
Anxiety
In a Russian trial of 62 people with generalized anxiety or neurasthenia, Selank and the benzodiazepine medazepam had similar anxiety relief. Selank also reduced fatigue.1

Thr-Lys-Pro-Arg-Pro-Gly-Pro, a tuftsin analogue (TP-7)
Most anxiety medicines work by turning down the brain’s alarm. Selank comes from an unexpected place, an immune peptide, and Russian researchers have studied it alongside benzodiazepines as well as in their place.
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Selank is a seven-amino-acid peptide built on tuftsin, a short immune peptide, and developed in Russia as an anxiety medicine. Receptor-binding work suggests it modulates GABA receptors, and it slowed the breakdown of enkephalins, the body’s own calming peptides, in blood samples. Small Russian trials found anxiety relief comparable to benzodiazepines, with less fatigue, but independent human data are scarce.
Medically reviewed by Robert Lufkin, MD (opens in a new tab)
Chief Medical Officer, Vitals Vault · Updated · 18 sources
Selank seems to work in several ways. The best evidence is for the brain’s calming system.
In lab tests, Selank helped the brain’s main calming signal land more easily. Benzodiazepines act on the same system.34
Selank slowed the enzymes that break down enkephalins, the body’s own calming peptides. They broke down faster in people with anxiety.21
In rats, it changed a brain growth signal in memory and mood areas. In people with anxiety, it shifted immune signals in the blood.5610
The human evidence is small, mostly Russian and mostly from the groups that developed Selank. Animal data fill in the mechanism.
Boosted calming-signal binding in receptor tests and slowed enkephalin-breaking enzymes in blood samples.32
Shows a mechanism
In rats, it changed the activity of 45 brain genes and prevented memory problems during alcohol withdrawal.45
Shows an effect in a body
Small Russian trials found anxiety relief similar to benzodiazepines. None was a large placebo-controlled trial.111
Shows it works in people
The evidence level is human trials of limited quality. The clinical work is small, run in Russia and published mostly by developer-affiliated groups. The mechanism data are from rats and cells. None of the studies cited here is a large placebo-controlled trial or an independent replication outside Russia.1124
The full guide to Selank
Why would anyone look for an anxiety medicine inside the immune system? The story starts with tuftsin, a tiny four-amino-acid peptide discovered by the biochemist Victor Najjar that acts on phagocytes, the immune cells that swallow bacteria and debris. In 1999, a review marking 30 years of tuftsin research listed effects well beyond immunity, including antimicrobial, antiviral and antitumor activity, and effects on the brain.
A team in Moscow took tuftsin’s sequence, Thr-Lys-Pro-Arg, and added Pro-Gly-Pro to the end, a tail usually described as slowing breakdown in the body. The result was a seven-amino-acid peptide they called Selank, framed from the start as an anxiolytic. The same tail ends Semax, a sibling peptide from the Institute of Molecular Genetics in Moscow.
Their goal was a calmer kind of anxiety medicine. Benzodiazepines, the class that includes diazepam, work quickly but bring sedation, memory problems and dependence. The Moscow researchers framed Selank as a mild agent, part of a growing interest in neuropeptides that might ease anxiety with fewer of those costs.
Over the next two decades they tested it in cells, rats and small groups of patients. The resulting picture is unusual. Selank appears to touch the GABA system, the enkephalin system, BDNF and the immune system all at once, and one of its most interesting human findings involves working alongside a benzodiazepine.159314
GABA is the brain’s main braking signal. Benzodiazepines work by making GABA receptors respond more strongly when GABA arrives. In 2018, receptor-binding experiments from Selank’s home institute found that Selank also boosts GABA binding as a positive allosteric modulator, meaning it changes the receptor’s shape so the natural signal lands more easily. The authors suggested this effect depends on receptor subtype and concentration.
Gene studies point the same way. In a 2016 rat study comparing Selank with GABA, 45 of 84 neurotransmission genes in the frontal cortex changed activity an hour after dosing, and 22 three hours after. At one hour, the changes after Selank correlated with the changes after GABA itself, which the authors read as further evidence of a GABA-linked mechanism.
