Selank comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Analog of the tetrapeptide tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Reported consistently across pharmacopoeial descriptions |
| Appearance | White to off-white lyophilized powder | Typical form of research-grade material |
| Solubility | Freely soluble in water | Aqueous buffers; poor in nonpolar solvents |
| Typical storage temperature | -20 degrees Celsius | Lyophilized powder; protect from moisture |
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
Reported pharmacological effects center on reduced anxiety-like behavior in animal models and on measures of memory and learning. Proposed contributing mechanisms include modulation of GABAergic signaling, shifts in monoamine turnover, and changes in the activity of enzymes that degrade neuropeptides. Effects on the expression of genes linked to neuroplasticity have also been described. No single molecular target is widely accepted, and whether the behavioral findings arise from one pathway or several remains an open question.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed as a stabilized analogue of tuftsin, a naturally occurring tetrapeptide fragment derived from the immunoglobulin heavy chain. The additional Pro-Gly-Pro segment at the carboxyl terminus is intended to slow enzymatic cleavage. The compound is usually described in the literature as a synthetic peptide with anxiolytic and cognitive-related activity, a label that reflects a research context rather than an approved therapeutic category.
Most published work on selank originates from a small number of research groups in the Russian Federation. A large share of that record appears in Russian-language journals, which limits access for readers who rely on English-indexed databases. Independent replication by laboratories outside the original research network is sparse in publicly available sources. This concentration of origin and language is a frequently noted feature when the compound is summarized in broader reviews of synthetic peptides.
=== Characters === Nathan Byrn: The 17-year-old protagonist. He has straight black hair, olive skin and black eyes. He looks like his father. Raised in a family of White witches, but with a Black witch father, he is a Half Code. He can self-heal extraordinarily fast. Jessica Byrn: Nathan's oldest half-sister who hates him. She later becomes a Hunter. Arran Byrn: Nathan's half-brother, with whom Nathan has a loving relationship. Deborah Byrn: Nathan's half-sister. She (like Arran) loves Nathan. Marcus Edge: Nathan's father, the most feared Black witch of all time. He killed Nathan's siblings' father, among numerous others. His Gift is transforming into animals but he has also stolen Gifts from many other witches by killing them and eating their hearts. Cora Byrn: Nathan's mother, a White witch who died by suicide. Her gift was healing. Gabriel Boutin: A Black witch stuck in the body of a Fain. He helps Mercury to get Nathan to her in order to get his witch body back and later falls in love with Nathan. Annalise O'Brien: A White witch, some months older than Nathan. She runs away from her cruel family. She and Nathan were in love as young teens. Soul O'Brien: The uncle of Annalise and a White witch. Mercury: A powerful Black witch who has stolen the blood of every witch family. Rose: A White witch and Mercury's assistant, who always blushes and giggles. Celia: A White witch, Nathan's mentor with whom he was sent to live. She appears to treat Nathan cruelly and even would lock him in a cage.
=== Body odor and acne === Rising levels of androgens can change the fatty acid composition of perspiration, resulting in a more "adult" body odor. This often precedes thelarche and pubarche by one or more years. Another androgen effect is increased secretion of oil (sebum) from the skin. This change increases the susceptibility to acne, a skin condition that is characteristic of puberty. Acne varies greatly in its severity.
In business and investing, a megacap stock (also mega-cap or mega cap) is a stock whose market capitalization (market cap) is among the very largest. These are stocks of the largest publicly traded companies in the world. The market capitalization of a stock is the total value of the shares outstanding, calculated as (shares outstanding x share price). Stocks with large market caps, but smaller than megacaps, instead fall within the large-cap segment of the stock market. There is no official definition of, or full consensus agreement about, the exact market cap cutoff value for a stock to qualify as megacap, and it may vary internationally. However, for the 2020s US market, a minimum market cap value of $200 billion is often cited. Index providers, investment funds, and investment managers may have other definitions.
Sources: en.wikipedia.org
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== Interactions == Substances that act as inhibitors of the CYP3A4 enzyme such as ketoconazole, erythromycin, cimetidine, and furanocoumarin derivatives (found in grapefruit) lead to increased plasma levels of loratadine — that is, more of the drug was present in the bloodstream than typical for a dose. This did not have clinically significant effects in controlled trials of 10 mg loratadine treatment (as opposed to the same studies with Terfenadine (Seldane)). That is, while the drug levels increased, it did not prolong the QTc interval which can lead to the potentially fatal dysrhythmia known as Torsades de Point. Antihistamines should be discontinued 48 hours before skin allergy tests, since these drugs may prevent or diminish otherwise positive reactions to dermal activity indicators.
10 August – 2022 monkeypox outbreak: Evidence of human-to-dog transmission is reported.On 4 August, a preprint reports that early post-exposure ring vaccination despite high efficacy "did not completely prevent breakthrough infections".On 15 August, a preprint suggests the virus has potential to infect a diverse range of native animals across Europe.On 16 August, a review recommends a 'living guideline' framework for needed clinical management research.On 19 August, a CDC study summarizes current knowledge about the transmission of monkeypox.Wastewater surveillance, which substantially expanded during the COVID-19 pandemic is used to detect monkeypox, with one team of researchers describing their qualitative detection method on 31 August.
== Methodology == To begin HPTLC, a stationary phase has to be determined to separate different compounds within a mixture. Around 90% of all pharmaceutical separations are performed on normal phase silica gel; however, other stationary phases such as alumina can be used for samples with dissociating compounds and cellulose for ionic compounds. The reverse-phase HPTLC method (similar methodology to reverse-phase TLC) is used for compounds with high polarity. After the selection of the stationary phase, plates are generally washed with methanol and dried in an oven to remove excess solvent. Selection for the mobile phase is one of the most important processes of HPTLC and follows a 'trial and error' pathway. However, the 'PRISMA' system stands as a guideline for finding the optimal mobile phase. The mobile phase is dependent on the absorptivity of the stationary phase and the composition of the compound of interest. The compound is first tested with solutions such as diethyl ether, ethanol, dichloromethane, chloroform for normal phase HPTLC, or solutions such as methanol, acetonitrile, and tetrahydrofuran for reverse phase HPTLC. The retardation factors (Rf) of the compounds with the selected solvent are then analyzed and the solvent that gives the largest Rf is chosen to be the mobile phase for the compound. Then, the mobile solvent strength is tested against hexane (for normal HPTLC) and water (for reverse-phase HPTLC) to determine the need for adjustment.
Sources: en.wikipedia.org
Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.
The first four residues of Selank reproduce the tuftsin sequence Thr-Lys-Pro-Arg. A Pro-Gly-Pro extension at the C-terminus was added to slow enzymatic breakdown and extend residence time.
It holds marketing authorization in Russia, where nasal drop formulations are sold. No equivalent approval exists in the European Union, the United States, or most other countries.
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.