A practical reference on amino acid sequence: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-02-13. Anything still debated is marked as such rather than presented as settled.
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.
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.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic heptapeptide | Stabilized analog of tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form: TKPRPGP |
| Molecular formula | C33H57N11O9 | Monoisotopic mass about 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as lyophilized solid |
| Solubility | Freely soluble in water | Also soluble in common polar solvents |
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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
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.
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
Because 10 to 30 percent of older people may be unable to effectively absorb vitamin B12 naturally occurring in foods, those older than 50 years should meet their RDA mainly by consuming foods fortified with vitamin B12 or a supplement containing vitamin B12. As for safety, tolerable upper intake levels (known as ULs) are set for vitamins and minerals when evidence is sufficient. In the case of vitamin B12 there is no UL, as there is no human data for adverse effects from high doses. Collectively the EARs, RDAs, AIs, and ULs are referred to as dietary reference intakes (DRIs). The European Food Safety Authority (EFSA) refers to the collective set of information as "dietary reference values", with population reference intake (PRI) instead of RDA, and average requirement instead of EAR. AI and UL are defined by EFSA the same as in the United States. For women and men over age 18, the adequate intake (AI) is set at 4.0 μg/day. AI for pregnancy is 4.5 μg/day, and for lactation 5.0 μg/day. For children aged 1–14 years, the AIs increase with age from 1.5 to 3.5 μg/day. These AIs are higher than the U.S. RDAs. The EFSA also reviewed the safety question and reached the same conclusion as in the United States—that there was not sufficient evidence to set a UL for vitamin B12. The Japan National Institute of Health and Nutrition set the RDA for people ages 12 and older at 2.4 μg/day. The World Health Organization also uses 2.4 μg/day as the adult recommended nutrient intake for this vitamin. For U.S.
== Health concerns == Energy drinks have been associated with health risks, such as masking the effects of intoxication when mixed and consumed with alcohol, and excessive or repeated consumption can lead to cardiac and psychiatric conditions. However, the European Food Safety Authority (EFSA) concluded that an adequate consumption of Monster and other popular energy drinks is safe and that the amount of caffeine in standard Monster cans is unlikely to interact adversely with other typical constituents of energy drinks or with alcohol. Energy drinks have the effects that caffeine and sugar give, but there is no distinct evidence that the wide variety of other ingredients has any effect. In December 2011, 14-year-old Anais Fournier died of "cardiac arrhythmia due to caffeine toxicity" after drinking two 24 US fluid ounces (710 mL) cans of Monster Energy drink containing 240 mg of caffeine per can. Fournier had a pre-existing heart condition, as well as Ehlers–Danlos syndrome. In October 2012, her parents sued the company. Monster Energy has insisted that its energy drink played no role in Fournier's death. A request under the U.S. Freedom of Information Act revealed that from 2003 to 2012 the Food and Drug Administration (FDA) had received reports of five deaths occurring after drinking Monster Energy. The reports did not prove a causal link between the drink and any health problems. In May 2015, the Food Safety and Standards Authority of India (FSSAI) banned the sale of Monster and other energy drinks that contained both caffeine and ginseng.
BASF operates in a variety of markets. As of 2020 its business is organized in the segments of Chemicals, Plastics, Performance Products, Functional Solutions, Agricultural Solutions, and Oil and Gas.
Sources: en.wikipedia.org
=== Subspecies === Sixteen subspecies are traditionally recognized; however, a 2015 genetic study did not support designating some of these, such as the Florida black bear, as distinct subspecies. Listed alphabetically according to subspecific name:
=== Names === Etilefrine is the generic name of the drug and its INNTooltip International Nonproprietary Name and BANTooltip British Approved Name, while étiléfrine is its DCFTooltip Dénomination Commune Française and etilefrina is its DCITTooltip Denominazione Comune Italiana. In the case of the hydrochloride salt, its generic name is etilefrine hydrochloride and this is its BANMTooltip British Approved Name and JANTooltip Japanese Accepted Name. Synonyms of etilefrine include ethylnorphenylephrine, ethylphenephrine, etiladrianol, aethyladrianol, and M-I-36. Brand names of the drug include Effortil, Circupon, Apocretin, Palsamin, Kertasin, Pressoton, Effoless, and Sanlephrin.
== Prevention == The American College of Obstetricians and Gynecologists recommends all people thinking of becoming pregnant be tested to see if they have thalassemia. Genetic counseling and genetic testing are recommended for families who carry a thalassemia trait. Understanding the genetic risk, ideally before a family is started, would hopefully allow families to understand more about the condition and make an informed decision that is best for their family. A screening policy exists in Cyprus to reduce the rate of thalassemia, which, since the program's implementation in the 1970s (also including prenatal screening and abortion), has reduced the number of children born with the disease from one of every 158 births to almost zero. Greece also has a screening program to identify people who are carriers. In Iran as a premarital screening, the man's red cell indices are checked first. If he has microcytosis (mean cell hemoglobin < 27 pg or mean red cell volume < 80 fl), the woman is tested. When both are microcytic, their hemoglobin A2 concentrations are measured. If both have a concentration above 3.5% (diagnostic of thalassemia trait) they are referred to the local designated health post for genetic counseling. Large-scale awareness campaigns are being organized in India both by government and non-government organizations to promote voluntary premarital screening, with marriage between carriers strongly discouraged.
