The short version of Certificate of analysis fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-07-06 and is reviewed periodically as new material appears.
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.
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.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Derived from the seven-residue sequence |
| Molecular weight | About 751.9 g/mol | Average mass; the monoisotopic value is slightly lower |
| Residue count | Seven amino acids | Thr-Lys-Pro-Arg-Pro-Gly-Pro |
| Parent compound | Tuftsin (Thr-Lys-Pro-Arg) | Selank extends tuftsin at the C-terminus |
| Compound class | Synthetic short peptide | Studied in a research setting; not a licensed drug in most markets |
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
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 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.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
=== Fermented dry sausage === Adding sake kasu when mixing the ingredients for fermented dry sausage can increase the speed of decomposition in both sarcoplasmic and myofibrillar proteins. It also can increase the amount of peptides and free amino acids, causing the fermented dry sausage to increase in hardness and acidity.
The witch doctor drinks a very small amount each time and knows well how many times he can sample the brew without losing his senses to properly conduct the ritual and lead the choir". Another report produced in 1737 by the missionary Pablo Maroni, describes the use of a psychoactive liana called ayahuasca for divination in the Napo River, Ecuador: "For divination, they use a beverage, some of white datura flowers, which they also call Campana due to its shape, and others from a vine commonly known as Ayahuasca, both highly effective at numbing the senses and even at taking one's life if taken in excess. They also occasionally use these substances for the treatment of common illnesses, especially headaches. So, the person who wants to divine drinks the chosen substance with certain rituals, and while deprived of their senses from the mouth downwards, to prevent the strength of the plant from harming them, they remain in this state for many hours and sometimes even two or three days until the effects run their course, and the intoxication subsides. After this, they reflect on what their imagination revealed, which occasionally remains with them for delirium. This is what they consider accomplished and propagate as an oracle." Latter reports were produced by Juan Magnin in 1740, describing ayahuasca use as a medicinal plant by the "Jivaroan" peoples (called ayahuessa) and by Franz Xaver Veigl in 1768, that reports about several "dangerous plants", including a bitter liana used for precognition and sorcery.
They found increases in plasma oxytocin following a social interaction were correlated with faster wound healing. They hypothesized this was due to oxytocin reducing inflammation, thus allowing the wound to heal more quickly. This study provides preliminary evidence that positive social interactions may directly influence aspects of health. According to a study published in 2014, silencing of oxytocin receptor interneurons in the medial prefrontal cortex (mPFC) of female mice resulted in loss of social interest in male mice during the sexually receptive phase of the estrous cycle. Oxytocin evokes feelings of contentment, reductions in anxiety, and feelings of calmness and security when in the company of the mate. This suggests oxytocin may be important for the inhibition of the brain regions associated with behavioral control, fear, and anxiety, thus allowing orgasm to occur. Research has also demonstrated that oxytocin can decrease anxiety and protect against stress, particularly in combination with social support. It is found that endocannabinoid signaling mediates oxytocin-driven social reward. During a 2008 study, a lack of oxytocin in mice was associated with abnormalities in emotional behavior. Another study conducted in 2014 saw similar results with a variation in the oxytocin receptor connected with dopamine transport and how levels of oxytocin are dependent on the levels of dopamine transporter levels.
Tadalafil is used to treat erectile dysfunction, benign prostatic hyperplasia, and pulmonary arterial hypertension. In the United States, tadalafil (as Cialis) is indicated for the treatment of erectile dysfunction and the signs and symptoms of benign prostatic hyperplasia; and (as Adcirca) for the treatment of pulmonary arterial hypertension to improve exercise ability.
