Everything below concerns selank. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-07-23. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Identity confirmation | Reversed-phase HPLC retention time versus reference standard | Retention depends on column, gradient, and ion-pairing agent |
| Mass confirmation | Electrospray or MALDI mass spectrometry | Doubly protonated ion near m/z 377 is consistent with about 752 Da |
| Typical purity specification | 95 percent or higher by chromatographic peak area | Lower values suggest truncated or modified peptide species |
| Storage of lyophilized powder | -20 °C, desiccated, protected from light | Powder tolerates long storage better than solution |
| Storage of solution | 2-8 °C for short periods | Freeze-thaw cycling promotes aggregation and surface adsorption |
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.
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 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.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
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 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.
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.
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.
== Sources == Ahuja, I., Dauksas, E., Remme, J. F., Richardsen, R., & Løes, A. K. (2020). Fish and fish waste-based fertilizers in organic farming - With status in Norway: A review. Waste management (New York, N.Y.), 115, 95–112. Anu Prasanna, V., Chandrasekhar, T., Riazunnisa, K., Kumar, P. R., Teja, S. V. R., Rajeswari, D., Reddy, M. C., Wee, Y.-J., & Lebaka, V. R. (2023). Fish Waste: A Potential Source of Biodiesel. Fermentation, 9(9), 861. Bekker-Nielsen T (2005) Ancient fishing and fish processing in the Black Sea region Volume 2 of Black Sea studies, Aarhus University Press, ISBN 978-87-7934-096-1. Bremner HA (2003) Safety and Quality Issues in Fish Processing Woodhead Publishing Limited, ISBN 978-1-85573-678-8. Brewer DJ and Friedman RF (1989) Fish and Fishing in Ancient Egypt Cairo press: The American University in Cairo. ISBN 978-977-424-224-3 Cutting CL (1955) Fish saving; a history of fish processing from ancient to modern times, L. Hill. FAO and WHO (2012) Codex Alimentarius: Code of practice for fish and fishery products Rome. ISBN 978-92-5-107018-5. Gosławski, S., & Borowski, S. (2026). Valorization of Fish Waste via Anaerobic Digestion: A Systematic Literature Review and Future Research Agenda. Energies, 19(17), 4077. Hall GM (1997) Fish processing technology Springer, ISBN 978-0-7514-0273-5. Luten JB, Jacobsen C and Bekaert K (2006) Seafood research from fish to dish: quality, safety and processing of wild and farmed fish Wageningen Academic Publishers. ISBN 978-90-8686-005-0.
After slight decreases in opioid fatalities 2017–2018, overdose deaths in the US increased in 2019, due largely to an increase in non-medical use of fentanyl. The COVID-19 pandemic's interference with both social safety and health care delivery systems has intensified the opioid epidemic. US media, on national, state, and local levels, infer that overdose deaths are increasing. But there is no national reporting system on overdose mortality to confirm these reports. Conclusions on the relationship between increasing overdose fatalities and the COVID-19 pandemic will require more research. Studies, such as those by Wainwright et al. and Ochalek et al. estimate that opioid use and overdose deaths may be increasing, just as reported by the media. But more study is needed. Statistics reveal that during the COVID-19 epidemic, drug overdoses increased. According to statistics from the Centers for Disease Control and Prevention, there were 91,799 overdose fatalities in the United States in 2020, a more than 30% rise from 2019. Drug-related overdose fatalities increased to more over 106,000 in 2021, the greatest number of overdose deaths recorded in a 12-month period. Most of these deaths were caused by synthetic opioids other than methadone (mostly fentanyl or analogues) and methamphetamine. During this time, non-Hispanic Black and non-Hispanic American Indian populations had the highest rate of overdose deaths, and non-Hispanic American Indian and white populations had the greatest increase in overdose rates.
==== Grafting ==== In biotextiles, grafting onto surfaces refers to the process of attaching or bonding functional molecules, such as proteins, peptides, or polymers, onto the surface of textile materials. This process is often performed to modify the surface properties of textiles, such as enhancing biocompatibility, promoting cell adhesion, or enabling controlled drug release. Grafting onto surfaces can be achieved through various techniques, including chemical modification, plasma treatment, or surface coating methods. These modified biotextiles find applications in biomedical fields such as tissue engineering, wound healing, and medical implants, where tailored surface properties are critical for desired biological interactions.
Sources: en.wikipedia.org
Evidence contradicts Neel's hypothesis in studies of the Pima Indians, which suggest that individuals with higher insulin sensitivity tended to have higher weights, whereas those with insulin resistance tended to weigh less on average within this demographic. Modern hypotheses propose that insulin metabolism serves as a socio-ecological adaptation, with insulin serving as the mechanism for allocating energy to different body components and insulin sensitivity being an adaptation to regulate this energy allocation. The Behavioral Switch Hypothesis suggests that insulin resistance leads to two methods of altering reproductive and behavioral strategies. These strategies are termed "r to K" and "soldier to diplomat". The "r to K" strategy involves directing insulin through the placenta to the fetus, resulting in weight gain in the fetus but not the mother, indicating an increase in parental investment (K strategy). In the "soldier to diplomat" strategy, the insensitivity of skeletal muscle to insulin could redirect glucose to the brain, which does not require insulin receptors. This has been shown to enhance cognitive development across various studies.