For instance, the Lois lab at Caltech is using engineered artificial ligands and receptors on neurons to trace information flow in the brain. They are specifically using ligand-induced intramembrane proteolysis to unravel the wiring of the brain in Drosophila and other models. When the artificial ligand on one neuron binds to the receptor on another, GFP expression is activated in the acceptor neuron demonstrating the usefulness of ligand binding assays in neuroscience and biology.
Sources: en.wikipedia.org
Tryptamines are derivatives of tryptamine and are structurally related to the monoamine neurotransmitter serotonin (also known as 5-hydroxytryptamine or 5-HT). Many tryptamines act as non-selective serotonin receptor agonists, including of the serotonin 5-HT2A receptor. Some tryptamines also act as monoamine releasing agents, including of serotonin, norepinephrine, and/or dopamine. Examples of psychedelic tryptamines include psilocin and psilocybin, dimethyltryptamine (DMT), 5-MeO-DMT, bufotenin, α-methyltryptamine (αMT), 4-AcO-DMT (psilacetin), 4-HO-MET, 5-MeO-MiPT, and 5-MeO-DiPT, among others. Harmala alkaloids like harmaline and iboga-type alkaloids like ibogaine are cyclized tryptamines and may also be considered hallucinogenic tryptamines.
=== Early career === Prismall grew up in Werribee, Victoria. He was drafted from the Western Jets Under 18s. He was Geelong's first pick in the 2004 draft, pick 32 overall, coincidentally this is the number he wore on his guernsey. The number 32 was made famous by Geelong player Garry Hocking. Prismall spent all of the 2005 season playing in the Victorian Football League (VFL) for Geelong's VFL team.
The Beltrán-Leyva Cartel was founded by the four Beltrán Leyva brothers: Marcos Arturo, Carlos, Alfredo and Héctor. In 2004 and 2005, cartel leader Arturo Beltrán Leyva led groups of enforcers to compete for trafficking routes in northeastern Mexico against the Sinaloa Cartel. The Beltrán-Leyva Cartel infiltrated Mexico's political, judicial, and police institutions, including the Interpol in Mexico, to feed classified information about anti-drug operations against its rivals. Following the 2009 killing of Arturo Beltrán Leyva, the cartel entered into an internal power struggle between Arturo's brother, Héctor Beltrán Leyva, and his top enforcer Edgar Valdez Villarreal. Meanwhile, the cartel continued to dissolve with factions such as the South Pacific Cartel, La Mano Con Ojos, Independent Cartel of Acapulco, and La Barredora forming and the latter two cartels starting yet another intra-Beltrán Leyva Cartel conflict. The Mexican Federal Police considers the cartel to have been disbanded, and their last leader, Héctor Beltrán Leyva, was captured in October 2014.
== Physiological effects == Maintenance of the ECF volume (space), and its subcompartment the vascular space, is crucial for survival. These compartments are maintained within a narrow range, despite wide variations in dietary sodium intake. There are three volume regulating systems: two salt saving systems, the renin angiotensin aldosterone system (RAAS) and the renal sympathetic system (RSS); and the salt excreting natriuretic peptide (NP) hormone system. When the vascular space contracts, the RAAS and RSS are "turned on"; when the atria expand, NPs are "turned on". Each system also suppresses its counteracting system(s). NPs are made in cardiac, intestinal, renal, and adrenal tissue: ANP in one of a family of cardiac NPs: others are BNP, CNP, and DNP. ANP binds to a specific set of receptors – ANP receptors. Receptor-agonist binding causes the increase in renal sodium excretion, which results in a decreased ECF and blood volume. Secondary effects may be an improvement in cardiac ejection fraction and reduction of systemic blood pressure.
Although one-letter symbols are included in the table, IUPAC–IUBMB recommend that "Use of the one-letter symbols should be restricted to the comparison of long sequences". The one-letter notation was chosen by IUPAC-IUB based on the following rules:
Sources: en.wikipedia.org
Selank is a synthetic heptapeptide designed as a stabilized analog of the natural tetrapeptide tuftsin. It has been investigated mainly for anxiolytic and cognitive effects. It is not an approved pharmaceutical in most countries.
It was developed in Russia, at the Institute of Molecular Genetics of the Russian Academy of Sciences, during the 1990s. Most published research originates from Russian institutions. Independent international replication remains limited.
Tuftsin is a natural tetrapeptide with the sequence Thr-Lys-Pro-Arg that participates in immune signaling. Selank extends that sequence with Pro-Gly-Pro at the C-terminus. The added residues are linked to greater resistance to enzymatic breakdown.
Reports describe modulation of GABA signalling, changes in monoamine turnover and effects on neurotrophic factor expression. These observations come mainly from animal and cell studies. A single unifying mechanism has not been demonstrated.