One of the most interesting areas of research into Selank is its potential impact on brain-derived neurotrophic factor (BDNF). BDNF is a protein that plays a crucial role in neuron 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 to maintain the proper function and integrity of existing neurons.
Evidence linking Selank to BDNF regulation primarily comes from preclinical studies. In a study by Levitskaya et al., intranasal administration of Selank altered the expression of BDNF in the rat hippocampus – a brain region closely associated with memory, emotional regulation, and stress responses [1]. The results indicated that Selank can influence neurotrophic signalling pathways upon administration, providing direct evidence for the peptide's interaction with BDNF regulatory mechanisms in vivo.
These observations are particularly significant as reduced BDNF activity is linked to chronic stress, anxiety disorders, depression, and cognitive impairment. By affecting neurotrophic signalling, Selank may contribute to some of the cognitive, emotional, and neuroprotective effects observed in experimental and clinical studies.
Despite promising results, it should be remembered that the current evidence mainly comes from animal studies. Large-scale human clinical trials that directly assess changes in BDNF levels following the use of Selank have not yet been conducted. Therefore, while the available data suggest an interaction between Selank and BDNF-related pathways, it cannot currently be stated that Selank consistently increases BDNF levels in humans.
What does BDNF Research Suggest about Selank?
Available research suggests that Selank's action extends beyond simple neurotransmitter modulation. Experimental studies indicate that the peptide may influence gene expression, neuronal adaptation, and pathways related to neuroplasticity, including those involving BDNF [1,2].
This broader mechanism of action distinguishes Selank from many conventional anxiolytics, which exert their effects primarily through interactions with neurotransmitter receptors, without directly influencing neurotrophic signalling. 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 impact on GABA-ergic signalling, endogenous opioid peptides like enkephalins, and neuroimmunological pathways, rather than direct stimulation of dopaminergic activity [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 can secondarily affect neuronal circuits associated with dopamine, particularly those responsible for cognitive processes and emotional regulation [2].
Does Selank Increase Dopamine?
There is currently 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 act primarily as a regulatory neuropeptide. Its reported effects on mood, cognitive function and mental performance are therefore likely related to general neurochemical balance rather than direct dopaminergic stimulation.
This is a significant 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 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 influence systems involved in 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. As Selank has demonstrated anxiolytic effects in both clinical and experimental studies, many researchers are wondering if serotonin plays a role in these effects.
Current evidence does not definitively confirm that Selank directly increases serotonin levels. Most published studies have focused on the modulation of GABA receptors, enkephalin metabolism, neurotrophic signalling, and changes in gene expression, rather than direct stimulation of the serotonergic system [2,3].
However, scientists emphasise that Selank's anxiolytic profile is likely due to 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 Do the Studies Show?
Clinical studies have shown that Selank may reduce anxiety symptoms and improve emotional functioning in individuals with generalised 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 demonstrates anxiolytic effects, current evidence does not allow us to conclude that increased serotonin is the main mechanism responsible for these effects.
The most scientifically substantiated interpretation suggests that Selank may indirectly influence serotonin pathways as part of broader neurochemical regulation, although a direct increase in serotonin has not yet been confirmed.
Does Selank Lower Cortisol?
Cortisol is commonly referred to as the body's main 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 often arises as to whether the peptide Selank directly lowers cortisol levels.
Interestingly, no major clinical studies have directly assessed the cortisol response following Selank administration. Most published research has focused on outcomes related to anxiety, neurochemical regulation, enkephalin metabolism, BDNF expression, and GABA-ergic system activity [1–4].
Does Selank Lower Cortisol?
Although direct measurements of cortisol are lacking, several research findings suggest that Selank may influence physiological stress responses.
Clinical trials have shown a reduction in anxiety symptoms in individuals with generalised anxiety disorder and neurasthenia [3]. Experimental studies have also shown that Selank modulates neurochemical systems involved in adaptation to stress, including GABA-ergic signalling and the action of endogenous opioid peptides [2,4].
As these systems are closely linked 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 is currently impossible to state definitively that Selank lowers cortisol levels.
What conclusions can be drawn?
Available evidence supports the role of Selank as an anxiolytic peptide capable of reducing behavioural 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 investigations assessing endocrine biomarkers, including cortisol, will be essential in determining the extent of Selank's impact on physiological stress regulation.
Summary
Current research suggests that Selank interacts with multiple neurobiological systems involved in neuroplasticity, stress adaptation, and emotional regulation. Preclinical studies indicate that it may affect pathways related to BDNF, while its interaction with dopamine, serotonin, and cortisol appears indirect and is not yet fully understood.
Although available evidence supports Selank's role as a multifunctional neuroregulatory peptide, many proposed mechanisms of action have yet to be fully confirmed in large-scale human clinical trials. Further research will be necessary to more accurately 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 studies suggest Selank may impact neuroplasticity, neurotransmitter regulation, and stress-related pathways, many proposed mechanisms require further validation.
For research purposes only: Selank products offered by Semax Polska are intended solely for laboratory and scientific research. They are not approved for human consumption, medical use, diagnosis, treatment or the prevention of disease. Further clinical trials involving humans are required to fully characterise 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 the 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 Generalised 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 Tranquillisers and Peptide Anxiolytic Selank in BALB/c Mice. Neurochemical Journal, 19, 743–748. https://doi.org/10.1134/S1819712425700783