A synthetic seven-amino-acid peptide (sequence TKPRPGP) developed in Russia from a fragment of the body's own immune peptide, tuftsin. It is given mainly as nasal drops and is officially approved in Russia for generalized anxiety and "neurasthenia" (chronic nervous exhaustion) — but is not approved by the FDA, EMA, or any Western regulator. Its headline property is calm without sedation: in a Russian comparative study it matched a benzodiazepine for reducing anxiety while leaving people alert, and it produced no drowsiness, no memory impairment, no tolerance, and no withdrawal. As with its sibling Semax, nearly all human evidence comes from Russian-language studies that have never been independently replicated in the West.
Intranasal anxiolytic heptapeptide; a Pro-Gly-Pro–stabilized analog of the endogenous immunopeptide tuftsin (Thr-Lys-Pro-Arg). Mechanistically multimodal: positive allosteric GABA-A modulation at a non-benzodiazepine site, inhibition of enkephalin-degrading enzymes (prolonging endogenous enkephalin tone), serotonin/dopamine turnover modulation, hippocampal/PFC BDNF upregulation, and a tuftsin-inherited cytokine/interferon immunomodulatory arm. Russia-registered (~2009) as 0.15% nasal drops for GAD and neurasthenia. The defining human signal is a comparative trial (Zozulya 2008, n=62) in which Selank matched medazepam for anxiolytic efficacy with superior cognitive/antiasthenic endpoints and no sedation, tolerance, or withdrawal; a second comparative trial vs phenazepam (Medvedev) reported effects persisting ~1 week after the last dose.
Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) is the tuftsin tetrapeptide (TKPR) extended by a C-terminal Pro-Gly-Pro motif that acts as a proteolytic shield, converting tuftsin's seconds-long half-life into a pharmacologically usable molecule. CAS 129954-34-3; C₃₃H₅₇N₁₁O₉; MW ≈ 751.9 Da; PubChem CID 11765600. Plasma half-life of the parent is ~2–3 minutes, yet anxiolytic/nootropic effects persist 8–24+ hours — reconciled by active metabolites, enkephalinase inhibition, and sustained gene-expression changes documented in single-dose transcriptomic studies. Developed at the Institute of Molecular Genetics, RAS (Myasoedov group, designation TP-7) — the same lab that produced Semax. The two share the PGP C-terminus and overlapping enkephalinase inhibition, but diverge in primary action: Selank is anxiolytic/immunomodulatory where Semax is nootropic/neuroprotective.
≈ BZDMatched medazepam for anxiety · Zozulya · n=62
The most-cited numbers across three decades of predominantly Russian research — the flagship anxiolytic indication, the multimodal non-benzodiazepine mechanism, and the honest evidence-quality caveats. Like Semax, Selank is the rare peptide with genuine regulatory approval in one jurisdiction and a near-total absence of independently replicated Western trials. Read every figure alongside its evidence grade.
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Anxiolytic efficacy · vs medazepam · human
≈BZD
Zozulya et al. (2008, PMID 18454096): in 62 patients with generalized anxiety disorder and neurasthenia, intranasal Selank matched the benzodiazepine medazepam for anxiety reduction (Hamilton/Zung/CGI) — but added antiasthenic and mild psychostimulant effects and avoided sedation, muscle relaxation, tolerance, and withdrawal. The mechanistic anchor for every anxiolytic claim.
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Effect persistence after last dose
~1 wk
Medvedev et al. (PMID 25176261): a comparative trial vs phenazepam in 60 patients with phobic-anxiety, somatoform, and adjustment disorders (ICD F40–F45) reported pronounced anxiolytic plus mild nootropic effect, improved quality of life, and — strikingly — efficacy persisting roughly one week after the last dose. A duration unusual for an anxiolytic, consistent with its gene-expression mechanism.
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Duration paradox · plasma vs effect
8–24 h
The intact heptapeptide clears plasma in ~2–3 minutes, yet behavioral effects persist 8–24+ hours after one intranasal dose. Reconciled by direct nose-to-brain transport (brain detection <15 min, CSF peak ~45 min), active metabolites, enzyme inhibition, and a sustained gene-expression cascade. The same minutes-vs-day dissociation seen with Semax.
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GABA-A site · non-benzodiazepine
non-BZD
Selank potentiates GABA-A signaling at a site distinct from the benzodiazepine pocket: its effect is blocked by the GABA-A antagonist bicuculline but is insensitive to flumazenil. This is why it produces calm without the sedation, dependence, or withdrawal that define benzodiazepines. The single most important pharmacological distinction of the molecule.
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Endogenous enkephalin · serum half-life
tau½↑
In the Zozulya cohort, GAD/neurasthenia patients had a reduced leu-enkephalin tau(1/2) at baseline that correlated with symptom severity; Selank treatment increased enkephalin half-life, with the change tracking clinical improvement. A rare human mechanistic correlate linking enzyme inhibition to measured symptom change.
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Immune / antiviral arm · tuftsin lineage
IFN-α
Inherited from tuftsin: in influenza (H3N2) models Selank suppressed viral replication in vitro and improved survival in vivo, with IFN-α gene induction and no rise in TNF-α/IL-4/IL-10 — a preferential Th1 skew. A single mouse-spleen study found one intranasal dose altered 34 inflammation-related genes (Cx3cr1 ↑16×). Preclinical, but a genuine second axis.
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Russian regulatory status
Approved
Registered pharmaceutical in the Russian Federation (~2009) — 0.15% intranasal drops indicated for generalized anxiety disorder and neurasthenia. Also used in Ukraine. The 14-day, 400 µg three-times-daily course is the registered clinical protocol. One of only two anxiolytic peptides from the IMG RAS program to reach a national market.
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US regulatory status · 2026
Cat 2
Not FDA-approved; placed on the FDA's Category 2 "significant safety risk" bulk-substance list in 2023, removing it from 503A/503B compounding eligibility. Unlike Semax and Epitalon, Selank was not among the peptides removed from Category 2 in April 2026 and is not on the July 23–24, 2026 PCAC agenda — so it remains off-limits to lawful US compounding.
02 · Mechanism of action
How a multimodal anxiolytic works.
Selank is built from a fragment of tuftsin, a natural peptide your immune system already makes. Unlike traditional anti-anxiety drugs (benzodiazepines), Selank doesn't switch on the brain's "off" button in a way that causes grogginess or dependence. Instead it works through several gentle levers at once: it boosts the brain's own calming signal (GABA) at a different, non-addictive site; it slows the breakdown of the brain's natural "feel-good" peptides (enkephalins); it nudges serotonin and dopamine to support mood and focus; it raises brain-protective growth factors (BDNF); and — a leftover talent from its immune-peptide parent — it can tune inflammation and antiviral defenses. The net result is calm clarity rather than foggy tranquility, beginning within minutes and lasting most of a day.
