Enkephalinase comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-07-07. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Free peptide form |
| Molecular mass | About 751.9 Da | Calculated average mass |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form TKPRPGP |
| Structural basis | Tuftsin analogue | Extended version of a natural tetrapeptide |
| Development origin | Russian Academy of Sciences | Work carried out from the 1980s onward |
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.
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
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.
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.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
Quality assessment of Selank samples typically combines purity determination with identity confirmation and counter-ion analysis. Purity is usually reported as a percentage by chromatographic area, with values above 95 percent often quoted for research-grade material. Water content and residual solvents are checked in lyophilized batches because they affect both stability and accurate mass determination. A reported purity figure does not by itself establish that a sample is the intended sequence, so orthogonal methods are needed to rule out sequence isomers or truncation products.
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.
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.
Neuromuscular drugs are chemical agents that are used to alter the transmission of nerve impulses to muscles, causing effects such as temporary paralysis of targeted skeletal muscles. Most neuromuscular drugs are available as quaternary ammonium compounds which are derived from acetylcholine (ACh). This allows neuromuscular drugs to act on multiple sites at neuromuscular junctions, mainly as antagonists or agonists of post-junctional nicotinic receptors. Neuromuscular drugs are classified into four main groups, depolarizing neuromuscular blockers, non-depolarizing neuromuscular blockers, acetylcholinesterase inhibitors, and butyrylcholinesterase inhibitors. Clinically, neuromuscular drugs are used in anesthesia to cause paralysis of targeted skeletal muscles. It is most commonly applied in endotracheal intubation by reducing the incidence of hoarseness in vocal cords and esophageal injuries. It is also applied to improve surgical operating conditions by aiding mechanical ventilation in patients with lowered lung compliance. Other than surgical indications, neuromuscular drugs can also be indicated for the use of Alzheimer's disease, Parkinson's disease, etc. Common adverse effects of neuromuscular drugs include abnormal heart rate, blood pressure, and cardiac output.
Glutamate has a long history in cooking. Fermented fish sauces (garum), which are rich in glutamate, were used widely in ancient Rome, fermented barley sauces (murri) rich in glutamate were used in medieval Byzantine and Arab cuisine, and fermented fish sauces and soy sauces have histories going back to the third century in China. Cheese varieties are rich in glutamate and umami flavor. In the late 1800s, chef Auguste Escoffier, who opened restaurants in Paris and London, created meals that combined umami with salty, sour, sweet, and bitter tastes. However, he did not know the chemical source of this unique quality. Umami was first scientifically identified in 1908 by Kikunae Ikeda, a professor of the Tokyo Imperial University. He found that glutamate was responsible for the palatability of the broth from kombu seaweed. He noticed that the taste of kombu dashi was distinct from sweet, sour, bitter, and salty and named it umami. Shintaro Kodama, a disciple of Ikeda, discovered in 1913 that dried bonito flakes (a type of tuna) contained another umami substance. This was the ribonucleotide IMP. In 1957, Akira Kuninaka realized that the ribonucleotide GMP present in shiitake mushrooms also conferred the umami taste. One of Kuninaka's most important discoveries was the synergistic effect between ribonucleotides and glutamate. When foods rich in glutamate are combined with ingredients that have ribonucleotides, the resulting taste intensity is higher than would be expected from merely adding the intensity of the individual ingredients.
They become more frequent with advancing gestational age and are therefore commonly encountered in mature term placentas. Their presence alone is physiological; only a diffuse or excessive increase relative to gestational age may indicate abnormal villous maturation or maternal vascular malperfusion.
Sources: en.wikipedia.org
Wound licking is an instinctive response in humans and many other animals to cover an injury or second degree burn with saliva. Dogs, cats, small rodents, horses, and primates, including humans, all lick wounds. Saliva contains tissue factor which promotes the blood clotting mechanism. The enzyme lysozyme is found in many tissues and is known to attack the cell walls of many gram-positive bacteria, aiding in defense against infection. Tears are also beneficial to wounds due to the lysozyme enzyme. However, there are also infection risks due to bacteria in the mouth.
