Selank is a synthetically produced heptapeptide version of Tuftsin, a naturally occurring immunopeptide, with several highly beneficial nootropic and immunomodulatory effects demonstrated in clinical studies. Initially created at the Institute of Molecular Genetics at the Russian Academy of Science, Selank is similar to Semax, both in its discovery at the aforementioned institute and in its beneficial effects on immune system and brain function.
In research studies conducted on both animal and human test subjects, scientists studying Selank have observed profound anxiolytic (anti-anxiety) and antidepressant effects. Importantly, these benefits have been observed to occur in subjects without the negative side effects common to benzodiazepine medications, including addictive, sedative, and withdrawal side effects. Moreover, like the natural peptide Tuftsin, Selank has been shown to have immunoprotective effects. Additionally, it also has been observed in studies to improve attention span, enhance learning capacity, and restore exploratory activity in brain-damaged rat test subjects . Further study has similarly shown Selank to restore vital cognitive processes in rats damaged by artificial inhibition. Ultimately, the discovery of and subsequent research into Selank has sparked great interest in the research community due to its fascinating and profound nootropic effects coupled with minimal, if any, negative side effects.
Selank is a synthetic heptapeptide with the structure Thr-Lys-Pro-Arg-Pro-Gly-Pro. As previously mentioned, Selank mimics many of the effects and mechanisms of action of the naturally occurring peptide Tuftsin. As a result of its natural derivation and simple peptide structure (it is composed simply of seven amino acids), Selank has been extremely well tolerated in clinical study test subjects. It has been observed to exhibit a virtually nonexistent toxicity level, even at high overdose concentrations in research studies. Additionally, Selank has been observed to have highly selective and targeted effects on study subjects, further encouraging research into future therapeutic applications.
A 2009 study revealed that one way Selank is able to exert its beneficial effects is through modulating the natural compound serotonin . In the study, researchers compared the effects of both Selank and its natural counterpart Tuftsin on serotonin metabolism. While Tuftsin had no apparent effect on serotonin metabolism, Selank was observed to increase serotonin metabolism in the brain stem only 30 minutes after administration. In turn, this revealed another possible avenue of Selank research, namely, as a future remedy for dysfunction in serotonin metabolism .
In further studies on rat test subjects, researchers observed that in addition to increasing the metabolism of serotonin, Selank was also highly effective in enhancing learning and memory processes in rat subjects as well. In the experiment, rat subjects underwent 30 trials per day, after which they would receive a reward (food). Following the tenth trial, either Selank or saline (for control group) was administered to animal test subjects. 30 minutes after administration, study researchers elaborated on the subjects conditioned reflexes with a reward, and subjects’ recall was measured 1 day, 7 days, and 1 month after treatment. Researchers found that one administration of Selank effectively enhanced the serotonin metabolism in test subjects’ brain stems for up to 2 hours afterward. As a result, memory trace stability was significantly enhanced, demonstrating that Selank can indeed improve the brain’s recall and storage of memories. Researchers concluded that this beneficial effect was more than likely caused by Selank’s modulation of serotonin metabolism.
Additional studies have revealed that Selank has a beneficial impact on other critical neurotransmitters in the brain as well. A 2008 study found that Selank was able to increase the level of norepinephrine in the brain of mice test subjects shortly after administration. Conversely, other neurotransmitter monoamine levels remained unaffected. As a result, researchers concluded that Selank is highly specific and targeted in its effects on neurotransmitters, a desirable quality in a potential future therapeutic.
As a potent anxiolytic, antidepressant, and nootropic peptide, Selank holds much promise for future development into therapeutic aids. As a result, there have been many studies conducted on Selank on both human and animal test subjects in order to unveil the extent of its beneficial properties. Perhaps most exciting is the ability of Selank to exhibit antidepressant and psychostimulant properties in studies without the undesirable negative effects of commonly used medications. Related actions of Selank, including the enhancement of dopamine synthesis, also hold much promise for the scientific research community.
In a 2008 study, researchers sought to delve deeper into Selank’s antidepressant effects by looking at its impact on genetically inherited depression symptoms versus those caused by situations . Researchers found that Selank had a significant positive impact on depression symptoms caused by a situation as measured by a forced swimming test . While researchers noted that Selank did not have a significant impact on rats with genetically inherited depression symptoms, they concluded that Selank’s impact on situational symptoms clearly demonstrated its antidepressant effects .
A 2008 study demonstrated the profound immunomodulatory properties of Selank in human test subjects in addition to its antidepressant and anxiolytic effects . Researchers administered Selank to a group of patients with Generalized Anxiety Disorder (GAD) and neurasthenia, as well as to a control group. They observed that Selank had beneficial immunomodulatory effects on those patients with GAD . Additionally, they concluded that Selank may have beneficial therapeutic impact on combating infectious diseases in at-risk subsets of the population, including the elderly and those people exposed to toxins and stressors in the environment .
A 2006 study further explored Selank’s adaptogenic effects, looking at restoring normal cognitive function in rat test subjects that had suffered hypoxia. Researchers discovered that test subjects administered Selank demonstrated significant improvements in brain function. Sensory attention in test subjects increased 200 - 300%, while learning capacity was enhanced 150%. Further tests revealed that exploratory activity as measured by specific tests was returned to normal, and the activity of the serotonergic and noradrenergic brain systems were restored to normal balance. Researchers concluded that these findings suggested that Selank had great potential in combating the effects of brain injury due to hypoxia.
As Selank has demonstrated significant potential as a future therapeutic agent, much research has focused on its anxiolytic properties, both in isolation and when combined with more traditional pharmaceutical treatments. Indeed, Selank has been observed in research studies to exhibit similar anxiolytic effects to pharmaceuticals containing benzodiazepine, possessing similar mechanisms of action without the same potential for addictive, withdrawal, or other negative side effects.
Researchers had postulated that one way Selank may exert its effects was through a similar mechanism of action as benzodiazepine medications; namely, by modulating the performance of the GABAergic system. To find out, researchers tested Selank’s effects on gene expression of 84 specific genes as well as on GABA (gamma-aminobutyric acid). They then compared these effects to those of olanzapine . Researchers concluded that the results of the experiment only partially confirmed their hypothesis. Importantly, however, they did note that their results indicated that olanzapine’s effects may be enhanced in combination with Selank.
As a result, a 2017 study published in Behavioural Neurology sought to investigate the anti-anxiety effects of Selank when administered solo and when utilized in combination with diazepam. The effect on anxiety induced either through administration of test substances or through mild unpredictable stress conditions was observed. After testing, researchers concluded that Selank alone was most effective as an anti-anxiety aid when combating high anxiety induced through administration of test substances. However, study subjects saw the greatest reduction in anxiety brought on by unpredictable mild stress conditions when administered both Selank and diazepam. Still, Selank alone had a very significant effect on anxiety levels, no matter what the initial cause. Researchers observed that Selank was able to exert its effects by affecting the GABAergic system, supporting an earlier hypothesis. Importantly, researchers concluded that Selank could be used in the future along with diazepam to treat patients suffering from anxiety, allowing patients to take a smaller dose of diazepam and minimize that medicine’s side effects.