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.
Updated 2026-08-01. Numbers and descriptions here follow the published literature rather than marketing material.
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
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 |
|---|---|---|
| Molecular class | Synthetic heptapeptide | Stabilized analog of tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form: TKPRPGP |
| Molecular formula | C33H57N11O9 | Monoisotopic mass about 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as lyophilized solid |
| Solubility | Freely soluble in water | Also soluble in common polar solvents |
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
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.
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.
Responsibility for educational supervision in Germany is primarily organised within the individual states. Optional kindergarten education is provided for all children between three and six years old, after which school attendance is compulsory for at least nine years depending on the state. Primary education usually lasts for four to six years. Secondary schooling is divided into tracks based on whether students pursue academic or vocational education. A system of apprenticeship called Duale Ausbildung leads to a skilled qualification which is almost comparable to an academic degree. It allows students in vocational training to learn in a company as well as in a state-run trade school. This model is well regarded and reproduced all around the world. Most of the German universities are public institutions, and students traditionally study without fee payment. The general requirement for attending university is the Abitur. According to an OECD report from 2014, Germany is the world's third leading destination for international study. The established universities in Germany include some of the oldest in the world, with Heidelberg University (established in 1386), Leipzig University (established in 1409) and the University of Rostock (established in 1419) being the oldest in the country. The Humboldt University of Berlin, founded in 1810 by the liberal educational reformer Wilhelm von Humboldt, became the academic model for many Western universities.
== Etymology and historical development == The term internal medicine in English has its etymology in the 19th-century German term Innere Medizin. Originally, internal medicine focused on determining the underlying "internal" or pathological causes of symptoms and syndromes through a combination of medical tests and bedside clinical examination of patients. It emphasized treatment of the diseases affecting the internal organs of the body. This approach differed from earlier generations of physicians, such as the 17th-century English physician Thomas Sydenham, known as the father of English medicine or "the English Hippocrates." Sydenham developed the field of nosology (the study of diseases) through a clinical approach that involved diagnosing and managing diseases based on careful bedside observation of the natural history of disease and their treatment. Sydenham emphasized understanding the internal mechanisms and causes of symptoms rather than dissecting cadavers and scrutinizing the internal workings of the body. In the 17th century, there was a shift towards anatomical pathology and laboratory studies, and Giovanni Battista Morgagni, an Italian anatomist of the 18th century, is considered the father of anatomical pathology. Laboratory investigations gained increasing significance, with contributions from physicians like German physician and bacteriologist Robert Koch in the 19th century. During this time, internal medicine emerged as a field that integrated the clinical approach with the use of investigations.
Ulrich Hersel; Claudia Dahmen; Horst Kessler (2003). "RGD modified polymers: biomaterials for stimulated cell adhesion and beyond". Biomaterials. 24 (24): 4385–4415. doi:10.1016/s0142-9612(03)00343-0. PMID 12922151. Wikidata Q34223126. Marco Arnold; Elisabetta A Cavalcanti-Adam; Roman Glass; Jacques Blümmel; Wolfgang Eck; Martin Kantlehner; Horst Kessler; Joachim P Spatz (2004). "Activation of integrin function by nanopatterned adhesive interfaces". ChemPhysChem. 5 (3): 383–388. doi:10.1002/cphc.200301014. PMID 15067875. Wikidata Q44832858. Kessler, Horst (July 1982). "Conformation and Biological Activity of Cyclic Peptides". Angewandte Chemie International Edition in English. 21 (7): 512–523. doi:10.1002/anie.198205121. ISSN 0570-0833. Dechantsreiter MA; Planker E; Mathä B; Lohof E; Hölzemann G; Jonczyk A; Goodman SL; Kessler H (1999). "N-Methylated cyclic RGD peptides as highly active and selective alpha(V)beta(3) integrin antagonists". Journal of Medicinal Chemistry. 42 (16): 3033–3040. doi:10.1021/jm970832g. PMID 10447947. Wikidata Q30580638. Elisabetta A Cavalcanti-Adam; Tova Volberg; Alexandre Micoulet; Horst Kessler; Benjamin Geiger; Joachim Pius Spatz (2007). "Cell spreading and focal adhesion dynamics are regulated by spacing of integrin ligands". Biophysical Journal. 92 (8): 2964–2974. doi:10.1529/biophysj.106.089730. PMC 1831685. PMID 17277192. Wikidata Q30479140. Kessler, Horst (2023). NMR: Mein Kompass in der Organischen und Medizinischen Chemie [NMR: my compass in organic and medicinal chemistry]. Berlin: GNT Publishing GmbH. ISBN 978-3-86225-132-2.