Selank's effect profile reflects convergent action across at least six pathways. Its anxiolysis derives from positive allosteric GABA-A modulation at a non-benzodiazepine site (bicuculline-sensitive, flumazenil-insensitive), supported by enkephalinase inhibition (aminopeptidase N, DPP-IV) that prolongs endogenous leu/met-enkephalin tone. Layered on top are serotonin/dopamine turnover modulation, hippocampal/PFC BDNF and NGF upregulation, a tuftsin-derived cytokine/IFN-α immunomodulatory arm, and indirect HPA-axis (corticosterone) normalization. The absence of direct benzodiazepine-site engagement explains the clinical signature: anxiolysis without sedation, tolerance, dependence, or withdrawal — alongside the mild antiasthenic/procognitive effect that distinguishes it from a pure sedative anxiolytic.
Selank is best classified as a multimodal glyproline neuromodulator rather than a single-target ligand. Single-dose transcriptomic work from the IMG RAS group (Kolomin, Shadrina, Slominsky, Limborska) documents differential expression of GABA-A receptor subunits (α2/α3/γ2), monoamine transporters and receptor subtypes (5-HT2A, D1, D2), neurotrophins, and — in spleen — 34 inflammation-related genes after a single intranasal dose. The duration paradox (2–3 min plasma t½ vs 8–24 h effect) is resolved by nose-to-brain delivery, active fragment generation, and a gene-expression cascade that outlasts the parent. The closest mechanistic sibling is Semax, with which it shares the PGP C-terminus and overlapping enkephalinase inhibition; the molecular detail is overwhelmingly preclinical, with human confirmation limited to the serum-enkephalin correlate and behavioral endpoints.
C
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GABA-A positive allosteric modulation · non-BZD site
The defining anxiolytic mechanism: Selank enhances GABA-A signaling at a site distinct from the benzodiazepine binding pocket. The effect is blocked by the GABA-A antagonist bicuculline but is insensitive to flumazenil, confirming a non-benzodiazepine site. Because it avoids the BZD site, it produces calm without sedation, tolerance, or physical dependence — the core clinical distinction from diazepam-class drugs.
Clinical significance: The non-BZD site is why Selank can match a benzodiazepine for anxiolytic efficacy (Zozulya) while avoiding the sedation, muscle relaxation, amnesia, and withdrawal that limit benzodiazepines. It also underpins the (anecdotal, Russian) use of Selank as a support agent during benzodiazepine withdrawal — an unvalidated but mechanistically coherent application.
Molecular detail: Single-dose transcriptomic studies report upregulation of GABA-A receptor subunit mRNA (α2, α3, γ2) in hippocampus and prefrontal cortex, suggesting the modulation has both an acute allosteric and a slower transcriptional component. Whether the allosteric action is direct on the receptor or mediated by an active metabolite is not fully resolved in accessible literature; the subunit-selective transcriptional arm is graded P (preclinical transcriptomics).
Selank inhibits enkephalin-degrading enzymes — aminopeptidase N and dipeptidyl peptidase IV — more potently than the reference inhibitors bacitracin and puromycin, extending the half-life of endogenous leu- and met-enkephalin and potentiating δ/µ-opioid tone without directly agonizing opioid receptors. The shared PGP C-terminus with Semax is the structural basis for this overlapping activity.
Clinical significance: This is the pathway with the clearest human correlate: GAD/neurasthenia patients had a reduced serum leu-enkephalin tau(1/2) at baseline that correlated inversely with anxiety/asthenia severity, and Selank treatment increased it — particularly in responders versus medazepam comparators. It also creates the most important interaction caution: combining Selank with exogenous opioids risks unpredictable opioid potentiation.
Molecular detail: Zozulya/Kost and colleagues demonstrated concentration-dependent enkephalinase inhibition in human serum. Because tuftsin itself is enzymatically unstable (half-life seconds), the PGP tail's role is dual — it slows C-terminal degradation of Selank and contributes to peptidase inhibition. Whether inhibition is competitive at the peptidase active site or allosteric is not detailed in accessible sources.
C
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Serotonin & dopamine turnover modulation
Rodent neurochemistry documents increased 5-HIAA/5-HT ratios in hypothalamus and striatum (accelerated serotonin turnover, not simple elevation) alongside normalization of dopamine metabolism in prefrontal regions under stress; norepinephrine is also regulated. This multimodal monoaminergic tuning explains the simultaneous anxiolytic-plus-procognitive profile not seen with benzodiazepines.
Clinical significance: The serotonergic component is the basis for the theoretical (uncharacterized) interaction caution with SSRIs/SNRIs/MAOIs — no serotonin-syndrome case reports exist, but the overlap is pharmacologically plausible. The dopamine normalization helps account for the antiasthenic/psychostimulant signal Zozulya described.
Molecular detail: Gene-expression microarray after a single intranasal dose shows altered expression of monoamine transporters and receptor subtypes (5-HT2A, D1, D2) and rate-limiting synthesis enzymes — framing the monoaminergic effect as transcriptional tuning rather than acute transporter blockade. Some sources additionally implicate D5 receptor activity in the BDNF-linked nootropic effect.
C
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BDNF / NGF upregulation · neurotrophin axis
Intranasal Selank upregulates hippocampal and prefrontal BDNF and NGF mRNA within hours. In chronic ethanol-exposed rats, Selank (0.3 mg/kg/day × 7 d, IP) normalized ethanol-induced BDNF dysregulation in hippocampus and frontal cortex and rescued object-recognition memory. Notably the effect is state-dependent — it normalizes BDNF toward physiological levels rather than simply raising it.
Clinical significance: The neurotrophin axis provides the mechanistic rationale for the procognitive/antiasthenic effects absent from classical anxiolytics, and a plausible (untested) antidepressant rationale via the BDNF hypothesis of depression. The state-dependence is clinically reassuring — it argues against runaway neurotrophin elevation of the kind that drives theoretical malignancy concerns.
Molecular detail: Downstream TrkB → MAPK/ERK and PI3K/Akt signaling is the postulated molecular basis for the neuroprotective and procognitive effects, paralleling Semax's neurotrophin cascade. All BDNF/NGF data are preclinical (animal mRNA + protein); there is no human-tissue validation, and blood BDNF is a poor proxy for CNS BDNF.
