamine enhancer.
Does Selank Increase Serotonin?
Serotonin is one of the most important neurotransmitters involved in mood regulation, emotional processing, anxiety control, and psychological well-being. Since Selank has shown anxiolytic effects in both clinical and experimental studies, many researchers wonder if serotonin plays a role in these effects.
Current evidence does not unequivocally confirm that Selank directly increases serotonin levels. Most published studies have focused on GABA receptor modulation, enkephalin metabolism, neurotrophic signaling, and changes in gene expression, rather than direct stimulation of the serotonergic system [2, 3].
However, scientists emphasize that Selank's anxiolytic profile likely results from the interaction of multiple neurotransmitter systems. Anxiety regulation depends on complex relationships between GABAergic, opioid, immunological, and neurotrophic pathways, which can indirectly affect serotonin activity.
What Does Research Show?
Clinical studies have shown that Selank can reduce anxiety symptoms and improve emotional functioning in individuals with generalized anxiety disorder and related conditions [3]. However, these studies did not directly measure serotonin levels or the activity of serotonergic receptors.
Consequently, although Selank clearly exhibits anxiolytic effects, current evidence does not allow us to state that increased serotonin is the primary mechanism responsible for these effects.
The most scientifically substantiated interpretation assumes that Selank may indirectly influence serotonin pathways as part of broader neurochemical regulation, however, a direct increase in serotonin has not yet been confirmed.
Does Selank lower cortisol?
Cortisol is commonly referred to as the body's primary stress hormone. Elevated cortisol levels are often associated with chronic stress, anxiety, sleep disturbances, impaired cognitive function, and mood-related issues. Due to its well-documented anxiolytic properties, the question frequently arises whether Selank, a peptide, directly lowers cortisol levels.
Interestingly, no major clinical trials have directly assessed the cortisol response following Selank administration. Most published studies have focused on outcomes related to anxiety, neurochemical regulation, enkephalin metabolism, BDNF expression, and GABAergic system activity [1–4].
Does Selank lower cortisol?
Although direct cortisol measurements are lacking, some research findings suggest that Selank may influence physiological stress responses.
Clinical studies have shown a reduction in anxiety symptoms in people with generalized anxiety disorder and neurasthenia [3]. Experimental studies have also shown that Selank modulates neurochemical systems involved in stress adaptation, including GABAergic signaling and the action of endogenous opioid peptides [2,4].
Since these systems are tightly related to the regulation of the hypothalamic-pituitary-adrenal (HPA) axis, researchers suggest that Selank may indirectly affect stress hormone activity. However, without direct hormonal measurements, it cannot currently be stated that Selank definitively lowers cortisol levels.
What conclusions can be drawn?
Available evidence supports Selank's role as an anxiolytic peptide capable of reducing behavioral and psychological symptoms of stress [2–4]. However, the question of whether these effects are accompanied by measurable changes in cortisol levels remains open.
Future clinical trials evaluating endocrine biomarkers, including cortisol, will be essential to determine the extent of Selank's impact on physiological stress regulation.
Summary
Current research suggests that Selank acts on multiple neurobiological systems related to neuroplasticity, stress adaptation, and emotion regulation. Preclinical studies indicate it may affect pathways related to BDNF, while its impact on dopamine, serotonin, and cortisol appears indirect and is not yet fully understood.
Although the available evidence supports Selank's role as a multifunctional neuroregulatory peptide, many of its proposed mechanisms of action have not yet been fully confirmed in large human clinical trials. Further research will be necessary to more precisely define its effects on neurotrophic factors, neurotransmitter systems, and endocrinological responses.
Disclaimer
The content is for educational and informational purposes only and does not constitute medical advice, diagnosis, or therapeutic recommendations. Selank remains a research peptide in many countries, and much of the discussed mechanisms are based on in vitro, animal, or early clinical studies. While published research suggests Selank may influence neuroplasticity, neurotransmitter regulation, and stress-related pathways, many of its proposed mechanisms still require further verification.
For research purposes only: Selank products offered by Semax Polska are intended exclusively for laboratory and scientific research. They are not approved for human consumption, medical use, diagnosis, treatment, or prevention of disease. Further clinical studies involving humans are needed to fully characterize the effects of Selank on BDNF, dopamine, serotonin, cortisol, and related neurobiological systems.
References
[1] Levitskaya, N. G., Andreeva, L. A., Mezentseva, M. V., Shapoval, I. M., Podchernyaeva, R. Y., Shcherbenko, V. E., Potapova, L. A., Russu, L. I., Ershov, F. I., & Myasoedov, N. F. (2010). Intranasal Administration of the Peptide Selank Regulates BDNF Expression in Rat Hippocampus In Vivo. Doklady Biological Sciences, 431, 79–82. Available from: https://www.researchgate.net/profile/Natalia-Levitskaya/publication/23306196_Intranasal_administration_of_the_peptide_Selank_regulates_BDNF_expression_in_the_rat_hippocampus_in_vivo
[2] Vyunova, T. V., Andreeva, L., Shevchenko, K., & Myasoedov, N. F. (2018). Peptide-Based Anxiolytics: The Molecular Aspects of Heptapeptide Selank Biological Activity. Protein and Peptide Letters, 25(10), 914–923. https://doi.org/10.2174/0929866525666180925144642
[3] Zozulia, A. A., Neznamov, G. G., Siuniakov, T. S., Kost, N. V., Gabaeva, M. V., Sokolov, O. Y., Serebriakova, E. V., Siranchieva, O. A., Andriushenko, A. V., Telesheva, E. S., Siuniakov, S. A., Smulevich, A. B., Myasoedov, N. F., & Seredenin, S. B. (2008). Efficacy and Possible Mechanisms of Action of a New Peptide Anxiolytic Selank in the Therapy of Generalized Anxiety Disorders and Neurasthenia. Journal of Neurology and Psychiatry named after S.S. Korsakov, 108(4), 38–48. https://pubmed.ncbi.nlm.nih.gov/18454096/
[4] Zozulya, A. A., Kost, N. V., Sokolov, O. Y., Gabaeva, M. V., Grivennikov, I. A., Andreeva, L. N., Zolotarev, Y. A., Ivanov, S. V., Andryushchenko, A. V., Myasoedov, N. F., & Smulevich, A. B. (2001). The Inhibitory Effect of Selank on Enkephalin-Degrading Enzymes as a Possible Mechanism of Its Anxiolytic Activity. Bulletin of Experimental Biology and Medicine, 131(4), 315–317. https://doi.org/10.1023/A:1017979514274
[5] Kost, N. V., Sokolov, O. Y., Zozulya, S. A., & Myasoedov, N. F. (2025). Combined Action of Benzodiazepine Tranquilizers and Peptide Anxiolytic Selank in BALB/c Mice. Neurochemical Journal, 19, 743–748. https://doi.org/10.1134/S1819712425700783