What Is Selank Used For?

Selank is a synthetic heptapeptide — a chain of seven amino acids, Thr-Lys-Pro-Arg-Pro-Gly-Pro — designed in Russia as a metabolically stable version of tuftsin, a four-amino-acid peptide that occurs naturally as a fragment of the heavy chain of human immunoglobulin G. It belongs to a small family of peptides known as glyprolins. So what is Selank used for? In the published research, mainly anxiety — it has been investigated primarily as an anxiolytic — with a smaller thread on attention and memory. This page is about what that research covers, how good it is, and what it does not answer.

What Selank is and where it came from

Selank was developed by the group of N.F. Myasoedov at the Institute of Molecular Genetics, Russian Academy of Sciences in Moscow, in collaboration with the V.V. Zakusov Research Institute of Pharmacology. Sources place the work in the late 1990s to early 2000s; the earliest published Selank research dates to 2001. The stated design goal was an anti-anxiety effect without the drawbacks of conventional anxiolytics.

The starting material matters for understanding the rest of the research. Tuftsin is a tetrapeptide (Thr-Lys-Pro-Arg) cleaved from the heavy chain of human immunoglobulin G, and it is an immune-signalling molecule, not a neurotransmitter. Appending Pro-Gly-Pro to its C-terminus produced a molecule stable enough to survive administration while retaining that immunological heritage — which is why a compound studied for anxiety also has a literature on cytokines and inflammatory gene expression. Selank is not a steroid and not a stimulant in the caffeine or amphetamine sense; its reported profile is anxiolytic with a secondary cognitive, or nootropic, component.

What is Selank used for in practice

Selank is used, in the countries where it is available by prescription and in the published research, mainly for anxiety — specifically generalized anxiety disorder, and asthenic or neurasthenic presentations where low stress tolerance, fatigue and weakness sit alongside the anxiety. A secondary research thread looks at attention and memory, which is why it sits in Promise's brain health and memory category. Everything below that headline is either small human trials or animal work.

The three research uses with actual data attached are:

1. Anxiety symptoms, including phobic-anxiety and somatoform presentations, studied in two Russian trials against benzodiazepine comparators.
2. Asthenic symptoms — the fatigue-and-low-resilience cluster captured by the neurasthenia diagnosis in the 2008 trial.
3. Attention and memory, studied in rats rather than people, in a model of alcohol-related cognitive disturbance.

Research on Selank has not shown it to be a solution for severe anxiety disorders needing immediate intervention, and it is not a substitute for psychotherapy or for approved medications where those are clinically indicated. Nothing here means Selank will produce any particular result for any individual.

The blend above pairs Selank with Semax, an ACTH(4-10)-derived peptide with its own separate literature. Worth being precise about what that is and is not: no published trial has administered Semax and Selank together. The blend is two separately studied compounds that a provider may choose to prescribe as one preparation on mechanistic reasoning, not a combination with its own trial evidence. A side-by-side look at the two compounds is covered separately.

How Selank has been studied for anxiety in people

Two published human trials exist, both Russian, both comparing selank against a benzodiazepine, together enrolling 122 patients. A third human study, in 52 healthy volunteers, measured brain connectivity rather than symptoms. That is the whole human evidence base — three studies, none large, none replicated outside Russia.

The 2008 trial also carried a biochemical marker. Patients with generalized anxiety disorder and neurasthenia had a shortened half-life of leu-enkephalin at baseline, and how short it was correlated with how long they had been ill, how severe their anxiety and asthenia were, and how disturbed their autonomic symptoms were. That half-life lengthened during selank treatment, mostly in the generalized anxiety disorder patients. It is a small, single-trial finding, but it is the rare case of a peptide trial reporting a mechanism-linked measurement rather than symptom scores alone.

How Selank appears to work in the brain

Selank does not have one clean mechanism; it has four partly-connected ones, three of which come from animal or cell work. The most direct evidence is receptor-binding work showing that Selank acts as a positive allosteric modulator at GABA-A receptors — the same broad receptor family benzodiazepines act on, but not by the same footprint.

