This is a working overview of Selank, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-07-17 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.
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.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
| 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 |
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.
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.
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.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
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.
Clinical Chemistry is a peer-reviewed medical journal covering the field of clinical chemistry. It is the official journal of the American Association for Clinical Chemistry. The journal was first published in 1955 on a bi-monthly basis "to raise the level at which chemistry is practiced in the clinical laboratory"; monthly publication commenced in 1964. The editor-in-chief is Nader Rifai (Harvard Medical School).
N-Linked glycans derive their name from the fact that the glycan is attached to an asparagine (Asn, N) residue, and are amongst the most common linkages found in nature. Although the majority of N-linked glycans take the form GlcNAc-β-Asn other less common structural linkages such as GlcNac-α-Asn and Glc-Asn have been observed. In addition to their function in protein folding and cellular attachment, the N-liked glycans of a protein can modulate the protein's function, in some cases acting as an on-off switch.
Dalman et al. (2024) proposed the new name Tyrannosaurus mcraeensis for the holotype (NMMNH P-3698), referencing the McRae Group, the rock layers to which the Hall Lake Formation belongs. The holotype of T. mcraeensis is found in the strata that are around a few million years older than the accepted range of T. rex, which existed at the end of the Maastrichtian. The rock layers were initially estimated to date to between 72.7 and 70.9 Ma, correlating to the latest Campanian or earliest Maastrichtian. However, in a 2024 conference abstract, the specific stratigraphic layer which yielded T. mcraeensis was estimated to be younger than 69.0 ± 0.4 Ma and older than 66.0 Ma based on the sandstone from the same fossil locality, which would suggest that the age of T. mcraeensis is much closer to T. rex than previously thought. T. mcraeensis was estimated at 12 metres (39 ft) long, which is similar to the size of an adult T. rex. The two are distinguished by characters of the skull. Amongst these, the dentary of T. mcraeensis is proportionately longer and possesses a less prominent chin, and the lower jaw shallower than that of T. rex, suggesting a weaker bite. The teeth are likewise blunter and more laterally compressed, while the post orbital crests are less prominent. Likewise, the skeletal anatomy showcases shared characteristics with Tarbosaurus and Zhuchengtyrannus. The validity of T. mcraeensis was questioned by other researchers in 2025. Morrison and colleagues noted the uncertainty in the previous age estimate and argued that the inclusion of the titanosaurian fossil (cf.
H2S ⇌ HS− + H+ Hydrogen sulfide gas and the hydrosulfide anion are extremely toxic to mammals, due to their inhibition of the oxygen-carrying capacity of hemoglobin and certain cytochromes in a manner analogous to cyanide and azide.
== Discovery == In the year 1975, timoprazole was found to inhibit acid secretion irrespective of stimulus, extracellular or intracellular. Studies on timoprazole revealed enlargement of the thyroid gland due to inhibition of iodine uptake as well as atrophy of the thymus gland. A literature search showed that some substituted mercapto-benzimidazoles had no effect on iodine uptake and introduction of such substituents into timoprazole resulted in an elimination of the toxic effects, without reducing the antisecretory effect. A derivative of timoprazole, omeprazole, was discovered in 1979, and was the first of a new class of drug that control acid secretion in the stomach, a proton pump inhibitor (PPI). Addition of 5-methoxy-substitution to the benzimidazole moiety of omeprazole was also made and gave the compound much more stability at neutral pH. In 1980, an Investigational New Drug (IND) application was filed and omeprazole was taken into Phase III human trials in 1982. A new approach for the treatment of acid-related diseases was introduced, and omeprazole was quickly shown to be clinically superior to the histamine H2 receptor antagonists, and was launched in 1988 as Losec in Europe, and in 1990 as Prilosec in the United States. In 1996, Losec became the world's biggest ever selling pharmaceutical, and by 2004 over 800 million patients had been treated with the drug worldwide.
Sources: en.wikipedia.org
An androgen prohormone, or proandrogen, is a prohormone (or prodrug) of an anabolic-androgenic steroid (AAS). They can be prohormones of testosterone or of synthetic AAS, for example, nandrolone (19-nortestosterone). Dehydroepiandrosterone (DHEA), DHEA sulfate (DHEA-S), and androstenedione may all be considered proandrogens of testosterone. Since 2005, the use of steroid precursors (prohormones) has been illegal in the U.S.
Chromatography is a widely used technique for protein purification, allowing for the separation of proteins based on various properties, including charge, size, and binding affinity. Here are the main types of chromatography used in protein purification:
Reynolds was powerless to prevent the inevitable; although leading at half-time, Geelong kicked five goals to Essendon's two points in the third quarter to set up victory by 11 points. Essendon slumped to 8th in 1952, but Coleman was in strong form, managing 103 goals for the year. Two seasons later, Coleman's career was ended after he dislocated a knee during the Round 8 clash with the North Melbourne Football Club at Essendon. Aged just 25, he had kicked 537 goals in only 98 VFL games. Following Coleman's career-ending knee injury, Essendon won no further premierships in the 1950s. In 1957, Essendon defeated Melbourne by 16 points in the Second Semi-Final, but lost the grand final to Melbourne by 61 points. The 1959 season ended with a 37-point grand final loss to Melbourne. Essendon would win their next premiership three years later in 1962.
