Everything below concerns Research chemical. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-11-14. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Development work on the compound began in the 1980s and 1990s at the Institute of Molecular Genetics in Moscow, within the same research programme that produced the peptide Semax. Early investigators sought a tuftsin derivative with improved resistance to enzymatic breakdown and with activity in the central nervous system after peripheral administration. Most of the primary literature from this period was published in Russian, a factor that still shapes how easily the findings can be checked by outside groups.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
| Property | Value | Notes |
|---|---|---|
| Primary route studied | Intranasal | Also examined parenterally in animal work |
| Reported plasma half-life | Minutes to tens of minutes | Values vary widely between reports |
| Main model systems | Rodent behavioural and cell assays | Human trials are few and small |
| Principal proposed targets | GABA-A receptor, GABA transaminase | Monoamine and neurotrophic pathways also reported |
| Evidence grade | Preliminary | Limited independent replication |
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.
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.
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
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.
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.
==== Withdrawn ==== Amanda Edwards, former at-large Houston city councilor (2016–2020), candidate for U.S. Senate in 2020, candidate for this district in 2024, and runner-up in the 2025–26 special election (remained on ballot)
English blood (Old English blod) derives from Germanic and has cognates with a similar range of meanings in all other Germanic languages (e.g. German Blut, Swedish blod, Gothic blōþ). There is no accepted Indo-European etymology.
Compared to traditional cigarettes, reusable e-cigarettes do not create waste and potential litter from every use in the form of discarded cigarette butts. Traditional cigarettes tend to end up in the ocean where they cause pollution, though once discarded they undergo biodegradation and photodegradation. A 2025 review in Nicotine & Tobacco Research concluded that the chemical, metallic and electrical composition of e-cigarettes could qualify them as hazardous and electronic waste, and recommended clear, enforceable disposal and recycling requirements, including manufacturer responsibility and consumer-facing recycling information, in jurisdictions where e-cigarettes are legally sold. E-cigarettes that are not reusable contribute to the problem of electronic waste, which can create a hazard for people and other organisms. If improperly disposed of, they can release heavy metals, nicotine, and other chemicals from batteries and unused e-liquid. A 2024 open-access study in Science of the Total Environment that dismantled nine popular disposable vapes reported a complex mix of plastics and metals, including toxic or potentially toxic elements such as lead and mercury, which the authors noted could pose environmental hazards through leaching after littering or landfilling. A July 2018–April 2019 garbology study found e-cigarette products composed 19% of the waste from all traditional and electronic tobacco and cannabis products collected at 12 public high schools in Northern California.
=== Delivery of biologic drugs === Delivering biological drugs such as peptides, proteins, antibodies, and genetic material, comes with unique challenges. Because of their large size and electrical charges, these molecules are often poorly absorbed and easily broken down by enzymes in the body. To overcome these hurdles, scientists have been developing advanced delivery methods using tools like liposomes, nanoparticles, fusion proteins, and protein-based nanocages. Some strategies take inspiration from how toxins naturally enter cells by adapting those mechanisms for therapeutic use. Among the macromolecules studied, RNA delivery has made progress, especially with the success of RNA-based COVID-19 vaccines. While protein and DNA delivery have shown progress, proteins in live animals and DNA in lab settings, delivering these large molecules, still remain a complex task. Although oral administration is generally preferred by patients for convenience, it's rarely effective for biologics due to poor absorption. That being said, innovative technologies such as enzyme inhibitors, permeation enhancers, lipid-based nanoparticles, and microneedles are being used to improve oral bioavailability for these drugs. One of the recent developments that has been successful is the use of lipid nanoparticles (LNPs) to deliver messenger RNA (mRNA). LNPs protect fragile mRNA from degradation and escape from endosomes so it can reach the cytoplasm and produce proteins.
Sources: en.wikipedia.org
=== Metabolic disorders === Opioids are primarily metabolized in the liver, before being excreted through urine. Opioids are metabolized by phase 1 and/or phase 2 metabolism, which can lead to the activation or inhibition of these drugs. Phase 1 metabolism is the CYP pathway which consists of different cytochrome P450s – a set of enzymes that catalyze hydrolysis, reduction, and oxidation reactions – to create an active metabolite. In contrast, Phase 2 metabolism causes the opioids to undergo conjugation, with little to no interaction with the CYP pathway. The opioids undergo phase 1 and phase 2 metabolism until they are hydrophilic enough to be renally excreted. Various factors play a role in how an opioid is metabolized. In phase 1 metabolism, the CYP family has several polymorphisms, which can account for the difference in therapeutic responses within each individual. This diversification leads to opioids being modified at varying rates, which can cause the drug to remain in the bloodstream for either a longer or shorter period. Therefore, these polymorphisms control opioid tolerance and facilitate overdose.