The second thread runs through enkephalins, small peptides the body makes to dampen pain and stress. In a 2001 study, people with generalized anxiety disorder broke down enkephalins unusually fast, while people with panic disorder and agoraphobia did not. Selank inhibited the enzymes responsible in a dose-dependent way, and it did so more strongly than two standard enzyme blockers used in the lab.
That finding came back in a 2008 trial. Patients with generalized anxiety and neurasthenia started with a shortened enkephalin half-life, and the shortening tracked how long and how severely they had been ill. During treatment with Selank, enkephalin half-life rose. It is a rare case in this field where a proposed mechanism was measured in the same patients as the clinical result.3421
Selank never lost its tuftsin roots. In a 2008 study, researchers exposed blood cells to Selank in a dish. In cells from people with depression, it completely suppressed the gene for IL-6, an inflammatory messenger. In cells from healthy people, it did not. Yet the amount of IL-6 protein in the patients’ cell cultures rose with Selank, so the picture is mixed rather than simply anti-inflammatory.
The same team measured cytokines in the blood of people with generalized anxiety and neurasthenia who received Selank. The balance between Th1 and Th2 signals, two arms of the immune response, shifted during treatment. The authors proposed that Selank could act as an immunomodulator in anxiety with fatigue, and suggested a role in preventing infections, which the study did not test.
This matters because the line between immunity and mood is thinner than it looks. Inflammation can raise anxiety and fatigue, and anxiety can change immune signalling. A peptide that touches both systems is plausible biology. Separately, FDA flagged immunogenicity, the risk that an injected peptide provokes an immune reaction, linked to peptide aggregation and impurities.1017
The best-known trial was published in 2008. Sixty-two people with generalized anxiety disorder or neurasthenia, a diagnosis of chronic fatigue and irritability used in Russian psychiatry, received either Selank or medazepam, a benzodiazepine. Anxiety scores fell similarly in both groups, measured on the Hamilton, Zung and clinical global impression scales.
Selank did something extra. It also had antiasthenic and psychostimulant effects, meaning patients felt less worn out and more alert. Benzodiazepines tend to push the other way, so a calming medicine that leaves people more awake is the kind of profile the developers were hoping for.
A 2014 study compared Selank with phenazepam, a benzodiazepine widely used in Russia, in 60 people with phobic, anxiety and somatoform disorders. The researchers reported a pronounced anxiolytic effect, a mild nootropic effect, better quality of life, and an anxiolytic effect that lasted about a week after the last dose.
These are encouraging results with clear limits. The trials were small, published in a Russian journal, and run by teams that include Selank’s developers. The abstracts describe comparisons with active drugs rather than placebo, which makes it harder to separate a real effect from expectation and the natural ups and downs of anxiety.111
Selank is usually pitched as a replacement for benzodiazepines. Its most interesting study tested something else. In 2015, the Moscow group gave 30 people with anxiety disorders phenazepam alone and 40 people phenazepam plus Selank, then tracked both relief and side effects.
The combination group improved sooner on the HDRS rating scale. The bigger finding was on the cost side. With Selank added, people had fewer of phenazepam’s typical side effects, including trouble with attention and memory, fatigue, sedation, oversleeping, sexual problems, emotional flatness and dizziness on standing. The benefit held during treatment and after the tranquilizer was stopped, and quality of life rose.
Animal and lab work hint at why this might happen. In stressed rats, diazepam plus Selank brought anxiety measures back to their pre-stress level, the best result under stress. Yet in receptor assays, the joint action of Selank and some benzodiazepines was not simply additive, and Selank could even block diazepam’s modulating effect. The two seem to share a neighborhood on the receptor without stacking on top of each other.