Sources: en.wikipedia.org
From 1980 to 2013, the prevalence of overweight and obesity in children increased by nearly 50%. Currently 10% of children worldwide are either overweight or obese. In 2014, the World Health Organization established a high-level commission to end childhood obesity. With more than 42 million overweight children around the world, childhood obesity is increasing worldwide. Since 1980, the number of obese children has doubled in all three North American countries – Mexico, the United States, and Canada. Although the rate of childhood obesity in the United States has stopped increasing, the current rate remains high. In 2010, 32.6 percent of six- to eleven-year-olds were overweight, and 18 percent of six- to nine-year-olds were obese.
== Diagnosis == The clinical presentation of ALD can vary greatly, making diagnosis difficult. With the variety of phenotypes, clinical suspicion of ALD can result from a variety of different presentations. Symptoms vary based on the disease phenotype, and even within families or between twins. When ALD is suspected based on clinical symptoms, the initial testing usually includes plasma very long chain fatty acid (VLCFA) determination using gas chromatography-mass spectrometry. The concentration of unsaturated VLCFA, particularly 26 carbon chains is significantly elevated in males with ALD, even prior to the development of other symptoms. Confirmation of ALD after positive plasma VLCFA determination usually involves molecular genetic analysis of ABCD1. In females, where plasma VLCFA measurement is not always conclusive (some female carriers will have normal VLCFA in plasma), molecular analysis is preferred, particularly in cases where the mutation in the family is known. Although the clinical phenotype is highly variable among affected males, the elevations of VLCFA are present in all males with an ABCD1 mutation. Because the characteristic elevations associated with ALD are present at birth, well before any symptoms are apparent, there have been methods developed in the interests of including it in newborn screening programs. One of the difficulties with ALD as a disease included in universal newborn screening is the difficulty in predicting the eventual phenotype that an individual will express.
=== Structural details === The X−H distance is typically ≈110 pm, whereas the H···Y distance is ≈160 to 200 pm. The typical length of a hydrogen bond in water is 197 pm. The ideal bond angle depends on the nature of the hydrogen bond donor. The following hydrogen bond angles between a hydrofluoric acid donor and various acceptors have been determined experimentally:
=== Column selection === The choice of column depends on the sample and the active measured. The main chemical attribute regarded when choosing a column is the polarity of the mixture, but functional groups can play a large part in column selection. The polarity of the sample must closely match the polarity of the column stationary phase to increase resolution and separation while reducing run time. The separation and run time also depends on the film thickness (of the stationary phase), the column diameter and the column length.
