If you have been reading about BDNF 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 2026-02-18. Where a claim depends on a specific study, the study is described rather than over-claimed.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH(4-10) fragment, while the terminal Pro-Gly-Pro extension was added to improve metabolic stability. Its molecular formula is C37H51N9O10S and its monoisotopic mass is approximately 813.9 Da. The compound is classified as a peptide research chemical and as a registered pharmaceutical product in Russia, but it does not hold marketing approval in the European Union or the United States. Naming conventions vary across supplier catalogs.
Development of the compound took place in the Soviet Union during the 1980s, largely through peptide research groups affiliated with the Shemyakin-Ovchinnikov Institute and Moscow State University. Investigators screened fragments of adrenocorticotropic hormone for activity on the central nervous system while attempting to separate cognitive effects from hormonal ones. The shortened sequence was selected because it retained behavioral activity in animal models without stimulating corticosteroid release. Early publications described the molecule as an ACTH(4-10) analog.
Solid semax is typically supplied as a lyophilised powder that is hygroscopic and sensitive to moisture, light, and repeated temperature cycling. Long-term storage of the dry peptide is generally recommended at approximately -20 degrees Celsius, while shorter working periods may use refrigeration at 2 to 8 degrees Celsius. Vials should remain tightly closed and desiccated when brought to room temperature, because condensation can damage the material before it is weighed. Dividing a batch into aliquots is preferable to thawing one container repeatedly.
Dissolution is normally performed in water, phosphate-buffered saline, or normal saline, since the peptide is freely soluble in aqueous media and is rarely handled with strong organic solvents. Solution pH should be kept near neutral, because extreme acidity or alkalinity accelerates backbone hydrolysis and encourages oxidation of the methionine side chain. Once dissolved, the material is less stable than the dry powder and is commonly divided into single-use portions and frozen. Buffers containing primary amines, such as Tris, are often avoided because of possible side reactions.
Purity assessment relies mainly on reversed-phase high-performance liquid chromatography, which separates the target heptapeptide from truncated sequences, deletion analogues, and oxidised forms. Mass spectrometry, usually coupled to liquid chromatography, confirms identity through the expected molecular ion and reveals modifications such as methionine sulfoxide formation. Amino acid analysis can verify composition, and tandem mass spectrometry supports sequence confirmation. Ultraviolet detection near 254 to 280 nanometres is convenient because the phenylalanine and histidine residues absorb in that region. Nuclear magnetic resonance is rarely used for routine release testing.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Seven-residue peptide |
| Molecular mass | 813.9 Da | Monoisotopic value |
| Appearance | White to off-white powder | Lyophilized form |
| Solubility | Freely soluble in water | Also soluble in saline and polar solvents |
| Storage (dry) | -20 °C or lower | Desiccated, protected from light |
The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It corresponds to the ACTH(4-7) fragment extended at the C-terminus by a Pro-Gly-Pro tripeptide, an addition intended to slow enzymatic breakdown. The molecular formula is C37H51N9O10S and the molecular mass is approximately 814 daltons. In the literature it is often described as an ACTH(4-10) analog, although that label reflects a naming convention as much as a precise structural relationship. The compound was developed in Russia and remains most closely associated with that research tradition.
Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.
Published studies are dominated by animal models of stroke, ischemia, and cognitive impairment, with a smaller number of human trials conducted in Russia. Many of the human reports are small, single-center, and published in Russian-language journals, which limits independent scrutiny. Outcome measures vary between studies and often rely on clinician-rated scales rather than objective biomarkers. Systematic reviews have noted the methodological weaknesses and called for larger, preregistered trials before firm conclusions can be drawn.
Claims about enhanced focus, memory, or mood in healthy people rest mostly on anecdotal reports and community discussion rather than on controlled data. It remains unclear whether any cognitive benefit observed in patients recovering from brain injury would extend to uninjured users. Dose-response relationships, long-term safety, and interactions with other drugs are not well characterized in the peer-reviewed literature. Questions about optimal route of administration and treatment duration likewise remain open.
Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.
Laboratory work points toward modulation of neurotrophic signaling, particularly expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal tissue. Studies also describe effects on monoamine turnover, inflammatory mediators, and oxidative markers. These observations come mainly from animal models and cultured cells, so the causal chain in humans is not firmly established. Whether the reported molecular changes translate into measurable clinical benefit is an open question. Reviews generally present the mechanism as plausible rather than demonstrated.