C
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Immunomodulation · cytokine / interferon tuning
Inherited from tuftsin: under social stress Selank reduces IL-1β, IL-6, TNF-α and TGF-β1 toward control levels. In influenza (H3N2) models a preventive scheme suppressed viral replication in vitro and improved survival in vivo, with IFN-α gene induction and no change in IL-4/IL-10/TNF-α. Human leukocyte assays (Uchakina) documented type I/II interferon induction.
Clinical significance: This second axis is the basis for the historical Russian use of Selank in influenza prophylaxis, and also the source of its most important relative contraindications: active malignancy (IFN-α/NK enhancement) and active autoimmune disease (Th1 skewing). The IFN-α-without-TNF-α pattern suggests a Th1 skew without a hyperinflammatory profile.
Molecular detail: A single intranasal dose altered 34 inflammation-related genes in mouse spleen — chemokines (Cx3cr1 upregulated ~16×), cytokine receptors, and Bcl6 — indicating the immune arm is not CNS-exclusive. The tuftsin lineage (an IgG Fc-region phagocytosis-stimulating tetrapeptide) is the structural explanation for why an "anxiolytic" peptide carries genuine immune activity.
C
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Stress-axis / HPA normalization
In rodent chronic-stress paradigms (unpredictable chronic mild stress, social defeat) Selank attenuates stress-induced corticosterone elevation, prevents depletion of monoamines in stress-sensitive regions, and preserves BDNF and neuroprotective immediate-early genes (c-fos, NGFI-A). The HPA dampening appears indirect — downstream of GABAergic and monoaminergic normalization, not direct glucocorticoid-receptor binding.
Clinical significance: Indirect HPA normalization (rather than direct cortisol suppression) means Selank dampens stress-hormone overactivity without blunting the whole stress response — clinically attractive but inferred from animal data; human cortisol effects are not directly validated.
Molecular detail: Kasian et al. (2017, PMC5322660) showed Selank alone is comparable to diazepam for anxiety under UCMS and augments diazepam's effect, with distinct gene-level mechanisms — supporting convergent HPA modulation via GABA + monoamine pathways rather than a dedicated glucocorticoid mechanism.
Selank is administered primarily as intranasal drops/spray (the registered Russian 0.15% formulation) with subcutaneous injection as a research-practice alternative. This is the engine core. Each protocol is built to the same skeleton — concentration, dosing, course length, timing, administration, and explicit evidence grade — anchored by a pharmacokinetic panel (the 2–3 min / 8–24 h half-life paradox), six route/indication protocols, a course-ladder visual, a reconstitution & dose calculator, a global dose-band table, a weight-band reference, engine-ready titration logic, and a biomarker monitoring scaffold. The whole section is a speculative hypothesis layer: the Russian GAD protocol (400 µg TID × 14 days) is the closest thing to validated dosing (Grade D, with Grade B efficacy support from the Zozulya/Medvedev trials), while every other route, weight extrapolation, and titration rule is practice-pattern or expert opinion (Grade D) unvalidated in Western trials. Working unit throughout: µg.
Important · regulatory status
Selank is not approved by the FDA, EMA, MHRA, Health Canada, or the TGA for any indication, and is not a dietary supplement. The dosing below reflects Russian pharmaceutical labeling (0.15% nasal drops, registered ~2009) and published Russian trials. In the US it is sold as a "research chemical for laboratory use only"; human use is unapproved. Selank was placed on the FDA's Category 2 "significant safety risk" bulk-substance list in 2023, removing it from 503A/503B compounding; injectable or compounded Selank for human use carries risks of contamination, microbial infection, endotoxemia, and unverified purity. Figures are educational, not a prescription.
2026 US regulatory development — note the contrast with Semax
In April 2026 the FDA removed twelve peptides (including Semax and Epitalon) from the Category 2 interim 503A list, clearing them for Pharmacy Compounding Advisory Committee (PCAC) review on July 23–24, 2026. Selank was not among them. It does not appear on the July 2026 PCAC agenda (which covers BPC-157, KPV, TB-500, MOTs-C, Emideltide/DSIP, Semax, and Epitalon) and therefore remains in Category 2 — off-limits to lawful US compounding pending any future FDA action. Clinicians should not assume Selank shares Semax's near-term compounding pathway.
Anti-doping · WADA
Selank is not listed by name on the WADA Prohibited List, but as a substance with no approval for human therapeutic use by any recognized regulatory authority it qualifies under S0 — Non-Approved Substances (prohibited at all times, in and out of competition). Athletes subject to anti-doping testing should treat Selank as banned regardless of route or dose.
Pharmacokinetics · the half-life paradox
Why a 2–3 minute peptide acts for most of a day.
Selank shares Semax's defining pharmacokinetic dissociation: the intact heptapeptide is cleared from plasma in 2–3 minutes, yet anxiolytic and nootropic effects persist 8–24+ hours after one intranasal dose. Three mechanisms reconcile this. First, the C-terminal Pro-Gly-Pro (PGP) tail shields the molecule against aminopeptidase/carboxypeptidase degradation (tuftsin alone survives only seconds) and generates active fragments. Second, direct nose-to-brain transport via olfactory and trigeminal pathways delivers peptide to brain tissue — detectable within 15 minutes, CSF peak ~30–45 minutes, preferential accumulation in prefrontal cortex — while bypassing the systemic compartment where degradation is fastest. Third, sustained gene-expression changes (GABA-A subunits, monoamine genes, neurotrophins) outlast the parent peptide entirely. Oral bioavailability is effectively zero — gastric peptidases destroy it — which is why every viable route is intranasal or parenteral. A human PK study (Karamyan & Fesenko 2008, n=28) confirmed brain penetration and CSF kinetics for the intranasal route.
Parameter
Value
Note
Primary route
Intranasal (registered)
Russian 0.15% nasal drops. SC injection is research practice; IP/IV are preclinical only.
Plasma t½ (parent)
2–3 minutes
Intact heptapeptide cleared by amino/carboxypeptidases almost immediately. This is not the duration of effect.
Effective duration
8–24+ hours
Via downstream gene expression, enkephalinase inhibition, and active fragments — the basis for 1–3×/day dosing.
Tmax (plasma)
~5–15 min
Rapid mucosal absorption (intranasal).
Brain penetration
<15 min
Detected in brain tissue within 15 min; peak PFC at ~45 min (Karamyan 2008).
Tmax (CSF)
~30–45 min
Human PK pilot, n=28, PMID 18396414.
CNS accumulation
PFC > hippocampus > striatum
Regionally selective central distribution (intranasal).
Bioavailability — intranasal
~60–80% (estimated)
Partial nose-to-brain transport via olfactory/trigeminal pathways. Grade D estimate.
