N-Acetyl Selank Amidate

N-Acetyl Selank Amidate is a modified form of Selank, a synthetic seven-amino-acid peptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro) modeled on tuftsin, the endogenous immune peptide Thr-Lys-Pro-Arg ⁶. Selank belongs to the glyproline family of regulatory peptides and is reviewed alongside Semax and Dihexa for effects on BDNF and HGF/c-Met pathways tied to neuroplasticity ².

The amidate version adds an N-terminal acetyl cap and a C-terminal amide. These caps protect the charged ends of the peptide from the exopeptidase trimming that breaks Selank into fragments such as TKPRP, TKP, RP, and GP ⁴. Selank itself is registered as an anxiolytic drug in the Russian Federation and has completed phase II and phase III programs ³. Outside Russia, both forms circulate as unregulated research peptides, including lyophilized powder and nasal sprays ⁵.

No published study has directly characterized N-Acetyl Selank Amidate. The clinical evidence described here comes from the parent peptide, while the amidate's prolonged stability is a mechanistic expectation from its terminal caps ⁴. Studied indications for the parent peptide include generalized anxiety and neurasthenia, post-COVID asthenia, adjustment disorder, benzodiazepine add-on therapy, and atopic dermatitis, with animal work on alcohol and opioid withdrawal ⁹.

The parent peptide Selank reduces anxiety through two main actions: positive allosteric modulation of GABA-A receptors and inhibition of enkephalin-degrading enzymes ⁷. N-Acetyl Selank Amidate carries the same tuftsin core, while its terminal caps block the exopeptidase routes that degrade the parent peptide ⁴. Direct pharmacodynamic studies of the capped form have not been published.

GABAergic potentiation

In radioligand assays, Selank increases GABA binding in a concentration-dependent, subtype-selective manner. Its binding site partially overlaps the benzodiazepine site but is not identical to it ²⁹. At the synapse, Selank increases the amplitude and frequency of inhibitory postsynaptic currents in hippocampal neurons, consistent with stronger inhibitory tone ³². It also changes expression of GABA-related neurotransmission genes within one hour in rodent frontal cortex ³⁰.

Opioid tone through enkephalinase inhibition

Selank inhibits enkephalin-degrading enzymes in human serum and plasma at roughly 15–20 µM, more potently than bacitracin or puromycin, and the pentapeptide fragment retains this action ⁷. In patients with generalized anxiety disorder, shortened plasma leu-enkephalin half-life lengthens during Selank treatment, correlating with clinical improvement ⁹. Behavioral effects are naloxone-sensitive, supporting an opioid-system contribution ³¹.

Secondary mechanisms

• NMDA glycine site: intranasal Selank changes NMDA glycine-site binding density in rodents, with region- and strain-dependent effects shared by Semax and Noopept ⁴⁴.
• Serotonin: Selank activates serotonin metabolism in hypothalamus and brainstem and supports memory-trace stability after depletion of serotonin stores ⁵⁵.
• Neurotrophin signaling: Selank is associated with BDNF and HGF/c-Met pathways related to neuroplasticity ².
• Transcriptomic normalization: in experimental cerebral ischemia, Selank downregulated most ischemia-induced gene-expression disturbances rather than producing a broad stimulant effect ¹.
• Route-dependent bias: intranasal Selank raised hippocampal NMDA-receptor binding by 23% in mice, while intraperitoneal Selank raised frontal-cortex GABA-A binding by 38% ³⁶.

All direct efficacy data below come from human and animal studies of the parent peptide Selank. For N-Acetyl Selank Amidate itself, no published efficacy studies exist, so the evidence is extrapolated through its shared mechanism and tuftsin core ⁴.

Human studies

• Anxiety versus phenazepam: in a 60-patient comparison, Selank matched phenazepam's anxiolytic effect while adding a mild nootropic effect, and the anxiolysis persisted about one week after the last dose ¹¹.
• Benzodiazepine add-on: in a 70-patient trial, Selank plus phenazepam produced earlier improvement on the Hamilton Depression Rating Scale than phenazepam alone and reduced benzodiazepine side effects such as sedation, memory impairment, and asthenia ¹².
• Anxiety versus medazepam: in 62 patients with generalized anxiety disorder and neurasthenia, Selank matched medazepam and added antiasthenic and psychostimulant effects ⁹.
• Post-COVID asthenia: a 64-patient open-label study used intranasal Selank, 2–3 drops of a 1.5 mg preparation four times daily for 30 days, and reported improvement in asthenia, mental work capacity, and anxiety/depressive symptoms ¹³.
• Adjustment disorder: a 2-week course reduced PHQ subscores for somatic symptoms, eating, and alcohol misuse in a 30-patient controlled study ¹⁴.
• Atopic dermatitis: in 124 patients, Selank enhanced standard anti-inflammatory therapy, with the largest effect when combined with narrowband UVB and UVA phototherapy ¹⁵.
• Fast brain changes: resting-state fMRI in 52 healthy volunteers showed altered amygdala-temporal functional connectivity within 5–20 minutes of a Selank injection ¹⁷.

