If you have been reading about Selank and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-03-07. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Lyophilised material kept dry at minus 20 degrees Celsius or colder is the most stable form, and suppliers commonly state a shelf life of two years or more under those conditions. Once dissolved, degradation accelerates through hydrolysis and deamidation, particularly at alkaline pH or elevated temperature. Working solutions are usually divided into single-use aliquots to avoid repeated freeze-thaw cycles. The choice of reconstitution solvent affects both stability and the ionic strength of the final preparation.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Dry storage temperature | -20 C or below | Sealed, desiccated, protected from light |
| Solution stability | Hours to days at 2-8 C | Depends on buffer and microbial load |
| Preferred pH range | Near neutral to slightly acidic | Alkaline pH accelerates hydrolysis |
| Main degradation routes | Hydrolysis and deamidation | No cysteine or methionine in sequence |
| Identity confirmation | Electrospray mass spectrometry | Observed mass compared with 751.9 Da |
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
The neurons of the raphe nuclei are the principal source of 5-HT release in the brain. There are nine raphe nuclei, designated B1–B9, which contain the majority of serotonin-containing neurons (some scientists chose to group the nuclei raphes lineares into one nucleus), all of which are located along the midline of the brainstem, and centered on the reticular formation. Axons from the neurons of the raphe nuclei form a neurotransmitter system reaching almost every part of the central nervous system. Axons of neurons in the lower raphe nuclei terminate in the cerebellum and spinal cord, while the axons of the higher nuclei spread out in the entire brain. It is the dorsal part of the raphe nucleus that contains neurons projecting to the central nervous system. Serotonin-releasing neurons in this area receive input from a large number of areas, notably from prefrontal cortex, lateral habenula, preoptic area, substantia nigra and amygdala. These neurons are thought to communicate the expectation of rewards in the near future, a quantity called state value in reinforcement learning.
== Research == The current 'best' practice in the UK is to treat the underlying venous reflux once an ulcer has healed. It is questionable whether endovenous treatment should be offered before ulcer healing, as current evidence would not support this approach as standard care. The EVRA (Early Venous Reflux Ablation) ulcer trial, a randomised clinical trial funded by the National Institute for Health and Care Research (NIHR) to compare early versus delayed endovenous treatment of superficial venous reflux in patients with chronic venous ulceration, opened for recruitment in October 2013. The study hopes to show an increase in healing rates from 60% to 75% at 24 weeks. Research from the University of Surrey and funded by the Leg Ulcer Charity looked at the psychological impact of having a leg ulcer, on the relatives and friends of the affected person, and the influence of treatment.
== History == The All-China Federation of Supply and Marketing Cooperatives traces its origins to the former Central Cooperation Administration, founded by central government in November 1949. The first representative conference of all cooperative workers in China was held in July 1950, and the conference passed documents such as the "Law of the People's Republic of China on Cooperatives (Draft)" (中华人民共和国合作社法（草案）) and the "Articles of Association of the All China Federation of Cooperatives (Draft)" (中华全国合作社联合总社章程（草案）). The All-China Federation of Cooperatives (中华全国合作社联合总社) was established, which unified the leadership and management of supply and marketing, production, fisheries, handicrafts, consumption, and credit cooperatives throughout the whole country. The All-China Federation of Supply and Marketing Cooperatives became a member of the International Cooperative Alliance (ICA) on 14 August 1985.
Sources: en.wikipedia.org
== Adverse effects == Preclinical, phase I, and phase II clinical trials indicated that tirzepatide exhibits adverse effects similar to those of other established GLP-1 receptor agonists, such as dulaglutide (sold as Trulicity) and semaglutide (sold as Wegovy, Ozempic, and Rybelsus). These effects occur largely in the gastrointestinal tract. In the phase-II randomized controlled trial of tirzepatide for type II diabetes published in The Lancet in 2018, the most frequently observed symptoms were nausea, diarrhea, and vomiting, which increase in incidence as dosage increases. The proportion of patients who discontinued taking tirzepatide also increased as the dosage increased, with patients taking 15 mg having a 25% discontinuation rate and 5.1% of those taking 5 mg. To a slightly lesser extent, patients also reported reduced appetite. Other side effects reported were dyspepsia, constipation, abdominal pain, dizziness, and hypoglycemia. A systematic review published in 2024 found that tirzepatide was well tolerated and not associated with pancreatitis, but later case reports have found that pancreatitis sometimes follows initiation of treatment with tirzepatide. In 2026, the UK Medicines and Healthcare products Regulatory Agency (MHRA) updated its guidance on GLP-1 medications after an increase in reports to the agency's Yellow Card Scheme of acute pancreatitis, with fatalities, in patients taking semaglutide or tirzepatide, to warn of a small risk of developing severe acute pancreatitis.