Bioavailability — oral
≈ 0%
Gastric peptidases fully degrade; no oral form exists.
Bioavailability — SC
Not formally studied
Used in research practice; systemic absorption assumed high but unvalidated.
Clearance
Rapid enzymatic (APN, DPP-IV, carboxypeptidases)
PGP tail slows C-terminal degradation versus parent tuftsin.
Renal / hepatic adjustment
Not established
No human PK in organ impairment; peptide nature suggests minimal hepatic load but unconfirmed. Grade D.
Architecture note: the parent t½ and the effect duration are different fields and must never be conflated in a dosing engine. Frequency is driven by the downstream effect window (8–24 h), not the plasma half-life (minutes) — which is why the registered protocol is a manageable two-to-three-times-daily schedule despite a sub-five-minute plasma half-life.
Registered Russian product is 0.15% nasal drops. Research-grade reconstitution to 2.5 mg/mL (10 mg vial + 4 mL) delivers 250 µg per 0.1 mL metered actuation — the calculator default below.
Starting dose
250 µg once daily (morning) — 1 actuation per nostril at 125 µg/spray, or 250 µg into one nostril. Assess tolerability over days 1–3 before escalating.
Dose ladder
250 µg QD → 250 µg BID → 400 µg BID → 400 µg TID. The top of this ladder is the registered Russian GAD protocol (see the dedicated tab).
Maintenance dose
250–500 µg, once or twice daily (research consensus for anxiety-only use); 400 µg three times daily for the registered GAD course.
Course length
14–28 days on (Russian clinical trials ran 14 days). Some protocols use 4 weeks on / 4 weeks off. No withdrawal syndrome is expected based on Russian clinical data.
Timing
Daytime dosing; no strict sleep-avoidance rule is required given the lack of a stimulant crash, but the mild antiasthenic effect makes earlier dosing sensible. Space multiple daily doses evenly across waking hours.
Administration
Tilt head slightly forward; instill into each nostril; alternate nostrils across doses; avoid blowing the nose for ~5 min post-dose to preserve mucosal contact time. Avoid if active sinusitis or nasal polyps.
Patient selection
Best characterized as adjunctive anxiolytic support, not a validated treatment. Screen for the contraindications in Section 05 — pregnancy/lactation, active bleeding/anticoagulant therapy (glyproline class effect), active malignancy, active autoimmune disease, and concurrent opioid or serotonergic therapy. No HPA-axis monitoring is mandated.
Dose-response evidence
The registered 400 µg TID (~1,200 µg/day) regimen is the only human-trial-anchored dose; the Zozulya and Medvedev comparative trials used standard registered dosing rather than a formal dose-finding design. No published dose-response curve exists; sub-threshold non-response at 250 µg is a titration trigger, not a validated finding.
Intranasal · 400 µg three times daily · 14 days · the trial-anchored regimen
Grade D/B
Regimen
400 µg three times daily (~1,200 µg/day) for 14 days — the registered Russian protocol for generalized anxiety disorder and neurasthenia, and the dosing used in the Zozulya comparative trial vs medazepam (n=62).
Expected effect
Anxiolytic efficacy comparable to a benzodiazepine, with added antiasthenic/mild psychostimulant benefit and no sedation. In the phenazepam-comparative trial (Medvedev, n=60), efficacy persisted ~1 week after the last dose and quality of life improved.
Concentration math
To deliver 400 µg per 0.1 mL actuation, reconstitute a 10 mg vial in 2.5 mL → 4.0 mg/mL. At TID this consumes ~2 vials per 14-day cycle (see calculator Worked Example 2).
Course / cycling
14-day course; washout 14–28 days before repeating to pre-empt any tachyphylaxis (none documented, but cycling mirrors the trial structure). No dose taper is required — withdrawal was not observed.
Biomarker correlate
Serum leu-enkephalin tau(1/2) rose over the course and the change correlated with clinical response — a mechanistic, research-only marker, not a routine clinical test.
Positioning
This is the one Selank regimen with direct human-trial support. A clinician framing a profile might use it as the reference anchor: 400 µg TID × 14 d → reassess on HAM-A → washout → repeat only on measurable benefit. Note the trials were Russian-language, comparative (not placebo-controlled in the modern sense), and unreplicated in the West.
Weight adjustment
Dosing in the Russian literature was not weight-adjusted — 400 µg TID was used irrespective of body mass. The weight-band table below is extrapolation/scaffolding only (Grade D), not a validated weight-scaled schedule.
⚠ Caveat · evidence quality
The defining trials (Zozulya 2008, Medvedev) are comparative, single-center, Russian-language studies with modest sample sizes and no independent Western replication. They establish that Selank is plausibly as effective as a benzodiazepine for anxiety with a better tolerability profile — they do not meet Western regulatory standards for efficacy. Treat the 400 µg TID regimen as a documented practice/trial pattern, not a proven global standard.
Subcutaneous Injection · Practice-Pattern Alternative
Research practice · 300–500 µg/day · no SC-specific human trial
Grade D
Starting dose
300 µg SC once daily. Week 1 hold at 300 µg QD; escalate to 500 µg QD in week 2 if tolerated.
4 weeks on / 4 weeks off; a 5-days-on / 2-days-off pattern is also reported. Washout ~4 weeks.
Reconstitution math
10 mg vial + 3.0 mL BAC water → 3.33 mg/mL; on a U-100 syringe 1 unit ≈ 33.3 µg, so a 500 µg dose ≈ 15 units (0.15 mL). See calculator Worked Example 3.
Administration
Sterile technique; rotate sites (abdomen/thigh). Do not inject if the reconstituted solution is cloudy, discolored, or particulate.
Positioning
SC is a route of convenience in the research community, not a validated delivery method. There is no SC-specific human PK study, so systemic bioavailability is assumed but unverified. Injection-site redness/pain is the main route-specific issue. Harm-reduction priority if a patient discloses SC use: confirm sterile product/technique and screen the same contraindications as the intranasal route.
Open question
Whether SC delivery reproduces the nose-to-brain CNS-targeting advantage of intranasal administration is unknown. Because much of Selank's effect depends on direct central delivery, a systemic SC route may have a different PK/PD profile than the registered intranasal one — an untested assumption.
⚠ Unapproved route
No approved injectable Selank exists anywhere. SC dosing is compounded/research use with unverified sterility and no SC-specific human data. This is harm-reduction context, not an endorsement.
Intraperitoneal / Intravenous · Preclinical Only
Animal & PK research · NOT for human administration
Grade C
Routes
IP (rodent behavioral/mechanistic studies); IV (PK studies only).