One hypothesis is that Selank fine-tunes the GABA receptor rather than pushing it harder, which would fit a calmer, clearer combination. That is unproven, and it cuts both ways. A peptide that changes how a benzodiazepine behaves is, by definition, a drug interaction. The finding is a reason to involve a prescriber, never a reason to combine them on your own.1273
Anxiety and memory share hardware. The amygdala flags threats, and the hippocampus and prefrontal cortex decide what to remember and how to respond. Selank research has looked at both ends. In rats, a nasal dose changed BDNF expression in the hippocampus, the growth factor at the center of Semax research too.
A 2019 rat study tested Selank in a harsher setting. Rats drank alcohol as their only fluid for 30 weeks. During withdrawal, untreated animals developed memory and attention problems, while Selank prevented them. It also prevented the alcohol-driven rise in BDNF in the hippocampus and frontal cortex, a reminder that what Selank does to BDNF depends on the setting, and that no study here sets a BDNF target for people.
In people, the best look comes from a 2020 imaging study of 52 healthy volunteers. After Selank, Semax or placebo, scans showed changes in the connection between the right amygdala and the right temporal cortex, with effects specific to each peptide. That shows measurable changes in an anxiety-related circuit soon after a dose, without directly tracking the peptide itself. It does not yet show a change in how anyone feels or thinks.658
The human record fits in a short list. A 62-person trial against medazepam, a 60-person trial against phenazepam, a 70-person trial of phenazepam with and without Selank, a study of immune cytokines in anxious patients, and an imaging study in 52 healthy volunteers. That is more than most peptides in this guide.
All of it comes from Russian research centers, and most of it from teams that include the peptide’s developers. Outside Russia, a 2021 review in the Journal of Clinical Pharmacology grouped Selank with phenibut as poorly studied Russian drugs with GABA-related mechanisms that are sold to US consumers as supplements, and urged proper evaluation of abuse potential before public access.
Put plainly, the clinical signal is consistent but local. None of the studies cited here is a large placebo-controlled efficacy trial or an independent replication outside Russia. The fair summary is a promising Russian anxiety peptide that the rest of the world has not yet tested.1111210813
The developers’ reports describe Selank as free of the side effects typical of most anxiolytics, and the 2015 study suggests it may even soften a benzodiazepine’s side effects. The 2014 and 2015 trials did assess tolerability, the 2015 one with a standard side-effect scale, but trials of 60 to 70 people cannot rule out uncommon problems, and the studies cited here do not establish long-term safety.
FDA’s April 2026 compounding safety page lists selank acetate. It states that FDA lacks important information on safety in humans and notes a risk of immunogenicity from peptide aggregation and impurities. That concern fits a peptide built from an immune signal and sold in products of unknown purity.
The 2021 pharmacology review adds a broader warning. Drugs that act on GABA receptors can cause dependence and withdrawal, and combining them with other sedatives has caused serious harm. The review does not show that Selank does this. It does urge proper evaluation of abuse potential before public access, which is exactly the point.
In practice, the people who should talk to a clinician first are anyone taking a benzodiazepine, sleep medicine or other sedative, anyone on psychiatric medicine, people with autoimmune conditions, and anyone pregnant or breastfeeding.2121713
Anxiety has common physical drivers that a blood test can catch. TSH screens the thyroid, because an overactive gland produces a racing heart, restlessness and poor sleep that feel exactly like anxiety. Cortisol is worth checking when a clinician suspects an adrenal problem, though a single reading is not a measure of anxiety.
Red-cell magnesium and vitamin B12 round out the picture. Low magnesium is linked with tension and poor sleep, and low B12 can show up as fog, low mood and nervousness. None of these is a Selank marker, and none is a required gate before standard anxiety care. They are targeted checks a clinician may order when symptoms or history suggest a physical contributor.
This is how Vitals Vault approaches peptide care. A blood panel at Quest Diagnostics comes first, and a licensed clinician reviews your results and history before discussing any option. Selank is not currently a compounding option in the US, which makes finding the treatable cause even more useful.1718
Selank is not FDA-approved for any use. FDA’s compounding safety page lists selank acetate among bulk substances that may present significant safety risks, and it was not among the six peptides covered by FDA’s October 29, 2026 enforcement discretion for 503A pharmacies.