Animal and preclinical findings

• Stress models: chronic restraint-stress rats given 750 µg/kg showed anxiolytic effects and 250 µg/kg antidepressant effects, with reduced serum corticosterone ¹⁸. Selank also reduced stress-induced colon damage and restored colon microbiocenosis ¹⁹.
• Opioid withdrawal: a single 0.3 mg/kg intraperitoneal dose reduced naloxone-precipitated morphine withdrawal by 39.6% and raised tactile threshold nearly 9-fold in rats ²¹.
• Alcohol: Selank reduced alcohol withdrawal anxiety, prevented mechanical allodynia, blocked ethanol-induced hyperlocomotion, and prevented ethanol-induced memory impairment with BDNF normalization ²².
• Learning: 300 µg/kg intraperitoneally optimized conditioned-avoidance learning in low-performing rats, outperforming piracetam at 400 mg/kg ⁴².
• Stroke and injury models: Selank normalized ischemia-induced gene-expression changes in the frontal cortex and improved neurologic scores after experimental hemorrhage ¹.
• Nonhuman primates: intranasal Selank produced long-lasting compensation of neurotic behavior and memory disturbances ²⁸.

The human trials are small, largely single-country, and not replicated in Western registries; a 2020 European regulatory report states Selank and Semax have not completed clinical trials by Western standards ⁵.

No published dose-finding study exists for N-Acetyl Selank Amidate. Community dosing is extrapolated from Selank clinical trials and the amidate's expected resistance to degradation ⁴.

Published clinical protocol for parent Selank

• Post-COVID asthenia: intranasal 2–3 drops of a 1.5 mg preparation, four times daily for 30 days ¹³.
• Anxiety disorders: intranasal clinical dosing for 14 days, with some trials using standard registered clinical dosing ⁹.
• Adjustment disorder: intranasal clinical dosing for 2 weeks ¹⁴.

Community protocols for the amidate

• Subcutaneous once daily: 100–400 µg for 4–8 weeks, with a 2-week minimum to assess response.
• Subcutaneous split dosing: 150–250 µg twice daily, typically morning and early afternoon, for 2–6 weeks.
• Intranasal amidate: 100–200 µg one to two times daily for 2–6 weeks.

Route and timing considerations

Route selection appears meaningful in rodents. Intraperitoneal Selank raised frontal-cortex GABA-A binding, while intranasal Selank raised hippocampal NMDA binding, suggesting intranasal access may favor nootropic engagement and systemic access may favor anxiolytic engagement ³⁶. Intranasal delivery reaches brain tissue with measurable peptide in animal studies ⁴.

Daytime dosing is standard because Selank is non-sedating and mildly activating ⁹. Animals in stress protocols were dosed about 15 minutes before stressor exposure ¹⁸. Community protocols describe 4–8 week courses with equal off-periods, and human trials reported no tolerance or dependence signal, with anxiolysis persisting about one week after the final dose ¹¹.

Animal milligram-per-kilogram doses are benchmarks, not human protocols. They should not be scaled arithmetically into human cycles.

N-Acetyl Selank Amidate is supplied as lyophilized powder for injection, and Selank-class peptides are also found in ready-made nasal sprays ⁵. The Pro-Gly-Pro motif of glyproline peptides gives them stability unusual for short peptides ⁶. The amidate's terminal caps are designed to block the exopeptidase cleavage that breaks unmodified Selank into TKPRP, TKP, RP, and GP fragments ⁴.

For multi-dose subcutaneous preparations, bacteriostatic water containing 0.9% benzyl alcohol is the standard diluent. Saline-based vehicles are described for intranasal preparations. Mixing should be done against the vial wall by gentle rolling, not shaking.

