Question 1

What is Selank?

Accepted Answer

Selank is a short synthetic peptide built from a fragment of an immune molecule, and the literature studies it for anxiety. A 2018 paper gives the structure plainly. Heptapeptide Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) exhibits prolonged anti-anxiety and nootropic effects. Heptapeptide means a chain of seven amino acids, and nootropic is the word that literature uses for something meant to sharpen thinking. The parent molecule is tuftsin. A 2022 rat study calls it Selank, a Peptide Analog of Tuftsin, and a 2017 review of tuftsin describes that family as immunomodulators, designed to regulate the immune response of the organism against infections of varying etiology. So the starting material is an immune signal and the use it is studied for is anxiety. That gap between where the molecule came from and what it is given for runs through the whole literature.

Question 2

What is N-acetyl Selank amidate?

Accepted Answer

It is a name for a chemically capped version of the same sequence, and the published work does not test it on its own. What the research describes is the plain heptapeptide. A 2018 paper names it as Heptapeptide Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro), and a 2008 behavioural paper repeats the identical sequence, calling it a synthetic derivative of the endogenous peptide tuftsin heptapeptide selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro). The words N-acetyl and amidate describe modifications at the two ends of that chain. That is chemistry rather than evidence, and no study among the research behind this page compares a capped version against the plain one. So every human and animal result set out below belongs to the uncapped sequence. Whether a capped version behaves the same way is a separate question that has not been asked.

Question 3

Where does the Selank evidence come from?

Accepted Answer

Almost all of it comes from one research community, and that is material to how a reader should weigh it. The titles say so directly. The largest patient study is titled Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia. A second patient study carries the title Immunomodulatory effects of selank in patients with anxiety-asthenic disorders. Both of those titles are printed in square brackets in PubMed, which is the index's way of marking an article published in a language other than English, and so are most of the other papers cited below. The rest sit in Bulletin of Experimental Biology and Medicine, Doklady Biological Sciences and Molecular Immunology. This is not a judgement about the research. It is a point about replication, because a finding reproduced by groups who do not share methods, assumptions or reagents is stronger than the same finding repeated inside one tradition, and the second is what this literature mostly offers.

Question 4

Does Selank actually work for anxiety?

Accepted Answer

Three published trials have set it against a benzodiazepine in patients, and their design decides how much weight they carry. In the largest, sixty-two patients with generalized anxiety disorder (GAD) and neurasthenia were studied, and the effect of selank (30 patients) was compared to that of medazepam (32 patients). The anxiolytic effects of both drugs were similar but selank had also antiasthenic and psychostimulant effects. A 2014 study examined 60 patients with phobic-anxiety- and somatoform disorders. Pronounced anxiolytic and mild nootropic effects of selank were demonstrated, and the anxiolytic effect lasted for a week after last receiving the peptide. A third trial added it on top of a benzodiazepine rather than testing it alone. Now read the design rather than the result. Each of the three set selank against an active drug instead of a dummy, and none of them describes blinding. To match a benzodiazepine in a trial where everyone knew what was given is a lower bar than the sentence first suggests.

Question 5

How far into people has Selank been tested?

Accepted Answer

Six published studies, and only one of the six was placebo-controlled. Three are the anxiety comparisons already described. A fourth examined patients with various forms of anxiety and phobic disorders (according to DSM-4 criteria) and measured a blood enzyme rather than a symptom. A fifth measured immune signals, finding changes of the Th1/Th2 cytokine balance in vivo in the serum of patients with generalized anxiety disorder and neurasthenia who received Selank during 14 days. The sixth is the controlled one. It was aimed at the assessment of effects of anxiolytic Selank and nootropic Semax on the whole-brain resting-state functional connectivity in 52 healthy participants, with scanning before, after 5 and 20 min of the injection of either Semax, or Selank, or placebo. Weigh what that controlled study measured. It found a difference in how brain regions co-activate at rest, which shows that something reached the brain rather than showing that anything useful follows from it.

Question 6

Does Selank do anything if nothing is wrong?

Accepted Answer

This is the most useful question in the literature, and the animal work answers it better than the human work does. A 2016 mouse study compared two strains side by side. The anxiolytic and nootropic efficiency of selank administered via both routes was observed only in BALB/c mice, which were characterized by initially reduced exploratory activity and higher levels of anxiety as compared to C57BL/6 mice. The calmer strain showed nothing at all. A 2008 study found the same pattern in a different model. Selank did not affect the level of general locomotor activity and anxiety in WAG/Rij rats, and did not exert substantial effect on the behavior of control Wistar rats. Correcting a deficit and improving a working system are different questions. The rodent work has repeatedly found the first and repeatedly failed to find the second, and every patient study enrolled people who already carried a diagnosis.

