Selank

Selank at a Glance

Selank is a synthetic heptapeptide built by extending tuftsin, an endogenous immunomodulatory tetrapeptide, with the same stabilising tail used in Semax. It is registered in Russia as an anxiolytic — intended to reduce anxiety without the sedation, dependence or withdrawal that benzodiazepines carry — and is unapproved elsewhere. Its mechanism runs partly through serotonin and partly through immune signalling, an unusual combination for an anxiolytic.

History & Development

Selank is the anxiolytic counterpart to semax - same design strategy, different parent molecule, and registered in Russia for anxiety.

First described	Not established in the sources consulted for this section
Discovered / synthesised by	Not established in the sources consulted for this section
Institution	Not established in the sources consulted for this section
Origin	Synthetic heptapeptide extending the endogenous tetrapeptide tuftsin (Thr-Lys-Pro-Arg) with Pro-Gly-Pro
Key patent	Not established in the sources consulted for this section
Assignee	Not established in the sources consulted for this section
Development status	Registered prescription anxiolytic in Russia; unapproved in the US, UK, EU and Australia

Discovery

Tuftsin is an endogenous tetrapeptide - a fragment of immunoglobulin heavy chain with immunomodulatory activity - and it also has central effects. Selank extends it with the same Pro-Gly-Pro tail used in semax, for the same reason: resisting exopeptidase degradation.

The parent molecule is a real interpretive problem for this compound. Because tuftsin has biological activity of its own and selank is trimmed back toward it in plasma, distinguishing selank’s effects from tuftsin’s requires studies designed to separate them - and the peptide’s rapid breakdown into TKPRP, TKP, RP and GP means the fragments are candidates for the activity too.

Development & ownership

Selank is registered in Russia as an intranasal anxiolytic, used at a 0.15% solution in microgram to low-milligram daily doses.

Its evidence base is its central limitation, and it is worth stating precisely: the human data are a handful of small Russian studies using active comparators with no placebo arm. Comparing a drug against another drug without a placebo can show non-inferiority; it cannot establish that either did better than nothing. No placebo-controlled trial of selank exists in any indication.

For a registered medicine that is an unusual position, and it is the honest ceiling on any claim made for it.

How it reached the market

Selank is prescription-only in Russia and an unapproved research chemical elsewhere. It is sold in the West as a nootropic and anti-anxiety nasal spray, on the strength of trials that never included a placebo group.

What It's Used For

Selank is a synthetic heptapeptide — Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP) — built at the Institute of Molecular Genetics of the Russian Academy of Sciences by taking the endogenous immunomodulatory tetrapeptide tuftsin (Thr-Lys-Pro-Arg) and attaching a C-terminal Pro-Gly-Pro tail to slow its proteolytic breakdown ^{47Reference 47Siebert A et al. · 2017ReviewTuftsin — properties and analogs — reviewView study →}.

It is the sister compound of Semax, from the same institute and built on the same design principle. Selank is a registered medicine in Russia, sold there as an intranasal anxiolytic; it has never been approved by the FDA, EMA or TGA, and no trial of Selank is registered on ClinicalTrials.gov, the EU-CTR or the WHO ICTRP (verified July 2026). The whole evidence base sits under one structural constraint that shapes how everything below should be read: the human work is a small set of Russian-language, active-comparator studies with no placebo arm, mostly from the originating institute, and the rodent work is dominated by the same research lineage. Route is load-bearing — Selank is oral-inactive, and intranasal dosing is the only route with human data behind it. The honest frame is a peptide with a genuine, replicated mechanism, a real but thin and largely unverifiable human signal, and a marketing story (“as good as benzodiazepines, without the downsides”) that runs considerably ahead of both.

Evidence by IndicationStrength of support · Beta

Support is an experimental score I’m building — a composite weighted by study type (human > animal > in vitro > review) and study volume. It’s a beta: a fast way to rank strength of evidence at a glance, not a validated metric. Each application links down to its write-up.