Sources: en.wikipedia.org
Splenectomy (operative): This is the operative removal of the entire spleen by a surgeon, thus stopping the extravascular hemolysis, but also removing the immune functions that the spleen naturally provides to the body. Partial splenectomy (operative): This is when only a section of the spleen is removed, instead of the entire organ. The goal is to lower the extravascular hemolysis to a level compatible with homeostasis of the patient, while preserving the immune function of the spleen's presence. Research on outcomes is currently ongoing, and is routine at children's hospitals within the United States of America. Splenic ablation (interventional radiology): This option is non-operative, and is when an interventional radiologist (instead of a surgeon) uses radiologic techniques to coil or cauterize vasculature within the splenic circulation. There are various points in the circulatory pathway where the treatment can be applied to produces varying amounts of retained viability of the spleen, thus giving the option to attempt to preserve splenic immune function. All operative and interventional treatments require the immunization of HS patients against the influenza virus, SARS-CoV-2, and encapsulated bacteria such as Streptococcus pneumoniae and meningococcus. Antibiotics are no longer recommended for maintenance use, even in post-splenectomy HS patients. Since the spleen is important for protecting against encapsulated organisms, sepsis caused by encapsulated organisms is a possible complication of splenectomy. Additional elective treatments offered:
Mass spectrometry Macromolecular crystallography Neutron diffraction Proteolysis Nuclear magnetic resonance spectroscopy of proteins (NMR) Electron paramagnetic resonance (EPR) Cryogenic electron microscopy (cryoEM) Electron crystallography and microcrystal electron diffraction Multiangle light scattering Small angle scattering Ultrafast laser spectroscopy Anisotropic terahertz microspectroscopy Two-dimensional infrared spectroscopy Dual-polarization interferometry and circular dichroism Most often researchers use them to study the "native states" of macromolecules. But variations on these methods are also used to watch nascent or denatured molecules assume or reassume their native states. See protein folding. A third approach that structural biologists take to understanding structure is bioinformatics to look for patterns among the diverse sequences that give rise to particular shapes. Researchers often can deduce aspects of the structure of integral membrane proteins based on the membrane topology predicted by hydrophobicity analysis. See protein structure prediction.
=== Life expectancy === The maximum lifespan of bats is three-and-a-half times that of other mammals of similar size; a Siberian bat (Myotis sibiricus) was recaptured in the wild after 41 years, making it the oldest known bat. One hypothesis consistent with the rate-of-living theory links this to the fact that they slow their metabolic rate while hibernating: bats that hibernate, on average, have a longer lifespan than bats that do not. Another hypothesis states that lower mortality is linked to flying, which would also be true for birds and gliding mammals. In addition, female bats that give birth to multiple pups annually generally have reduced lifespans compared to those that have one pup. Also, cave-roosting species may have a longer lifespan than non-roosting species due to less predation in caves.
His expertise in treating children with keratoconus using CXL has led to his involvement in shaping safety standards and best practice models for treatment. Hafezi has implemented other CXL treatments in more recent times. The keratoconus treatment via pediatric application and also using CXL principles for treating infectious keratitis. Hafezi also hold two medical patents, both related to CXL technology and treatments.
Stoess, on the other hand, had reestablished relations with Eastman Kodak in the United States and was bringing large quantities of much-needed foreign exchange to Germany. After World War II, Paul Koepff Jr. became managing director of the Stoess company in Eberbach. In 1949, he built up a gelatin capsule factory there. In the course of the decades, DGF AG bought various factories worldwide. In 1965, it was taken over by the "Chem. Werke Stoess" in Heidelberg. In that year Heinrich Koepff took over the majority of shares of the Göppingen plant and through his marriage to the granddaughter of the company founder, Gerda Stoess, the companies merged. In 1972, the association traded under the name DGF Stoess & Co. GmbH. In 1989, the company was converted into a public limited company. The gelatin production division was renamed the Gelita Group in 1999. In 2005, all entities started to sell gelatine under the brand name Gelita.
Sources: en.wikipedia.org
Selank is a synthetic heptapeptide designed as a stabilized analog of the natural tetrapeptide tuftsin. It has been investigated mainly for anxiolytic and cognitive effects. It is not an approved pharmaceutical in most countries.
It was developed in Russia, at the Institute of Molecular Genetics of the Russian Academy of Sciences, during the 1990s. Most published research originates from Russian institutions. Independent international replication remains limited.
Tuftsin is a natural tetrapeptide with the sequence Thr-Lys-Pro-Arg that participates in immune signaling. Selank extends that sequence with Pro-Gly-Pro at the C-terminus. The added residues are linked to greater resistance to enzymatic breakdown.
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.