That leaves no standard US prescription route. Products sold online as research chemicals are not intended for people, and a supplement label does not establish identity, purity or safety, which matters more than usual for a peptide FDA has flagged for immunogenicity.171813
Selank is an immune peptide turned anxiety medicine, with a coherent lab story around GABA and enkephalins and a handful of small Russian trials that look encouraging. Its most original finding is that it may make a benzodiazepine easier to live with, and that same finding marks it as a drug interaction to respect.
If anxiety is what brings you here, the better first question is what is feeding the alarm. Sleep, thyroid, blood sugar and a few nutrients are testable today. Once those are answered, the next question for a clinician is whether you need a brake at all, or a quieter engine.1123
The first step is a clinician’s assessment of what drives your anxiety, with a history and, where they fit, labs such as thyroid or B12. Because Selank is not FDA-approved or covered by the October 2026 policy, the conversation with a US clinician centers on those drivers and on approved options.
On timing, the Russian trials describe calm building over a course of treatment, and one reported that the effect lasted about a week after the last dose. In the 2015 study, relief came sooner when Selank was added to a benzodiazepine. These are small studies, so treat any timeline as a rough guide.111217
Zozulya et al., 20012
Lab and patient blood study · People with anxiety and phobic disorders
Enkephalins broke down faster in generalized anxiety; Selank inhibited the enzymes responsible
Limits: Mechanism study, not a treatment trial
Zozulia et al., 20081
Comparative clinical trial · 62 people with generalized anxiety or neurasthenia (30 Selank, 32 medazepam)
Similar anxiety relief to medazepam, plus less fatigue and more alertness
Limits: No placebo group; developer-linked
Uchakina et al., 200810
Lab and clinical immune study · People with depression, anxiety and neurasthenia; healthy controls
Suppressed IL-6 gene expression in patient cells only; shifted blood cytokine balance
Limits: Immune markers, not symptoms
Medvedev et al., 201411
Comparative clinical trial · 60 people with anxiety, phobic and somatoform disorders
Clear anxiety relief and mild nootropic effect; the anxiety relief lasted about a week after stopping
Limits: Small; abstract gives few comparison details
Medvedev et al., 201512
Comparative clinical trial · 70 people with anxiety disorders (30 phenazepam alone, 40 phenazepam plus Selank)
Faster relief and fewer benzodiazepine side effects with Selank added
Limits: No placebo; developer-linked; small
Panikratova et al., 20208
Placebo-controlled imaging study · 52 healthy volunteers
Changed amygdala-temporal cortex connectivity after a single dose
Limits: Brain activity, not symptoms
Selank is a synthetic peptide with GABA-related effects. A 2021 pharmacology review called it poorly studied and criticized its sale as a supplement, and FDA notes a lack of human safety information.1317
It acts on the same GABA receptor family, but lab work shows its effect is not simply additive with benzodiazepines, and it also acts on enkephalins, BDNF and immune signals. Patients in a 2008 trial reported less fatigue, which benzodiazepines rarely produce.312
The human trials enrolled 60 to 70 people each, were run in Russia and mostly compared Selank with active drugs. None of the studies cited here is a large placebo-controlled or independent trial.11112
There is no FDA-approved dose of Selank for any use. It is registered as a nasal medicine in Russia, and the one human study we found that reports a dose gave it into the nose every day for about two weeks in adults with generalized anxiety disorder; that dose is listed in the table on this page. Most Russian trial abstracts do not state a dose. Your clinician decides whether any use is appropriate and sets the dose.16
Selank is given into the nose. The only human dose we could confirm comes from a small Russian study in adults with generalized anxiety disorder, reported as a conference abstract; the larger Russian trials do not state a dose in their abstracts. There is no FDA-approved dose, and your clinician decides whether any use is appropriate and sets the dose.
Already have a prescribed dose? The peptide dosage calculator turns it into the units to draw on an insulin syringe.
Human trial · Into the nose
2,700 µg a day (900 µg single dose)
Daily; number of doses a day not stated16
20 adults aged 24 to 52 with generalized anxiety disorder, followed to day 14; congress abstract
A clinician makes the call. These are the questions they will ask first.
