Everything below concerns reverse-phase HPLC. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-06-29. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Dry storage temperature | -20 C or below | Sealed, desiccated, protected from light |
| Solution stability | Hours to days at 2-8 C | Depends on buffer and microbial load |
| Preferred pH range | Near neutral to slightly acidic | Alkaline pH accelerates hydrolysis |
| Main degradation routes | Hydrolysis and deamidation | No cysteine or methionine in sequence |
| Identity confirmation | Electrospray mass spectrometry | Observed mass compared with 751.9 Da |
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.
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.
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.
Lithium is known to be a potential precipitant of serotonin syndrome in people concurrently on serotonergic medications such as antidepressants, buspirone and certain opioids such as pethidine (meperidine), tramadol, oxycodone, fentanyl and others. Lithium co-treatment is also a risk factor for neuroleptic malignant syndrome in people on antipsychotics and other antidopaminergic medications. High doses of haloperidol, fluphenazine, or flupenthixol may be hazardous when used with lithium; irreversible toxic encephalopathy has been reported. Indeed, these and other antipsychotics have been associated with an increased risk of lithium neurotoxicity, even with low therapeutic lithium doses. A high incidence of seizures has been reported with serotonergic psychedelics like psilocybin and LSD in people taking lithium. In an analysis of online reports, 47% of 62 accounts reported seizures when a psychedelic was taken while on lithium. Of these instances, 39% sought emergency medical treatment.
== Medical uses == Bremelanotide is used for the treatment of generalized hypoactive sexual desire disorder (HSDD) in premenopausal women. Specifically, it is only recommended in those who have the condition without an underlying cause, such as medical, psychiatric, or relationship problems. Researchers have questioned the relevance and validity of the rating scales and outcomes on which bremelanotide was assessed, as well as the drug's effect sizes for these, concluding that benefits may only be modest. It should be used at least 45 minutes before anticipated sexual activity. Only one dose per 24 hours or no more than eight doses per month is recommended. It should be stopped after eight weeks if there is no improvement in sexual desire and associated distress.
== Hormonal regulation == Insulin is a peptide hormone that is critical for managing the body's metabolism. Insulin is released by the pancreas when blood sugar levels rise, and it has many effects that broadly promote the absorption and storage of sugars, including lipogenesis. Insulin stimulates lipogenesis primarily by activating two enzymatic pathways. Pyruvate dehydrogenase (PDH), converts pyruvate into acetyl-CoA. Acetyl-CoA carboxylase (ACC), converts acetyl-CoA produced by PDH into malonyl-CoA. Malonyl-CoA provides the two-carbon building blocks that are used to create larger fatty acids. Insulin stimulation of lipogenesis also occurs through the promotion of glucose uptake by adipose tissue. The increase in the uptake of glucose can occur through the use of glucose transporters directed to the plasma membrane or through the activation of lipogenic and glycolytic enzymes via covalent modification. The hormone has also been found to have long term effects on lipogenic gene expression. It is hypothesized that this effect occurs through the transcription factor SREBP-1, where the association of insulin and SREBP-1 lead to the gene expression of glucokinase. The interaction of glucose and lipogenic gene expression is assumed to be managed by the increasing concentration of an unknown glucose metabolite through the activity of glucokinase. Another hormone that may affect lipogenesis through the SREBP-1 pathway is leptin. It is involved in the process by limiting fat storage through inhibition of glucose intake and interfering with other adipose metabolic pathways.
Tea is an aromatic beverage prepared by infusion of hot or boiling fresh water with fresh or cured leaves of Camellia sinensis, an evergreen shrub native to East Asia that originated in the borderlands of southwestern China, northeast India and northern Myanmar. Tea has a stimulant effect in humans primarily due to its caffeine content. After plain drinking water, tea is the most widely consumed beverage in the world. There are many varieties of tea according to differences in cultivars, processing and blends; some have a cooling, slightly bitter and astringent flavor, while others have taste profiles that include sweet, nutty, floral or grassy notes. Traditionally, tea is made by steeping loose tea leaves in hot water (usually in a teapot or teacup) for a period of time, or in the case of compressed and fermented tea, via decoction (simmering) in a kettle. Convenient preparations, such as tea bag, infuser and press as well as powdered instant tea such as matcha, konacha and chai latte, are also common. Tea is most commonly consumed as a hot beverage in a plain hot water infusion, although it can also be in mixed drink forms, such as milk tea and butter tea, sometimes sweetened with added sugar or sugar substitutes, or alternatively flavored with salt and spices. In modern times, tea can also be served as a cold beverage in the form of iced tea or in soft drink mixtures such as bubble tea. Early credible record of tea drinking dates to the 3rd century AD, in a Chinese medical text written by Eastern Han dynasty physician Hua Tuo.
