If you have been reading about Semax 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 2026-02-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| 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.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
Development work on the compound began in the 1980s and 1990s at the Institute of Molecular Genetics in Moscow, within the same research programme that produced the peptide Semax. Early investigators sought a tuftsin derivative with improved resistance to enzymatic breakdown and with activity in the central nervous system after peripheral administration. Most of the primary literature from this period was published in Russian, a factor that still shapes how easily the findings can be checked by outside groups.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
Stephen Dank (born c. 1963) is an Australian biochemist who worked as a sports scientist at several professional sports club. He is known for his key role in two major sports drug cheating scandals, the Essendon Football Club supplements saga and the Cronulla-Sutherland Sharks supplements saga, where he injected players with illegal substances to improve their performance. He is known for his unorthodox treatment and diagnostic methods, including using calf blood and profiling players' DNA. Des Hasler described Dank as 'a great analytical thinker', in particular highlighting his contributions in the area of GPS application, statistical science, and altitude simulation training. In light of his unorthodox treatment methods, in November 2016 Dank was given a life-long ban from association with the Australian Football League. On 28 November 2016, the Australian Sports Anti-Doping Authority (ASADA), (known as Sport Integrity Australia since July 1 2020), officially acknowledged the decision of the AFL Appeal Board He worked with National Rugby League clubs the Manly Sea Eagles and Cronulla Sharks and Australian rules football clubs, Essendon Football Club and the Gold Coast Suns.
Due to its location, Mexico has long been used as a staging and transshipment point for narcotics and contraband between Latin America and United States markets. Mexican bootleggers supplied alcohol to American gangsters throughout Prohibition in the U.S., and the onset of the illegal drug trade with the U.S. began when Prohibition came to an end in 1933. In 1940, under president Lázaro Cárdenas and the impulsion of Mexican psychiatrist Leopoldo Salazar Viniegra, Mexico legalized all drugs, in an early attempt to prevent the development of illegal drug trafficking organizations. The law was in effect for about 5 months when the Mexican government repealed it, allegedly under the increasing economic and political pressure from the U.S. During World War II, the United States experienced shortages of medical morphine after opium supplies from Asia were disrupted by the Pacific War. In response, Mexican authorities, in cooperation with U.S. officials, expanded regulated opium poppy cultivation in northwestern Mexico, including rural areas surrounding Culiacán in the state of Sinaloa. Farmers in the mountainous regions of Sierra Madre Occidental near Culiacán, produced opium that was processed into legal morphine for wartime medical use by Allied forces. Although the program ended after 1945, the agricultural knowledge, smuggling routes, and local intermediary networks developed during the wartime period persisted. Historians and criminologists have identified these postwar networks as an early foundation for later illicit drug trafficking organizations in Sinaloa.
Based on scientific tests over five decades, government safety agencies have determined that polystyrene is safe for use in foodservice products. For example, polystyrene meets the stringent standards of the U.S. Food and Drug Administration and the European Commission/European Food Safety Authority for use in packaging to store and serve food. The Hong Kong Food and Environmental Hygiene Department reviewed the safety of serving various foods in polystyrene foodservice products and reached the same conclusion as the U.S. FDA. From 1999 to 2002, a comprehensive review of the potential health risks associated with exposure to styrene was conducted by a 12-member international expert panel selected by the Harvard Center for Risk Assessment. The scientists had expertise in toxicology, epidemiology, medicine, risk analysis, pharmacokinetics, and exposure assessment. The Harvard study reported that styrene is naturally present in trace quantities in foods such as strawberries, beef, and spices, and is naturally produced in the processing of foods such as wine and cheese. The study also reviewed all the published data on the quantity of styrene contributing to the diet due to migration of food packaging and disposable food contact articles, and concluded that risk to the general public from exposure to styrene from foods or food-contact applications (such as polystyrene packaging and foodservice containers) was at levels too low to produce adverse effects. Polystyrene is commonly used in containers for food and drinks.
COL1A1/2-related osteogenesis imperfecta is inherited in an autosomal dominant manner. The proportion of cases caused by a De novo COL1A1 or COL1A2 mutations are the cause of osteogenesis imperfecta in the vast majority of perinatally lethal osteogenesis imperfecta, and progressively deforming osteogenesis imperfecta. In classic non-deforming osteogenesis imperfecta with blue sclerae or common variable osteogenesis imperfecta with normal sclerae, nearly 60% of cases are de novo. COL1A1/2-related osteogenesis imperfecta is identified by repeated fractures with trivial trauma, defective dentinogenesis imperfecta (DI), and hearing loss. The clinical features of COL1A1/2-related osteogenesis imperfecta can be highly variable ranging from severe and lethal perinatal fractures to individuals with minimal tendency to repeated fractures and skeletal deformities and with a normal stature and life span. In between the clinical spectrum may include individuals with various degrees of disabling skeletal deformities and short stature. The radiographic findings of osteogenesis imperfecta include; long bone deformations such as bowing of the tibias and femurs, pencil-like deformity and tapering of bones, cortical thinning and rarefaction, pathologic fractures at various degrees of healing, bone shortening and vertebral wedging. Accordingly, COL1A1/2-related osteogenesis imperfecta has been classified into four sub-types (I, II, III, and IV) built upon the diversity of the radioclinical features.
