Selank: what the anxiety trials actually tested, and where

Four clinical studies of selank for anxiety have been published. All were run in Russia, all were small, and none of them compared the peptide against a placebo. All four describe the same thing: anxiety eased about as much as it did on a benzodiazepine, without the sedation, the memory problems or the sexual side effects. One network has produced that finding four times over eighteen years. Nobody outside it has run the study that would confirm it.

What selank is

Selank is seven amino acids long: threonine, lysine, proline, arginine, proline, glycine, proline. The first four are tuftsin, a fragment of the antibody molecule IgG that Victor Najjar's group in Boston described in 1970 as a signal that nudges immune cells to engulf bacteria [1]. On its own, tuftsin breaks down within minutes in blood. Researchers at the Institute of Molecular Genetics in Moscow added a Pro-Gly-Pro tail to stabilise it, the same trick they used on its sister peptide Semax [7].

Three mechanisms have been proposed for how it might work, all of them from lab work rather than from people: it slows the breakdown of enkephalins, the body's own opioid-like peptides, in human blood serum [6]; it changes how the calming neurotransmitter GABA binds its receptors in membranes taken from rat brain, loosely the way benzodiazepines do [7]; and it shifts the activity of GABA-related genes in a human neuroblastoma cell line [8]. None of the three has been shown to explain what happens in a patient, so treat all of it as theory rather than as the reason the trials found what they found.

Two bodies of evidence, and why we count both

Evidence hierarchies exist for a reason, and we use them. A randomised, placebo-controlled trial is the best tool anyone has invented for telling whether a molecule caused a change or was merely present when one happened.

The hierarchy's blind spot usually runs one way: it has no shelf for the recorded experience of the people who actually used something. Here it runs the other way. For selank, the problem is not that nobody looked. Four groups looked, published, and found a consistent result. What is missing is the single design feature that separates a drug from an expectation: a placebo arm. Every one of those four studies is a comparison against another active drug, in an open design where patients and doctors both knew who was getting what.

There is also no compiled real-world dataset for selank, and we are not going to pretend otherwise: no case series, no clinical audit, no practitioner's log of outcomes. What exists is the four trials below, a brain-imaging study, and a large rodent literature. That is a smaller evidence base than most peptides on this site, and we say so rather than dressing it up.

The published human evidence

We found four clinical papers on anxiety and one small brain-imaging study. All were published in Russian journals, and the peptide's co-developer, N. F. Myasoedov, is an author on most of them.

The 2008 study by Zozulia and colleagues is the one most often quoted. Its abstract says the anxiolytic effects of the two drugs were similar and that selank also had "antiasthenic and psychostimulant" effects [2]. The same team measured how fast enkephalin broke down in patients' blood and found it was faster in people with generalised anxiety, and that selank treatment moved that measure back [2]. That fits their own enzyme theory, and it is a correlation in a small unblinded group rather than a demonstration of cause.

A 2014 study by Medvedev and colleagues compared selank with phenazepam, a benzodiazepine widely prescribed in Russia, in 60 people with phobic, anxiety and somatoform disorders [3]. The authors report a "pronounced" anxiolytic effect lasting a week after the last dose. The abstract gives no numbers, no group sizes and no description of blinding.

The 2015 follow-up is the most detailed. Thirty patients took phenazepam alone and 40 took phenazepam plus selank [4]. The combination group improved faster on the Hamilton scale and reported fewer benzodiazepine side effects, including memory and attention problems, sedation and sexual difficulties, both during treatment and after the tranquilliser was stopped [4]. An open design cannot separate the peptide from expectation, and the authors do not claim it does: what they describe is a difference between two groups that both knew which treatment they were on.

A smaller 2008 paper looked at immune markers. It reported that 14 days of selank shifted the balance of Th1 and Th2 cytokines in the blood of people with generalised anxiety and neurasthenia [5]. What that means clinically has not been established.

The most recent human work, from 2020, was a brain-scanning study in 52 healthy volunteers who received selank, Semax or placebo [11]. Resting-state MRI showed changes in how the right amygdala connected with parts of the temporal lobe within 20 minutes of dosing. It had a placebo arm, and it is the one human study here that did. It measured brain connectivity rather than anxiety, so it shows selank reaches the brain and changes something measurable there.

Three limits apply to all of it, and they are the same three every time: no placebo arm, one research network, and abstracts that omit allocation, dose, dropouts and the actual score changes. We have not reported effect sizes because none of these papers publishes one we could check.

Why nobody outside Moscow has run the trial that would settle it

Selank is an approved prescription nasal medicine in Russia and nowhere else. The institute that developed it has published its own trials, which is how a drug reaches market in a system where the developer and the sponsor are the same body. What has never happened is a Western-standard trial: randomised, blinded, placebo-controlled, run by people with nothing riding on the answer.

That trial is not expensive. Sixty patients, twelve weeks, a validated anxiety scale. It is one of the cheapest studies in medicine and it is the only one that would settle the question. It has not been run because nobody in the West owns selank. It is not licensed in the UK, the EU or the US, no company holds it with a route to a price it could set, and a Moscow institute has no reason to fund a study that would only matter in markets it cannot sell into.