Question 7

How does Selank make you feel?

Accepted Answer

The published trials did not ask that question directly, and what they did record points two ways at once. The 2008 comparison found that the anxiolytic effects of both drugs were similar but selank had also antiasthenic and psychostimulant effects. Antiasthenic means acting against fatigue and weakness, which is roughly the opposite of what a sedative does. The 2014 study reports pronounced anxiolytic and mild nootropic effects of selank, and adds that selank had a positive impact on the quality of life of the patients. Quality of life there is a questionnaire score, which is narrower than mood and much narrower than how a day actually feels. Every one of those readings came from patients with a diagnosed anxiety disorder, assessed by clinicians who knew what they were giving. They describe a clinical impression rather than a sensation anyone recorded directly.

Question 8

Does Selank give you energy?

Accepted Answer

No study among the research behind this page measured alertness, heart rate or sleep in anyone taking Selank. What the trials do report is one word that keeps the question alive. The 2008 patient comparison records that selank had also antiasthenic and psychostimulant effects alongside its anxiolytic ones. Psychostimulant is a strong word, and the animal work puts a boundary around it. A 2008 rat and mouse study uses the same description, saying selank possesses an anxiolytic and psychostimulant effect, and then reports that Selank did not affect the level of general locomotor activity and anxiety in WAG/Rij rats. An animal given a stimulant moves about more, and these animals did not. So the word appears in the clinical descriptions and the matching behaviour does not appear in the animals. Those are different questions, and only the second of them was measured directly.

Question 9

Is Selank like a benzodiazepine?

Accepted Answer

The two are compared constantly in this literature, and the comparison is about effect rather than about mechanism. A 2016 rat study states the clinical position it was built on. Clinical studies have shown the similarity of the spectrum of physiological effects of Selank and classical benzodiazepines, such as diazepam and phenazepam. A 2017 cell study puts it more strongly, and records that Selank had an anxiolytic effect comparable to that of classical benzodiazepine drugs. The receptor work points at something much quieter. GABA is the brain's main calming signal. A 2018 study showed that Selank affect the [3H]GABA binding as a positive allosteric modulator, which means it nudges the receptor rather than switching it on. The same work found that Selank is able to block the modulatory activity of Diazepam and Olanzapine. Read that last part with care. A compound that blocks what diazepam does at a receptor is not doing the same thing as diazepam, however alike the two look in a clinic.

Question 10

What happens when Selank is stopped?

Accepted Answer

One trial measured exactly that, and the answer is unusual for an anti-anxiety compound. The 2014 comparison in 60 patients reports that the anxiolytic effect lasted for a week after last receiving the peptide. A week of carry-over is a long time for a short peptide, and nothing in the paper explains how it happens. A 2015 trial looked at the other side of stopping. In those patients the combined treatment decreased the level of undesirable side-effects of phenazepam during the course of treatment and after the tranquilizer withdrawal. Both readings come from open comparisons with no placebo arm, so expectation and clinician attention are not ruled out. What they do suggest is that whatever selank does, it does not stop the moment the course does.

Question 11

Can Selank be habit-forming?

Accepted Answer

No study among the research behind this page has measured dependence, tolerance or withdrawal in a person given Selank. The animal work went the other way, and looked at withdrawal from other things. Intraperitoneal, in both of the studies below, means into the belly rather than under the skin. One 2022 rat study used the naloxone-precipitated morphine withdrawal model. Single intraperitoneal injection of Selank in an anxiolytic dose of 0.3 mg/kg reduced the total index of morphine withdrawal syndrome by 39.6% in those rats. A 2014 study ran the same idea with drink. In alcohol-preferring animals, single intraperitoneal injection of selank in a dose of 0.3 mg/kg eliminated anxiety induced by ethanol withdrawal in tests elevated plus maze and social interaction tests. Easing another thing's withdrawal and being free of its own are different questions. The second one has not been asked in any species among the research behind this page.

Question 12

Does Selank affect the immune system?

