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.
Updated 2025-11-17. Numbers and descriptions here follow the published literature rather than marketing 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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Typical purity specification | 95 percent or higher by RP-HPLC | Area percentage of the main peak |
| Identity confirmation | Electrospray ionization mass spectrometry | Observed mass compared with the theoretical value near 751.9 Da |
| Recommended dry storage | -20 °C, desiccated | -80 °C for multi-year archival material |
| Solution handling | Prepare fresh; avoid long storage | Sterile filtration reduces microbial load |
| Common synonyms | TKPRPGP; TP-7 | Sequence code and laboratory designation used interchangeably |
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
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.
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
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.
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.
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.
=== Food === Food is another source of cadmium. Plants may contain small or moderate amounts in non-industrial areas, but high levels may be found in the liver and kidneys of adult animals. The daily intake of cadmium through food varies by geographic region. Intake is reported to be approximately 8 to 30μg in Europe and the United States versus 59 to 113 μg in various areas of Japan. A small study of premium dark chocolate samples found 48% had high levels of cadmium, the source commonly being the presence of cadmium in soil in which they were grown.
Medical incubator: a business incubator focused on medical devices and biomaterials This type of business incubator focuses on start-up advice for medical devices and biomaterials. Medical technologies are always changing and improving, and therefore this type of incubator is ideal for encouraging innovation and entrepreneurship within the medical field.
Fluorine-18 (18F, also called radiofluorine) is a fluorine radioisotope which is an important source of positrons. Its half-life is 109.734 minutes, less than two hours, and one of the shortest of radioisotopes with use outside research. It decays by positron emission 96.7% of the time and electron capture 3.3% of the time. Both modes of decay yield stable oxygen-18.
Sources: en.wikipedia.org
CRC Press, 2001 Tracy, Douglas S.; Nash, Robert A., "A Validation Approach for Laboratory Information Management Systems", Journal of Validation Technology, 2002, 9(1), 6-14 Perry, Douglas, "Laboratory Informatics: Origin, Scope, and its Place in Higher Education", Journal of the Association for Laboratory Automation, 2004, 9(6), 421 - 428 Sterling, James D., "Laboratory Automation Education", Journal of the Association for Laboratory Automation, 2004, 9(5), A11-A12 Sterling, James D., "Laboratory automation curriculum at Keck Graduate Institute", Journal of the Association for Laboratory Automation, 2004, 9(5), 331-335 Taylor, Keith, "The status of electronic laboratory notebooks for chemistry and biology", Current Opinion in Drug Discovery & Development, 2006, 9(3): 348-353 Wood, Simon, "Comprehensive Laboratory Informatics: A Multilayer Approach", American Laboratory, 2007, 39(16), 20-23 Metrick, Gloria, "Three Issues of LIMS/Laboratory Informatics That Can Cost Money", American Laboratory, 2007, 39(21), 10-11 Calva, Diana; Lehman, Mario, "An analysis of the possible applications of Artificial Intelligence Techniques to a Clinical Laboratory Information Management System", International Journal of Computer Science and Network Security, 2008, 8(12), 82-86 Shah, Kim, "Elevating laboratory informatics to assist decision-making", Pharmaceutical Technology Europe, 2009, 21(5)
== Society and culture == Multiple black market sellers of the peptide emerged before approval of the Lilly drug, leading to multiple lawsuits with Lilly as the plaintiff. Eli Lilly sued six entities: Lone Star Peptide Co., Aesthetic Envy Cosmetic Centers, Striker Pharmacy, Texas Peptides, Astra LLC (Astra Peptides), and Legendary Peptides.
== Constituents == The main compounds in skullcap are flavonoids. Isolated chemical compounds include wogonin, wogonoside, and 3,5,7,2',6'-pentahydroxyl flavanone found in Scutellaria. Other constituents include baicalin, apigenin, oroxylin A, and scutellarein.
==== Ofatumumab ==== Ofatumumab is a second generation human IgG1 antibody that binds to CD20. It is used in the treatment of chronic lymphocytic leukemia (CLL) because the cancerous cells of CLL are usually CD20-expressing B-cells. Unlike rituximab, which binds to a large loop of the CD20 protein, ofatumumab binds to a separate, small loop. This may explain their different characteristics. Compared to rituximab, ofatumumab induces complement-dependent cytotoxicity at a lower dose with less immunogenicity.