==== Coffee ==== According to the Encyclopédie ou Dictionnaire raisonné des sciences, des arts et des métiers, the Germans use potatoes as coffee, either by using the whole tuber, boiled, scraped, cut into small cubes and put to dry, or by using the peels, chopped and dried; in both cases, the dried material is roasted, ground, prepared and served like ordinary coffee, with cream for those who prefer it.
Subcutaneous administration is the insertion of medications beneath the skin either by injection or infusion. A subcutaneous injection is administered as a bolus into the subcutis, the layer of skin directly below the dermis and epidermis, collectively referred to as the cutis. The instruments are usually a hypodermic needle and a syringe. Subcutaneous injections are highly effective in administering medications such as insulin, morphine, diacetylmorphine and goserelin. Subcutaneous administration may be abbreviated as SC, SQ, subcu, sub-Q, SubQ, SUBQ, or subcut. SUBQ is the preferred abbreviation to reduce the risk of misunderstanding and potential errors. Subcutaneous tissue has few blood vessels and so drugs injected into it are intended for slow, sustained rates of absorption, often with some amount of depot effect. Compared with other routes of administration, it is slower than intramuscular injections but still faster than intradermal injections. Subcutaneous infusion (as opposed to subcutaneous injection) is similar but involves a continuous drip from a bag and line, as opposed to injection with a syringe.
Psychiatrist alumnus Rick Strassman conducted seminal early work with DMT—at the time the first Food and Drug Administration-approved clinical research on psychedelics in over 20 years—and hypothesized that DMT is produced endogenously. Notable psychologist alumni include Daniel Stern, who wrote The Interpersonal World of the Infant. Other alumni include Howard Dean—governor of Vermont, 2004 presidential candidate, and Democratic National Committee chairman—and Baruch Goldstein, perpetrator of the 1994 Cave of the Patriarchs massacre.
Sources: en.wikipedia.org
CrCl3 + Al + 6 CO → Cr(CO)6 + AlCl3 The use of metal alkyls, such as triethylaluminium and diethylzinc, as the reducing agent leads to the oxidative coupling of the alkyl radical to form the dimer alkane:
Carvedilol, sold under the brand name Coreg among others, is a beta blocker medication, that may be prescribed for the treatment of high blood pressure (hypertension) and chronic heart failure with reduced ejection fraction (also known as HFrEF or systolic heart failure). Beta-blockers as a collective medication class are not recommended as routine first-line treatment of high blood pressure for all patients, due to evidence demonstrating less effective cardiovascular protection and a less favourable safety profile when compared to other classes of blood pressure-lowering medications. Common side effects include dizziness, tiredness, slowed heart rate, low blood pressure, nausea, and shortness of breath. Severe side effects may include bronchospasm. Safety during pregnancy or breastfeeding is unclear. Use is not recommended in those with liver problems. Carvedilol is a nonselective beta blocker and alpha-1 blocker. How it improves outcomes is not entirely clear but may involve dilation of blood vessels. Carvedilol was patented in 1978 and approved for medical use in the United States in 1995. Carvedilol is a therapeutic alternative on the World Health Organization's List of Essential Medicines. It is available as a generic medication. In 2023, it was the 35th most commonly prescribed medication in the United States, with more than 16 million prescriptions.
=== Food labeling === Ultimately, federal and local governments in the U.S. are willing to create political solutions that will reduce obesity ratings by "recommending nutrition education, encouraging exercise, and asking the food and beverage industry to promote healthy practices voluntarily." In 2008, New York City was the first city to pass a "labeling bill" that "require[d] restaurants" in several cities and states to "post the caloric content of all regular menu items, in a prominent place and using the same font and format as the price." Furthermore, adding better labels to food and drink products can help to improve diets. According to a 2021 study, proper labeling on the front side of products has been proven to reduce the amount of unhealthy food purchased. On the other hand, there has been an increase in purchases of healthier products. These labels help consumers to be more health conscious about the food they are buying. Many states have started to adopt policies allowing only healthier drinks such as milk and water. In general, the Affordable Care Act (ACA) started to require chain restaurants to post calorie information on their menus, menu boards, and to provide additional nutrition information such as saturated fat and added sugars to customers upon request. The Food and Drug Administration's rules that enforce this provision took effect in 2018. It has applied to supermarkets, convenience stores, delis, movie theaters, and stadiums. Retails with fewer than 20 locations don't have to abide by these rules.
Sources: en.wikipedia.org
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.
Lyophilized powder is normally stored desiccated at -20 °C, protected from light and moisture. Powder kept under these conditions is generally stable for long periods. Solutions are less stable and are usually prepared immediately before use.
A purity value from one chromatographic method does not capture every possible impurity. Related peptides with similar retention behavior, counterions, and residual solvents may not appear in the same analysis. Independent testing with an orthogonal method provides stronger assurance of identity and content.
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.