稳定性主要由水解与氧化两条路径支配。肽键在中性或弱酸性条件下相对稳定，遇到强碱或长时间高温则明显断裂；甲硫氨酸侧链容易被氧化成亚砜，使主峰前移并拉低实际含量。金属离子、光照和反复冻融会进一步促进降解或聚集。冻干粉在低温避光条件下可存放较长时间，配制后的水溶液通常需要冷藏并尽快用完。
纯度评估以反相高效液相色谱为主，通过主峰面积百分比给出粗略结果，再配合电喷雾质谱核对分子量。氨基酸分析可验证组成比例，手性色谱或毛细管电泳用于检查残基构型。常见杂质包括缺失序列的短肽、氧化产物与二聚体。由于多数市售品不附带完整检验报告，独立第三方检测常被用来核实标称值。
从分子层面看，Semax 是线性七肽，没有二硫键、糖基或脂链修饰，N 端为游离氨基，C 端为游离羧基。分子含组氨酸与谷氨酸侧链，因此在水和甲醇等极性溶剂中溶解良好，在非极性溶剂中溶解有限。计算分子量约为 814 Da，与其质子化离子的质荷比吻合，可用于质谱确认。
The President directed other U.S. government agencies to put their technical assistance in developing countries under FOA's management as well. USDA in particular transferred OFAR's programs to FOA, while reconstituting the Foreign Agricultural Service for the task of building global markets for U.S. farm products. Administrative functions were consolidated as the various agencies came into FOA, and the Mutual Security Act of July 1953 instructed FOA to reduce personnel by at least 10% within 120 days. A large number of TCA's senior professionals were summarily dismissed, and FOA's administrator mounted an effort to compensate for lower U.S. government staffing by drawing on experts from U.S. universities and private voluntary organizations. The ExIm Bank's lending volume in developing countries was also cut dramatically in 1953. While a "trade not aid" strategy required the U.S. to import more goods from its allies, the administration was unable to convince Congress to liberalize import policy. On the contrary, the main foreign commercial measure taken at this time went in the other direction: the U.S. ramped up subsidies for exports of U.S. agricultural products. The 1953 amendment to the Mutual Security Act and the much larger Agricultural Trade Development and Assistance Act of 1954, known as "PL-480", allowed the U.S. government to buy U.S. farm surpluses and sell them in developing countries for inconvertible local currencies. Much of PL-480's foreign-currency revenue was returned to developing countries as a supplement to U.S. development assistance.
It often happens that the amount of antibody available to the researcher for their immunoprecipitation experiment is less than sufficient to saturate the agarose beads to be used in the immunoprecipitation. In these cases the researcher can end up with agarose particles that are only partially coated with antibodies, and the portion of the binding capacity of the agarose beads that is not coated with antibody is then free to bind anything that will stick, resulting in an elevated background signal due to non-specific binding of lysate components to the beads, which can make data interpretation difficult. While some may argue that for these reasons it is prudent to match the quantity of agarose (in terms of binding capacity) to the quantity of antibody that one wishes to be bound for the immunoprecipitation, a simple way to reduce the issue of non-specific binding to agarose beads and increase specificity is to preclear the lysate, which for any immunoprecipitation is highly recommended.
Molecular dynamics (MD) simulations are useful for simulating the motions of atoms and molecules according to physical laws. MD simulations are often applied to lipids to study atom-scale properties that may be difficult to observe otherwise. Force field parameters vary based on atom and molecule types. MD simulations may observe interactions between targeted lipids, proteins, hydrocarbons, water, hydrophilic/hydrophobic regions, ions, solvents, and other components that are present near the exterior and interior of a biomembrane.
=== Leigh syndrome === Leigh syndrome is a neurodegenerative disorder that has been linked to a defect in an enzymatic formylation reaction. Leigh syndrome is typically associated with defects in oxidative phosphorylation, which occurs in the mitochondria. Exome sequencing, has been used to identify a mutation in the gene coding for mitochondrial methionyl-tRNA formyltransferase (MTFMT) in patients with Leigh syndrome. The c.626C>T mutation identified in MTFMT yielding symptoms of Leigh Syndrome is believed to alter exon splicing leading to a frameshift mutation and a premature stop codon. Individuals with the MTFMT c.626C>T mutation were found to have reduced fMet-tRNAMet levels and changes in the formylation level of mitochondrially translated COX1. This link provides evidence for the necessity of formylated methionine in initiation of expression for certain mitochondrial genes.