=== Pharmacokinetics === Absorption of topical corticosteroids depends on several factors such as the vehicle, or delivery system used by the drug, the integrity of the epidermal barrier, and whether or not an occlusive bandage is used in combination with the drug. The absorption of topical betamethasone dipropionate is theoretically minuscule; however, if absorbed it follows the same pharmacokinetic profile as is typical of systemic corticosteroids. It is metabolized primarily by the liver by hydrolysis to its metabolites betamethasone 17-monopropionate (primary) and betamethasone and the 6β-hydroxy derivatives of those metabolites, and it is excreted primarily by the kidneys.
== Clinical trials == Remogliflozin etabonate was shown to enhance urinary glucose excretion in rodents and humans. Early studies in diabetics improved plasma glucose levels. Remogliflozin etabonate has been studied at doses up to 1000 mg. A pair of 12-week phase 2b randomized clinical trials of diabetics published in 2015, found reductions in glycated hemoglobin and that it was generally well tolerated. In a meta-analysis published by Dutta et al. involving data from 3 randomized controlled trials (535 patients), remogliflozin was noted to have similar glycaemic efficacy (reduction in HbA1c and fasting glucose) as compared to dapagliflozin and pioglitazone. A study concluded that concomitant administration of remogliflozin etabonate, either 500 mg or 750 mg BID (twice a day), with metformin 2000 mg BID was safe and effective in patients with type 2 diabetes mellitus during the observation period.
Sources: en.wikipedia.org
=== Generic names === Nandrolone is the generic name of the drug and its INNTooltip International Nonproprietary Name, BANTooltip British Approved Name, DCFTooltip Dénomination Commune Française, and DCITTooltip Denominazione Comune Italiana. The formal generic names of nandrolone esters include nandrolone cyclohexylpropionate (BANMTooltip British Approved Name), nandrolone cyclotate (USANTooltip United States Adopted Name), nandrolone decanoate (USANTooltip USAN, USPTooltip United States Pharmacopeia, BANMTooltip British Approved Name, JANTooltip Japanese Accepted Name), nandrolone laurate (BANMTooltip British Approved Name), nandrolone phenpropionate (USPTooltip United States Pharmacopeia), and nandrolone phenylpropionate (BANMTooltip British Approved Name, JANTooltip Japanese Accepted Name).
=== Spray drug testing === Spray (sweat) drug test kits are non-invasive. It is a simple process to collect the required specimen, no bathroom is needed, no laboratory is required for analysis, and the tests themselves are difficult to manipulate and relatively tamper-resistant. The detection window is long and can detect recent drug use within several hours. There are also some disadvantages to spray or sweat testing. There is not much variety in these drug tests, only a limited number of drugs can be detected, prices tend to be higher, and inconclusive results can be produced by variations in sweat production rates in donors. They also have a relatively long specimen collection period and are more vulnerable to contamination than other common forms of testing.
Because impact factor is commonly accepted as a proxy for research quality, some journals adopt editorial policies and practices, some acceptable and some of dubious purpose, to increase their impact factor. For example, journals may publish a larger percentage of review articles which generally are cited more than research reports. Research undertaken in 2020 on dentistry journals concluded that the publication of "systematic reviews have significant effect on the Journal Impact Factor ... while papers publishing clinical trials bear no influence on this factor. Greater yearly average of published papers ... means a higher impact factor." Journals may also attempt to limit the number of "citable items"—i.e., the denominator of the impact factor equation—either by declining to publish articles that are unlikely to be cited (such as case reports in medical journals) or by altering articles (e.g., by not allowing an abstract or bibliography in hopes that Journal Citation Reports will not deem it a "citable item"). As a result of negotiations over whether items are "citable", impact factor variations of more than 300% have been observed. Items considered to be uncitable—and thus are not incorporated in impact factor calculations—can, if cited, still enter into the numerator part of the equation despite the ease with which such citations could be excluded. This effect is hard to evaluate, for the distinction between editorial comment and short original articles is not always obvious. For example, letters to the editor may be part of either class.
Sources: en.wikipedia.org
It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.
The core four residues correspond to tuftsin, which occurs naturally as part of immunoglobulin G. The full seven-residue sequence, however, is not a known endogenous peptide. It is a laboratory-designed analogue intended to combine tuftsin-like activity with greater resistance to breakdown.
No single receptor has been confirmed as the primary target. Reports describe involvement of the GABAergic system, interference with enkephalin degradation, and shifts in neurotrophic factor expression. Because these observations come from different models and assays, they have not yet been integrated into one accepted mechanism.
Selank is a synthetic peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.