Kendall was elected to the United States National Academy of Sciences in 1950, and both the American Academy of Arts and Sciences and the American Philosophical Society in 1951. Kendall's career at Mayo ended in 1951, when he reached mandatory retirement age. He moved on to Princeton University, where he was a visiting professor in the Department of Biochemistry. He remained affiliated with Princeton until his death in 1972. In addition to the Nobel Prize, Kendall received other major awards including the Lasker Award, the Passano Foundation Award and the Cameron Prize for Therapeutics of the University of Edinburgh. Kendall received the Golden Plate Award of the American Academy of Achievement in 1966. He was awarded honorary doctorates from the University of Cincinnati, Western Reserve University, Williams College, Yale University, Columbia University, National University of Ireland, and Gustavus Adolphus College.
Sources: en.wikipedia.org
Simple compounds that join to create a macromolecule. For example, fatty acids join to form phospholipids. In turn, phospholipids and cholesterol interact noncovalently in order to form the lipid bilayer. This reaction may be depicted as follows:
=== Medical management === Medical management is usually reserved for horses that do not adequately respond to diet and exercise alone. The two most commonly used drugs for EMS are metformin and levothyroxine sodium. Metformin is a drug used in humans for type II diabetes, and has been shown to improve insulin sensitivity and reduce output of glucose by the liver. However, it has low bioavailability in horses, and does not appear to affect insulin sensitivity at doses that are commonly used. Its current mechanism of action in horses is thought to be a reduction in intestinal glucose absorption, and therefore postprandial glucose levels, when it is given before meals. Levothyroxine, a T4 analogue, improves insulin sensitivity and weight loss in horses. After desired body weight has been reached, horses are slowly weaned off the drug. Although it does not appear to produce signs of hyperthyroidism in horses, safety of long-term usage has not been evaluated.
==== Quarantine/isolation ==== Cats with suspected or diagnosed FPLV should be kept in isolation. This non-enveloped virus is very resistant to environmental conditions and many disinfectants, is highly contagious, and rapidly accumulates in the environment due to high shedding of virus from affected animals. Strict protocols for containment – with isolation, minimal handling, and disinfection of all potential sources of fomites – is warranted. Recovered cats can still shed the virus for up to six weeks and can carry it on their body for prolonged periods.
The asymmetric atom is called a chirality center, a type of stereocenter. A chirality center is also called a chiral center or an asymmetric center. Some sources use the terms stereocenter, stereogenic center, stereogenic atom or stereogen to refer exclusively to a chirality center, while others use the terms more broadly to refer also to centers that result in diastereomers (stereoisomers that are not enantiomers). Compounds that contain exactly one (or any odd number) of asymmetric atoms are always chiral. However, compounds that contain an even number of asymmetric atoms sometimes lack chirality because they are arranged in mirror-symmetric pairs, and are known as meso compounds. For instance, meso tartaric acid (shown on the right) has two asymmetric carbon atoms, but it does not exhibit enantiomerism because there is a mirror symmetry plane. Conversely, there exist forms of chirality that do not require asymmetric atoms, such as axial, planar, and helical chirality. Even though a chiral molecule lacks reflection (Cs) and rotoreflection symmetries (S2n), it can have other molecular symmetries, and its symmetry is described by one of the chiral point groups: Cn, Dn, T, O, or I. For example, hydrogen peroxide is chiral and has C2 (two-fold rotational) symmetry. A common chiral case is the point group C1, meaning no symmetries, which is the case for lactic acid.
Sources: en.wikipedia.org
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.
Hydrolysis of peptide bonds and deamidation of arginine and proline residues are the main degradation routes. Alkaline pH and higher temperatures accelerate both processes. Buffered, near-neutral solutions stored cold generally degrade more slowly than unbuffered ones.
Reverse-phase chromatography gives the clearest single view of related impurities and truncated sequences. Mass spectrometry then confirms that the main peak carries the expected mass. Neither test detects enantiomeric impurities, which require a separate chiral assay.
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.