=== TNXB (functional gene) === The TNXB gene localizes to the major histocompatibility complex (MHC class III) region on chromosome 6. The structure of this gene is unusual in that it overlaps the CREBL1 and CYP21A2 genes at its 5' and 3' ends, respectively.
Von Willebrand disease (VWD) is a type of blood-clotting disorder. It is the most common hereditary coagulopathy in humans, affecting 1% of the population. An acquired form of VWD can sometimes result from other medical conditions. Most people with VWD have no symptoms. Those that do usually have bleeding of varying intensity, including repeated bruising and nosebleeds. VWD arises from a deficiency in the quality or quantity of von Willebrand factor (VWF), a protein required for platelet adhesion through the binding to other proteins, particularly factor VIII. The disease is known to affect several breeds of dogs as well as humans. Four types of hereditary VWD have been described, including platelet-type VWD, with VWD type 1 being the most common. Types 1 and 2 are inherited through an autosomal dominant pattern, meaning at least one parent must also have the disease. Diagnosis is typically confirmed through blood tests. Managing VWD includes the use of desmopressin after minor trauma or before surgery, which allows the body to release more VWF. The disease is named after the Finnish physician Erik Adolf von Willebrand, who first described the condition in 1926.
Sources: en.wikipedia.org
== Contraindications == Allergy to sulfonylureas or sulfonamides Diabetes mellitus type 1 Diabetic ketoacidosis Patients that underwent removal of the pancreas Acute porphyria Severe liver disease accompanying with liver insufficiency Several conditions (e.g., infectious diseases or major surgical intervention), when insulin administration is required Pregnancy or breastfeeding
=== Chinese involvement === Two China based companies were sanctioned by America in 2024 for providing "dual-use materials and components needed to manufacture, maintain, and deploy an arsenal of advanced missiles and unmanned aerial vehicles (UAVs) against U.S. and allied interests." A report by the Foundation for Defense of Democracies stated that the Houthis were using weapons made in China for their attacks on shipping in the Red Sea in exchange for Chinese ships having safe passage through the Sea. Another report from Israel's i24 News stated that China provided the Houthis with "advanced components and guidance equipment" for their missiles. The Institute for the Study of War reported that the Houthis supplement their weaponry through additional arms and dual use components sourced from Russia or China. For example, Yemeni border customs seized 800 Chinese-made drone propellers in a shipment bound for the Houthis, and in August 2024 had also purchased Hydrogen Fuel Cylinders from Chinese suppliers which aimed to increase the range and payloads of the Houthis' drones. According to The Wall Street Journal, the Houthis sent a group from Saada to Beijing to study Mandarin and manage the supply of drones and missile guidance systems from China and Hong Kong to Yemen. According to the United States Department of State, Chinese state-owned Chang Guang Satellite Technology Corporation has provided geospatial intelligence to the Houthis to target U.S. warships in the Red Sea.
A clinical trial produces data that could reveal quantitative differences between two or more interventions; statistical analyses are used to determine whether such differences are true, result from chance, or are the same as no treatment (placebo). Data from a clinical trial accumulate gradually over the trial duration, extending from months to years. Accordingly, results for participants recruited early in the study become available for analysis while subjects are still being assigned to treatment groups in the trial. Early analysis may allow the emerging evidence to assist decisions about whether to stop the study, or to reassign participants to the more successful segment of the trial. Investigators may also want to stop a trial when data analysis shows no treatment effect.
Sources: en.wikipedia.org
Dry powder is best kept sealed, protected from light, and held at minus 20 degrees Celsius or below. Desiccant packaging helps limit moisture uptake because the material is hygroscopic. A sealed vial should be allowed to equilibrate to room temperature before opening to reduce condensation.
Hydrolysis of peptide bonds and deamidation of arginine and proline residues are the main degradation routes. Alkaline pH and higher temperatures accelerate both processes. Buffered, near-neutral solutions stored cold generally degrade more slowly than unbuffered ones.
Reverse-phase chromatography gives the clearest single view of related impurities and truncated sequences. Mass spectrometry then confirms that the main peak carries the expected mass. Neither test detects enantiomeric impurities, which require a separate chiral assay.
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.