Selank: What It Is, Where to Get It Prescribed, and What It Costs

Selank is a heptapeptide — seven amino acids, sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. The first four, Thr-Lys-Pro-Arg, are tuftsin, a fragment of the immunoglobulin G molecule that the body produces naturally and that was first characterised for its effects on immune cells. The remaining three, Pro-Gly-Pro, were added by the designers to slow enzymatic breakdown so the peptide survives long enough to act. That is the whole design: a natural immune-signalling fragment with a stabilising tail.

It is not a hormone and it is not a steroid. It does not bind an androgen receptor, does not suppress anything the body produces, and is not a stimulant in the pharmacological sense. Structurally it sits closer to a signalling fragment than to a drug that forces an outcome.

Selank was developed in Russia, at the Institute of Molecular Genetics of the Russian Academy of Sciences with the Zakusov Institute of Pharmacology in Moscow, and nearly all of the published research comes from those groups. It is registered in Russia as a prescription medicine in an intranasal form. It has never been approved by the FDA or by any regulator outside Russia and its neighbours, and the clinical trials described below were published in Russian-language journals. That provenance is not a mark against the compound, but it is the most important fact for reading the evidence honestly: the human data is real, and almost all of it was generated by the people who invented the molecule.

It is not a benzodiazepine, even though it is repeatedly compared with one. The Russian trials used medazepam and phenazepam as comparators because those are the standard anxiolytics in that system, and the published work describes Selank as acting without the sedation, memory impairment and dependence associated with that class. That is a description from the research, not a guarantee. It is not an antidepressant, it is not a treatment for panic disorder, and it is not a substitute for psychiatric care where that is what is needed.

The mechanism most often cited is at the GABA-A receptor, the same receptor family benzodiazepines act on. A 2018 paper in Protein and Peptide Letters used radioligand binding on isolated rat brain-cell membranes and reported that Selank changed the binding of labelled GABA in the manner of a positive allosteric modulator — it did not act on the receptor directly but altered how GABA itself bound. Selank and diazepam together produced a binding pattern that was not simply the sum of the two, which the authors read as partially overlapping but distinct binding sites. This is cell-membrane work, not a whole-animal or human finding.

The oldest proposed mechanism concerns the enkephalins, the body's short opioid peptides involved in stress and mood regulation. A 2001 paper in the Bulletin of Experimental Biology and Medicine reported that Selank inhibited the enzymes that degrade leu-enkephalin in human plasma, dose-dependently and more potently than the reference inhibitors bacitracin and puromycin. Mouse work from the same group in 2002 described the anxiolytic effect and the enkephalinase inhibition tracking together in one strain and both absent in another. The 2008 clinical paper discussed below measured the same enkephalin marker in patients, which makes this the one mechanism with a human correlate.

Brain-derived neurotrophic factor is the growth factor most closely tied to neuronal plasticity. A 2008 report in Doklady Biological Sciences described intranasal Selank changing BDNF expression in the rat hippocampus, and a 2019 paper in the Bulletin of Experimental Biology and Medicine reported that Selank given to rats exposed to chronic ethanol prevented the ethanol-related shift in BDNF in the hippocampus and frontal cortex, alongside better object-recognition performance. This is the line of work behind the "nootropic" language attached to the compound; it is animal work.

A 2016 study in Frontiers in Pharmacology measured 84 neurotransmission genes in rat frontal cortex after Selank or GABA and reported changes in 45 of them at one hour, with the pattern correlating with what GABA itself produced. A 2017 follow-up in the same journal found that in a human neuroblastoma cell line Selank alone changed none of those genes, but altered the response to GABA when the two were combined. Read together, the picture is a peptide that modifies GABA signalling rather than driving it on its own.

The catalog description mentions serotonin because Russian animal work has reported changes in serotonin turnover; that line is less developed than the GABA and enkephalin work and should be weighted accordingly. The immune side follows from tuftsin's origin: a 2008 paper in the Korsakov Journal of Neurology and Psychiatry reported Selank suppressing IL-6 gene expression in blood cells taken from depressed patients but not from healthy controls, and shifting the Th1/Th2 cytokine balance in patients with anxiety-asthenic disorders over fourteen days of treatment.

This is where the compound started. The 2003 paper in Neuroscience and Behavioral Physiology compared Selank and ten related tuftsin-family peptides across rats and mice selected for different emotional reactivity, using a conflict-situation model of emotional stress, and reported positive emotional and anti-stress effects. The 2002 mouse study reported an anxiolytic effect in the open-field test in BALB/c mice and no effect in C57Bl/6 mice. That strain difference is worth noting: even in animals the response was not uniform.

The 2019 rat work described a cognitive-stimulating effect in the object-recognition test in older animals not exposed to alcohol, and prevention of the memory and attention disturbances that otherwise developed during alcohol withdrawal. Several of the clinical papers describe a "mild nootropic" effect in patients on attention and verbal-fluency tests, but the animal work is where memory is actually measured against controls.

The tuftsin heritage shows up as cytokine changes in patient blood and in cultured cells. None of this establishes a clinical immune benefit, and Pepti does not prescribe Selank for immune purposes.

