If you have been reading about Selank and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-05-16. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| 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 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.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
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.
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.
==== Alleged and observed psychological disorders ==== Penis panic (koro in Malaysian/Indonesian) — delusion of shrinkage of the penis and retraction into the body. This appears to be culturally conditioned and largely limited to Ghana, Sudan, China, Japan, Southeast Asia, and West Africa. In April 2008, Kinshasa, Democratic Republic of Congo, the West African police arrested 14 suspected victims (of penis snatching) and sorcerers accused of using black magic or witchcraft to steal (make disappear) or shrink men's penises to extort cash for cure, amid a wave of panic. Arrests were made in an effort to avoid bloodshed seen in Ghana a decade before, when 12 penis snatchers were beaten to death by mobs. Penis envy — the contested Freudian belief of all women inherently envying men for having penises.
=== Post-Spark Therapeutics === In January 2021, High joined Asklepios Biopharmaceutical, or AskBio, a clinical-stage adeno-associated virus (AAV) gene therapy company and wholly owned subsidiary of Bayer AG, as the company's new President of Therapeutics and as a board member for AskBio. In 2024 she became Chief Executive Officer of the genetic medicine company RhyGaze.
Molybdenum forms chemical compounds in oxidation states −4 and from −2 to +6. Higher oxidation states are more relevant to its terrestrial occurrence and its biological roles, mid-level oxidation states are often associated with metal clusters, and very low oxidation states are typically associated with organomolybdenum compounds. The chemistry of molybdenum and tungsten show strong similarities. The relative rarity of molybdenum(III), for example, contrasts with the pervasiveness of the chromium(III) compounds. The highest oxidation state is seen in molybdenum(VI) oxide (MoO3), whereas the normal sulfur compound is molybdenum disulfide MoS2.
In the laboratory, the strength of this interaction can be measured by finding the melting temperature Tm necessary to break half of the hydrogen bonds. When all the base pairs in a DNA double helix melt, the strands separate and exist in solution as two entirely independent molecules. These single-stranded DNA molecules have no single common shape, but some conformations are more stable than others.
Sources: en.wikipedia.org
== Methods == The production of biologically interesting molecules using cloning and culturing methods allows the study and manufacture of relevant molecules. Except for excreted molecules, cells producing molecules of interest must be disrupted. This page discusses various methods. Another method of disruption is called cell unroofing.
In addition, DMT is a potent serotonin releasing agent with an EC50Tooltip half-maximal effective concentration value of 81–114 nM and an EmaxTooltip maximal efficacy of 78%. As with other so-called "classical hallucinogens", a large part of DMT psychedelic effects can be attributed to a functionally selective activation of the 5-HT2A receptor. DMT concentrations eliciting 50% of its maximal effect (half maximal effective concentration = EC50) at the human 5-HT2A receptor in vitro are in the 0.118–0.983 μmol/L range. This range of values coincides well with the range of concentrations measured in blood and plasma after administration of a fully psychedelic dose. DMT is one of the only psychedelics that isn't known to produce tolerance to its hallucinogenic effects. The lack of tolerance with DMT may be related to the fact that, unlike other psychedelics such as LSD and DOI, DMT does not desensitize serotonin 5-HT2A receptors in vitro. This may be due to the fact that DMT is a biased agonist of the serotonin 5-HT2A receptor. More specifically, DMT activates the Gq signaling pathway of the serotonin 5-HT2A receptor without significantly recruiting β-arrestin2. Activation of β-arrestin2 is linked to receptor downregulation and tachyphylaxis. Similarly to DMT, 5-MeO-DMT is a biased agonist of the serotonin 5-HT2A receptor, with minimal β-arrestin2 recruitment, and likewise has been associated with little tolerance to its hallucinogenic effects. On the other hand, the lack of apparent tolerance of DMT and similar agents may simply be related to their very short durations.
Narrated by Piers Gibbon, produced by Will Aslett, directed by Peter Webber, made with Discovery Channel 12 April Living Dangerously, about people who take risks, if that involves low monoamine oxidase, with John Henry (toxicologist); two base jumpers, John and Elliott, climb a 500 ft television transmitter in December 1998; men have lower levels of MAO than women, and MAO increases with age, so men in their 20s have the least aversion to risk; possible dangers of the Minulet contraceptive (ethinylestradiol/gestodene); health scares may be out of proportion to the risk involved, and is overegging the pudding. Directed by Chris Wells, produced by Hilary Lawson, made by TVF Media with the Discovery Channel 19 April Riddle of the Leaning Tower, about the Leaning Tower of Pisa; in 1995, the tower was moving at 1mm a year; civil engineer John Burland; construction began in 1172, and construction stopped for 100 years; Piero Pierotti of the University of Pisa; the 1997 Umbria and Marche earthquake took place on 26 September 1997; haste was required, so in 1998 soil extraction was approved to attempt to moderate the lean of the tower; soil extraction began in February 1999, and the tower began to move.