Vitals Vault peptide care starts with a blood panel and a licensed clinician, and ends with a retest.
Get early access to peptide careAnxiety can have physical drivers that a blood test can catch, such as an overactive thyroid, low magnesium or low B12. A peptide that acts on the brain’s calming system is unlikely to fix a problem that starts elsewhere.
So the sensible first step is to find out what is feeding the alarm, then decide whether anything more is needed.35
A blood test before you start and a retest after shows what actually changed for you. It is how Vitals Vault approaches every treatment.
No. Selank is not FDA-approved for any use. FDA’s compounding safety page lists selank acetate among bulk substances that may present significant safety risks, noting immunogenicity concerns for some routes and a lack of human safety information. It is not one of the six peptides covered by FDA’s October 2026 enforcement discretion.1718
1999
A review marks 30 years since Victor Najjar discovered tuftsin, the immune peptide Selank is built on.15
2001
Russian team reports that Selank inhibits the enzymes that break down enkephalins, a proposed route for its anxiolytic effect.2
2008
Trial in 62 people with generalized anxiety or neurasthenia compares Selank with medazepam; a separate study reports immune cytokine changes.110
2014
Trial in 60 people with anxiety disorders compares Selank with phenazepam.11
2015
Adding Selank to phenazepam reduces the benzodiazepine’s side effects in 70 people.12
2018
Binding studies show Selank acts as a positive allosteric modulator at GABA receptors.3
2020
Brain-imaging study in 52 healthy volunteers compares Selank, Semax and placebo.8
April 2026
FDA’s compounding safety page lists selank acetate and notes the lack of human safety information.17
October 29, 2026
FDA grants enforcement discretion for six peptides. Selank is not one of them.18

Selank was developed in Russia and is studied for anxiety, neurasthenia, stress and memory. It is not FDA-approved to treat any condition, and nearly all human studies come from Russian groups.
In a Russian trial of 62 people, Selank had anxiolytic effects similar to the benzodiazepine medazepam, with less fatigue. In another study, adding it to phenazepam reduced that drug’s side effects. In rats, it protected memory and changed BDNF levels.
Receptor-binding work suggests Selank modulates GABA receptors. It also slowed the breakdown of enkephalins in blood samples and changed BDNF and immune signals in rat and cell studies. The exact route in people is not settled.
Both are Russian peptides with a Pro-Gly-Pro tail. Selank comes from tuftsin and is studied for anxiety. Semax comes from ACTH and is studied for stroke, memory and focus. FDA’s October 2026 policy covers Semax but not Selank.
Only under a clinician’s care. A 2015 Russian study found adding Selank to phenazepam reduced side effects, but lab work shows Selank changes how benzodiazepines act at their receptor, so the combination is an interaction to manage, never a DIY experiment.
Russian researchers report it lacks the side effects typical of most anxiolytics, and two trials assessed tolerability, but the studies were small and short. The studies cited here do not establish long-term safety, and FDA notes a lack of human safety information.
There is no FDA-approved dose. In a small Russian study of adults with generalized anxiety disorder, Selank was given into the nose every day for about two weeks, and that dose is listed in the dosage table on this page. Most Russian trials do not report a dose in their abstracts. Your clinician decides whether any use is appropriate and sets the dose.
No. Selank is not FDA-approved for any use and is not one of the six peptides covered by FDA’s October 2026 compounding policy. FDA’s compounding page lists it among substances that may present significant safety risks.
It is not an approved drug, and it is not covered by FDA’s October 2026 enforcement discretion. Vials sold online as "research use only" are not made for people and are not regulated as medicine.
Vitals Vault is opening clinician-led peptide care that starts with a blood test. Join the peptides waitlist to hear first. A licensed clinician reviews your history and labs and decides whether Selank is right for you.

Vitals Vault is opening peptide care that starts with your blood work, is prescribed by licensed US clinicians and ends with a retest. Join the waitlist to hear first.