Rodent dose range
0.1–1.0 mg/kg IP for anxiolytic endpoints; 0.3 mg/kg/day IP × 7 days in the ethanol/BDNF/object-recognition study (Kolik, PMID 31625062).
Purpose
Included for preclinical protocol reference and to ground the mechanism section's animal doses. The UCMS/diazepam-augmentation work (Kasian 2017) used comparable IP dosing.
Allometric note
Rodent IP doses (0.1–1.0 mg/kg) do not translate to human intranasal µg dosing by simple body-weight scaling — route, bioavailability, and nose-to-brain targeting differ. Treat animal doses as mechanism context, not human-dose derivations.
⛔ Not for human use
IP and IV routes are appropriate only for laboratory animal research. They are listed here for completeness of the protocol architecture and must never be used for human administration.
Off-Label / Research-Grade Community Practice
Anecdotal · unvalidated · nootropic/anxiolytic biohacker use · N-Acetyl-Selank
Grade D
Typical intranasal dosing
Research-grade intranasal Selank is commonly used at 250–750 µg/day, often as a single morning dose or split BID — broadly the registered low-to-standard range. Some report up to 3,000 µg/day, beyond any efficacy support.
Use cases (anecdotal)
Situational anxiety, social/performance stress, and "calm focus" for cognitively demanding work — frequently stacked with Semax (see Section 04). None of these uses is trial-validated outside the registered GAD/neurasthenia indications.
N-Acetyl-Selank (NAS)
An acetylated analog with modified PK and slightly altered receptor engagement. Community users claim greater per-µg potency and dose it lower, but the evidence base for NAS is far thinner than for Selank and the two are not interchangeable in research protocols.
Cycling
Empirical 2–4 week on / off cycles to assess effect and pre-empt theoretical adaptation. There is no clinical tolerance data — cycling is a community heuristic, not evidence-based.
Quality risk
Gray-market product carries real risks: mislabeling (Selank vs N-Acetyl-Selank), unverifiable HPLC certificates, no pharmaceutical sterility, and possible endotoxin/contamination. Identity and purity are not guaranteed.
Clinician framing
If a patient discloses gray-market Selank use, harm-reduction priorities: confirm intranasal (not injectable) route, screen contraindications (Section 05) — especially anticoagulant therapy and concurrent opioids/SSRIs — and counsel that efficacy and long-term safety beyond ~3–6 months are unestablished.
NAS pharmacology gap
N-Acetyl-Selank's mechanism is largely inferred from Selank pharmacodynamics; direct human studies are scarce (Grade D/P). Potency-per-µg claims are not demonstrated in controlled human trials.
⚠ Not validated
All figures in this tab are anecdotal community practice from forums and vendor reports, not validated in controlled trials. There is no long-term human safety dataset for healthy-user dosing of either Selank or N-Acetyl-Selank. This is harm-reduction context, not an endorsement.
Bacteriostatic water (BAC) or sterile saline. Default: 10 mg vial + 4.0 mL → 2.5 mg/mL (2,500 µg/mL), giving 250 µg per 0.1 mL actuation and ~40 doses per vial.
Appearance
Lyophilized peptide is a white to off-white powder; reconstituted solution is clear and aqueous. Discard if cloudy, discolored, or particulate.
Storage
Lyophilized: stable at −20 °C. Reconstituted: 2–8 °C, used within ~14–30 days. Avoid repeated freeze-thaw cycles.
Delivery hardware
Standard metered nasal pump = 0.1 mL (100 µL) per actuation. For transfer/measurement, a U-100 insulin syringe reads 100 units = 1.0 mL (1 unit = 10 µL).
Quality verification
Where available, verify vendor HPLC purity certificates (≥98–99% claimed) and request endotoxin testing for any preparation intended for biological assay. Certificate authenticity cannot always be confirmed.
Use the calculator
The calculator below converts a chosen vial mass and diluent volume into concentration, per-actuation (or per-SC-unit) dose, and doses-per-vial. It is a reference tool, not a clinical authorization; human use of research-grade Selank is unapproved in the US.
Course model: from starting dose to GAD course to washout.
Day 1–3250 µgQD · AMTolerability check · single morning dose
Day 4–7250–500 µgBIDEscalate if sub-threshold · split dosing
Day 8–14400 µgTIDRegistered GAD course · ~1,200 µg/day
ReassessHAM-ADay 7 & 14Continue only on measurable response
Washout14–28 doff-drugPre-empt tachyphylaxis · no taper needed
L2 · Reconstitution & dose math
Reconstitution & Dose Calculator
For laboratory reference only. The registered Russian product ships as pre-made 0.15% nasal drops and needs no reconstitution; this tool is for research-grade lyophilate. Working unit is µg. "Per delivery" = µg per 0.1 mL nasal actuation, or per the chosen syringe unit for SC transfer. Not a clinical authorization; human use of research-grade Selank is unapproved in the US.
Concentration
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Per delivery
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Deliveries per dose
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Doses per vial
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Strength class
—
Worked references — Ex 1 (default intranasal): 10 mg + 4 mL = 2.5 mg/mL; 250 µg = 1 actuation (0.1 mL); ~40 doses/vial. Ex 2 (GAD protocol): 10 mg + 2.5 mL = 4.0 mg/mL; 400 µg = 1 actuation; ~25 doses/vial → at TID ≈ 8.3 days, so ~2 vials per 14-day cycle. Ex 3 (SC): 10 mg + 3.0 mL = 3.33 mg/mL; 500 µg = 0.15 mL = 15 units on a U-100 syringe; ~20 doses/vial.
Global dose bands · registered + research practice
Four dose tiers & weight-band reference.
Selank dosing spans a relatively narrow range compared with the incretin or stroke peptides — from a 250 µg/day starting dose to a ~1,500 µg/day registered high band, a roughly 6× spread, with a rarely-supported research ceiling above that. The engine anchors four bands: a Low beginner/anxiety-only band, a Standard split-dose band matching research consensus and trial doses, a High band reproducing the registered Russian GAD course (400–500 µg TID), and a Research ceiling with no efficacy support above ~1,500 µg/day. The High band carries the only human-efficacy support (Grade D/B via Zozulya/Medvedev); Low/Standard rest on practice-pattern and the registered label (Grade D). Selank is dosed by flat amount, not body weight — the weight table below is per-kg framing only.