This is the honest part, and it is more than most peptides on this site can say. There are controlled human trials of Selank — Russian ones, small, published in Russian, compared against an active drug rather than placebo, and not described as randomised or blinded in the published abstracts. In detail:

• Zozulya and colleagues, 2008, Korsakov Journal of Neurology and Psychiatry: 62 patients with generalised anxiety disorder or neurasthenia, 30 given Selank and 32 given the benzodiazepine medazepam, assessed on the Hamilton, Zung and CGI scales. The anxiolytic effect of the two was reported as similar, with Selank additionally described as anti-asthenic and mildly activating. Serum leu-enkephalin half-life was low in patients and rose during Selank treatment, particularly in the GAD group.
• Medvedev and colleagues, 2014, same journal: 60 patients with anxiety-phobic and somatoform disorders (ICD-10 F40–F45), Selank compared with phenazepam. The authors reported a pronounced anxiolytic effect, a mild nootropic effect, an anxiolytic effect persisting about a week after the last dose, and improved quality-of-life scores.
• Medvedev and colleagues, 2015, same journal: 70 patients with anxiety-spectrum disorders, 30 on phenazepam alone and 40 on phenazepam plus Selank, assessed on HDRS, CGI, Spielberger, the UKU side-effect scale, Stroop and verbal-fluency tests and the SF-36. The combination was reported to bring the benzodiazepine's effect on earlier and to reduce its side effects — attention and memory impairment, sedation, longer sleep, sexual disturbance — during treatment and after the benzodiazepine was withdrawn.
• Uchakina and colleagues, 2008: the fourteen-day immune-marker study in patients with anxiety-asthenic disorders, described above.

The limitations sit alongside the findings. The trials are small, 60 to 70 patients. They compare Selank with an active benzodiazepine rather than with placebo, so they show "similar to medazepam" rather than "better than nothing." Blinding is not described. The outcomes are clinician-rated scales. All of the trials come from the developing institutions and their clinical partners, and none has been replicated by an independent group outside Russia. A 2021 review in the Journal of Clinical Pharmacology, one of the few Western appraisals, characterised Selank as poorly studied outside its country of origin, which is fair.

That does not make the data worthless — comparator-controlled trials on validated anxiety scales are a stronger evidence base than the animal-only case behind most peptides. But the honest framing is "reported in small Russian comparator trials," not "proven." Any source telling you it has been established in Western clinical trials is wrong.

• It does not establish an effect size against placebo. No placebo-controlled trial exists in the PubMed-indexed literature.
• It does not establish efficacy for any diagnosis in the way a regulator would recognise. It is not FDA approved for anything.
• It does not establish a dose–response relationship for the subcutaneous route. The Russian trials and the Russian product are intranasal; the subcutaneous form has not been the subject of a published trial.
• It does not establish long-term safety over years of continuous use. The trials ran for weeks.
• It does not establish anything about combining Selank with SSRIs, SNRIs or other psychiatric medication, because that has not been studied.

Prescribers commonly describe any change as subtle: a sense of being less reactive to stress rather than any noticeable effect at the time of injection. There is no "kick." Some people notice nothing in the first week, which is normal and not a sign the course is not working.

This is the window the Russian trials worked in, and where prescribers describe the clearest change if it occurs: lower baseline anxiety, easier concentration under pressure, and in some people better sleep onset as a downstream effect. One vial at Monday-through-Friday dosing covers roughly this period, which is why it is sized that way.

The 2014 trial reported the anxiolytic effect persisting about a week after the last dose, which is one reason the weekday-only schedule is used: the weekend gap is not described as a loss of effect. Whether to continue past the first vial is a conversation with your physician based on what changed, not a default.

No withdrawal syndrome and no rebound anxiety are described in the published trials, in contrast to the benzodiazepine comparators. That is a reported finding from small studies, not a guarantee, and it is worth telling your physician if anything shifts when you stop.

The directions are written in millilitres and in insulin-syringe units because that is what you can actually read off the barrel. 0.25 mL is 25 units on a U-100 syringe. You are not calculating anything — the number is printed on your medication.

Subcutaneous means into the fat layer, not the muscle. Abdomen and thigh are the usual sites, rotated so the same spot is not used repeatedly. There is no reason to inject near the head or neck; the peptide is carried systemically and the site does not matter for a compound acting on the brain. Your directions will say.

20 doses at once daily, Monday through Friday, is four weeks, which is why refills run on a 28-day cycle. The weekend gap is part of the schedule, not a missed dose. One vial per fill, always — not a stockpile.

Refrigerated, and it ships that way in insulated packaging with ice packs. Beyond-use dating runs from first puncture and is on the label. Keep it out of light, do not freeze it, and do not shake the vial.

Same Russian programme, same institute, related design — Semax is a fragment of ACTH with a Pro-Gly-Pro tail, Selank a fragment of tuftsin with the same tail — and different targets. Semax is described around BDNF, attention and neuroprotection; Selank around GABA modulation, enkephalins and anxiety. Prescribers tend to reach for Semax when the complaint is focus, Selank when it is stress, and both together when it is the familiar combination. Semax was recommended for the 503A Bulks List by the advisory committee in July 2026; Selank has not been reviewed.

DSIP is aimed at sleep, specifically slow-wave sleep and night-time stress hormones. Selank is aimed at the daytime experience of anxiety. Where poor sleep is downstream of a racing mind, some physicians start with Selank; where sleep is the primary complaint, DSIP is the more direct conversation. The SERENITY blend exists for people describing both.

The single vial on this page contains 10 mg of Selank. The blends that include it — Semax + Selank, SERENITY, SYNAPSE and ELEVATE — carry 5 mg of Selank per vial alongside their other components. A blend makes sense when several of those components are indicated; the single makes sense when anxiety is the one thing being treated, or when a physician wants to see what Selank alone does first.

The injectable on this page and Pepti's separate Selank Nasal Spray are the same peptide by two routes. Intranasal is the route the Russian product and trials used; subcutaneous delivers a measured dose without depending on nasal absorption. The two have not been compared in a published human trial. Which is prescribed is a physician's decision, and there is no pepti Pen for Selank.