This is a working overview of heptapeptide, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-09-24 and is reviewed periodically as new material appears.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilised solid form |
| Solubility class | Freely soluble in water | Hydrophilic heptapeptide |
| Dry storage temperature | -20 degrees Celsius or lower | Sealed, desiccated, protected from light |
| Solution storage | 2 to 8 degrees Celsius short term | Avoid repeated freeze-thaw cycles |
| Common identification method | Reversed-phase HPLC with mass spectrometry | Confirms purity and molecular mass |
Selank is not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
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.
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.
The Napoleonic Wars (1803–1815) were a global series of conflicts fought by a fluctuating array of European coalitions against the French First Republic (1803–1804) under the First Consul followed by the First French Empire (1804–1815) under the Emperor of the French, Napoleon. The wars originated in political forces arising from the French Revolution (1789–1799) and French Revolutionary Wars (1792–1802) and produced a period of French domination over continental Europe. The wars are categorised as seven conflicts, five named after the coalitions that fought Napoleon, plus two named for their respective theatres: the War of the Third Coalition, War of the Fourth Coalition, War of the Fifth Coalition, War of the Sixth Coalition, War of the Seventh Coalition, the Peninsular War, and the French invasion of Russia. The first stage of the wars broke out when Britain declared war on France on 18 May 1803. After minor campaigns, Britain allied with Austria, Russia, and minor powers, to form the Third Coalition in April 1805. Napoleon defeated the allied Russo-Austrian armies in the subsequent war which climaxed in French victories at Ulm and at Austerlitz, leading to the dissolution of the Holy Roman Empire and Austria being forced to make peace. Britain and Russia remained at war with France. Concerned about increasing French power, Prussia joined Britain and Russia in the Fourth Coalition, which resumed war in October 1806.
Sequence comparisons indicate an evolutionary relationship between gelsolin, villin, fragmin, and severin. Six large repeating segments occur in gelsolin and villin, and 3 similar segments in severin and fragmin. The multiple repeats are related in structure (but barely in sequence) to the ADF-H domain, forming a superfamily (InterPro: IPR029006). The family appears to have evolved from an ancestral sequence of 120 to 130 amino acid residues. Asgard archaea encode many functional gelsolins.
Lodenafil (also known as hydroxyhomosildenafil, trade name Helleva) is a drug belonging to a class of drugs called PDE5 inhibitors, which many other erectile dysfunction drugs such as sildenafil, tadalafil, and vardenafil also belong to. Like udenafil and avanafil, it belongs to a new generation of PDE5 inhibitors. Lodenafil is formulated as a prodrug in the form of the carbonate ester dimer, lodenafil carbonate, which breaks down in the body to form two molecules of the active drug lodenafil. This formulation has higher oral bioavailability than the parent drug. It is manufactured by Cristália Produtos Químicos e Farmacêuticos in Brazil and sold there under the brand-name Helleva. It has undergone Phase III clinical trials, but is not yet approved for use in the United States by the U.S. Food and Drug Administration.
In the 1990s, the national health ministries of the listed countries reviewed the pertinent studies for causal links among silicone-gel breast implants and systemic and diagnosed autoimmune diseases and breast cancer. A study by researchers at the U.S. National Institute of Health reported an increase in four types of cancer among women with breast implants compared to other plastic surgery patients of the same age and similar demographic traits and health habits. This increase in cancer was attenuated but did not disappear when the researchers followed the women for 5 more years, with a 43% increase in brain cancer and a 63% increase in respiratory cancer compared to other plastic surgery patients. A study by Watad et al. evaluated the medical records of more than 24,000 women with breast implants compared to more than 98,000 women with the same demographic traits who did not have breast implants. The researchers found a statistically significant 22 percent increase in several diagnosed diseases, increasing to more than 60% for Sjogren's syndrome, multiple sclerosis, and sarcoidosis After investigating this issue, in 2021 the U.S. FDA revised its "black box warnings" on breast implants to acknowledge the association between breast implants and systemic autoimmune, rheumatologic, and neurological symptoms to state: "Patients receiving breast implants have reported a variety of systemic symptoms, such as joint pain, muscle aches, confusion, chronic fatigue, autoimmune diseases, and others. Individual patient risk for developing these symptoms has not been well established.
Sources: en.wikipedia.org
=== Direct printing === Two different methods for the direct application of indigo were developed in England in the 18th century and remained in use well into the 19th century. The first method, known as "pencil blue" because it was most often applied by pencil or brush, could be used to achieve dark hues. Arsenic trisulfide and a thickener were added to the indigo vat. The arsenic compound delayed the oxidation of the indigo long enough to paint the dye onto fabrics.