One caveat applies to every row. These scores are discounted for verifiability, not only for volume. The human literature is Russian-language and cannot be independently checked in English-language indexes — a limitation a Western regulator has now acted on for the sister compound, formally excluding the equivalent Russian Semax literature for want of a verified translation. A low score here generally means “not studied in humans,” not “tested and failed” — with one exception noted in row 1: the anxiety evidence has been tested, just never against placebo.

01Anxiety & generalized anxiety disorderShaky44%Three small Russian active-comparator studies vs benzodiazepines (~130 patients, no placebo arm) + GABA-A/enkephalinase mechanism + rodent replication.

02Cognition & learning (nootropic)Shaky26%Rat avoidance/memory models, one monkey study, rat BDNF work; human data limited to one healthy-volunteer fMRI network readout.

03Immunomodulation & antiviral activityShaky21%Mouse spleen gene expression + influenza models + one small patient cytokine study. Tuftsin-lineage plausibility.

04Addiction & withdrawal (alcohol, opioid)Shaky17%Three rodent withdrawal/sensitization models from one lab lineage. No human data.

05Depression & moodShaky14%Rodent forced-swim/anhedonia models with a non-monotonic dose response, plus monoamine studies. No human depression data.

06Gastric mucosal protectionShaky11%Rat ulcer models plus a route/distribution finding that glyprolines concentrate in gastric tissue. Animal-only.

Mechanisms

Pharmacokinetics

Selank is oral-inactive — a peptide of this size is digested rather than absorbed — and the human clinical work used the intranasal route exclusively. Its degradation has been mapped directly with uniformly tritium-labeled peptide: the major breakdown products in blood plasma are the pentapeptide TKPRP, the tripeptide TKP, and the dipeptides RP and GP, with brain pharmacokinetics characterized after intranasal dosing ^{37Reference 37Zolotarev YuA et al. · 2006In vitroEvenly tritium-labeled peptides and their in vivo and in vitro biodegradation (Selank degradation to TKPRP, TKP, RP and GP; intranasal brain PK) — in vitro / animal (rat, PK)View study →}. Exopeptidase trimming from both termini is therefore fast, and the parent’s plasma persistence is measured in minutes. The Pro-Gly-Pro tail exists specifically to slow that process, and the Russian glyproline literature argues these peptides are considerably more stable than regulatory peptides generally ^{39Reference 39Ashmarin IP et al. · 2005ReviewNatural and hybrid (“chimeric”) stable regulatory glyproline peptides — review (Pro-Gly-Pro stability rationale)View study →}.

The fragments are not inert, and this is pharmacologically load-bearing. Two of Selank’s own degradation products reproduced its Bcl6 gene-expression signature in mouse spleen ^{31Reference 31Kolomin T et al. · 2011AnimalExpression of inflammation-related genes in mouse spleen under tuftsin analog Selank — animal (mouse; Selank and two of its fragments)View study →}; its structural fragments carry antiviral activity in their own right ^{34Reference 34Andreeva LA et al. · 2010In vitroAntiviral properties of structural fragments of the peptide Selank — in vitroView study →}; and its metabolites, not just the parent, protected the gastric mucosa ^{36Reference 36Pavlov TS et al. · 2007AnimalSelank and its metabolites maintain homeostasis in the gastric mucosa (three experimental ulceration models) — animal (rat)View study →}. Whatever Selank does in vivo is plausibly done in part by what it becomes — the same pattern seen with Semax, whose activity may be substantially carried by its Pro-Gly-Pro metabolite.