Direct vs Indirect link PKPD models Direct vs Indirect response PKPD models Time variant vs time invariant Cell lifespan models Complex response models PKPD modeling has its importance at each step of the drug development and it has shown its usefulness in many diseases. The Food and Drug Administration also provides guidances for Industry to recommend how exposure-response studies should be performed.
A recent study suggested "a multifaceted global strategy is needed to prevent substandard and falsified medicines especially in childrens, emphasizing that effective prevention requires strong regulatory enforcement, improved pharmaceutical supply chains, healthcare education, international collaboration, and access to quality medicines to reduce the associated health risks and disease burden. The study suggested two novel proposals not widely discussed before are (1) a Global Pediatric Drug Quality Index, to rank countries based on regulatory strength, testing capacity, and reporting systems for pediatric medicines, and (2) a Zero-Tolerance Supply Chain Protocol combining blockchain, community surveillance, and mini-labs to enforce transparency and prevent pediatric drug counterfeiting.
Sources: en.wikipedia.org
In March 1929, in response to the Nehru Report, Muhammad Ali Jinnah, the founder of Pakistan, issued his fourteen points, which included proposals to safeguard the interests of the Muslim minority in a united India. These proposals were rejected. In his 29 December 1930 address, Allama Iqbal advocated the amalgamation of Muslim-majority states in North-West India, including Punjab, North-West Frontier Province, Sind, and Baluchistan. The perception that Congress-led British provincial governments neglected the Muslim League from 1937 to 1939 motivated Jinnah and other Muslim League leaders to embrace the two-nation theory. This led to the adoption of the Lahore Resolution of 1940, presented by Sher-e-Bangla A.K. Fazlul Haque, also known as the Pakistan Resolution. By 1942, Britain faced considerable strain during World War II, with India directly threatened by Japanese forces. Britain had pledged voluntary independence for India in exchange for support during the war. However, this pledge included a clause stating that no part of British India would be compelled to join the resulting dominion, which could be interpreted as support for an independent Muslim nation. Congress under the leadership of Mahatma Gandhi launched the Quit India Movement, demanding an immediate end to British rule. In contrast, the Muslim League chose to support the UK's war efforts, thereby nurturing the possibility of establishing a Muslim nation.
Tiratricol, sold under the brand name Téatrois among others, is a thyroid hormone analogue. It is a thyroid hormone receptor agonist. Tiratricol it administered by mouth. The most common side effects include excessive sweating, irritability, anxiety, nightmares, diarrhea, vomiting, rash, and excessive sweating. Tiratricol was authorized for medical use in the European Union in February 2025, and approved for medical use in the United States in September 2026.
Myofascial pain syndrome (MPS), also known as chronic myofascial pain (CMP), is a syndrome characterized by chronic pain in multiple myofascial trigger points ("knots") and fascial (connective tissue) constrictions. It can appear in any body part. Symptoms of a myofascial trigger point include: focal point tenderness, reproduction of pain upon trigger point palpation, hardening of the muscle upon trigger point palpation, pseudo-weakness of the involved muscle, referred pain, and limited range of motion following approximately 5 seconds of sustained trigger point pressure. The cause is believed to be muscle tension or spasms within the affected musculature. However, emerging evidence suggests that fascial tissue and its biomechanical and neurophysiological properties may also contribute to the development and persistence of myofascial pain. Diagnosis is based on the symptoms and possible sleep studies. Treatment may include pain medication, physical therapy, mouth guards, and occasionally benzodiazepine. It is a relatively common cause of temporomandibular pain.
Sources: en.wikipedia.org
Reports describe modulation of GABA signalling, changes in monoamine turnover and effects on neurotrophic factor expression. These observations come mainly from animal and cell studies. A single unifying mechanism has not been demonstrated.
The peptide enters plasma rapidly and is broken down by ordinary proteases into amino acids and shorter fragments. Reported half-lives are short. Whether meaningful amounts of the intact molecule reach the brain is an open question.
Most clinical reports are small, published in Russian and not independently replicated. English-language reviews highlight the absence of large randomised trials. Conclusions about efficacy should be treated as provisional.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, commonly written as TKPRPGP. It shares the first four residues with tuftsin and carries three prolines in the chain. The proline-rich tail is the main structural feature that separates it from the parent tetrapeptide.