Storage follows these general rules:

• Lyophilized powder is stored at −20°C for long-term stability, with 2–8°C adequate for short-term use.
• Reconstituted solution is refrigerated at 2–8°C and used within 14–30 days.
• Peptide solutions should be protected from light and heat, and repeated freezing of reconstituted solution is avoided.
• A clear, colorless solution is expected; cloudy or particulate solution should be discarded.

The interactive calculator above handles specific vial sizes, diluent volumes, and resulting dose volumes. Analytical LC-MS/MS methods exist for identity verification of seized Selank preparations ⁵.

All documented interactions concern the parent peptide Selank. No interaction studies exist for N-Acetyl Selank Amidate, but the caps are stability modifications rather than receptor changes, so parent-peptide interactions are assumed to carry over ⁴.

Benzodiazepines

The best-documented interaction. In anxious mice, Selank amplified diazepam and mezapam anxiolysis in the elevated plus maze while blocking their sedative and motor-suppressant effects ³. In rats under chronic mild stress, diazepam plus Selank restored anxiety indices to pre-stress baseline ⁴⁹. In humans, add-on Selank accelerated phenazepam's anxiolytic response and reduced its side-effect burden ¹². The mechanism is not simple additivity: Selank and diazepam occupy overlapping but distinct GABA-site regions ²⁹.

Opioids

Selank inhibits enkephalin-degrading enzymes in human serum and plasma ⁷. In mice, Selank raised morphine antinociception from 9% to about 30% maximal possible effect without producing analgesia on its own ⁴⁶. In rats, it reduced naloxone-precipitated morphine withdrawal symptoms ²¹. Naloxone attenuates Selank's anxiolytic effect in some rodent models, so opioid-receptor antagonists may alter its activity ³¹.

Alcohol

In rodents, Selank blocked ethanol-induced hyperlocomotion, prevented expression of behavioral sensitization, and prevented ethanol-induced memory impairment with BDNF normalization ²³. It reduced withdrawal anxiety and mechanical allodynia in alcohol-drinking rats ²². In a human adjustment-disorder trial, Selank reduced alcohol-misuse scores ¹⁴. Regulatory review literature classifies Selank among GABAergic sedative-hypnotic agents ³⁸, so conventional central-nervous-system depressant caution applies to human co-ingestion.

Other documented interactions

• Anticoagulants and antiplatelets: thromboelastography shows Selank shifts coagulation toward hypocoagulation, with the strongest effect among tested glyproline peptides ³⁵.
• Atypical antipsychotics: Selank blocks olanzapine-induced motor suppression but not haloperidol's in mice ³, and Selank plus olanzapine changes more GABA-related genes in neuroblastoma cells than olanzapine alone ⁵³.
• Immunomodulators and antivirals: Selank has direct antiviral activity against influenza A and herpesviruses in vitro and in vivo, with interferon-alpha induction ³³. In stressed rats it normalized elevated IL-1β, IL-6, TNF-α, and TGF-β1 ⁴¹.
• Hepatotoxic regimens: in a tuberculosis-drug hepatitis model, Selank and Semax restored liver biochemistry and histology better than Essentiale N and Mexidol, with Selank showing the strongest regenerative activity ²⁶.
• Serotonergic antidepressants: a clinical report proposes Selank potentiates SSRI efficacy, and animal work shows serotonin-metabolism support after serotonin depletion ⁵⁴.

No formal drug-interaction study has been published for stimulants, anticonvulsants, or CYP-metabolized drugs.

The only human co-administration evidence is Selank added to phenazepam, which improved anxiety outcomes and reduced benzodiazepine side effects ¹². Other combinations are described in community research practice or inferred from shared mechanisms.

Cognitive stacks

• Semax: shares enkephalinase inhibition and NMDA glycine-site modulation with Selank ⁷. Selank and Semax were studied together for hepatoprotection in a tuberculosis-drug model ²⁶. Community reports commonly pair the amidate with Semax for cognition.
• Noopept: intranasal Noopept and intranasal Selank produce similar reductions in cortical NMDA glycine-site binding in mice, so combined intranasal use may duplicatively affect the same NMDA site ⁴⁴.