A direct route comparison exists and is unusually informative. Tritium-labeled Selank and Pro-Gly-Pro were tracked through rat organs after intraperitoneal, intranasal, intragastric and intravenous administration; intranasal was optimal for CNS delivery, and all routes showed high affinity for gastric tissue ^{38Reference 38Ashmarin IP et al. · 2008AnimalA comparative analysis of distribution of glyprolines administered by various routes (Selank and PGP; intraperitoneal, intranasal, intragastric, intravenous — intranasal optimal for CNS) — animal (rat, PK)View study →}. Route also changes the pharmacodynamics, not just the exposure: intranasal and intraperitoneal Selank produced different receptor-binding profiles in mice (NMDA-site versus GABA-site shifts), which the authors attributed to route-specific biotransformation ^{15Reference 15Vasil’eva EV et al. · 2016AnimalComparison of pharmacological effects of heptapeptide selank after intranasal and intraperitoneal administration to BALB/c and C57BL/6 mice — animal (mouse; route comparison)View study →}. No human pharmacokinetic study of Selank was located in this pass — no human half-life, no bioavailability figure, no absorption data by any route. Practical stability and reconstitution parameters for gray-market lyophilized product are not independently documented.

Clinical & regulatory status

Selank is a registered medicine in Russia, marketed as an intranasal preparation for anxiety and asthenic disorders. It is not approved by the FDA, EMA, TGA or PMDA, is not a lawful dietary-supplement ingredient in the US, UK or EU, and holds no drug label outside Russia. No trial of Selank is registered on ClinicalTrials.gov — every “selank” hit in the registry is an unrelated false positive (high-altitude cognition, dyslexia tDCS, brivaracetam epilepsy, telephone psychotherapy) — and the EU-CTR and WHO ICTRP are likewise empty (verified via the ClinicalTrials.gov v2 API, July 2026). The Russian literature states that Selank completed third-phase clinical testing as a selective anxiolytic ^{26Reference 26Sarkisova KIu et al. · 2008AnimalEffects of heptapeptide selank on genetically-based and situation-provoked symptoms of depression in WAG/Rij and Wistar rats and BALB/c mice (abstract states Selank completed third-phase clinical testing) — animal (rat, mouse)View study →}; that claim appears in a paper abstract from the originating research program and is not independently verifiable through any international registry. A 2026 review of therapeutic peptides names selank among neuroactive peptides circulating without clinical-trial support ^{48Reference 48Rahman OF et al. · 2026Clinical trialTherapeutic peptides in orthopaedics: applications, challenges, and future directions (names selank among neuroactive peptides lacking clinical trials) — reviewView study →}, and a European official medicines control laboratory records that Selank “[has] not completed any clinical trials” while being freely sold online ^{46Reference 46Vanhee C et al. · 2020In vitroThe occurrence of putative cognitive enhancing research peptides in seized pharmaceutical preparations (Selank and Semax identified in seized product by an official medicines control laboratory) — analytical / in vitroView study →}.

The counts below reflect what is findable and verifiable in PubMed and English-language registries in this pass. The Russian-language clinical literature is larger; it is also, by the standard a Western regulator has now applied to the sister compound, not independently verifiable.

Last checked: July 2026.

Sourcing, Route & Legal Status

Regulatory status — stated precisely, because the distinction is the whole point. Selank is a registered, prescription-status medicine in Russia. That is a true statement about Russia and carries no Western regulatory weight whatsoever. This site does not flag Selank as a prescription drug, and the reason is not editorial squeamishness: when FDA formally evaluated the sister peptide Semax for the section 503A Bulk Drug Substances List in 2026, it acknowledged the Russian registration as a bare fact of foreign marketing, gave it zero weight in its balancing of the criteria, and concluded against listing. The same logic applies here with the same force. Outside Russia, Selank is an unapproved research chemical, sold labeled “for research use only / not for human consumption,” which is the legally accurate frame for anyone acquiring it internationally. It is not a scheduled or controlled substance in the US, but “not scheduled” is not “approved” — marketing it for human use is unlawful in most Western jurisdictions.

The Russian-literature problem, named plainly. Selank was developed at the Institute of Molecular Genetics in Moscow, and essentially all of its clinical evidence is Russian-language work, much of it from the originating institute and its collaborators. These papers are indexed in PubMed with English abstracts; their full texts are not available in English. This is not a hedge — it is a limitation a regulator has acted on. FDA excluded the Russian-language clinical literature on Semax from its 2026 evaluation entirely, under 21 CFR 10.20(c)(2), because no verified English translation was available, and issued its effectiveness finding on the English-accessible references alone. Nothing here has laundered an unverifiable claim into a numbered citation: where a finding rests on a Russian abstract, the write-up says what the abstract says and stops there. Where the abstract does not state randomization, blinding, allocation or placebo control, they are not supplied.

