Selank

Selank is a synthetic heptapeptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro): the endogenous immunopeptide tuftsin, a fragment of immunoglobulin G, extended with a Pro-Gly-Pro tail that confers resistance to tissue peptidases and permits central penetration. It was developed at the Institute of Molecular Genetics in Russia.

It has been an approved prescription medication in Russia since 2009 for generalised anxiety disorder and neurasthenia, marketed as the nasal spray Selanc and listed on the Russian List of Vital and Essential Drugs. It is not FDA approved and is available in the United States as a research chemical. It is not currently a WADA prohibited substance.

The defining feature is benzodiazepine-comparable anxiolysis without the benzodiazepine liabilities. In a 62-patient trial in generalised anxiety disorder and neurasthenia (Zozulya et al., 2008), Selank matched medazepam for anxiolytic effect while additionally producing antiasthenic and psychostimulant effects the benzodiazepine did not, with no sedation, cognitive impairment, tolerance, or dependence. Comparison against phenazepam (Medvedev et al., 2014) showed pronounced anxiolysis with mild nootropic effect and benefit persisting roughly one week after the final dose.

It also retains tuftsin's immunomodulatory activity, acting on macrophage function and cytokine balance, and it is a nootropic in its own right through BDNF and dopaminergic signalling. Modified variants exist — N-Acetyl Selank and N-Acetyl Selank Amidate, with one or both termini protected for greater metabolic stability — but all published human clinical data used the original sequence.

For the injectable route the lyophilised powder is reconstituted with bacteriostatic water and administered subcutaneously.

GABAergic modulation. Selank acts as an allosteric modulator of the GABAergic system rather than a direct GABA-A ligand. Volkova et al. (2016) profiled 84 neurotransmission-related genes in rat frontal cortex and found 45 differentially expressed at 1 hour and 22 at 3 hours, with strong positive correlation to the signature produced by direct GABA administration. Because it potentiates endogenous GABAergic tone rather than forcing the channel open, it avoids the sedation, amnestic effect, tolerance, and withdrawal that characterise benzodiazepines.

Enkephalin protection. Zozulya et al. (2001) showed dose-dependent inhibition of enzymatic hydrolysis of plasma enkephalin with an IC50 of 15 micromolar, more potent than the reference peptidase inhibitors bacitracin and puromycin. Patients with generalised anxiety disorder show shortened enkephalin half-life relative to healthy controls, and treatment raised this parameter in the 2008 trial, where decreased enkephalin levels correlated with symptom severity.

Monoaminergic modulation. Serotonergic and dopaminergic tone is shifted across systems rather than by single-transporter reuptake blockade. At the 3-hour timepoint Volkova et al. (2016) found Selank uniquely activated Drd5 (dopamine receptor D5) expression, a receptor supporting long-term potentiation, memory formation, and learning — the likely substrate for the reported focus and clarity.

Neurotrophic signalling. Selank raises BDNF expression in hippocampus and prefrontal cortex. Inozemtseva et al. (2008) confirmed intranasal Selank regulates hippocampal BDNF in vivo, and Kolik et al. (2019) showed protection against ethanol-induced memory impairment via BDNF regulation in hippocampus and frontal cortex.

Immune and cytokine regulation. As a tuftsin analogue it retains immunomodulatory activity: activation of tissue-resident macrophages in liver, spleen, and lymph nodes and mobilisation of leukocytes. Under social stress it reduced IL-1 beta, IL-6, and TNF-alpha, restored IL-4, and suppressed TGF-beta 1 (Yasenyavskaya et al., 2021); Kolomin et al. (2011) found altered expression of 34 inflammation-related genes in mouse spleen, notably Bcl6. In patients with anxiety-asthenic disorders, 14 days of treatment shifted Th1/Th2 balance and completely suppressed peripheral blood IL-6 gene expression at certain concentrations (Uchakina et al., 2008).

Route dependence. Vasil'eva et al. (2016) compared intranasal and intraperitoneal administration in BALB/c and C57BL/6 mice: intraperitoneal Selank increased frontal cortex GABA-receptor binding sites by 38 percent without altering NMDA receptors, while intranasal increased NMDA receptor binding by 23 percent without affecting GABA receptors. Anxiolytic and nootropic effects appeared only in the anxiety-prone BALB/c strain. The parenteral route therefore skews GABAergic, the nasal route glutamatergic — a genuine pharmacodynamic difference, not just a pharmacokinetic one.

Functional imaging. Panikratova et al. (2020) used resting-state fMRI in 52 healthy participants and found significant changes in functional connectivity between right amygdala and right temporal cortex, a circuit central to emotion regulation.

Anxiolysis without sedation is the primary effect. In 62 patients with generalised anxiety disorder and neurasthenia (30 Selank, 32 medazepam), anxiety reduction was equivalent, but the Selank arm additionally showed antiasthenic and psychostimulant effects absent in the benzodiazepine arm, which carried the expected sedation and cognitive impairment. Against phenazepam, anxiolysis was pronounced with mild nootropic effect and benefit persisting approximately one week after the final dose, alongside improved quality of life.