Sources: en.wikipedia.org
However, it has been found that when administered intravenously in lipid emulsion, better pharmacokinetics and tissue distribution were achieved. The lipid emulsion administration had a higher AUC and lower clearance than the solution form, which meant that there was an increased bioavailability of cinnarizine, allowing for an improved therapeutic effect. Plasma pharmacokinetics of cinnarizine administered intravenously follows a three-compartment model first with a fast distribution phase, followed by a slower distribution phase, and ending with a very slow elimination. The Vss (steady state apparent volume of distribution) for lipid emulsion administration was 2× lower (6.871 ± 1.432 L/kg) than that of cinnarizine given in solution (14.018 ± 5.598 L/kg) and it was found that significantly less cinnarizine was taken up into the lung and brain in the lipid emulsion condition. This is significant because it would reduce the likelihood of toxic side effects in the central nervous system.
Neuromuscular diseases affect the muscles and their nervous control. In general, problems with nervous control can cause spasticity or paralysis, depending on the location and nature of the problem. A number of movement disorders are caused by neurological disorders such as Parkinson's disease and Huntington's disease where there is central nervous system dysfunction. Symptoms of muscle diseases may include weakness, spasticity, myoclonus and myalgia. Diagnostic procedures that may reveal muscular disorders include testing creatine kinase levels in the blood and electromyography (measuring electrical activity in muscles). In some cases, muscle biopsy may be done to identify a myopathy, as well as genetic testing to identify DNA abnormalities associated with specific myopathies and dystrophies. A non-invasive elastography technique that measures muscle noise is undergoing experimentation to provide a way of monitoring neuromuscular disease. The sound produced by a muscle comes from the shortening of actomyosin filaments along the axis of the muscle. During contraction, the muscle shortens along its length and expands across its width, producing vibrations at the surface.
Analyses have cast doubt on this claim, but the "race-corrected" eGFR remains the standard." They concluded saying "As long as uncertainty persists about the cause of racial differences in serum creatinine levels, we should favor practices that may alleviate health inequities over those that may exacerbate them." In February 2022, the National Kidney Foundation (NKF) and American Society of Nephrology (ASN)'s Joint Task Force on Reassessing the Inclusion of Race in Diagnosing Kidney Diseases recommended use of the 2021 CKD-EPI equation which discontinues using a race modifier. In July 2022 the OPTN Board eliminated race-based calculations for transplant candidate listing across all transplant hospitals in the US.
Evidence from the study of carbon and oxygen isotope composition of tooth enamel of equids, bovids and hippopotamids from Melka Wakena and Gadeb, interpreted as indicative of presence of montane grasslands with shrubs and aquatic habitats in Ethiopian highlands that provided recurrent access to water and vegetation to mammals (including Acheulean-making hominins) in the late Early Pleistocene, is presented by Briatico et al. (2026). Evidence from the study of the composition of Middle and Late Pleistocene small mammalian assemblages from the East European Plain, interpreted as consistent with presence of semi-arid and arid steppe habitats during the warmest and driest phases of the Pleistocene interglacials, is presented Markova, Puzachenko & Tsatskin (2026). Robu et al. (2026) reconstruct trophic relationships of Late Pleistocene mammals from cave sites in the Romanian Carpathians with and without bears on the basis of an isotopic analysis of their bones, reporting evidence of overall similar dietary behavior of the studied mammals throughout Europe during Marine Isotope Stage 3, as well as evidence of mainly herbivorous diet of cave bears that included varying levels of animal protein consumption, and interpret the dietary behavior of the studied cave bears as possibly influenced by abundance of the carnivores. Russo et al. (2026) study the composition of Pleistocene faunal assemblages from the Naame, Nahr Ibrahim and Ras el-Kelb sites (Lebanon) and tooth wear of ungulates from these sites, while Russo et al.
== Pulsed SILAC == Pulsed SILAC (pSILAC) is a variation of the SILAC method where the labelled amino acids are added to the growth medium for only a short period of time. This allows monitoring differences in de novo protein production rather than raw concentration.
Sources: en.wikipedia.org
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.
A reported purity value reflects the share of the main peak in one chromatographic run and says nothing about identity. Confirming that the expected sequence is present requires a separate measurement such as mass spectrometry. Purity and identity are distinct questions.
A mass spectrum reports the molecular masses present in a sample and shows whether they match the value expected for selank, near 751.9 Da. It also flags common artifacts such as truncation or adduct formation. It does not establish correct stereochemistry or complete sequence order on its own.
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.