Accepted Answer

It was built from an immune molecule, so two studies went looking, one in patients and one in mice. Cytokines are the chemical messengers immune cells use, and Th1 and Th2 name two arms of that response. A 2008 patient study found changes of the Th1/Th2 cytokine balance in vivo in the serum of patients with generalized anxiety disorder and neurasthenia who received Selank during 14 days. A 2014 mouse study looked at genes instead. Selank and its short fragment Gly-Pro influence the expression of genes that mediate different types of immune responses, thereby maintaining the balance of the immune system, measured in mouse spleen. Notice how both are phrased. Each describes a shift in a measurement rather than an outcome anybody would feel, and neither followed a participant long enough to find out whether it mattered.

Question 13

How is Selank given in studies?

Accepted Answer

Two routes run through the animal work, and one 2016 mouse study compared them head to head. It set out to compare pharmacological effects of intraperitoneal (i.p.) and intranasal (i.n.) administration of heptapeptide selank (300 microg/kg/day for 5 days) in two strains of mice. Both routes did something, and they did not do the same thing. In BALB/c mice, the injected route increased the number of binding sites with GABA-receptors in the frontal cortex by 38%, without change in binding to NMDA receptors in the hippocampus. The nasal route ran the other way, with no effect on GABA receptors in those animals. That is a real finding and an awkward one. The nose and the needle are different ways into the brain rather than interchangeable ones, and that comparison has not been repeated in a person among the research behind this page.

Question 14

Is Selank approved anywhere?

Accepted Answer

One Russian paper describes a completed phase 3 programme. Outside Russia the position is that it carries no approval at all. The clearest statement comes from 2008, inside a behavioural paper rather than a regulatory one. It calls the heptapeptide a working element of a new peptide drug having completed the third phase of the clinical testing as a selective anxiolytic. A 2026 orthopaedic review covering selank among neuroactive peptides records the broader position in a single line: there is a current lack of clinical trials. That review was written eighteen years after the phase 3 sentence above. An approval in one country is a real fact, but it is not a transferable one. It says that one regulator accepted one dossier, and nothing at all about what another regulator would make of the same evidence.

Question 15

What is documented about harm?

Accepted Answer

No controlled study among the research behind this page set out to measure harm from Selank over any length of time. One animal experiment came closest. A 2017 study tested several peptides on mouse embryonic stem cells and concluded that these peptide compounds do not produce toxic effect during the embryonic and fetal period of life. In the same work on mouse cells, Selank decreased the ratio of these cells by 61 per cent in comparison with the control, as they turned into one kind of neuron. The literature's own framing is worth noticing. A 2001 paper introduces the compound as one which attenuates behavioral anxiety reactions and does not cause side effects typical of most anxiolytics. That is a motivation for studying it rather than a measurement taken from anybody. A 2026 review covering selank records a current lack of clinical trials, and that sentence governs everything above it.

Question 16

Does Selank help memory or learning?

Accepted Answer

Only in animals that were struggling to begin with, which is the same pattern the anxiety work shows. A 2003 rat study compared animals with initially low levels of learning ability against normal ones. Selank significantly activated the learning process in rats with initially poor learning ability, with effects apparent after first dose on training day 1. Two damage models point the same way. In Wistar rats given a neurotoxin, Selank (300 microg/kg) restored cognitive processes disordered by chronic artificial inhibition of the cerebral catecholaminergic system. A 2008 paper reports that the peptide recovers learning and memory impaired by damage of the noradrenergic (NA) brain system in Wistar rats. In the healthy animals of that first study the effect was slower and smaller. A compound that repairs a deficit is not the same thing as a compound that lifts a working memory, and only the first has been shown here in rodents.

Question 17

How is Selank thought to work?

Accepted Answer

Three routes are proposed, and each of them was measured in tissue rather than in a living person. The first runs through GABA, the brain's main calming signal. A 2018 study showed that Selank affect the [3H]GABA binding as a positive allosteric modulator. In plain words, it nudges that receptor rather than switching it on. The second runs through enkephalin, one of the body's own pain and mood signals. A 2001 study found that Selank dose-dependently inhibited enzymatic hydrolysis of plasma enkephalin in those patients. Put simply, it slowed down the enzyme that breaks the signal apart. The third route is gene expression. A 2016 rat study found significant changes in the expression of 45 genes 1 h after the administration of the compounds, in rat frontal cortex. A 2026 review adds that selank, semax, and dihexa enhance brain-derived neurotrophic factor, which is a protein that helps nerve cells grow and survive.

Selank