Orthogonal combinations

• Repair peptides such as BPC-157, TB-500, and GHK-Cu act on wound healing and angiogenesis pathways that are largely separate from the amidate's GABA, opioid, and monoamine targets ². No known conflict appears in the literature.
• Growth hormone secretagogues target the IGF-1 and satellite-cell axis, orthogonal to the amidate's neurotrophic and neurotransmitter effects ².
• Recovery peptides such as Epithalon, DSIP, and Pinealon target circadian and mitochondrial pathways and are sometimes described as complementary evening additions in community protocol reports.

Benzodiazepine co-use remains the only stack supported by a controlled human trial ¹². Community stacking reports often pair the amidate intranasally with Semax or Noopept for cognition, but effect duplication is possible at high combined doses ⁴⁴.

Selank is registered as a medicinal anxiolytic in the Russian Federation ³. The same record includes phase II and phase III clinical programs ⁸. The parent peptide is not FDA- or EMA-approved, and N-Acetyl Selank Amidate is not registered as a drug in any jurisdiction covered by the published literature.

In the United States, neither the amidate nor parent Selank has an IND, NDA, or US trial registration in the published record. A pharmacology review describes Selank as a poorly studied Russian drug sold to US consumers as a dietary supplement ³⁸. No DEA or CSA scheduling of Selank or the amidate is documented in the published literature.

In the European Union, Selank and Semax have been identified in seized preparations and analyzed by LC-MS/MS as research peptides sold online as lyophilized powder and nasal sprays ⁵. A 2020 European regulatory report states these peptides have not completed clinical trials by Western standards ⁵.

Anti-doping

No published antidoping review or WADA list entry covers Selank or the amidate. Under WADA's S0 logic, substances that are not approved human pharmaceuticals in most jurisdictions are typically prohibited in and out of competition by the catch-all category. No athlete sanction involving Selank is documented in the provided literature.

Published safety data concern the parent peptide Selank. N-Acetyl Selank Amidate has no dedicated toxicology literature, so exposure-dependent effects could differ because the caps slow degradation ⁴.

Tolerability profile

Across Russian clinical work, Selank is described as practically devoid of the sedation, muscle relaxation, amnesia, and dependence typical of benzodiazepines ⁹. The 60-patient phenazepam comparison reported better tolerability than phenazepam, and the 64-patient post-COVID trial reported benefit with no serious adverse events ¹¹. Selank adds antiasthenic and psychostimulant effects, which may appear as over-arousal or delayed sleep onset when dosed late in the day ⁹.

Community reports describe brief drowsiness, transient jitteriness or over-arousal, mild headache, and nasal irritation with intranasal formulations. In anesthetized cats, a very high intravenous dose lowered arterial pressure transiently by about 32% and raised cerebral blood flow about 24% ⁴⁰; human relevance at microgram-range doses is unclear.

Uncommon and theoretical effects

• Anticoagulant activity: thromboelastography shows Selank shifts coagulation parameters toward hypocoagulation, with the strongest effect among the glyproline peptides tested ³⁵. This is the strongest documented contraindication signal.
• Cytokine modulation: Selank normalized stress-elevated IL-1β, IL-6, TNF-α, and TGF-β1 in rats ⁴¹, and in anxiety-asthenic patients it shifted Th1/Th2 cytokine balance ¹⁶. The direction may depend on baseline immune state.
• Opioid potentiation: Selank raises endogenous enkephalin tone and potentiates morphine analgesia in animals, so concurrent opioid therapy may require a conservative opioid dose ⁷.
• Benzodiazepine alteration: Selank can remove the sedation signal of benzodiazepines while preserving anxiolysis, so impairment should not be assumed ³.
• Abuse potential: US pharmacology literature places Selank among poorly studied GABAergic substances sold as supplements and notes abuse potential has not been formally evaluated ³⁸.
• Developmental in-vitro signal: at 100 µM, Selank reduced GABA-positive neuron differentiation from mouse embryonic stem cells by 61%, although overall stem-cell survival showed no toxicity ³⁹.

Contraindications in the literature

Researchers list active bleeding, hemophilia, or coagulopathy as the strongest exclusion based on the anticoagulant profile ³⁵. Relative cautions include anticoagulant or antiplatelet therapy ³⁵, opioid therapy ⁴⁶, daily benzodiazepines ¹², hypotension ⁴⁰, autoimmune disease ¹⁶, heavy alcohol use ²³, and prior hypersensitivity to peptide drugs.

No human pregnancy, lactation, pediatric, or long-term safety data beyond 30 days exist for either form. No dependence or withdrawal signal emerged in trials, but amidate-specific toxicology remains unpublished ¹¹.