Cognition. BDNF elevation, Drd5 activation, and enhanced enkephalin availability converge on focus, memory consolidation, mental clarity, and processing speed. Kolik et al. (2019) demonstrated protection against ethanol-induced memory and attention disturbance during alcohol withdrawal in rats via hippocampal and frontal cortical BDNF regulation.

Mood. Simultaneous modulation of serotonergic, GABAergic, and enkephalinergic tone stabilises affect without the emotional blunting associated with SSRIs.

Stress resilience and immunity. Cytokine normalisation (IL-1 beta, IL-6, TNF-alpha down; IL-4 restored) plus BDNF support buffers the neurological and immunological cost of chronic stress rather than masking symptoms. Th1/Th2 rebalancing and IL-6 suppression have been shown in human anxiety-asthenic disorder. Retained tuftsin activity covers macrophage activation in liver, spleen, and lymph nodes and leukocyte mobilisation against infectious and neoplastic targets.

Benzodiazepine interaction profile. Kasian et al. (2017) found Selank plus diazepam the most effective combination under unpredictable chronic mild stress in rats, while Selank alone was most effective for elevated anxiety without chronic stress. Medvedev et al. (2015) found adding Selank to phenazepam reduced benzodiazepine side effects — attention and memory impairment, sedation, increased sleep duration, sexual disturbance, emotional indifference — both during treatment and after withdrawal.

No tolerance, dependency, or withdrawal has been documented across the clinical literature; discontinuation requires no taper.

Efficacy is best supported for generalised anxiety disorder and situational stress; evidence in panic disorder and severe social anxiety is weaker and user reports are less consistent. It is not a hypnotic and may impair sleep onset if dosed late.

Response is bimodal. Neznamov et al. (2012) dosed 20 patients aged 24 to 52 with generalised anxiety disorder at 2700 mcg per day intranasally: 40 percent were rapid responders with abrupt resolution of the full symptom set within 1 to 3 days, HARS falling from 20.3 to 7.0 by Day 3; the remaining 60 percent responded gradually, reaching clinically significant change at Day 14. Rapid responders had more prominent asthenic and cognitive symptoms at baseline and showed marked EEG change after a single dose — increased beta rhythm with decreased theta and low-frequency alpha.

Pharmacokinetics are strikingly brief. After intranasal administration Selank is detectable in blood within 30 seconds, peaks rapidly, and concentration falls within 5 to 5.5 minutes. No urinary metabolites are detected, consistent with rapid hydrolysis by tissue peptidases. Downstream effects on gene expression, BDNF, and neurotransmitter balance far outlast plasma presence, which is why dosing frequency does not track plasma kinetics.

Anecdotal reporting, not published data: perceptible calming and mental clarity within the first few days of consistent use; stronger nootropic and mood-stabilising effects over 1 to 2 weeks; memory and learning gains most pronounced at 4 to 6 weeks. Some report onset within 10 to 20 minutes of intranasal dosing with single-dose effects lasting 12 to 24 hours; others need a week or more before anything registers. Inter-individual variation is substantial.

Evaluate at 1 to 2 weeks of consistent use, not earlier — effects build over 5 to 14 days for most users. Discontinuation requires no taper and produces no withdrawal; anxiolytic benefit may persist approximately one week after the last dose.

Ceiling: efficacy is most consistent in mild to moderate and generalised anxiety and situational stress. Panic disorder and severe social anxiety disorder produce less reliable results, and the most common complaint is simply insufficient effect size rather than any adverse event.

No published dose-finding studies exist for subcutaneous Selank; the protocol reflects practice patterns and usual practice rather than trial data. All published human clinical work used intranasal administration.

Reconstitute the 10 mg vial with 2.5 mL (250 units) bacteriostatic water, giving 4 mg/mL. Use 0.3 mL / 30-unit syringes — the working range sits at the low end of the barrel, where a 100-unit syringe loses meaningful precision.

Subcutaneous: 100 to 300 mcg per day, once daily, morning preferred, for 4 to 6 weeks. Titrate from the lower bound upward only as required.

Intranasal, for comparison: 200 to 400 mcg per administration, 2 to 3 times daily, 400 to 1000 mcg total daily, for 10 to 14 days on the Russian clinical schedule or 4 to 6 weeks on extended practice-derived protocols. The approved 0.15 percent formulation is prescribed as 2 to 3 drops per nostril, three times daily, for 10 to 14 days. Intranasal bioavailability is 92.8 percent and it is the route behind all clinical evidence; subcutaneous offers more precise dosing and once-daily administration.

Route selection is a pharmacodynamic decision, not just a convenience one. Vasil'eva et al. (2016) found intraperitoneal administration raised frontal cortex GABA-receptor binding by 38 percent without altering NMDA receptors, while intranasal raised NMDA binding by 23 percent without affecting GABA receptors. The parenteral route therefore biases towards GABAergic anxiolysis.

