Selank

Overview

Selank (TP-7) is a synthetic heptapeptide developed at the Institute of Molecular Genetics of the Russian Academy of Sciences by Nikolai Myasoedov and colleagues. It is a structural analog of tuftsin — a naturally occurring tetrapeptide (Thr-Lys-Pro-Arg) that is an immunomodulatory fragment of the immunoglobulin G (IgG) heavy chain.

Selank was created by appending a three-amino-acid sequence (Pro-Gly-Pro) to the C-terminus of tuftsin. This modification was designed to enhance metabolic stability while preserving tuftsin's biological activity and adding anxiolytic and nootropic properties not present in the parent peptide.

In Russia, Selank has received regulatory approval as a nasal spray formulation (intranasal administration, 0.15% solution) for the treatment of generalized anxiety disorder (GAD) and as a nootropic agent. It has been available as a prescription medication in Russia since the 2000s and is also approved in some other CIS (Commonwealth of Independent States) countries.

The bulk of published research on Selank originates from Russian research institutions, with the Institute of Molecular Genetics and the V.V. Zakusov Institute of Pharmacology being the primary research centers. While this body of work is substantial, the limited representation in Western peer-reviewed journals and the absence of international clinical trials are frequently noted limitations.

Selank is often discussed alongside Semax, another Russian-developed regulatory peptide with nootropic properties, though the two compounds have distinct mechanisms and origins.

Amino Acid Sequence

Selank is a heptapeptide with the following structure:

Thr-Lys-Pro-Arg-Pro-Gly-Pro

• Molecular formula: C₃₃H₅₇N₁₁O₉
• Molecular weight: 751.87 g/mol
• CAS Number: 129954-34-3

Structural features:

• Positions 1–4 (Thr-Lys-Pro-Arg): The tuftsin core sequence, responsible for immunomodulatory activity
• Positions 5–7 (Pro-Gly-Pro): The stabilizing C-terminal extension; the two proline residues confer significant resistance to enzymatic degradation by carboxypeptidases and other proteases
• The Pro-Gly-Pro tail is derived from proline-rich peptide motifs found in connective tissue proteins, chosen specifically for their protease-resistant properties

Mechanism of Action

GABAergic System Modulation

Selank's anxiolytic effects are primarily attributed to modulation of the GABAergic system:

• Allosteric modulation of GABA-A receptor function, enhancing the inhibitory effect of GABA
• This mechanism is similar in downstream effect to benzodiazepines but through a distinct binding interaction
• Importantly, Selank does not produce the sedation, dependence, or withdrawal effects characteristic of benzodiazepine GABA-A modulators

Monoamine System Effects

Selank influences multiple monoamine neurotransmitter systems:

• Serotonin: Modulates serotonin metabolism and turnover in brain regions associated with anxiety and mood
• Dopamine: Influences dopaminergic signaling in the mesolimbic system
• Norepinephrine: Modulates noradrenergic tone in the locus coeruleus and prefrontal cortex
• Studies have shown Selank alters the balance of enkephalin and monoamine metabolism in brain structures including the hypothalamus, hippocampus, and frontal cortex

BDNF Expression

Selank has been shown to increase expression of brain-derived neurotrophic factor (BDNF) in the hippocampus, a finding with implications for:

• Neuroplasticity and learning
• Memory consolidation
• Neuroprotection against stress-related neuronal damage
• Potential antidepressant-like effects (BDNF upregulation is a common feature of effective antidepressants)

Immunomodulatory Effects (Tuftsin-Derived)

Retaining the tuftsin core, Selank preserves immunomodulatory activity:

• Enhancement of natural killer (NK) cell activity
• Modulation of cytokine expression, including IL-6 and TNF-alpha
• Influence on T-helper cell balance (Th1/Th2)
• Anti-inflammatory effects through modulation of the NF-kB pathway

Gene Expression Effects

Microarray studies have shown that Selank influences the expression of 84 genes related to:

• Inflammatory and immune response pathways
• Neurotransmitter signaling
• Ion channel regulation
• Neuroprotection and cell survival

Research Summary

Pharmacokinetics

• Half-life: Approximately several minutes in plasma (short, typical of small peptides); the Pro-Gly-Pro extension provides ~5x stability improvement over tuftsin
• Route: Intranasal (primary; approved formulation in Russia is 0.15% nasal drops); subcutaneous injection (research)
• Intranasal bioavailability: Direct access to CNS via the olfactory mucosa and trigeminal nerve pathways, bypassing the blood-brain barrier
• Onset of action: Anxiolytic effects reported within minutes of intranasal administration in some studies; full nootropic effects may require days of regular use
• CNS penetration: The intranasal route provides direct nose-to-brain delivery, which is critical for a peptide that would otherwise have limited blood-brain barrier permeability
• Metabolism: Proteolytic degradation by aminopeptidases and endopeptidases; the C-terminal prolines slow degradation
• Accumulation: No evidence of significant accumulation with repeated dosing

Dosing Protocols

The following dosing information is compiled from published research and community discussion for educational purposes only. No FDA-approved human dosing guidelines exist for most research peptides. Always consult a qualified healthcare professional.

Reconstitution

Dosing Schedule

Syringe Measurements (U-100 insulin syringe)

Cycle Guidelines

• Cycle length: 4 weeks on, 4 weeks off (repeat for 8-16 weeks total)
• Alternative schedule: 5 days on, 2 days off
• Route: Subcutaneous injection
• Timing: Consistent daily timing recommended
• Injection sites: Rotate between abdomen, thighs, and upper arms (injection site rotation)
• Note: Cycling recommended to prevent tachyphylaxis (tolerance)

Common Discussion Topics

1. Selank vs. Semax — The two most prominent Russian-developed neuropeptides are frequently compared. Selank is generally considered more anxiolytic, while Semax is considered more stimulating and cognitive-enhancing. Some community protocols combine both.

2. Intranasal administration — The nasal spray route is appealing for CNS-targeted peptides. Discussion centers on proper technique, nasal spray formulation stability, and whether subcutaneous injection offers advantages.

3. Benzodiazepine alternative — Selank's anxiolytic effects without sedation, dependence, or withdrawal is its most attractive feature for those seeking alternatives to benzodiazepines.

4. Russian research limitations — The concentration of published data in Russian journals and the limited number of international replication studies are commonly discussed limitations.

5. Immune system effects — The dual anxiolytic and immunomodulatory profile is unusual and generates interest for applications where stress and immune function intersect.

6. Nootropic stacking — Selank is discussed in nootropic communities as a component of cognitive enhancement stacks, often alongside Semax, racetams, or other nootropic compounds.

Related Compounds

• Semax — a Russian-developed ACTH analog neuropeptide with nootropic and neuroprotective properties; commonly discussed alongside Selank
• Tuftsin — the endogenous tetrapeptide from which Selank is derived; primarily immunomodulatory
• Diazepam/Benzodiazepines — conventional anxiolytics that Selank is compared to; Selank's advantage is the absence of sedation and dependence
• DSIP (Delta Sleep Inducing Peptide) — another neuropeptide studied for anxiety and sleep; occasionally discussed in the same context
• BPC-157 — unrelated structurally but shares the characteristic of broad, pleiotropic biological activity across multiple systems