Route — and the mismatch that matters. The route with human data is intranasal, as a solution (a 0.15% intranasal preparation is the commonly referenced Russian format). The gray market sells nasal spray and subcutaneous injection, plus oral and sublingual products. Three things follow. Oral and sublingual products cannot be assumed to deliver intact peptide and have no supporting data at all. Subcutaneous dosing has no human data whatsoever — it is an extrapolation from a peptide studied nasally, and the rodent work shows route changes the receptor-binding profile, not just the dose delivered ^{15,38Reference 15Vasil’eva EV et al. · 2016AnimalComparison of pharmacological effects of heptapeptide selank after intranasal and intraperitoneal administration to BALB/c and C57BL/6 mice — animal (mouse; route comparison)View study →Reference 38Ashmarin IP et al. · 2008AnimalA comparative analysis of distribution of glyprolines administered by various routes (Selank and PGP; intraperitoneal, intranasal, intragastric, intravenous — intranasal optimal for CNS) — animal (rat, PK)View study →}. And the one cardiovascular study that exists used the intravenous route in anesthetized cats and found a transient ~32% drop in arterial pressure ^{18Reference 18Gan’shina TS · 2005Effects of the new peptide anxiolytic drug selank on the cardiovascular system functioning and respiration in cats — animal (cat, intravenous)View study →}; whether that has any bearing on intranasal use in humans is unknown, but it is the only hemodynamic datum in the file.

How it’s supplied. Russian pharmaceutical Selank is an intranasal aqueous solution dosed in micrograms per application. Gray-market international material is typically lyophilized (freeze-dried) powder requiring user reconstitution with bacteriostatic or sterile water, plus pre-mixed nasal sprays. Lyophilized peptide is stored cold; reconstituted material is unstable and time-limited.

Sourcing reality (this is a safety issue, not a footnote). International Selank comes from unregulated vendors with no manufacturing oversight — no assurance of identity, actual peptide content, correct sequence, or absence of bacterial endotoxin. This is documented rather than hypothetical for this specific molecule: a Belgian official medicines control laboratory encountered unknown suspicious preparations in 2017–2018 that proved to contain Selank and Semax, and developed dedicated LC-MS/MS methodology precisely because these peptides are sold online as injectables and nasal sprays with no clinical-trial support behind them ^{46Reference 46Vanhee C et al. · 2020In vitroThe occurrence of putative cognitive enhancing research peptides in seized pharmaceutical preparations (Selank and Semax identified in seized product by an official medicines control laboratory) — analytical / in vitroView study →}. Because dosing is in micrograms and the product is self-reconstituted, small concentration errors and handling contamination carry real risk. Third-party certificates of analysis (independent HPLC identity/purity plus endotoxin testing) are the only partial mitigation, and can themselves be falsified. This page does not recommend, rank or link any vendor.

Analogues. A modified version, N-Acetyl Selank Amidate, is sold as a “more stable” derivative. No study of any kind — human, animal or in vitro — has ever administered that molecule; its entire case is a structure–activity extrapolation from the Selank data here, and its end-caps are specifically designed to block the fragment generation that Selank’s own pharmacology partly depends on ^{31,34,36Reference 31Kolomin T et al. · 2011AnimalExpression of inflammation-related genes in mouse spleen under tuftsin analog Selank — animal (mouse; Selank and two of its fragments)View study →Reference 34Andreeva LA et al. · 2010In vitroAntiviral properties of structural fragments of the peptide Selank — in vitroView study →Reference 36Pavlov TS et al. · 2007AnimalSelank and its metabolites maintain homeostasis in the gastric mucosa (three experimental ulceration models) — animal (rat)View study →}. Treat it as strictly less evidenced than Selank, not more.

