Everything below concerns Selank. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-07-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
| Property | Value | Notes |
|---|---|---|
| Identity confirmation | Reversed-phase HPLC retention time versus reference standard | Retention depends on column, gradient, and ion-pairing agent |
| Mass confirmation | Electrospray or MALDI mass spectrometry | Doubly protonated ion near m/z 377 is consistent with about 752 Da |
| Typical purity specification | 95 percent or higher by chromatographic peak area | Lower values suggest truncated or modified peptide species |
| Storage of lyophilized powder | -20 °C, desiccated, protected from light | Powder tolerates long storage better than solution |
| Storage of solution | 2-8 °C for short periods | Freeze-thaw cycling promotes aggregation and surface adsorption |
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
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== Packaging and ingredients == The size content of energy gels is commonly 1.2 oz (32g), with a range from 1 oz to 1.5 oz packets. The portable packaging is designed to facilitate uninterrupted training or performance conditions. Common ingredients include water, maltodextrin, fructose, and various micronutrients, preservatives, and flavor compounds or caffeine.
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=== Pharmacokinetics === The bioavailability of methamphetamine is 67% orally, 79% intranasally, 67 to 90% via inhalation (smoking), and 100% intravenously. Following oral administration, methamphetamine is well-absorbed into the bloodstream, with peak plasma methamphetamine concentrations achieved in approximately 3.13–6.3 hours post ingestion. Methamphetamine is also well absorbed following inhalation and following intranasal administration. Because of the high lipophilicity of methamphetamine due to its methyl group, it can readily move through the blood–brain barrier faster than other stimulants, where it is more resistant to degradation by monoamine oxidase. The amphetamine metabolite peaks at 10–24 hours. Methamphetamine is excreted by the kidneys, with the rate of excretion into the urine heavily influenced by urinary pH. When taken orally, 30–54% of the dose is excreted in urine as methamphetamine and 10–23% as amphetamine. Following IV doses, about 45% is excreted as methamphetamine and 7% as amphetamine. The elimination half-life of methamphetamine varies with a range of 5–30 hours, but it is on average 9 to 12 hours in most studies. The elimination half-life of methamphetamine does not vary by route of administration, but is subject to substantial interindividual variability. CYP2D6, dopamine β-hydroxylase, flavin-containing monooxygenase 3, butyrate-CoA ligase, and glycine N-acyltransferase are the enzymes known to metabolize methamphetamine or its metabolites in humans.
Sources: en.wikipedia.org
13 May The PAVN 6th Regiment and K-12 Sapper Battalion attacked the 2nd Battalion, 501st Infantry Regiment, 2nd Battalion, 11th Artillery and 2nd Battalion, 319th Artillery on Firebase Airborne killing 22 U.S. for the loss of 40 PAVN killed. Units of the PAVN 7th Infantry Division attacked Firebase Gela, the assault was repulsed for the loss of three U.S. and an estimated 39 PAVN soldiers killed.
== Prizes and honours == 1997, 1999 Merit scholarship to study Medical Laboratory Technology at Institute of Medicine, Tribhuvan University 2005 Gallwas membership Grant, AACC 2005 and 2007 International travel grant, AACC 2006 Young Achievers Award 2007 International Travel Grant, Asian & Pacific Federation of Clinical Biochemistry (APFCB) 2008 and 2010 KNU Honors Scholarship for Graduation Study (MS and PHD) 2012 Featured member of AACC, interview published at AACC website 2013 KNU Best Publication Award 2014 KNU Cell-Matrix Research Institute Winter Seminar Award
When anchoring a molecule to a solid support, intermediates cannot be isolated from one another without cleaving the molecule from the resin. Since many of the traditional characterization techniques used to track reaction progress and confirm product structure are solution-based, different techniques must be used. Gel-phase 13C NMR spectroscopy, MALDI mass spectrometry, and IR spectroscopy have been used to confirm structure and monitor the progress of solid-phase reactions. Gordon et al., describe several case studies that utilize imines and peptidyl phosphonates to generate combinatorial libraries of small molecules. To generate the imine library, an amino acid tethered to a resin is reacted in the presence of an aldehyde. The authors demonstrate the use of fast 13C gel phase NMR spectroscopy and magic angle spinning 1 H NMR spectroscopy to monitor the progress of reactions, showing that most imines could be formed in as little as 10 minutes at room temperature when trimethyl orthoformate was used as the solvent. The formed imines were then derivatized to generate 4-thiazolidinones, B-lactams, and pyrrolidines. The use of solid-phase supports greatly simplifies the synthesis of large combinatorial libraries of compounds. This is done by anchoring a starting material to a solid support and then running subsequent reactions until a sufficiently large library is built, after which the products are cleaved from the support.
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Sources: en.wikipedia.org
Identity is confirmed by matching the retention time in reversed-phase chromatography against a reference standard and by measuring the molecular mass with mass spectrometry. Tandem mass spectrometry or amino acid analysis can verify the sequence of the seven residues. Because the peptide contains no aromatic amino acids, detection at 280 nm is not useful.
Lyophilized powder is normally stored desiccated at -20 °C, protected from light and moisture. Powder kept under these conditions is generally stable for long periods. Solutions are less stable and are usually prepared immediately before use.
A purity value from one chromatographic method does not capture every possible impurity. Related peptides with similar retention behavior, counterions, and residual solvents may not appear in the same analysis. Independent testing with an orthogonal method provides stronger assurance of identity and content.
Sealed, desiccated storage at -20 °C or colder is the standard recommendation for research-grade material. Vials should reach room temperature before they are opened, which limits condensation. Repeated temperature cycling is discouraged.