Tuftsin 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.
Last reviewed on 2026-04-22. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Identity confirmation | Reversed-phase HPLC retention time versus reference standard | Retention depends on column, gradient, and ion-pairing agent |
| Mass confirmation | Electrospray or MALDI mass spectrometry | Doubly protonated ion near m/z 377 is consistent with about 752 Da |
| Typical purity specification | 95 percent or higher by chromatographic peak area | Lower values suggest truncated or modified peptide species |
| Storage of lyophilized powder | -20 °C, desiccated, protected from light | Powder tolerates long storage better than solution |
| Storage of solution | 2-8 °C for short periods | Freeze-thaw cycling promotes aggregation and surface adsorption |
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.
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.
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.
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.
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
Fluphenazine, sold under the brand name Prolixin among others, is a high-potency typical antipsychotic medication of the phenothiazine class. It is used in the treatment of chronic psychoses such as schizophrenia, and is about equal in effectiveness to low-potency antipsychotics like chlorpromazine. It is also used to treat depression in combination with nortriptyline. In addition to the oral form, fluphenazine comes in decanoate and enanthate depot injection versions for increased adherence. Fluphenazine is given by mouth, intramuscularly, or just under the skin. Common side effects include movement problems, sleepiness, depression and increased weight. Serious side effects may include neuroleptic malignant syndrome, low white blood cell levels, and the potentially permanent movement disorder tardive dyskinesia. In older people with psychosis as a result of dementia it may increase the risk of dying. It may also increase prolactin levels which may result in milk production, enlarged breasts in males, impotence, and the absence of menstrual periods. It is unclear if it is safe for use in pregnancy. Fluphenazine decanoate should not be used by people with severe depression. In up to 40% of those on long term phenothiazines, liver function tests become mildly abnormal. Fluphenazine is a dopamine antagonist, blocking mesolimbic dopamine receptors. Fluphenazine inhibits tubulin polymerization, a property shared with other phenothiazine derivatives including perphenazine, chlorpromazine, trifluoperazine, and triflupromazine.
In November 2015, an FDA Advisory Committee discussed the risks and benefits of fluoroquinolones for the treatment of acute bacterial sinusitis, acute bacterial exacerbation of chronic bronchitis, and uncomplicated UTIs based on new safety information. The new information focused on two or more side effects occurring at the same time and causing the potential for irreversible impairment. The advisory committee concluded that the serious risks associated with the use of fluoroquinolones for these types of uncomplicated infections generally outweighed the benefits for patients with other treatment options. The 21-member joint committee overwhelmingly recommended stronger label warnings on the containers because of rare but sometimes devastating side effects. On 12 May 2016, the FDA issued a drug safety communication advising that fluoroquinolones should be reserved for these conditions only when no other options are available due to potentially permanent, disabling side effects occurring together. The drug safety communication also announced the required labeling updates to reflect this new safety information. The FDA put out another label change in July 2017, strengthening the warnings about potentially disabling adverse effects and limiting use of these drugs to second-line treatments for acute sinusitis, acute bronchitis, and uncomplicated UTIs.
=== Dietary pattern === In general, a healthy dietary pattern is encouraged, and food modifications may be useful in promoting sperm quality. Some studies have concluded that intake of antioxidants is associated with better sperm parameters as high concentrations of reactive oxygen species can negatively affect the sperm. Consumption of an adequate portion of vegetables and fruits, dietary fibers, omega-3, poultry, and low-fat dairy products may help to lessen risk of male infertility. On the other hand, diets that have been negatively associated with male infertility include high intake of potatoes, soy foods, coffee, alcohol, and sweetened beverages. According to a review, higher consumers of cola showed a statistically significant decrease in semen volume. The high starch levels in potatoes promotes oxidative stress along with risk of inflammation from a resulting high glycemic index. Meanwhile, processed meats can possibly contain xenoestrogens and may compromise semen quality. However, additional research is warranted prior to recommending a set dietary regimen in regard to improving sperm parameters. Currently, the only general recommendation that can be made is to adhere to a healthy dietary pattern such as the DASH diet or Mediterranean diet. As low density of the sperm population is usually associated with infertility, hypospermia becomes an infertility issue when one is also identified to have oligospermia. Further semen analysis may be needed prior to being identified as oligospermic.
The amylin receptors (AMYRs) are a family of 3 receptors that are activated by amylin, a peptide hormone secreted together with insulin. They are each composed of a copy of the calcitonin receptor (CTR) bound to a receptor activity-modifying protein (RAMP), forming a heterodimer. They consist of AMY1 (RAMP1 with CTR), AMY2 (RAMP2 with CTR), and AMY3 (RAMP3 with CTR). Activation of these receptors appears to have a number of effects on eating behavior, including triggering feelings of satiation, reducing food intake, decreasing fat storage, and increasing energy usage. These effects have led to research into targeting these receptors with treatments for metabolic diseases and obesity. The amylin receptors are G protein-coupled receptor of the secretin receptor family. Consistent with their calcitonin receptor subunit, they appear to activate Gs alpha subunit pathways, and there have also been reports of Gq alpha subunit coupling. However, methodological difficulties related to amylin’s ability to bind with the calcitonin receptor have led some researchers to express uncertainty about these results.