Sources: en.wikipedia.org
The first stable human-animal chimeras to actually exist were first created by Shanghai Second Medical University scientists in 2003, the result of having fused human cells with rabbit eggs. In 2017 researchers led by the Salk Institute published in Cell experiments using CRISPR-Cas9 gene editing to aid in blastocyst complementation with pluripotent stem cells in various mammals. This included a human-pig chimera reported to have 0.001% human cells, with the remaining cells pig. The embryo consisted mostly pig cells and some human cells. Scientists stated that they hope to use this technology to address the shortage of donor organs. In 2021, a human-monkey chimera was created as a joint project between the Salk Institute in the US and Kunming University in China and published in the journal Cell. This involved injecting human stem cells into monkey embryos. The embryos were only allowed to grow for a few days, but the study demonstrated that some of these embryos still had human stem cells surviving at the end of the experiments. Because humans are more closely related to monkeys than other animals, it means there is more chance of the chimeric embryos surviving for longer periods so that organs can develop. The project has opened up possibilities into organ transplantation as well as ethical concerns particularly concerning human brain development in primates.
Wang, N.; He, Y.; Liu, S.; Makarcyzk, M. J.; Lei, G.; Chang, A.; Alexander, P. G.; Hao, T.; Padget, A. M.; De Pedro, N.; Menelaos, T.; Lin, H. (2022). "Engineering Osteoarthritic Cartilage Model". Science China Life Sciences. 65 (2): 309–327. doi:10.1007/s11427-021-1933-7. PMC 10077511. PMID 34109475. S2CID 235393377. Jogi, R.; Tager, M. J.; Perez, D.; Tsapekos, M. (2021). "Bovine Colostrum, Telomeres and Skin aging". Journal of Drugs in Dermatology. 20 (5): 538–545. doi:10.36849/JDD.5851. PMID 33938706. Shafa, M.; Walsh, T.; Panchalingam, K. M.; Richardson, T.; Menendez, L.; Tian, X.; Suresh Babu, S.; Dadgar, S.; Beller, J.; Yang, F.; Baghbaderani, B. A. (2019). "Long-term Stability and Differentiation Potential of Cryopreserved CGMP-compliant Human Induced Pluripotent Stem Cells". International Journal of Molecular Sciences. 21 (1): 108. doi:10.3390/ijms21010108. PMC 6982271. PMID 31877913. Samuel, P.; Tsapekos, M.; De Pedro, N.; Liu, A. G.; Casey Lippmeier, J.; Chen, S. (2022). "Ergothioneine Mitigates Telomere Shortening under Oxidative Stress Conditions". Journal of Dietary Supplements. 19 (2): 212–225. doi:10.1080/19390211.2020.1854919. PMID 33287595. S2CID 227953602. Mehkri, S.; Perez, Diego; Najarro, Pilar; Tsapekos, Menelaos; Bopanna, K. N. (July 2019). "Effect of Lutein (Lute-gen®) on Proliferation Rate and Telomere Length In Vitro and Possible Mechanism of Action". International Journal of Biology Research. 4 (3): 84–91. Phillippe, M.; Sawyer, M. R.; Edelson, P. K. (2019). "The Telomere Gestational Clock". American Journal of Obstetrics and Gynecology.
The major difference between quantification methods is some use labels on the peptides such as tandem mass tags (TMT) or dimethyl labels which are used to identify which cell a certain protein came from (proteins coming from each cell have a different label) while others do not use labels but rather quantify cells individually. The mass spectroscopy data is then analyzed by running data through databases that count the peptides identified to quantify protein levels. These methods are very similar to those used to quantify the proteome of bulk cells, with modifications to accommodate the very small sample volume.
== Interactions == A number of drugs add to the low blood pressure caused by nitrovasodilators: for example, other vasodilators, antihypertensive drugs, tricyclic antidepressants, antipsychotics, general anaesthetics, as well as ethanol. Combination with PDE5 inhibitors, including sildenafil (Viagra), is contraindicated because potentially life-threatening hypotension may occur. Nitrates increase the bioavailability of dihydroergotamine (DHE). High DHE levels may result in coronary spasms in patients with coronary disease. This interaction is not described for non-nitrate nitrovasodilators.
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.
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.