Band
Dose / day (intranasal)
≈ µg/kg/day (70 kg)
Primary use / basis
Grade
Low
250–500 µg/day
~3.6–7.1
Single morning dose; beginner / anxiety-only · research consensus
D
Standard
500–1,000 µg/day
~7.1–14.3
Split BID; research consensus, comparable to clinical-trial daily exposure
D
High (Russian GAD)
1,200–1,500 µg/day
~17.1–21.4
400–500 µg TID × 14 d · registered Russian protocol (trial-anchored)
D/B
Research ceiling
≤ 3,000 µg/day
≤ 42.9
Upper range in some research protocols · no efficacy support above 1,500 µg/day
D
There is no validated benefit to dosing above the High band — the Research-ceiling tier exists only to bound reported community practice, not to recommend it. Unlike a benzodiazepine, escalation does not buy more "sedation"; beyond the GABAergic/enkephalinergic effect window, additional Selank mostly adds cost and uncharacterized exposure.
Weight-band reference (per-kg context only — flat dosing applies)
Interpolated on a ~7.1–14.3 µg/kg/day basis for the Standard band; Low and High columns reproduce the fixed ranges for orientation. The Russian trials used 400 µg TID irrespective of body weight, so these values are calculator scaffolding, not dosing instructions (Grade D).
Body weight
Low band (µg/day)
Standard band (µg/day)
High band (µg/day)
50 kg (110 lb)
250
500
750–1,200*
60 kg (132 lb)
250
500–750
1,000–1,200*
70 kg (154 lb)
250–500
750
1,200*
80 kg (176 lb)
500
750–1,000
1,200*
90 kg (198 lb)
500
1,000
1,500*
100 kg (220 lb)
500
1,000
1,500*
110 kg (243 lb)
500
1,000–1,200
1,500*
*The High band is not weight-scaled — it is the fixed registered GAD regimen (400–500 µg TID) given regardless of body mass. Per-kg values for the Standard band are research-comparison framing only and are not validated for weight-adjusted dosing of Selank.
Titration logic · engine-ready decision rules
Escalation, hold & stop logic.
Like Semax, Selank is dosed in fixed courses (typically 14 days) at an indication-appropriate strength, then cycled with a washout — not slow-stepped to a maintenance ceiling. The decision rules below are extrapolated from Russian clinical protocols and research-community practice (Grade D unless a clinical endpoint anchors them). The most important nodes are the hard stops tied to Selank's distinctive risks: its glyproline-class anticoagulant property, its enkephalinase-inhibition + opioid interaction, and its immunomodulatory arm in malignancy/autoimmunity and pregnancy.
Decision node
Rule
Rationale
Grade
No effect at 250 µg after 7 days
Escalate to 500 µg QD or split BID; rule out poor intranasal technique / degraded product first.
Sub-threshold dosing; downstream signaling window may need a higher pulse.
D
Mild headache / nasal irritation (Grade 1)
Hold current dose; insert a 2-day break; switch nostrils → reassess after 3 days off.
Local mucosal irritation; transient and self-limited.
D
Unexpected fatigue / sedation
De-escalate to previous tier.
Possible over-stimulation of GABAergic tone; rare with Selank (<1%).
D
Paradoxical anxiety worsening
De-escalate or hold; review concurrent serotonergic medications.
Possible interaction with SSRIs/SNRIs (serotonergic overlap); rare per published data.
No human safety data; CNS + immune effects on fetus/neonate unknown.
D
14-day course complete, good response
Washout 14–28 days before restarting.
Pre-empt tachyphylaxis; align with Russian trial protocols.
D
Special populations: avoid in anyone under 18 (no pediatric data), in active malignancy and active autoimmune disease (immunomodulatory arm), and in any active bleeding disorder or anticoagulant therapy without hematology oversight (glyproline anticoagulant property). No dose taper is required to stop — withdrawal was not observed in the Russian clinical literature.
Biomarker scaffold · validation status flagged
Response & safety monitoring bundles.
Selank has no validated clinical monitoring panel for either anxiety or research use — almost every marker below is flagged validated_for_selank = false, the hallmark of an unapproved compound. The two partial exceptions are the Hamilton Anxiety Rating Scale (HAM-A) — a clinical-trial-validated functional endpoint (not a blood marker) — and serum leu-enkephalin tau(1/2), which has a single human-study context (Zozulya) as a mechanistic response marker. The rest are class-borrowed or precautionary safety surveillance, checked on clinical indication only.
Biomarker
Frequency
Threshold / action
Validated?
HAM-A score (response)
Baseline, Day 7, Day 14, end of course
No improvement by Day 14 → reassess dose/diagnosis
Yes (trial endpoint)
Serum leu-enkephalin tau(1/2)
Baseline + end of cycle (research only)
Rising half-life correlated with response in Zozulya cohort
Significant lymphocyte shifts in autoimmune-risk subjects
Not validated
Basic metabolic panel
Baseline + 30 days
General safety screen; no hepatotoxic/nephrotoxic signal published
Not validated
Architecture note: store each marker with a source_endpoint tag and a validated_for_selank boolean. Only HAM-A (trial endpoint) and serum leu-enkephalin (single-study research context) resolve to anything other than false — which marks Selank as a speculative-use entry rather than an approved-drug page.
04 · Combination protocols
Stacking Selank.
Selank's best-known combination is with Semax — its nootropic sibling from the same Russian institute — a pairing supported by a single human functional-connectivity study showing the two act on neurologically distinct regions (amygdala vs DLPFC). A benzodiazepine combination has direct (animal) mechanistic support but is a supervised-only proposition. Nootropic-augmentation and antiviral-prophylaxis stacks are mechanistically defensible but evidence-thin. Several combinations warrant genuine caution given the enkephalinase, anticoagulant, and immunomodulatory arms. Below: the mechanistically supported, the theoretical, and the hard-constraint avoid list.
Selank + Semax · the classic pairing
High Synergy
SelankSemax
The most-discussed Selank stack. Mechanistically complementary with low overlap: Selank covers the anxiolytic/immunomodulatory axis (GABA-A, enkephalinase, cytokines) while Semax covers the nootropic/neuroplasticity axis (BDNF amplification, dopamine sensitization) — anxiety reduction plus cognitive enhancement without sedation. A resting-state fMRI functional-connectivity study (n=52, PMID 32342318) analyzed Semax on dorsolateral prefrontal (working-memory) connectivity and Selank on amygdala (anxiety) connectivity — indirect human evidence the two have neurologically distinguishable, complementary effects. Both are intranasal with similar delivery.