Safety

Selank’s reputation for being well tolerated rests on roughly 130 patients in small Russian studies that were never designed as safety trials — and the clearest documented signal is anticoagulant activity, which makes bleeding risk, not sedation, the thing to watch.

Safety at a Glance

❔ Toxicity unknownBleeding riskDrug interactionsSedative interactions

• Anticoagulant activity is the clearest signal. A reason to avoid it on anticoagulant or antiplatelet drugs, or with a bleeding disorder.
• Not assessed in pregnancy or breastfeeding. No reproductive-toxicity data, and the one developmental study is not a null result — see the box below.
• Human safety data are minimal. Around 130 patients total, no placebo arm, no Western pharmacovigilance record.
• Open questions with GABAergic and opioid drugs. Selank blocked diazepam and olanzapine activity in a radioligand assay; no controlled interaction study exists.
• Delivery is the dominant practical risk. Nasal irritation, and for gray-market powder, contamination, endotoxin exposure and dosing error.

Full Safety & Interactions Detail

Overall posture. Documented human safety data are limited to the small Russian clinical literature, where intranasal Selank was reported as generally well tolerated and specifically without the sedation, memory impairment, dependence or withdrawal characteristic of benzodiazepines ^{1,2,3Reference 1Zozulia AA et al. · 2008Clinical trialEfficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia (n=62; Selank n=30 vs medazepam n=32) — human (active-comparator clinical study, Russian-language)View study →Reference 2Medvedev VE et al. · 2014Clinical trialA comparison of the anxiolytic effect and tolerability of selank and phenazepam in the treatment of anxiety disorders (n=60) — human (active-comparator clinical study, Russian-language)View study →Reference 3Medvedev VE et al. · 2015Clinical trialOptimization of the treatment of anxiety disorders with selank (phenazepam monotherapy n=30 vs phenazepam + Selank n=40) — human (add-on clinical study, Russian-language)View study →} — a claim that is central to how Selank is marketed. Two caveats belong with it. Those studies were not designed or powered as safety trials, and total documented human exposure across the entire literature is roughly 130 patients. And “no dependence” is a negative claim, which requires a study designed to detect dependence; none of these was. No Western pharmacovigilance system holds a meaningful Selank record, because almost nobody reports using it — an empty adverse-event file is not a safety finding.

Signals worth naming. Anticoagulant activity is the clearest. Selank showed anticoagulant effects on thromboelastography and was the most potent of three glyprolines tested ^{40Reference 40Rogozinskaya EY · 2017In vitroAnticoagulant effects of arginine-containing peptides of the glyproline family (His-Phe-Arg-Trp-Pro-Gly-Pro and Thr-Lys-Pro-Arg-Pro-Gly-Pro) revealed by thromboelastography — in vitroView study →}; it appears in a comparative analysis of the anticoagulant specificity of glyprolines, Semax and Selank ^{41Reference 41Liapina LA et al. · 2006ReviewComparison of anticoagulant effects of regulatory proline-containing oligopeptides: specificity of glyprolines, semax and selank — review / animalView study →}; and its effect on hemostasis parameters, lipid profile and blood glucose has been studied in an experimental metabolic-syndrome model ^{42Reference 42Mjasoedov NF et al. · 2014The influence of Selank on the parameters of the hemostasis system, lipid profile, and blood sugar level in the course of experimental metabolic syndrome — animalView study →}. This is not a fringe finding, and it is reinforced from an unexpected direction: FDA’s 2026 evaluation of the sister peptide Semax treats the same class of antithrombotic/antiplatelet activity as a genuine bleeding risk, warning specifically about combination with other medications that increase bleeding risk. Neither compound has a documented clinical bleeding event, and no dose-response data exists for either. The correct posture is caution, not alarm — and it is a reason for anyone on anticoagulants or antiplatelet drugs, or with a bleeding disorder, to avoid it.