GABA-A modulation. In radioligand-receptor assays on isolated brain-cell plasma membranes, Selank affected [3H]GABA binding as a positive allosteric modulator, in a way that was subtype-selective and concentration-dependent (Vyunova 2018, PMID 30255741 — original binding research, despite the review-sounding title). Selank's binding sites partially overlap benzodiazepine sites without being identical to them: when Selank and a benzodiazepine act together the effect on [3H]GABA binding is not cumulative and differs from either substance alone, and Selank can block the modulatory activity of diazepam and of olanzapine. That is a real pharmacological distinction from a benzodiazepine, though the studies here did not measure sedation as an endpoint, so the mechanism difference should not be read as a measured clinical difference.

Gene expression. A single intranasal dose of 300 μg/kg in rats changed transcription across a panel of 84 neurotransmission-related genes in the frontal cortex: 45 genes changed significantly at 1 hour, and 22 of 77 analyzable genes at 3 hours, with a 1.5-fold cut-off at p ≤ 0.05 and 10 animals per group (Volkova 2016, PMID 26924987). At 1 hour the Selank-induced changes correlated positively with GABA-induced changes (r = 0.86, p ≤ 0.05); by 3 hours the correlation had turned negative (r = −0.39, p ≤ 0.05), which is an important qualifier on the "Selank looks like GABA" headline. Individual genes moved dramatically and in both directions: mRNA for the GABA-A epsilon and theta subunits (Gabre, Gabrq) fell roughly 20-fold at 1 hour, then rose 16.1-fold and 13.3-fold respectively at 3 hours; hypocretin (Hcrt) fell about 25-fold at 1 hour and rose 128.3-fold at 3 hours; Drd3 rose 3.36-fold and Gabrb3 1.6-fold at 1 hour. Drd1a, Drd2, Ptgs2 and Slc6a13 changed under Selank but not under GABA.

A companion in-vitro study is worth naming because it is often described backwards. In human IMR-32 neuroblastoma cells, Selank alone produced no change in the mRNA levels of the genes studied; its effect appeared only in combination, where it suppressed GABA-induced expression changes and amplified olanzapine's (Filatova 2017, PMID 28293190). Cell-culture results do not overturn the rat data, but they do mean the gene-expression story is context-dependent rather than a simple on-switch.

Enkephalins. Selank inhibits enkephalin-degrading enzymes, slowing the breakdown of the body's own enkephalins. The original work measured dose-dependent inhibition of enkephalin hydrolysis in human plasma with an IC50 of 15 μM, more potent than either bacitracin or puromycin (Zozulya 2001, PMID 11550013). The same paper found that patients with generalized anxiety by DSM-IV criteria had a shortened enkephalin half-life and reduced total blood enkephalinase activity — and, notably, that this was not the case in panic disorder or agoraphobia. The enzyme finding is well documented; the frequently repeated add-on that Selank achieves this "without directly activating opioid receptors" is not sourced in the papers cited here.

BDNF. Brain-derived neurotrophic factor supports neuroplasticity, learning and memory, and Selank does interact with it — but direction matters and is often reported wrongly. In rats given 0.3 mg/kg/day intraperitoneally for 7 days after 30 weeks of 10% ethanol as their sole fluid, Selank prevented an ethanol-induced increase in BDNF content in the hippocampus and frontal cortex (p < 0.05) — it held down a rise, which is not the same as raising a level that was low (Kolik 2019, PMID 31625062). Separately, intranasal Selank has been shown to regulate BDNF expression in the rat hippocampus in vivo (Inozemtseva 2008, PMID 18841804). Neither result supports a flat "Selank raises BDNF" statement.

Monoamines. Selank's effect on serotonin and dopamine is strain-dependent, region-specific and bidirectional. In BALB/C and C57Bl/6 mice given 0.3 mg/kg by injection, noradrenaline rose in the hypothalamus of both strains; the dopamine metabolites DOPAC and HVA rose in the frontal cortex and hippocampus of C57Bl/6 mice but fell in BALB/C mice; and serotonin and its metabolite 5-HIAA fell in the BALB/C hippocampus while staying unchanged in C57Bl/6 (Narkevich 2008, PMID 19093364). The authors concluded that the anxiolytic effect is selective. This is not a compound that simply raises serotonin.