Sources: en.wikipedia.org
=== Chemical properties === Graphene has a theoretical specific surface area (SSA) of 2630 m2/g. This is much larger than that reported to date for carbon black (typically smaller than 900 m2/g) or for carbon nanotubes (CNTs), from ≈100 to 1000 m2/g and is similar to activated carbon. Graphene is the only form of carbon (or solid material) in which every atom is available for chemical reaction from two sides (due to the 2D structure). Atoms at the edges of a graphene sheet have special chemical reactivity. Graphene has the highest ratio of edge atoms of any allotrope. Defects within a sheet increase its chemical reactivity. The onset temperature of reaction between the basal plane of single-layer graphene and oxygen gas is below 260 °C (530 K). Graphene burns at very low temperatures (e.g., 350 °C (620 K)). Graphene is commonly modified with oxygen- and nitrogen-containing functional groups and analyzed by infrared spectroscopy and X-ray photoelectron spectroscopy. However, the determination of structures of graphene with oxygen- and nitrogen- functional groups require the structures to be well controlled. In 2013, Stanford University physicists reported that single-layer graphene is a hundred times more chemically reactive than thicker multilayer sheets. Graphene can self-repair holes in its sheets, when exposed to molecules containing carbon, such as hydrocarbons. Bombarded with pure carbon atoms, the atoms perfectly align into hexagons, filling the holes.
=== Underlying cause === PNP is ultimately caused by the presence of a tumor. There is a strong association between the development of PNP and malignancy of the tumor. However, it is not uncommon for the tumor to be benign, as in the case of afflictions such as thymoma and Castleman's disease. Only one patient without a tumor has met the diagnostic criteria for PNP. However, they rapidly reached their demise and it is suggested they may have had an undiagnosed tumor.
=== NAD-II Riboswitch === The NAD⁺-II riboswitch was first described as the pnuC RNA motif, discovered via computational searches for long GC-rich intergenic regions in bacterial genomes. The original consensus model consists of two base-paired stems (P1 and P1a) separated by a conserved internal loop, with a three-nucleotide segment predicted to form a pseudoknot by base-pairing with a portion of the Shine-Dalgarno sequence of the adjacent open reading frame. Its structure was subsequently confirmed by X-ray crystallography. In contrast to the NAD⁺-I class, NAD⁺-II riboswitches specifically and robustly recognize the oxidized form of the nicotinamide moiety either as part of NMN, NR, or intact NAD⁺. The original examples were found exclusively in the genus Streptococcus, where these riboswitches regulate pnuC genes encoding an NR/NMN transporter. In contrast to the NAD⁺-I class, NAD⁺-II riboswitches specifically and robustly recognize the oxidized form of the nicotinamide moiety either as part of NMN, NR, or intact NAD⁺. The original 43 examples were found exclusively in the genus Streptococcus, where these riboswitches regulate pnuC genes encoding an NR/NMN transporter.
=== Alternating tangential flow (ATF) === A diaphragm pump is used to produce an alternating tangential flow, helping to dislodge retained particles and prevent membrane fouling. Repligen is the largest producer of ATF systems.
== Career == In 1981, Valko joined the Hungarian Academy of Sciences, where she took on multiple roles, including heading the chromatography research group at the Central Research Institute for Chemistry of the Hungarian Academy of Sciences. Concurrently, she also served as a research scientist at the Institute of Enzymology from 1981 to 1985. Between 1993 and 1995, she worked as a senior research analytical chemist at Wellcome Research Laboratory. Subsequently, she held a position as a research investigator at GlaxoWellcome Medicines Research Centre from 1995 to 2000. From 2000 to 2015, she served as the senior research investigator at the Physicochemical Characterization Group at GlaxoSmithKline. In 2017, she founded Bio-Mimetic Chromatography and has been serving as its director since then. Later in 2019, she established Bio-Mimetic Cosmetics as a trading branch of Bio-Mimetic Chromatography. From 1977 to 1981, Valko served as a lecturer in the Department of Pharmaceutical Chemistry at Semmelweis University. Additionally, she held a Mappletorpe research fellowship in the School of Pharmacy at the University of London from 1991 to 1993. Since 2004, she has held the position of honorary professor at the University College London School of Pharmacy.
Sources: en.wikipedia.org
=== Joint operation against Niño Guerrero === In June 2026, a military operation was carried to kill Héctor Rusthenford Guerrero Flores, known as Niño Guerrero, the leader of the Venezuelan criminal gang Tren de Aragua. US president Donald Trump announced that Guerrero was killed in a airstrike on 12 June in Venezuela conducted in coordination with Venezuelan authorities. Venezuelan officials confirmed their participation in the operation.