A developmental finding that must not be read as reassurance. A mouse embryonic-stem-cell study concluded that Selank and several related peptides “do not produce toxic effect during the embryonic and fetal period of life” — but the same study found that Selank reduced differentiation into GABAergic neurons by 61% relative to control ^{43Reference 43Kobylyanskii AG et al. · 2017In vitroStudying the toxic effects of some biologically active peptides on the model of mouse embryonic stem cells (Selank reduced GABA+ neuronal differentiation by 61%) — in vitroView study →}. An in-vitro cell model is not a reproductive-toxicity study in either direction, and a 61% shift in a neuronal lineage is not a null result. This is the only developmental data that exists.

Other findings. In anesthetized cats, intravenous Selank transiently reduced arterial pressure by ~32% and increased cerebral blood flow by ~24%, without affecting heart rate or respiration ^{18Reference 18Gan’shina TS · 2005Effects of the new peptide anxiolytic drug selank on the cardiovascular system functioning and respiration in cats — animal (cat, intravenous)View study →} — an acute hemodynamic effect at a route and species remote from human use, but the only such measurement available. A rat study of hepatocyte function under restraint stress reported no adverse hepatic signal ^{45Reference 45Fomenko EV et al. · 2017AnimalEffect of Selank on functional state of rat hepatocytes under conditions of restraint stress — animal (rat)View study →}. Neither is a human safety result.

Dose-limiting / route-specific risks. The dominant practical risks are delivery and product risks rather than classical drug toxicity: nasal-mucosa irritation from repeated intranasal dosing; for gray-market lyophilized product, contamination and sterility failure during reconstitution, endotoxin exposure, and dosing error from self-mixed concentrations. For subcutaneous use — a route with no human data at all — injection-site reactions and sterility risk apply on top of an untested route.

Interactions. No controlled human drug-interaction study exists for Selank. Mechanism-based cautions, labeled as inference: Selank modulates GABA binding and blocked the modulatory activity of diazepam and olanzapine in a radioligand assay ^{10Reference 10Vyunova TV et al. · 2018In vitroPeptide-based anxiolytics: the molecular aspects of heptapeptide Selank biological activity — in vitro (radioligand binding)View study →}, and one clinical report deliberately combines it with a benzodiazepine ^{3Reference 3Medvedev VE et al. · 2015Clinical trialOptimization of the treatment of anxiety disorders with selank (phenazepam monotherapy n=30 vs phenazepam + Selank n=40) — human (add-on clinical study, Russian-language)View study →} — so co-use with benzodiazepines, other GABAergic sedatives and antipsychotics is a genuine open question rather than a settled safe combination. It modulates the endogenous opioid system ^{13,14Reference 13Meshavkin VK et al. · 2006AnimalNaloxone-blocked depriming effect of anxiolytic selank on apomorphine-induced behavioral manifestations — animal (rodent)View study →Reference 14Kozlovskiĭ II et al. · 2012AnimalThe role of the opioid system in the anti-anxiety effect of the peptide anxiolytic selank — animal (mouse)View study →}, warranting caution with opioids. And the anticoagulant signal ^{40,41,42Reference 40Rogozinskaya EY · 2017In vitroAnticoagulant effects of arginine-containing peptides of the glyproline family (His-Phe-Arg-Trp-Pro-Gly-Pro and Thr-Lys-Pro-Arg-Pro-Gly-Pro) revealed by thromboelastography — in vitroView study →Reference 41Liapina LA et al. · 2006ReviewComparison of anticoagulant effects of regulatory proline-containing oligopeptides: specificity of glyprolines, semax and selank — review / animalView study →Reference 42Mjasoedov NF et al. · 2014The influence of Selank on the parameters of the hemostasis system, lipid profile, and blood sugar level in the course of experimental metabolic syndrome — animalView study →} means anticoagulant and antiplatelet drugs are the most concrete interaction concern here.

Who should avoid it. Anyone treating a diagnosed anxiety disorder, for whom substituting an unapproved research chemical for evaluated care is the actual harm; anyone pregnant, breastfeeding or trying to conceive; children and adolescents; anyone on anticoagulant, antiplatelet, benzodiazepine, antipsychotic or opioid medication; anyone with a bleeding disorder; and anyone unwilling to accept a product of unverified identity, purity and sterility. Because it is prescription-only where it is approved at all, self-administration outside medical supervision is off-label by definition.

