BDNF 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.
Updated 2025-10-04. Numbers and descriptions here follow the published literature rather than marketing material.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
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.
| Property | Value | Notes |
|---|---|---|
| Route studied | Intranasal | Predominant route in published reports |
| Circulation stability | Short, minutes scale | Peptidases cleave it; the tail slows the process |
| Analytical method | RP-HPLC with mass spectrometry | Used for identity and purity assessment |
| Reported outcome domains | Anxiety and cognitive measures | Derived from small, mostly regional trials |
| Regulatory status | Marketed in Russia | Availability outside that market is limited |
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
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.
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.
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.
The pharmacokinetics of progesterone concerns the pharmacodynamics, pharmacokinetics, and various routes of administration of progesterone. Progesterone is a naturally occurring and bioidentical progestogen, or an agonist of the progesterone receptor, the biological target of progestogens like endogenous progesterone. Progesterone also has antimineralocorticoid and inhibitory neurosteroid activity, whereas it appears to have little or no glucocorticoid or antiandrogenic activity and has no androgenic activity. Because of its progestogenic activity, progesterone has functional antiestrogenic effects in certain tissues such as the uterus, cervix, and vagina. In addition, progesterone has antigonadotropic effects due to its progestogenic activity and can inhibit fertility and suppress sex hormone production. Progesterone differs from progestins (synthetic progestogens) like medroxyprogesterone acetate and norethisterone, with implications for pharmacodynamics and pharmacokinetics as well as efficacy, tolerability, and safety. Progesterone can be taken by mouth, in through the vagina, and by injection into muscle or fat, among other routes. A progesterone vaginal ring and progesterone intrauterine device are also available as pharmaceutical products.
=== 13 February === At least 30 people were reported killed in RSF attacks on al-Jamalab and Na'ima in White Nile State. Fifteen others drowned on the White Nile river while they were boarding a boat to escape the attacks.
== See also == Attending physician Fellowship (medicine) International medical graduate Internship (medicine) Medical resident work hours William Osler Post graduate year annotation (PGY) Physician training Dermatology Postdoctoral researcher Validation of foreign studies and degrees
== External links == Phil Baran: Molecule Magician, The Scientist Magazine The sultan of synthesis, Chemistry World, Royal Society of Chemistry Evolution from Academia to Industry – Interview with Professor Phil S. Baran, Oxbridge Biotech Roundtable
=== Template synthesis === The template synthesis method uses a nanoporous membrane template composed of cylindrical pores of uniform diameter to make fibrils (solid nanofiber) and tubules (hollow nanofiber). This method can be used to prepare fibrils and tubules of many types of materials, including metals, semiconductors and electronically conductive polymers. The uniform pores allow for control of the dimensions of the fibers so nanofibers with very small diameters can be produced through this method. However, a drawback of this method is that it cannot make continuous nanofibers one at a time.
Sources: en.wikipedia.org
=== Psychiatric and behavioral adverse effects === Gabapentin is sometimes recognized to cause a range of psychiatric and behavioral adverse effects that extend beyond its more common neurological side effects. Systematic reviews have documented atypical manifestations such as aggression, agitation, irritability, mood instability, and suicidal ideation, with some cases noting the emergence of mania, hallucinations, and psychosis, particularly in pediatric populations and individuals with preexisting psychiatric conditions, though such effects have also been reported in adults and in individuals without prior psychiatric history. Large cohort studies and post-marketing surveillance indicate that neuropsychiatric symptoms—including confusion, depression, and behavioral disturbances—can occur in up to 29% of gabapentin users. Most reactions are mild to moderate and often dose-dependent. There is also evidence associating gabapentin with an increased risk of suicidal behavior, especially in younger patients, and rare reports of violent or aggressive behavior. Causality is difficult to establish, and such events remain uncommon.
During the crisis, China primarily tapped into its corporate stockpiles, outside its official SPR of 1.23 billion barrels, to supply domestic needs. There could also be other previously unreported reserves in China. These corporate reserves can be used at one million barrels per day for a year. China's growing renewable energy sector and electric vehicle industry have also reduced the demand for petroleum products. Although China restricted overall exports of refined oil products during the war, it still supplied limited volumes to selected partner countries, either due to friendly relations or to secure diplomatic leverage. The conflict has also provided China with an opportunity to expand its renewable energy technologies in Asia.
=== 2014 traffic collision and lawsuit === On June 7, 2014, Morgan was a passenger in a Mercedes Sprinter minibus involved in a six-vehicle crash on the New Jersey Turnpike near Cranbury when it was struck from behind by a Walmart tractor-trailer, causing a chain reaction crash. Morgan and three other comedians, including Harris Stanton, along with Morgan's assistant and two limousine company employees, who were traveling on Morgan's "Turn it Funny" stand-up comedy tour, were involved in the crash. The crash killed Morgan's friend and collaborator, 62-year-old comedian James McNair (Jimmy Mack). Morgan was taken to the hospital with a broken femur, broken nose, a traumatic brain injury, and several broken ribs, and underwent surgery on his leg on June 8. From June 20 to July 12, Morgan stayed in a rehabilitation facility to recover from the injuries sustained during the crash. The driver of the truck which caused the accident pleaded not guilty to criminal charges, and an early investigation by National Transportation Safety Board found the driver had been on the road for nearly as many hours as the legal limit. Morgan also sued Walmart for negligence, settling in 2015 for an undisclosed amount. On June 1, 2015, Morgan made his first public appearance since the crash, in an interview with Matt Lauer on Today, stating he still suffered from symptoms of his injuries. On the November 3, 2016 episode of Conan, Morgan said that he was no longer angry about the collision and had forgiven the driver.
The human body needs iron for oxygen transport. Oxygen (O2) is required for the functioning and survival of nearly all cell types. Oxygen is transported from the lungs to the rest of the body bound to the heme group of hemoglobin in red blood cells. In muscle cells, iron binds oxygen to myoglobin, which regulates its release.
== Further reading == Centers for Disease Control and Prevention (2012). "Ch. 7: Haemophilus influenzae". In Atkinson W; Wolfe S; Hamborsky J (eds.). Epidemiology and Prevention of Vaccine-Preventable Diseases (12th ed.). Washington, D.C.: Public Health Foundation. pp. 87–100. Archived from the original on 2017-03-10. "Haemophilus influenzae". NCBI Taxonomy Browser. 727.
Sources: en.wikipedia.org
Reports describe effects on GABA-A receptor expression, monoamine turnover, and neurotrophic factor levels. These are proposed mechanisms drawn mainly from animal models. No single molecular target has been established.
Intranasal delivery is the route described in most published work. It is used because the peptide is degraded quickly once it reaches circulation. Direct evidence of brain penetration in humans is lacking.
Most trials are small, regionally concentrated, and often lack rigorous blinding or placebo control. Independent replication is limited. Reviews in English generally rate the evidence as preliminary.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.