The short version of intranasal delivery fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-02-28 and is reviewed periodically as new material appears.
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.
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.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
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.
| 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 |
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.
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
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.
== Composition == OFM comprises more than 24 collagens (most notably types I and III), but also contains many growth factors, polysaccharides and proteoglycans that naturally exist as part of the extracellular matrix and play important roles in wound healing and soft tissue repair. The composition includes more than 150 different proteins, including elastin, fibronectin, glycosaminoglycans, basement membrane components, and various growth factors, such as vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF) and platelet derived growth factor (PDGF). OFM has been shown to recruit mesenchymal stem cells, stimulate cell proliferation, angiogenesis and vascularogenesis, and modulate matrix metalloproteinase and neutrophil elastase. The porous structure of OFM has been characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), atomic force microscopy (AFM), histology, Sirius Red staining, small-angle x-ray scattering (SAXS), and micro computerized topography (MicroCT). OFM has been shown to contain residual vascular channels that facilitate blood vessel formation through angioconduction.
== Regulation and composition == CoQ10 is not approved by the U.S. Food and Drug Administration (FDA) for the treatment of any medical condition. However, it is sold as a dietary supplement not subject to the same regulations as medicinal drugs, and is an ingredient in some cosmetics and energy drinks. The manufacture of CoQ10 is not regulated, and different batches and brands may vary significantly.
=== Marriage === Seligman writes: "Unlike money, which has at most a small effect, marriage is robustly related to happiness... In my opinion, the jury is still out on what causes the proven fact married people are happier than unmarried people." (pp. 55–56). Married persons report higher levels of happiness and well-being than single people. Other data has shown a spouse's happiness depends on the happiness of their partner. When asked, spouses reported similar happiness levels to each other. The data also shows the spouses' happiness level fluctuates similarly to one another. If the husband is having a bad week, the wife will similarly report she had a bad week. There is little data on alternatives like polyamory, although one study stated wife order in polygyny did not have a substantial effect on life or marital satisfaction over all. This study also found younger wives were happier than older wives. On the other hand, at least one large study in Germany found no difference in happiness between married and unmarried people. Studies have shown that married couples are consistently happier and more satisfied with their life than those who are single. Some research findings have indicated that marriage is the only real significant bottom-up predictor of life satisfaction for men and women, and that those people who have a higher life satisfaction prior to marriage, tend to have a happier marriage. Self-reported satisfaction typically drops as the years of marriage roll on, particularly for couples who have children compared to those who do not.
Sources: en.wikipedia.org
== Further reading == Juego, Bonn (2017). "The Philippines 2017: Duterte-led authoritarian populism and its liberal-democratic roots" (PDF). Asia Maior; the Journal of the Italian Think Tank on Asia Founded by Giorgio Borsa in 1989. XXVIII. Viella s.r.l. & Associazione Asia Maior: 129–163. ISSN 2385-2526. Archived from the original (PDF) on December 1, 2022. Retrieved December 1, 2022. "The Punisher". Eye for an Eye. (Vice) Bethesda Softworks LLC. Archived from the original on March 10, 2016. Retrieved September 14, 2016.
==== Topical ==== There are several NSAIDs available for topical use, including diclofenac, which may provide symptomatic relief of osteoarthritis. Recessed joints (joints located deep within the body, rather than near the skin surface, such as the hips) may be less responsive to treatment with topical therapies. Transdermal opioid pain medications are not typically recommended in the treatment of osteoarthritis. The use of topical capsaicin to treat osteoarthritis is controversial, as some reviews found benefit while others did not.