Rowe, Federal Narcotics Laws and the War on Drugs: Money Down a Rat Hole. Binghamton, NY: Haworn Press, 2006. Eric Schneider, "The Drug War Revisited", Berfrois, November 2, 2011. Peter Dale Scott and Jonathan Marshall, Cocaine Politics: Drugs, Armies, and the CIA in Central America. Berkeley, CA: University of California Press, 1911. Dominic Streatfeild, Cocaine: An Unauthorized Biography. Macmillan, 2003. Douglas Valentine, The Strength of the Wolf: The Secret History of America's War on Drugs. New York: Verso, 2004.
==== Cofactors ==== Protein enzymes catalyze various chemical reactions, but over half of them incorporate cofactors to facilitate and diversify their catalytic activities. Cofactors are essential in biology, as they are based largely on nucleotides rather than amino acids. Ribozymes use nucleotide cofactors to create metabolism, with two basic choices: non-covalent binding or covalent attachment. Both approaches have been demonstrated using directed evolution to reinvent RNA dupes of protein-catalyzed processes. Lorsch and Szostak investigated ribozymes that could phosphorylate themselves and use ATP-γS as a substrate. However, only one of the seven classes of selected ribozymes had detectable ATP affinity, indicating that the ability to bind ATP was compromised. NAD+- dependent redox ribozymes were also evaluated. The selected ribozyme had a rate of enhancement of more than 107 fold and was proven to catalyze the reverse reaction - benzaldehyde reduction by NADH. Since the usage of adenosine as a cofactor is prevalent in current metabolism and is likely to have been common in the RNA world, these discoveries are essential for the evolution of metabolism in the RNA world.
Sources: en.wikipedia.org
=== Pharmacokinetics === Bromazepam is reported to be metabolized by a hepatic enzyme belonging to the cytochrome P450 family of enzymes. In 2003, a team led by Oda Manami at Oita Medical University reported that CYP3A4, a member of the Cytochrome P450 family, was not the responsible enzyme since itraconazole, a known inhibitor of CYP3A4, did not affect its metabolism. In 1995, J. van Harten at the Solvay Pharmaceutical Department of Clinical Pharmacology in Weesp reported that fluvoxamine, which is a potent inhibitor of CYP1A2, a less potent CYP3A4 inhibitor, and a negligible inhibitor of CYP2D6, does inhibit its metabolism. The major metabolite of bromazepam is hydroxybromazepam, which is an active agent too and has a half-life approximately equal to that of bromazepam.
In 2022, Biden blocked a national railroad strike planned by multiple labor unions. During the United Auto Workers strike, he expressed support for the workers. Biden joined striking UAW workers' picket line in Michigan, becoming the first president to join a picket line. He refused to block a port strike from the International Longshoremen's Association in October 2024. Over the course of five days in March 2023, three small- to mid-size U.S. banks failed, triggering a sharp decline in global bank stock prices and swift response by regulators to prevent potential global contagion. After Silicon Valley Bank collapsed, the first to do so, Biden expressed opposition to a bailout by taxpayers. He claimed that the partial rollback of Dodd-Frank regulations contributed to the bank's failure. At the beginning of the 118th Congress, Biden and congressional Republicans engaged in a standoff after the U.S. hit its debt limit, which raised the risk that the U.S. would default on its debt. Biden and House speaker Kevin McCarthy struck a deal to raise the debt limit, the Fiscal Responsibility Act of 2023, which suspended the debt limit until January 2025. Biden signed it on June 3, averting a default. The deal was generally seen as favorable to Biden. Biden extended the COVID-19 student loan pause through September 2023, with an "on ramp" period that extended some of the pause's protections against credit reporting, collection efforts, and late payment fees through September 30, 2024.
==== Andrea Cozzolino ==== Andrea Cozzolino's legal immunity was also removed by the European Parliament on 2 February 2023, when Andrea Cozzolino was in Italy. Cozzolino was arrested on 10 February 2023, after leaving a hospital in Naples where he was being treated for heart problems; he was taken to Poggioreale prison, but later allowed to go home under house-arrest. Cozzolino's lawyer Dimitri De Béco issued a statement that Cozzolino opposed being extradited to Belgium, because of the Belgian justice "way of proceeding". Cozzolino has repeatedly denied any wrong-doing. On 14 February, a Naples court granted a request from Cozzolino's lawyers to postpone the extradition hearing to 28 February so that the court could check the prison in Belgium that Cozzolino would be put in if extradited. In June he flew to Brussels and was placed by a Judge on parole, with conditions attached.
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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.
Reports describe effects on GABA-A receptor expression, monoamine turnover, and neurotrophic factor levels. These are proposed mechanisms drawn mainly from animal models. No single molecular target has been established.