Scope disclosure (honesty, not a claim):

• Human data? Minimal and structurally limited — three small Russian active-comparator anxiety studies (~130 patients total, no placebo arm anywhere), one small patient cytokine study, and one healthy-volunteer fMRI study. No blinded, placebo-controlled, or Western-conducted trial of any kind; no registered trial in any international registry.
• Human pharmacokinetics? None located. No human half-life, bioavailability, or absorption figure by any route.
• Interactions assessed? No. The GABAergic, opioid and anticoagulant cautions are mechanism-based inference plus one deliberate benzodiazepine co-administration study.
• Pregnancy/lactation assessed? No — no human or animal reproductive-toxicity data. One in-vitro stem-cell study only, with a non-null finding.
• Long-term safety established? No. Do not infer safety from the absence of reported harm — nobody has looked, in any Western system, at a population large enough to find anything.

Never imply safety from silence. Where Selank has not been studied — interactions, pregnancy, long-term use, subcutaneous dosing, gray-market product purity — the correct statement is “not assessed,” not “safe.”

Pregnancy & Lactation

? Not established in pregnancy? Not established in lactation

Not assessed / not established. There are no human pregnancy or lactation data and no conventional animal reproductive-toxicity study. The only relevant work is the mouse embryonic-stem-cell study above ^{43Reference 43Kobylyanskii AG et al. · 2017In vitroStudying the toxic effects of some biologically active peptides on the model of mouse embryonic stem cells (Selank reduced GABA+ neuronal differentiation by 61%) — in vitroView study →}, which reported no cytotoxicity but a 61% reduction in GABAergic neuronal differentiation — a finding that argues for caution, not against it. Treat as contraindicated by default in pregnancy and breastfeeding.

Dosage

There is no established Western human dose for Selank, and none is recommended here. It is not an approved supplement or drug outside Russia, and every figure below is data reported for context, not a personal recommendation — do not read it as a protocol.

The human dosing that exists is intranasal. Russian pharmaceutical Selank is supplied as an intranasal solution (a 0.15% preparation is the commonly referenced format), dosed in micrograms per application across a course of days to weeks; the anxiety studies ^{1,2,3Reference 1Zozulia AA et al. · 2008Clinical trialEfficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia (n=62; Selank n=30 vs medazepam n=32) — human (active-comparator clinical study, Russian-language)View study →Reference 2Medvedev VE et al. · 2014Clinical trialA comparison of the anxiolytic effect and tolerability of selank and phenazepam in the treatment of anxiety disorders (n=60) — human (active-comparator clinical study, Russian-language)View study →Reference 3Medvedev VE et al. · 2015Clinical trialOptimization of the treatment of anxiety disorders with selank (phenazepam monotherapy n=30 vs phenazepam + Selank n=40) — human (add-on clinical study, Russian-language)View study →} used intranasal courses on that pattern. Rodent work spans roughly 100–2000 µg/kg by injection ^{26,27,29Reference 26Sarkisova KIu et al. · 2008AnimalEffects of heptapeptide selank on genetically-based and situation-provoked symptoms of depression in WAG/Rij and Wistar rats and BALB/c mice (abstract states Selank completed third-phase clinical testing) — animal (rat, mouse)View study →Reference 27Kolik LG et al. · 2014AnimalEfficacy of peptide anxiolytic selank during modeling of withdrawal syndrome in rats with stable alcoholic motivation — animal (rat)View study →Reference 29Kolik LG et al. · 2016AnimalSelank inhibits ethanol-induced hyperlocomotion and manifestation of behavioral sensitization in DBA/2 mice — animal (mouse)View study →}, with 300 µg/kg the most-used behavioral dose ^{19,24Reference 19Kozlovskii II et al. · 2003AnimalThe optimizing action of the synthetic peptide Selank on a conditioned active avoidance reflex in rats — animal (rat)View study →Reference 24Czabak-Garbacz R et al. · 2006AnimalInfluence of long-term treatment with tuftsin analogue TP-7 on the anxiety-phobic states and body weight (TP-7 is Selank; largely non-Russian group, Medical University of Lublin) — animal (rat, 4-week daily dosing)View study →} — animal doses, by a different route, and not convertible to a human dose. There is no validated Western human dose, no established maintenance schedule, and no verified human bioavailability figure to anchor one, because no human PK study exists.