== Clinical significance == The enzymes that make and use NAD+ and NADH are important in both pharmacology and the research into future treatments for disease. Drug design and drug development exploits NAD+ in three ways: as a direct target of drugs, by designing enzyme inhibitors or activators based on its structure that change the activity of NAD-dependent enzymes, and by trying to inhibit NAD+ biosynthesis. Because cancer cells utilize increased glycolysis, and because NAD enhances glycolysis, nicotinamide phosphoribosyltransferase (NAD salvage pathway) is often amplified in cancer cells. It has been studied for its potential use in the therapy of neurodegenerative diseases such as Alzheimer's and Parkinson's disease as well as multiple sclerosis. A placebo-controlled clinical trial of NADH (which excluded NADH precursors) in people with Parkinson's failed to show any effect. NAD+ is also a direct target of the drug isoniazid, which is used in the treatment of tuberculosis, an infection caused by Mycobacterium tuberculosis. Isoniazid is a prodrug and once it has entered the bacteria, it is activated by a peroxidase enzyme, which oxidizes the compound into a free radical form. This radical then reacts with NADH, to produce adducts that are very potent inhibitors of the enzymes enoyl-acyl carrier protein reductase, and dihydrofolate reductase. Since many oxidoreductases use NAD+ and NADH as substrates, and bind them using a highly conserved structural motif, the idea that inhibitors based on NAD+ could be specific to one enzyme is surprising.
Most are bound to thyroxine-binding globulin (about 70%), transthyretin (10%), and albumin (15%). Only the 0.03% of T4 and 0.3% of T3 traveling freely have hormonal activity. In addition, up to 85% of the T3 in blood is produced following conversion from T4 by iodothyronine deiodinases in organs around the body. Thyroid hormones act by crossing the cell membrane and binding to intracellular nuclear thyroid hormone receptors TR-α1, TR-α2, TR-β1, and TR-β2, which bind with hormone response elements and transcription factors to modulate DNA transcription. In addition to these actions on DNA, the thyroid hormones also act within the cell membrane or within cytoplasm via reactions with enzymes, including calcium ATPase, adenylyl cyclase, and glucose transporters.
Sources: en.wikipedia.org
== Education == Maroon earned his B.S. degree in anatomy and physiology from Indiana University Bloomington in 1961 and his M.D. from the Indiana University School of Medicine (IUSM) in 1965. He received post-graduate education at IUSM (1966), Georgetown University Hospital (1967), John Radcliffe Hospital (1969), Oxford University, England, IUSM (1971), and the University of Vermont College of Medicine (1972).
== Toxicity == Information on the toxicity of 3-CMC is scarce, with only exploratory cytotoxicity studies conducted. Main concerns regarding toxicity of this compound origin in analogies to chloro-amphetamines (para-chloroamphetamine) which have confirmed neurotoxic effects. B-keto substitution in Cathinones completely alters their metabolism in comparison with amphetamines, rendering such analogies pointless. Recent study investigating toxicity of various chlorinated cathinones on SH-SY5Y human neuroblastoma cells showed LC50 (lower value indicating higher toxicity) of 2.1 mM for 4-MMC, 2.3 mM for 3-CMC and 1 mM for bupropion in study referred to as 3-Cl-TBC. To put that into perspective, similar studies show LC50 for 4-CA sitting around 0.5mM. Between November 2019 and June 2021, the EMCDDA reported ten deaths linked to 3-CMC exposure in Poland (7 cases) and Sweden (3 cases). Other substances were found in six cases, with alcohol being the only additional substance in two cases. Causes of death included multi-organ trauma caused by a traffic accident, toxic effects of 3-CMC, and intoxication with various substances. Details such as dosage and administration routes are lacking.
2,4,6-Triisopropylbenzenesulfonyl azide (trisyl azide) is an organic chemical used as a reagent to supply azide for electrophilic amination reactions, such as for the asymmetric synthesis of unnatural amino acids. Introduction of an azide on the α carbon of carboxylic acid derivatives using trisyl azide is an efficient alternative to electrophilic halogenation followed by nucleophilic substitution using anionic azide. Using an oxazolidinone as chiral auxiliary typically gives good induction of the stereochemistry at the α position. Subsequent reduction converts the α-azide to an α-amine.
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.
Most published work uses intranasal application, either as drops or as a nasal spray. Injection routes appear in a smaller set of animal experiments. Oral use is uncommon in the literature because peptide breakdown and poor absorption limit this route.