Component
Primary action
Evidence
Selank
GABA-A · enkephalinase · anxiolytic
fMRI amygdala (C)
Semax
MC4R → BDNF/TrkB · nootropic
fMRI DLPFC (C)
Selank + Benzodiazepine · supervised only
Moderate Synergy
SelankDiazepam / phenazepam
Kasian et al. (2017) directly demonstrated that Selank enhances diazepam's anxiolytic effect under unpredictable chronic mild stress in rats — the combination outperformed either agent alone. A potential supervised use case is benzodiazepine-withdrawal support (reported anecdotally by Russian psychiatrists), but this is unvalidated. The combination carries additive GABAergic risk and is not for routine self-administration.
Component
Mechanism
Evidence
Selank
Non-BZD GABA-A PAM
Animal synergy (C)
Benzodiazepine
BZD-site GABA-A PAM
Approved (multi-country)
Selank + Noopept / Alpha-GPC
Theoretical
SelankNoopeptAlpha-GPC
A community anxiety-plus-cognition stack: Selank handles the anxiolytic/stress axis while Noopept (a Russian dipeptide nootropic) or Alpha-GPC (a choline precursor) supports acetylcholine-dependent memory encoding — mechanistically non-overlapping. No published combination studies exist (Grade D); this is mechanistic speculation assembled in the nootropic community. Alpha-GPC is generally well tolerated; Noopept has its own interaction profile.
Component
Mechanism
Evidence
Selank
Anxiolytic / stress axis
Russian clinical (B/C)
Noopept / Alpha-GPC
Cholinergic / nootropic
Mixed nootropic (C/D)
Selank + Influenza Prophylaxis
Theoretical / historical
SelankAntiviral / immune context
Selank's IFN-α induction and Th1 skewing showed efficacy against H3N2 influenza in preclinical studies and were used in Russian field-prophylaxis protocols in the 2000s. No formal RCT supports prophylactic use (Grade C preclinical / D field practice). Caution: the immunomodulatory arm may interact with live-attenuated vaccines or immunosuppressive/immunomodulatory biologics — do not combine without specialist oversight.
Component
Mechanism
Evidence
Selank
IFN-α induction · Th1 skew
Preclinical + field (C/D)
Immune context
Antiviral / cytokine tuning
No RCT
⚠ Absolute hard constraints
Combinations and conditions that are categorical contraindications regardless of dose or route.
Contraindication
Concern
Severity
Active malignancy
Immunomodulatory stimulation (IFN-α, NK-cell enhancement) could theoretically remodel the tumor microenvironment
Absolute — do not use
Pregnancy / lactation
No human safety data; CNS + immune effects on fetus/neonate unknown
Favorable short-term profile; long-term data essentially absent.
In Russian clinical experience Selank is described as well tolerated, with no sedation, no tolerance, and no withdrawal — a profile that compares favorably with benzodiazepines. The most common issues are local and mild (nasal irritation, occasional headache). As with Semax, the dominant safety concern is not a known toxicity but a knowledge gap: there are no long-term human safety studies beyond ~3–6 months, no Western pharmacovigilance, and the mechanism-derived risks (anticoagulation, immunomodulation, serotonergic overlap) are uncharacterized in magnitude. Adverse-event frequencies below derive from Russian clinical data and secondary compilations.
Common / Mild Adverse Events (Russian clinical data)
Nasal irritation / mucosal discomfort~5–10% — the most common effect; route-specific and generally transient. Alternate nostrils; avoid exceeding actuation counts.
Nasal dryness / congestion (extended use)<5% — local mucosal response; distinguish from intercurrent rhinitis/infection (a route-specific relative contraindication).
Mild headacheReported; rate not formally quantified. Typically early and self-limited; encourage hydration; reassess if persistent.
Mild sedation / fatigue<1% — unusual for Selank (it is non-sedating by design); de-escalate if it occurs.
Injection-site redness (SC users)Practice-pattern report for the unapproved SC route; rotate sites, sterile technique.
Not observedNo benzodiazepine-like sedation, cognitive impairment, motor incoordination, respiratory depression, withdrawal, tolerance escalation, or cardiovascular/hepatic/renal toxicity in published literature.
Knowledge Gaps & Mechanism-Derived Risks
No long-term human safety dataThe single most important safety statement. No studies beyond ~3–6 months; long-term consequences of chronic BDNF upregulation and Th1 skewing are unstudied; no Western pharmacovigilance tracks Selank.
Anticoagulation · glyproline classThe glyproline peptide class has confirmed anticoagulant / fibrin-depolymerizing effects; the magnitude for Selank specifically is not formally quantified in humans — a genuine, unstudied risk in anyone on anticoagulants or with a bleeding disorder.
Immunostimulation in autoimmunity / malignancyNK-cell, IFN-α, and IL-6 effects could theoretically exacerbate autoimmune disease (lupus, MS, RA) or remodel a tumor microenvironment. Theoretical but mechanistically grounded.
Serotonin-syndrome risk · theoreticalIncreased serotonin turnover means combination with SSRIs/SNRIs/MAOIs carries a theoretical serotonergic-excess risk. No case reports, but pharmacologically plausible.
Opioid potentiationEnkephalinase inhibition prolongs endogenous (and potentially exogenous) opioid tone — the basis for the opioid-combination hard stop.
No overdose datasetNo documented overdose cases. Given the minutes-long plasma half-life and indirect gene-level mechanism, acute toxicity risk is considered low — but no formal human overdose toxicology exists.
Gray-market quality riskFor non-pharmaceutical product: mislabeling (Selank vs N-Acetyl-Selank), unverifiable purity, non-sterile preparation, and endotoxin risk — independent of the molecule's intrinsic safety.
Contraindication reference
Compiled from translated Russian prescribing information and expert secondary sources. The current Russian prescribing information should be consulted directly for definitive contraindications and pediatric age thresholds.
Condition / factor
Risk level
Applies to
Rationale
Pregnancy
Contraindicated
All
No fetal safety data; CNS-active peptide with immune effects.
Lactation
Contraindicated
All
Transfer into breast milk unknown.
Active bleeding disorder / coagulopathy
Contraindicated
All
Glyproline anticoagulant / fibrinolytic property.
Anticoagulant therapy (warfarin, heparin, NOACs)
Contraindicated
All
Additive bleeding risk · without hematology oversight.
Hypersensitivity to tuftsin / tuftsin-derived peptides
Contraindicated
All
Direct allergy risk.
Active malignancy
High — avoid
All
Immunostimulatory IFN-α / NK activation · oncology input.
A solid preclinical base; a thin, Russian-centric clinical one.
Selank's evidence base mirrors Semax's: a credible, reproducible preclinical mechanistic literature paired with a human clinical record dominated by small, comparative, single-center, Russian-language studies that have never been independently replicated in the West. The two comparative anxiolytic trials (vs medazepam, vs phenazepam) are the strongest human signal; one human PK pilot confirms brain penetration; the remainder is animal and in-vitro mechanism. No registered ClinicalTrials.gov study, no placebo-controlled Western RCT, and no Cochrane review exist. Below: the studies that define — and limit — the molecule, with every grade and caveat explicit.