This is not a molecule that failed. It is a molecule whose evidence stopped at the edge of the system that paid for it. That is the funding gap, and it is the same one that runs through almost every cheap peptide we cover: the question is not whether the molecule is interesting, it is who would own the answer. Those are different findings, and which one you are looking at changes what you should do with it.

Where the "nootropic" label comes from

Selank is often marketed online as a focus or memory aid, and the human basis for that is three passing mentions. The 2014 abstract refers to "mild nootropic effects" without saying how they were measured [3]; the 2008 trial describes "psychostimulant" effects in anxious, fatigued patients [2]; and the 2015 study used a Stroop test and a verbal fluency task, but its reported cognitive benefit was that people on the combination avoided the memory and attention problems caused by phenazepam [4]. Avoiding a drug's side effects is not the same as making a healthy person sharper, and no study we found tested selank on cognition in healthy adults. The memory findings people cite are from rats [10].

What the animal and lab work suggests

Most selank research is in rodents. In rats under chronic mild stress, adding selank to diazepam reduced anxiety-like behaviour more than diazepam alone [9]. In rats given alcohol, selank protected against memory problems and changed levels of the growth factor BDNF in the hippocampus and prefrontal cortex [10]. These are standard models, and they measure things like time spent in the open arm of a maze, which does not map neatly onto human anxiety.

The cell and membrane work described above [6–8] shows selank does something biologically. What it does not show is that those effects happen at the doses people use, or that they reach the brain after a nasal dose in humans.

Safety and side effects reported

The Russian trials describe selank as well tolerated, and the 2015 study reports that it reduced the side effects of phenazepam rather than adding its own [4]. None of these papers is large enough, long enough or transparent enough to detect uncommon harms. There is no published long-term safety data, no independent pharmacovigilance data we could find, and nothing on use in pregnancy, in children, or alongside other psychiatric drugs apart from benzodiazepines.

Products sold online as research peptides add a second unknown, because there is no guarantee they contain what the label says at the stated purity.

Legal and regulatory status

Selank is a prescription nasal medicine in Russia. It is not approved by the UK's MHRA, the European Medicines Agency or the US FDA, and we found no registered trials in those regions. In the UK and US it is sold only as a research chemical, which means it is not made or checked to medicine standards and is not intended for human use.

What is still open

• Whether selank beats a placebo for anxiety, which is the only question that matters and the only one nobody has asked in a controlled way.
• The effect size, since the published abstracts do not report the score changes.
• Whether nasal selank reaches the human brain in meaningful amounts. The MRI study says it changes connectivity; it does not say at what concentration.
• Whether the lab mechanisms, enkephalin protection and GABA modulation, operate in people at all.
• Long-term safety, and whether stopping causes rebound or withdrawal.
• Whether a group with no ties to the developers can reproduce any of it.

That selank does something measurable in the body is not in doubt: the cell work [6–8], the rodent work [9,10] and the imaging study [11] all show it. Whether it reduces anxiety more than a placebo is exactly as open as it was in 2008.

What this means

Four studies, one network, eighteen years, the same answer every time. That is not proof, and it is not nothing, and the honest thing is to hold both of those at once.

Our read is that selank probably does reduce anxiety, that the effect has never been measured against a placebo, and that the study capable of settling it is cheap enough that its absence is the most interesting fact in this article. Eighteen years is a long time to leave a question that a single well-run trial would close. What that tells you is not that the peptide failed. It is that the people who own it already have their answer, and the people who would need one do not own it.

If you are weighing it up: it is a prescription medicine in one country and a research chemical everywhere else, and nothing on the vial tells you which standards it met. Purity, sterility, endotoxin and heavy metals all have to be evidenced before you know what you were sent, and a certificate of analysis reporting purity alone has answered one question out of four. Our guide to reading a certificate of analysis covers what to look for.

If you have used it, tell us what happened, including if nothing did. Four studies from one network is a thin basis, and reader reports are how a picture gets wider.

Common questions

Does selank work for anxiety?

Four small clinical studies, all from Russia, reported anxiety easing about as much as on a benzodiazepine. None used a placebo group, and the abstracts omit key details such as score changes. Whether selank beats placebo is exactly as open as it was in 2008.

What is selank?

Selank is a seven-amino-acid peptide built from tuftsin, a fragment of the antibody molecule IgG, with a Pro-Gly-Pro tail added to stabilise it. It was developed at the Institute of Molecular Genetics in Moscow. Proposed mechanisms come from lab work rather than from people.

Is selank legal in the UK?

Selank is a prescription nasal medicine in Russia. It is not approved by the MHRA, the European Medicines Agency or the US FDA. In the UK and US it is sold only as a research chemical, which is not made or checked to medicine standards.

Does selank improve memory or focus?

The human basis for the nootropic label is three passing mentions in the anxiety papers. No study found tested selank on cognition in healthy adults. The memory findings people cite are from rats, so the focus claims are unsupported in humans.

Educational content only — not medical advice. Many peptides discussed on HPR are not approved for human use. Talk to a qualified clinician before making any decision about your health.