Studied doses for reference: the rapid-responder study used 2700 mcg per day intranasally as 900 mcg three times daily. Animal work used 300 mcg/kg per day intraperitoneally for 5 days in the route-comparison study and 0.3 mg/kg daily for 7 days in the memory protection study. The dose in the primary GAD comparison against medazepam was not specified in the available abstract.

Timing: morning and early afternoon. Selank is not classically stimulating, but its effects on alertness and cognition mean late dosing can impair wind-down in some users. No fasting requirement and no food-absorption interaction.

Cycling: 10 to 14 days for acute stress or a discrete event; 4 to 6 weeks for generalised anxiety or cognitive support; 1 to 3 week break between cycles. No tolerance development has been documented, so cycling is precautionary. No taper is required on cessation and anxiolytic effect may persist approximately one week after the last dose.

Variants: N-Acetyl Selank and N-Acetyl Selank Amidate protect one or both termini for greater metabolic stability without altering the mechanism. No human clinical data exists for either; all trial data is on the unmodified sequence.

The human evidence base is unusually strong for a research peptide but almost entirely Russian. Selank has been an approved prescription intranasal medication in Russia since 2009 for generalised anxiety disorder and neurasthenia, and is listed on the Russian List of Vital and Essential Drugs.

Zozulya et al., 2008: 62 patients with GAD and neurasthenia, 30 on Selank versus 32 on medazepam. Equivalent anxiolysis, with additional antiasthenic and psychostimulant effects absent in the benzodiazepine arm. The trial also identified decreased enkephalin levels correlating with symptom severity, raised by Selank treatment.

Neznamov et al., 2012: 20 patients aged 24 to 52 at 2700 mcg/day intranasally (900 mcg three times daily). Forty percent were rapid responders with abrupt full-symptom reduction within 1 to 3 days, HARS falling from 20.3 to 7.0 by Day 3, and marked single-dose EEG reactivity (increased beta, decreased theta and low-frequency alpha). Sixty percent responded gradually to clinical significance by Day 14. Rapid responders had more prominent asthenic and cognitive symptoms at baseline.

Medvedev et al., 2014: pronounced anxiolytic plus mild nootropic effect versus phenazepam, with therapeutic benefit persisting approximately one week after the final dose and positive quality-of-life impact. Medvedev et al., 2015: Selank added to phenazepam reduced benzodiazepine adverse effects — attention and memory impairment, sedation, increased sleep duration, sexual disturbance, emotional indifference — both during treatment and after withdrawal. Uchakina et al., 2008: 14 days of treatment in anxiety-asthenic disorders shifted Th1/Th2 cytokine balance and completely suppressed IL-6 gene expression in peripheral blood at certain concentrations.

Mechanistic work: Volkova et al., 2016 profiled 84 neurotransmission genes in rat frontal cortex, with 45 altered at 1 hour and 22 at 3 hours, strongly correlated with direct GABA administration, supporting allosteric GABAergic modulation, plus unique Drd5 activation at 3 hours. Zozulya et al., 2001 established dose-dependent inhibition of plasma enkephalin hydrolysis, IC50 15 micromolar, more potent than bacitracin and puromycin. Inozemtseva et al., 2008 confirmed intranasal regulation of hippocampal BDNF; Kolik et al., 2019 showed 0.3 mg/kg daily for 7 days prevented ethanol-induced memory and attention disturbance via BDNF in hippocampus and prefrontal cortex. Kasian et al., 2017 found Selank plus diazepam most effective under unpredictable chronic mild stress, while Selank alone was most effective without chronic stress. Yasenyavskaya et al., 2021 showed reduction of IL-1 beta, IL-6 and TNF-alpha with restoration of IL-4 and suppression of TGF-beta 1; Kolomin et al., 2011 found 34 inflammation-related genes altered in mouse spleen, notably Bcl6. Panikratova et al., 2020 used resting-state fMRI in 52 healthy participants, showing right amygdala to right temporal cortex connectivity changes for both Selank and Semax.

The principal limitation for the injectable route: all published clinical trials used intranasal administration, quoted at 92.8 percent bioavailability. Vasil'eva et al., 2016 demonstrated route-dependent divergence — intraperitoneal Selank raised frontal cortex GABA-receptor binding by 38 percent without altering NMDA receptors, while intranasal raised NMDA binding by 23 percent without affecting GABA receptors — and anxiolytic and nootropic effects appeared only in anxiety-prone BALB/c mice, not C57BL/6. Animal intraperitoneal dosing was 300 mcg/kg per day for 5 days in that study. No published dose-finding studies exist for the subcutaneous protocols used in practice.

Pharmacokinetically, plasma half-life is very short: detectable within 30 seconds of intranasal dosing, rapid peak, concentration falling within 5 to 5.5 minutes, no urinary metabolites, indicating rapid tissue peptidase degradation. Downstream gene expression, BDNF, and neurotransmitter effects persist far longer.