=== Neuropsychiatric === Mood disorders like bipolar disorder and clinical depression are the most common conditions underlying catatonia. Other psychiatric conditions that can cause catatonia include schizophrenia and other primary psychotic disorders, autism spectrum disorder, ADHD, and post-traumatic stress disorder. Psychodynamic theorists have historically interpreted catatonia as a psychological defense against the potentially destructive consequences of responsibility, with the passivity of the disorder providing relief.
== Posthumous honors == Rockefeller College at Princeton University was named in his honor in 1982. The John D. Rockefeller III National Tournament of Elementary School State Champions, an annual national-championship chess tournament run by US Chess, was named in his honor in 2020.
== Mechanical bonding and chemical reactivity == The introduction of a mechanical bond alters the chemistry of the sub components of rotaxanes and catenanes. Steric hindrance of reactive functionalities is increased and the strength of non-covalent interactions between the components are altered.
- Filomena Teixeira, 2019Teixeira called hospitals, traveled abroad many times, in one of those times she had to be hospitalized after seeing pedophilic material, searching for a lead of a boy in Switzerland. When failures in the investigation were highlighted in court, Teixeira said "it served to prove that I was saying the truth. For 13 years, I got called crazy, and now, after all this time, the come to tell me I was right: after all, I wasn't crazy, I was right. (...) I was said that they were going the wrong way, that they weren't looking, that they weren't doing anything..." Ricardo Sá Fernandes said that "we were shocked with what was said in court today, we were aware since the first moment that the inspectors knew about the prostitute Alcina Dias. They never heard her formally and justified it as forgetfulness." Manuel Mendonça believed that Dias could say something about Mendonça when in jail, since he got to choose and be put in a jail that looked like an "hotel" (when compared to the others).
Sources: en.wikipedia.org
Exosomal polycystin-1-interacting protein is a protein that, in humans, is encoded by the EPCIP gene. EPCIP is found on human chromosome 21, and it is thought to be expressed in tissues of the brain and reproductive organs. Additionally, EPCIP is highly expressed in ovarian surface epithelial cells during normal regulation, but is not expressed in cancerous ovarian surface epithelial cells.
In terms of race, the half-life is 25% higher in Asian patients compared to Caucasians. For the extended-release formulation, it has a half-life of 10.7-15.8 hours in healthy adult patients. Alprazolam has a volume of distribution following oral administration of 0.8-1.3L/kg. Its protein binding in plasma is 80% (mainly albumin bound) and capable of crossing the blood-brain barrier. It is metabolized to less effective metabolites by various CYP450 enzymes including CYP3A4, CYP3A5, CYP3A7, and CYP2C9. The majority of alprazolam metabolism is mediated by hydroxylation via CYP3As. 4-hydroxyalprazolam has 20% the binding affinity of the parent drug, alpha-hydroxyalprazolam has 66% the affinity, and the benzophenone metabolite has <1% the affinity. The drugs are mainly excreted in urine as unchanged Alprazolam. <10% of the dose is eliminated as alpha-hydroxy-alprazolam and 4-hydroxy-alprazolam.
S. aureus: 0.25 μg/mL to 4.0 μg/mL S. aureus (methicillin resistant or MRSA): 1 μg/mL to 138 μg/mL S. epidermidis: ≤0.12 μg/mL to 6.25 μg/mL Although once described as narrow-spectrum, numerous studies have now shown that vancomycin decreases the levels of a wide spectrum of bacteria, including members of the Gram-negative Bacteroidota that are important in the human gut.
== Side effects == In September 2020, the US Food and Drug Administration (FDA) required the boxed warning be updated for all benzodiazepine medicines to describe the risks of abuse, misuse, addiction, physical dependence, and withdrawal reactions consistently across all the medicines in the class.
Sources: en.wikipedia.org
Dry powder is normally held at -20 degrees Celsius or below in a sealed, light-protected container with desiccant. Brief room-temperature handling during weighing is generally tolerated. Storage instructions vary between suppliers, so the accompanying certificate of analysis should be followed.
Reversed-phase HPLC establishes purity, while mass spectrometry confirms the expected molecular mass. Sequence confirmation may use tandem mass spectrometry or peptide mapping. A certificate of analysis typically reports these results alongside the analytical method applied.
In Russia it is a registered medicine available by prescription. In many other countries it is not approved for human use and is supplied only as a research chemical. Import and possession rules differ by jurisdiction, and buyers are responsible for checking local requirements.
Selank is a synthetic heptapeptide designed as a stabilized analog of the natural tetrapeptide tuftsin. It has been investigated mainly for anxiolytic and cognitive effects. It is not an approved pharmaceutical in most countries.