What the animal and cell research adds

Beyond anxiety scores, the rodent literature covers cognition under alcohol stress, inflammatory cytokines, opioid-withdrawal signs and behaviour when dopamine neurons are damaged. All of it is rat or mouse work, mostly by intraperitoneal injection rather than the intranasal route used clinically, so it explains plausible mechanisms rather than predicting outcomes in people.

Cognition. In the Kolik 2019 rat study, Selank produced a cognitive-stimulating effect in 9-month-old rats not exposed to ethanol (p < 0.05) and prevented the formation of ethanol-induced memory and attention disturbances (p < 0.01), measured by object recognition. There is no maze-navigation memory data on Selank in this literature; the elevated-maze studies below measured anxiety behaviour, not learning.

Immune signalling. Under a 20-day social-confrontation stress model (10 minutes of confrontation daily), stress significantly raised serum IL-1β, IL-6 and TGF-β1 in rats; animals given 100 mcg/kg/day of Selank intraperitoneally across the stress period showed reduced IL-1β and IL-6, restoration of IL-4, and suppression of TGF-β1 practically to control values (Yasenyavskaya 2021, PMID 32621722). The stress-induced rise in TNF-α in that study was not statistically significant, so Selank cannot be credited with lowering elevated TNF-α on this data. At the gene level, a single 100 μg/kg intraperitoneal dose in mice altered expression of C3, Casp1, Il2rg and Xcr1 in the spleen, with C3 mRNA falling 3-fold at 30 minutes (Kolomin 2014, PMID 24291245). This is the tuftsin inheritance showing up as measurable immune effects — which is also why immune-mediated conditions come up in the caution list further down.

Combination with a benzodiazepine, with a caveat usually dropped. In rats under unpredictable chronic mild stress, Selank plus diazepam reduced elevated-plus-maze anxiety measures more than either compound alone (Kasian 2017, PMID 28280289). The same study found that a course of the test substances worsened anxiety indicators in rats that were not chronically stressed — and that Selank alone was the most effective at reducing that drug-course-induced anxiety. The combination result and the no-stress result come from the same experiment; carrying only the first is how this study usually gets misquoted.

Morphine withdrawal. In outbred rats with naloxone-precipitated morphine withdrawal, a single intraperitoneal dose of Selank reduced the total withdrawal index and attenuated convulsive reactions, ptosis and posture disorders (p < 0.0001), and diazepam did somewhat better on the same measures (Konstantinopolsky 2022, PMID 36322304):

The authors of that paper drew no conclusions about neuroprotection or neurodegenerative disease, and neither should anyone citing it.

Behaviour with damaged dopamine neurons. In rats with 6-OHDA-induced Parkinson-like damage, Selank still decreased anxiety behaviour in the elevated cross-shaped maze — Semax, tested in the same study, did not — and neither peptide affected motor activity or passive defensive behaviour (Slominsky 2017, PMID 28702721).

One thing this body of work does not describe is sedation or sleep. Selank has not been studied as a sleep aid in any of the research above, and if wind-down and sleep pressure are the main problem rather than daytime anxiety, a different compound is the more sensible conversation — DSIP is the compound in Promise's calming and stress-relief category, with its own separate evidence and its own intake questionnaire.

Which form and route the research used

Route is not a detail with Selank — it changes what the evidence means. The clinical product in Russia is a 0.15% intranasal solution, and the rat gene-expression work used a single intranasal dose. Most of the animal pharmacology, however, used intraperitoneal injection, and the human fMRI study's abstract describes injection. Oral administration is not a serious option, because peptides of this kind are degraded in the digestive tract.

Intranasal delivery is used because it reaches the central nervous system relatively directly and bypasses digestive breakdown. Quantitative bioavailability claims for the nasal route are not established in the studies cited here, so treat "better absorbed at lower doses" as reasoning rather than a measured figure. Which form and route is appropriate for any individual is the prescribing provider's decision, made with the clinical picture in front of them.