=== Controversy === On June 21, 2014, actor William Shatner raised an issue with several Engadget editorial staff and their verification status on Twitter. Besides the site's social media editor, John Colucci, Shatner also targeted several junior members of the staff for being "nobodies", unlike some of his actor colleagues who did not bear such distinction. Shatner claimed Colucci and the team were bullying him when giving a text interview to Mashable. Over a month later, Shatner continued to discuss the issue on his Tumblr page, to which Engadget replied by defending its team and discussing the controversy surrounding the social media verification. Twitter's practice and process for verifying accounts came under scrutiny again in 2017 after the company verified the account of white supremacist and far-right political activist, Jason Kessler. Many who criticized Twitter's decision to verify Kessler's account saw this as a political act on the company's behalf. In response, Twitter put its verification process on hold. The company tweeted, "Verification was meant to authenticate identity & voice but it is interpreted as an endorsement or an indicator of importance. We recognize that we have created this confusion and need to resolve it. We have paused all general verifications while we work and will report back soon." As of November 2017, Twitter continued to deny verification of Julian Assange's account following his requests.
Sources: en.wikipedia.org
The advertisement ends with the voiceover: "Join the worldwide celebration, of a man named Arthur". This gave rise to the event now known as Arthur's Day, described as "a series of events and celebrations taking place around the world to celebrate the life and legacy of Arthur Guinness and the much-loved Guinness beer which Arthur brought to the world." Following the COVID-19 pandemic and pub closures, Guinness produced a "Looks Like Guinness" advert in anticipation of pubs reopening in 2021. As of 2024, Guinness is the official beer of the Premier League.
=== 1995–1997: Temporary breakup, new members, Vrijeme Je Da Se Krene and Život Uživo === In 1995, the band briefly broke up, though Bare spent several months performing under the Majke moniker with members of Kojoti as his backing band. Around this time, Bare's wife died following a heroin overdose. Bare fell into a deep depression and started using heroin again as well as drinking heavily to cope with his wife's death. Late that year, the band reformed with a new lineup: Bare on vocals, Kilmister on bass, Čalić and Kruno Domaćinović on guitars, and Tihomir Jalšovec - Chaka on drums. The band released "Vrijeme Je Da Se Krene", their fourth and most commercially successful studio album, on Jabukaton records in 1996. Originally intended to be an EP, this album displayed a softer blues rock sound compared to their old, more aggressive garage rock style. The album had a much more sorrowful feel to it as the band was going through difficult times while recording the album, with Bare dealing with his wife's death, depression and addiction, as well as Kilmister's father dying in the middle of recording. The band utilized session musicians Davor Rodik and Gojko Tomljanović to play pedal steel guitar and keyboards respectively. The album contained several hits, the most famous being "Mene ne zanima", "Odvedi me" and "A ti još plačeš". A music video was filmed for Mene ne zanima, which won a Porin award. The title track and "Baretov Blues" became live staples as well, while original guitarist Ivica Duspara received a writing credit for "Nije lako".
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One way to effectively deal with the inherent multi-physics and the control systems development that is involved when including intelligent systems, is to adopt the V-Model approach to systems development, as has been widely used in the automotive industry for twenty years or more. In this V-approach, system-level requirements are propagated down the V via subsystems to component design, and the system performance is validated at increasing integration levels. Engineering of mechatronic systems requires the application of two interconnected "V-cycles": one focusing on the multi-physics system engineering (like the mechanical and electrical components of an electrically powered steering system, including sensors and actuators); and the other focuses on the controls engineering, the control logic, the software and realization of the control hardware and embedded software.
Antagonism of the 5-HT3 receptor has been found to enhance the increase in brain serotonin levels produced by serotonin reuptake inhibition in animal studies. Whether or not the 5-HT3 receptor antagonism of vortioxetine likewise does this in humans or contributes to its clinical antidepressant efficacy is unclear. SSRIs and 5-HT1A receptor agonists often produce nausea as a side effect, whereas 5-HT3 receptor antagonists like ondansetron are antiemetics and have been found to be effective in treating SSRI-induced nausea. It was thought that the 5-HT3 receptor antagonism of vortioxetine would reduce the incidence of nausea relative to SSRIs. However, clinical trials found significant and dose-dependent rates of nausea with vortioxetine that appeared to be comparable to those found with the SNRI duloxetine. Vortioxetine has been found to slightly reduce oxytocin levels in rodents. Serotonin 5-HT1A receptor agonists can enhance oxytocin release, but vortioxetine shows 10- to 15-fold lower affinity for the serotonin 5-HT1A receptor in rodents compared to humans.
Sources: en.wikipedia.org
Identity is confirmed by matching the retention time in reversed-phase chromatography against a reference standard and by measuring the molecular mass with mass spectrometry. Tandem mass spectrometry or amino acid analysis can verify the sequence of the seven residues. Because the peptide contains no aromatic amino acids, detection at 280 nm is not useful.
Lyophilized powder is normally stored desiccated at -20 °C, protected from light and moisture. Powder kept under these conditions is generally stable for long periods. Solutions are less stable and are usually prepared immediately before use.
A purity value from one chromatographic method does not capture every possible impurity. Related peptides with similar retention behavior, counterions, and residual solvents may not appear in the same analysis. Independent testing with an orthogonal method provides stronger assurance of identity and content.
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.