=== Tentoxin === Tentoxin is most commonly known as a naturally occurring phytotoxic cyclic tetra-peptide that is excreted by fungi of the Alternaria alternata family. There were four total syntheses of tentoxin that were published to this day that gave very poor total yields. These poor yields were mainly due to the introduction of the dehydro amino acid, more specifically the cyclization step. There was a method developed in order to stereospecifically introduce Z-dehydrophenylalanine by a modified Erlenmeyer adolization reaction. An aldol reaction is a transformation that is due to the dimerization of an aldehyde (or ketone) to a beta-hydroxy aldehyde (or ketone) by alpha C-H addition of one reactant molecule to the carbonyl group of a second reactant molecule. This reaction requires at least one of the reactants to have hydrogens. The precursor of tentoxin, the linear tetrapeptide (Boc-R1Ala-Leu-R2ΔZPhe-Gly-OMe), was obtained from Boc-Leu-Gly-OH with a 72% yield. This linear tetrapeptide with carbon-14 was utilized to study the four cyclization reagents, DPPA, DCC-PfpOH, HBTU, and HATU. By doing so, this gave the tentoxin an 81% cyclization yield.
For example, a CMAJ article noted that only two case reports and one small case series existed at the time of writing, and guidance documents typically state that micro-dosing is not yet a fully evidence-based alternative compared with standard induction. Furthermore, the phrase "without precipitating withdrawal" should be understood as "typically less likely to precipitate withdrawal" rather than guaranteed to avoid it. Clinicians adopting this method must do so with caution, informed consent, and close monitoring — particularly because many of the studies are small, heterogeneous, and variable in protocol.
In another phase II trial (006) of patients with relapsed and/or refractory multiple myeloma, carfilzomib in combination with lenalidomide and dexamethasone demonstrated an overall response rate of 69%. A phase II trial (007) for multiple myeloma and solid tumors showed promising results. In phase II trials of carfilzomib, the most common grade 3 or higher treatment-emergent adverse events were hematologic toxicity with thrombocytopenia, anemia, lymphopenia, neutropenia, pneumonia, fatigue and hyponatremia. In a frontline phase I/II study, the combination of carfilzomib, lenalidomide, and low-dose dexamethasone was highly active and well tolerated, permitting the use of full doses for an extended time in newly diagnosed multiple myeloma patients, with limited need for dose modification. Responses were rapid and improved over time, reaching 100% very good partial response. Furthermore, gastrointestinal disturbances, including diarrhea and nausea are non hematologic group of side effects commonly reported with proteasome inhibitors. Additionally, cardiovascular toxicity may be an outcome of carfilzomib treatment due to the effects on proteasomes in the myocardium. Thus, patient evaluation and risk assessment prior to initiation of therapy with carfilzomib is crucial.
Anti-trans actors employ various strategies in their spread of misinformation around transgender health care by inventing pseudoscientific concepts and attacking professionals and organizations that provide gender affirming care, trying to frame gender-affirming care as "dangerous" or "experimental" or claims that a majority of transgender youth will detransition, something scientists have refuted and named the desistance myth, or can be cured using conversion therapy.
Sources: en.wikipedia.org
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, designed as a metabolically stabilized analogue of the endogenous tetrapeptide tuftsin. It has been studied mainly against anxiety-related and cognitive endpoints rather than as an approved medicine in most jurisdictions.
Tuftsin contains four residues, while selank carries an additional Pro-Gly-Pro segment at the carboxyl end. That extension is intended to reduce enzymatic cleavage. Comparative pharmacokinetic data in humans remain limited.
No single receptor target is widely accepted as the definitive mediator of the reported effects. Proposed contributors include GABAergic modulation, shifts in monoamine turnover, and altered neuropeptide degradation. The mechanism is treated in the literature as unresolved.
Purity is usually reported as an HPLC area percentage, most often measured at 214 nm. Identity is confirmed separately by mass spectrometry. A certificate of analysis should state both the method and the observed value.