In 1992, Eric Taub brought ibogaine to an offshore location close to the United States, where he began providing treatments and popularizing its use. In Costa Rica, Lex Kogan, another leading proponent, joined Taub in systematizing its administration. The two men established medically monitored treatment clinics in several countries. In 1981, an unnamed European manufacturer produced 44 kg of iboga extract. The entire stock was purchased by Carl Waltenburg, who distributed it under the name "Indra extract" and used it in 1982 to treat heroin addicts in the community of Christiania, Copenhagen. Indra extract was available for sale over the Internet until 2006, when the Indra web presence disappeared. Various products are currently sold in several countries as "Indra extract", but it is unclear if any of them are derived from Waltenburg's original stock. Ibogaine and related indole compounds are susceptible to oxidation over time. The National Institute on Drug Abuse (NIDA) began funding clinical studies of ibogaine in the United States in the early 1990s, including conducting a clinical study in 1993, but terminated the project in 1995 following the unexpected death of a female participant. Data demonstrating ibogaine's efficacy in attenuating opioid withdrawal in drug-dependent human subjects was published by Alper et al. in 1999. A cohort of 33 patients were treated with 6 to 29 mg/kg of ibogaine; 25 displayed resolution of the signs of opioid withdrawal from 24 hours to 72 hours post-treatment, but one 24-year-old female, who received the highest dosage, died.
Sources: en.wikipedia.org
If a customer has the right to receive additional goods or services in exchange for a voluntary tip, the tip is not eligible. The tax deduction is not allowed if the individual is married and files their federal income tax return separately from their spouse. The tax deduction is not allowed if the individual does not include their social security number on their federal income tax return or if the social security number was issued on or after the due date, including extensions, of the federal income tax return . For a self-employed individual who receives tips in the course of their trade or business, eligible tips are tax deductible but they cannot create a net loss for the trade or business.
The American Expedition (1799–1804) was a scientific exploration of Spanish America conducted by the Prussian naturalist Alexander von Humboldt and the French botanist Aimé Bonpland. Over the course of five years, the expedition traversed across present-day Venezuela, Colombia, Ecuador, Peru, Cuba, Mexico, and parts of the United States. Humboldt and Bonpland conducted pioneering research in fields including geography, biology, geology, meteorology, and ethnography. They observed and described vast regions of South and Central America, mapping rivers like the Orinoco and investigating the Andes Mountains—including an attempt to climb Chimborazo, accompanied by local savants and informants. Their observations of plant and animal life, atmospheric phenomena, and indigenous cultures - influenced by the debates ongoing in Spanish American in those years - laid the foundations for modern biogeography and ecology.
=== Tourne === Compared to malic and citric acids, tartaric acid is usually considered microbiologically stable. However, some species of Lactobacillus (particularly L. brevis and L. plantarum) have the potential to degrade tartaric acid in wine, reducing a wine's total acidity by 3-50%. French winemakers had long observed this phenomenon and called it tourne (meaning "turn to brown") in reference to the color change that can occur in the wine at the same time likely due to other processes at work in addition to the tartaric loss. While Lactobacillus is the most common culprit of tourne, some species of the spoilage film yeast Candida can also metabolize tartaric acid.
Another research group has developed a platelet-mimicking particle with conformational flexibility to enhance clotting during vascular injury. Since natural platelets deform to increase surface area and promote clot formation, replicating this behavior in synthetic platelets is crucial. Their thrombin-sensitive platelet-like particles (TS-PLPs) were designed to respond to thrombin, a key clotting enzyme. The fabrication process involved modifying microgels with a custom peptide sequence, followed by the synthesis of thrombin-sensitive nanogels via precipitation polymerization. These nanogels were then functionalized with fibrin-binding motifs to create the final PLPs. When exposed to thrombin, the TS-PLPs alter their shape, improving clot contraction and accelerating wound healing compared to non-thrombin-sensitive PLPs. Additionally, researchers have developed platelet-like nanoparticles that replicate key attributes of natural platelets, including their discoidal shape, mechanical flexibility, ability to aggregate biophysically and biochemically, and targeted adhesion to vascular injury sites. The design process involved fabricating discoidal nanoparticles using a top-down lithographic approach to achieve precise shape and size control. To mimic platelet flexibility, the nanoparticles were composed of biocompatible polymers that allow deformation under shear forces, similar to natural platelets. Surface functionalization was performed to introduce multiple ligands, enabling specific interactions with von Willebrand Factor, collagen, and activated platelets.
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.