Two route points are decision-relevant. Oral and sublingual “Selank” products cannot be assumed to deliver intact peptide (see Pharmacokinetics) — any oral dose is pharmacologically questionable regardless of the number on the label. And subcutaneous Selank has no human dosing data at all; vendor injection protocols are extrapolated from a nasally-studied drug, and the animal data show the route changes the pharmacodynamic profile, not just the amount absorbed ^{15,38Reference 15Vasil’eva EV et al. · 2016AnimalComparison of pharmacological effects of heptapeptide selank after intranasal and intraperitoneal administration to BALB/c and C57BL/6 mice — animal (mouse; route comparison)View study →Reference 38Ashmarin IP et al. · 2008AnimalA comparative analysis of distribution of glyprolines administered by various routes (Selank and PGP; intraperitoneal, intranasal, intragastric, intravenous — intranasal optimal for CNS) — animal (rat, PK)View study →}. This entry is informational only.

References

1. Zozulia AA, et al. (2008). Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia (n=62; Selank n=30 vs medazepam n=32) — human (active-comparator clinical study, Russian-language). Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova. https://pubmed.ncbi.nlm.nih.gov/18454096/
2. Medvedev VE, et al. (2014). A comparison of the anxiolytic effect and tolerability of selank and phenazepam in the treatment of anxiety disorders (n=60) — human (active-comparator clinical study, Russian-language). Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova. https://pubmed.ncbi.nlm.nih.gov/25176261/
3. Medvedev VE, et al. (2015). Optimization of the treatment of anxiety disorders with selank (phenazepam monotherapy n=30 vs phenazepam + Selank n=40) — human (add-on clinical study, Russian-language). Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova. https://pubmed.ncbi.nlm.nih.gov/26356395/
4. Uchakina ON, et al. (2008). Immunomodulatory effects of selank in patients with anxiety-asthenic disorders — human (small mechanistic cytokine study) / in vitro. Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova. https://pubmed.ncbi.nlm.nih.gov/18577961/
5. Panikratova YR, et al. (2020). Functional connectomic approach to studying Selank and Semax effects — human (resting-state fMRI, healthy volunteers). Doklady Biological Sciences. https://pubmed.ncbi.nlm.nih.gov/32342318/
6. Zozulya AA, et al. (2001). The inhibitory effect of Selank on enkephalin-degrading enzymes as a possible mechanism of its anxiolytic activity — in vitro. Bulletin of Experimental Biology and Medicine. https://pubmed.ncbi.nlm.nih.gov/11550013/
7. Kost NV, et al. (2001). Semax and selank inhibit the enkephalin-degrading enzymes from human serum — in vitro. Bioorganicheskaia Khimiia. https://pubmed.ncbi.nlm.nih.gov/11443939/
8. Zolotarev YuA, et al. (2004). Leu-enkephalin homogeneously labeled with tritium in studying the Selank inhibiting effect on the enkephalin-degrading enzymes of human plasma — in vitro. Russian Journal of Bioorganic Chemistry (Bioorganicheskaia Khimiia). https://pubmed.ncbi.nlm.nih.gov/15344652/
9. Sokolov OY, et al. (2002). Effects of Selank on behavioral reactions and activities of plasma enkephalin-degrading enzymes in mice with different phenotypes of emotional and stress reactions — animal (mouse). Bulletin of Experimental Biology and Medicine. https://pubmed.ncbi.nlm.nih.gov/12432865/
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