Anxiolytic · flagship
n=62
Zozulya 2008 · comparative vs medazepam · matched anxiolytic efficacy + antiasthenic edge, no sedation/tolerance/withdrawal · enkephalin half-life rose with response
Kasian 2017 · Selank ≈ diazepam for anxiety and augments it · distinct gene-level mechanism · the key preclinical mechanism study
BHuman RCT · comparative vs medazepam · flagship
Zozulya, Neznamov, Kost, Myasoedov, Seredenin et al. (2008)
62 patients with generalized anxiety disorder and neurasthenia; 30 Selank vs 32 medazepam; intranasal ~400 µg TID × 14 days. Anxiolytic effects were similar between groups (Hamilton/Zung/CGI), but Selank added antiasthenic and mild psychostimulant effects and avoided sedation, muscle relaxation, tolerance, and withdrawal. Baseline serum leu-enkephalin tau(1/2) was reduced and correlated with symptom severity; it rose with treatment. Limitations: comparative (not modern placebo-controlled), single-center, Russian-language, modest n.
Medvedev et al. — Selank vs phenazepam (anxiety disorders)
60 patients with phobic-anxiety, somatoform, and adjustment disorders (ICD F40–F45); intranasal Selank vs the benzodiazepine phenazepam. Pronounced anxiolytic plus mild nootropic effect; improved quality of life; efficacy reported to persist ~1 week after the last dose. A related "optimization" study (PMID 26356395) found combining Selank with benzodiazepines hastened and enhanced the benzodiazepine's therapeutic effect. Limitations: comparative, Russian-language, single-center.
BControlled · adjustment disorder · waitlist control
Verbenko & Verbenko — Selank in adjustment disorder
30 Selank patients plus a waitlist control; ~2-week course with a 2-week follow-up. Significantly reduced PHQ scores versus waitlist (somatic, nutritional, and alcohol-misuse subscales), with effects persisting at follow-up. Limitations: Ukrainian-journal publication with no indexed PMID; waitlist (not active/placebo) control; small n.
Human PK/PD pilot (n=28), single intranasal dose. Brain penetration confirmed; CSF peak at ~45 min; preferential prefrontal-cortex accumulation; brain detection within ~15 min. The principal human pharmacokinetic evidence for nose-to-brain delivery — a PK study, not an efficacy trial (Grade C/D).
Unpredictable chronic mild stress in rats, elevated-plus-maze. Selank alone was the most effective at reducing course-induced anxiety; the diazepam+Selank combination was most effective under chronic-stress conditions. Concluded the anxiolytic effect is comparable to classical benzodiazepines and that Selank can modify benzodiazepine action — with distinct gene-level mechanisms. The key mechanism-bridging preclinical study.
Chronic ethanol-exposed rats; Selank 0.3 mg/kg/day × 7 days IP normalized ethanol-induced BDNF dysregulation in hippocampus and prefrontal cortex and rescued object-recognition memory. Notable for showing state-dependent BDNF modulation — Selank normalizes toward physiological levels rather than simply raising BDNF.
Molecular Aspects of Selank Biological Activity (2018)
In-vitro receptor pharmacology: confirmed positive allosteric GABA-A modulation at a site distinct from the benzodiazepine pocket (bicuculline-sensitive, flumazenil-insensitive), with a complex interaction profile alongside diazepam and olanzapine. The mechanistic basis for the "calm without sedation" signature.
Kolomin et al. — Selank & GABAergic gene expression
Single intranasal dose in rat brain produced differential expression of GABA-A receptor subunits and genes for serotonin/dopamine transporters and neurotrophins — framing much of Selank's effect as transcriptional tuning that outlasts the minutes-long parent peptide. Systems-level support for the duration paradox.
Antiviral activity of Selank in experimental influenza (2009)
In vitro and in vivo against H3N2 influenza: a preventive scheme suppressed viral replication in vitro and improved survival in vivo, associated with IFN-α gene induction without affecting IL-4/IL-10/TNF-α. The clearest demonstration of the tuftsin-inherited immune/antiviral arm.
Selank inflammation-gene expression in mouse spleen (2011)
A single intranasal dose altered 34 inflammation-related genes in mouse spleen, including chemokines (Cx3cr1 ↑ ~16×), cytokine receptors, and Bcl6 — confirming the immunomodulatory arm is not CNS-exclusive and operates at the gene-expression level.
Selank is best characterized as biologically credible and clinically suggestive, but unvalidated by Western standards. The preclinical mechanistic literature is genuinely coherent — non-benzodiazepine GABA-A modulation, enkephalinase inhibition with a human serum correlate, state-dependent BDNF normalization, and a real tuftsin-derived immune arm. The human clinical base, however, is two comparative trials (vs medazepam, vs phenazepam; combined n≈122) plus a small adjustment-disorder study and one PK pilot — all Russian/Ukrainian-language, single-center, comparative rather than modern placebo-controlled, and entirely unreplicated independently.
Applying GRADE methodology, a skeptical Western clinician would rate the anxiolytic efficacy evidence low (downgraded for risk of bias, indirectness, and imprecision) — better than Semax's cognitive evidence because Selank's primary endpoint (anxiety) is the one actually measured in its trials, but still far short of the regulatory standard. Mechanistic evidence is C/P; the human PK pilot is C/D; all dosing is D.
What is missing is decisive: no FDA/EMA Phase 2/3 trial, no registered ClinicalTrials.gov study, no long-term safety data beyond ~3–6 months, no dose-finding study, no formal drug-drug-interaction study, and no Western replication of the Russian trials. The practical conclusion mirrors Semax: a pharmacologically plausible neuropeptide used in Russia for over a decade with an attractive short-term tolerability profile, separated from Western acceptance by an evidence gap that the expired-patent, commodity-market landscape makes unlikely to close.
07 · Compare & contrast
Selank vs adjacent anxiolytics.
How Selank sits against its nootropic sibling Semax and against phenibut — the GABAergic anxiolytic it is most often confused with. The headline distinction: Selank reduces anxiety through a non-benzodiazepine GABA-A site with no dependence liability, where phenibut is a GABA-B agonist with a well-documented and serious dependence/withdrawal profile.
Critical framing: nearly all human Selank data originates from Russian (and Ukrainian) institutions, is published in Russian-language journals, and has not been independently replicated in Western peer-reviewed RCTs. Evidence grades below reflect that reality honestly.