Sources: en.wikipedia.org
Bog bodies are human remains which have been discovered in peat bogs around the world. They have been preserved naturally to varying degrees due to the specific conditions of peat bogs. Despite their natural preservation, these remains are sensitive to deterioration after being removed from their original locations. Freeze-drying is an accepted method of preserving bog bodies in museum collections. Some bog body discoveries include the Tollund Man of Denmark, the Elling Woman of Denmark, the Cashel Man of Ireland, the Huldremose Woman of Denmark, the Girl of the Uchter Moor of Germany, the Lindow Man of England, and the Yde Girl of the Netherlands. For a more comprehensive list of examples, see List of bog bodies. A record of the preservation of the Tollund Man's head, which took place in 1951 and involved replacing the bog water in the cells with liquid paraffin wax, can be read on the Tollund Man's website hosted by the Silkeborg Public Library, Silkeborg Museum, and Amtscentret for Undervisning.
That said, the residues of the C peptide that are conserved across species interact with similarly conserved residues on the A and B chains. Thus, it is hypothesized that these conserved residues are important for the functionality of mature insulin.
Skin hydration and surface lipids, on the other hand, did not significantly change with topical progesterone. These findings suggest that progesterone, like estrogen, also has beneficial effects on the skin and may be independently protective against skin aging.
Minoxidil was discovered in 1963 and was introduced for treatment of high blood pressure in 1971. In 1971, researchers unexpectedly discovered that minoxidil causes hair growth, resulting in it being repurposed for treatment of hair loss and approved in topical form for this use in 1988. Topical minoxidil became available over-the-counter in 1996. Low-dose oral minoxidil (LDOM) emerged for treatment of hair loss in 2015 and dramatically increased in popularity starting in 2022. Extended-release oral minoxidil and sublingual minoxidil were developed in the 2020s for hair loss and are in late-stage trials. Aside from its use in humans, minoxidil is extremely toxic to cats and dogs even in small amounts.
=== Inhibition === In unstimulated cells, the NF-κB dimers are sequestered in the cytoplasm by a family of inhibitors, called IκBs (Inhibitor of κB), which are proteins that contain multiple copies of a sequence called ankyrin repeats. By virtue of their ankyrin repeat domains, the IκB proteins mask the nuclear localization signals (NLS) of NF-κB proteins and keep them sequestered in an inactive state in the cytoplasm. IκBs are a family of related proteins that have an N-terminal regulatory domain, followed by six or more ankyrin repeats and a PEST domain near their C terminus. Although the IκB family consists of IκBα, IκBβ, IκBε, and Bcl-3, the best-studied and major IκB protein is IκBα. Due to the presence of ankyrin repeats in their C-terminal halves, p105 and p100 also function as IκB proteins. The c-terminal half of p100, that is often referred to as IκBδ, also functions as an inhibitor. IκBδ degradation in response to developmental stimuli, such as those transduced through LTβR, potentiate NF-κB dimer activation in a NIK dependent non-canonical pathway.
Sources: en.wikipedia.org
Diamondback moths cause US$4 to $5 billion of damage each year worldwide. The approach is similar to the sterile technique tested on mosquitoes, where males are transformed with a gene that prevents any females born from reaching maturity. They underwent field trials in 2017. Genetically modified moths have previously been released in field trials. In this case a strain of pink bollworm that were sterilized with radiation were genetically engineered to express a red fluorescent protein making it easier for researchers to monitor them. Silkworm, the larvae stage of Bombyx mori, is an economically important insect in sericulture. Scientists are developing strategies to enhance silk quality and quantity. There is also potential to use the silk producing machinery to make other valuable proteins. Proteins currently developed to be expressed by silkworms include; human serum albumin, human collagen α-chain, mouse monoclonal antibody and N-glycanase. Silkworms have been created that produce spider silk, a stronger but extremely difficult to harvest silk, and even novel silks.