Safety and tolerability: what has been reported

The reported tolerability profile is favourable and unremarkable: mild, local, short-lived effects when Selank is given intranasally — nasal irritation, dryness, or a tickling sensation attributed to the spray vehicle. What does not exist is incidence data. None of the studies discussed here publishes an adverse-event rate, and the human trials are small.

Several widely repeated safety statements are absence claims that no cited study ever tested. No trial in this literature measured sedation, cognitive impairment or motor coordination as an endpoint; no dependence, tolerance or withdrawal study of Selank has been published. The morphine-withdrawal paper concerns dependence on morphine, not dependence on Selank. Long-term safety data is limited because the published studies ran weeks to months, and drug-interaction data has not been systematically studied at all — which is the single most practical reason to have a real provider look at your medication list rather than reasoning from articles.

The caution list follows from missing data rather than from observed harm:

• Pregnancy and breastfeeding — no safety data, so it should be avoided.
• Autoimmune and other immune-mediated conditions — Selank has measurable immunomodulatory activity, so caution is warranted.
• Active psychiatric conditions or existing psychiatric medication — use only under medical supervision, and tell your prescriber everything you are taking.

Where Selank stands with regulators

Selank is a registered prescription medicine in Russia and has never been FDA-approved in the United States. Those two facts sit side by side and neither cancels the other. Secondary sources consistently report a 2009 Russian Ministry of Health registration for a 0.15% intranasal solution — sold under the brand name Selanc (Селанк) — indicated for generalized anxiety disorder and as an adjunct in neurasthenic conditions; no primary registration document was available for this article, so treat the date as reported rather than documented.

In the United States, Selank is not FDA-approved — there is no approved product, no approved indication and no approved application on file, and no FDA-approved counterpart product exists to compare it with. A US provider who prescribes it does so as a compounded preparation, made by a licensed compounding pharmacy for an individual patient.

Regulatory status is information, not a verdict. A licensed provider may still prescribe a compounded peptide after reviewing your history — that decision is between you and your doctor. Through Promise, a licensed provider reviews every request; not everyone qualifies, and the provider can decline when the clinical picture doesn't support prescribing.

What the research still does not tell us

The honest gaps are large. Two small human trials, one healthy-volunteer imaging study, and a rodent literature — all of it from Russian institutions, with no independent Western replication of the clinical results.

• No onset timeline. Claims that effects arrive within hours, within a day, or over weeks like an SSRI all circulate; none of the studies here supports any of them. The only rapid measurement in the literature is a brain-connectivity change at 5 and 20 minutes in healthy volunteers, which is a network measure, not a symptom measure.
• No long-term data, no interaction data, no dependence or tolerance study.
• No PTSD or performance-anxiety evidence, despite both being asserted in popular write-ups; no study in this literature examined either.
• No cortisol or HPA-axis measurement in any of the cited work, so mechanism stories built on cortisol normalization are speculation.
• No trial of Selank combined with Semax, which is why the blend is described as mechanistic reasoning rather than evidence.

If calmer focus is the goal

The interesting thing about Selank is not that it promises calm — it doesn't, and the evidence would not support that claim if it did. It is that a molecule borrowed from an immunoglobulin fragment turned out to touch GABA-A binding, enkephalin breakdown, cytokine levels and amygdala connectivity, and that a 62-patient trial put it next to a benzodiazepine and reported comparable anxiolytic scores with a different symptom profile alongside them. That is a genuinely unusual set of findings and a genuinely thin evidence base at the same time, and both halves belong in the conversation you have with a clinician.

If that conversation is one you want to have, the practical picture at Promise is straightforward: Selank on its own is a waitlist product with no intake form yet, so joining the waitlist is the way to be told when there is one; the Semax/Selank blend has a questionnaire today. Either way, what you bring to it — your history, your medications, what you have already tried — is what a provider actually needs.

This article is for educational purposes only and is not medical advice. Selank is not FDA-approved, and nothing here is a claim that it will produce any particular result. Talk with a licensed healthcare provider about your own situation.