=== Limitations of non-invasive electrical and magnetic methods === Brain tissue stimulation using non-invasive electrical and magnetic methods raises several concerns, including the following: The first issue is the uncertain dose for healthy stimulation. While neurophysiology lacks knowledge about the nature of such a treatment of nervous diseases at the cellular level, non-invasive electrical and magnetic therapies involve excessive exposure of the brain to an intense field, which is several times and even orders of magnitude higher than natural electromagnetic fields in the brain. Another significant challenge of non-invasive electrical and magnetic methods is to localize the effect of stimulation on specific neuronal networks that need to be treated. We still need to gain knowledge about mental processes at the cellular level. Neuronal correlates of cognitive functions are still intriguing questions for contemporary research. Non-invasive electrical and magnetic brain tissue stimulation targets a large area of poorly characterized tissue. Therefore, it is unclear whether electrical and magnetic fields reach only the neuronal networks of the brain that need treatment. Again, these methods involve excessive exposure to intense electrical and magnetic fields several times and even orders of magnitude higher than natural ones in the brain. However, non-invasive electrical and magnetic brain tissue methods cannot target only the neuronal networks that need to be treated. The undefined radiation target can destroy healthy cells during therapy.
== Examples of major bioenergetic processes == Glycolysis is the process of breaking down glucose into pyruvate, producing two molecules of ATP (per 1 molecule of glucose) in the process. When a cell has a higher concentration of ATP than ADP (i.e. has a high energy charge), the cell cannot undergo glycolysis, releasing energy from available glucose to perform biological work. Pyruvate is one product of glycolysis, and can be shuttled into other metabolic pathways (gluconeogenesis, etc.) as needed by the cell. Additionally, glycolysis produces reducing equivalents in the form of NADH (nicotinamide adenine dinucleotide), which will ultimately be used to donate electrons to the electron transport chain. Gluconeogenesis is the opposite of glycolysis; when the cell's energy charge is low (the concentration of ADP is higher than that of ATP), the cell must synthesize glucose from carbon- containing biomolecules such as proteins, amino acids, fats, pyruvate, etc. For example, proteins can be broken down into amino acids, and these simpler carbon skeletons are used to build/ synthesize glucose. The citric acid cycle is a process of cellular respiration in which acetyl coenzyme A, synthesized from pyruvate dehydrogenase, is first reacted with oxaloacetate to yield citrate. The remaining eight reactions produce other carbon-containing metabolites. These metabolites are successively oxidized, and the free energy of oxidation is conserved in the form of the reduced coenzymes FADH2 and NADH.
=== 1994–1999: Rise and critical acclaim === Carrey played the lead role in Ace Ventura: Pet Detective which was released in February 1994 and went on to gross $72 million in the United States and Canada. Following its success and before the release of his next film, The Mask, which was anticipated to be another hit, Morgan Creek Productions paid him $5 million to reprise his role as Ace Ventura and New Line Cinema offered him $7 million to make a sequel to The Mask and paid him $7 million to appear in Dumb and Dumber, a nearly tenfold increase on his salary for Ace Ventura. The Mask, released in July 1994, grossed $351 million worldwide, and Dumb and Dumber, released in December 1994, was another commercial success, grossing over $270 million worldwide. Carrey received his first Golden Globe Award nomination for Best Actor for his work in The Mask and was voted second on Quigley's Top Ten Money Making Stars Poll, behind Tom Hanks. Carrey portrayed the Batman villain the Riddler in the Joel Schumacher-directed superhero film Batman Forever (1995). The film received mixed reviews, but was a box office success. He reprised his role as Ace Ventura in Ace Ventura: When Nature Calls which was also released in 1995. Like the original film, it was well received by the public, but poorly received by critics. It was a huge box-office success, earning $212 million worldwide in addition to breaking records, with a $40 million opening weekend. Carrey became the first comic actor to be paid an upfront salary of $20 million for his next film, The Cable Guy (1996).
Sources: en.wikipedia.org
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.
The extension was introduced to slow enzymatic breakdown of the peptide in biological systems. Natural ACTH fragments are degraded rapidly by peptidases. Adding the tripeptide was intended to extend the window during which the molecule remains intact.
Most published work consists of animal experiments conducted in a small number of laboratories. Human data are limited in number and size. Whether the observed effects translate into reliable clinical benefit is still unresolved.
Dry powder is usually kept at about -20 degrees Celsius for long-term storage and at 2 to 8 degrees Celsius for short working periods. Containers should stay sealed and protected from light and moisture to limit degradation.