A practical reference on BDNF: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
The proposed mechanism centres on neurotrophic signalling rather than direct receptor activation. Semax is reported to increase expression of brain-derived neurotrophic factor and nerve growth factor in several brain regions, and to shift the balance between excitatory and inhibitory neurotransmitter systems. Interaction with melanocortin receptors has been suggested because of the parent ACTH fragment. Many of these findings come from rodent studies, and the extent to which they translate to human physiology remains an open question.
Scientific literature on semax is unevenly distributed. A substantial share of published work originates from a small number of laboratories in Russia, while independent replication elsewhere is limited. Human data consist mostly of small trials with short follow-up, and several reported outcomes rely on subjective rating scales. Questions about how much intact peptide reaches the central nervous system after nasal administration, and how long it persists there, are still unresolved. The compound is best described as an active research subject rather than a settled pharmacological agent.
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.
Semax binds to melanocortin receptors and is thought to influence neuronal survival and plasticity rather than to act through the adrenal axis. Laboratory work has shown increased expression of brain-derived neurotrophic factor and nerve growth factor in treated tissue. Changes in c-Fos, a marker of neuronal activation, have also been reported. Because the peptide is rapidly degraded by peptidases, its effects are generally attributed to downstream signaling cascades rather than to sustained receptor occupancy.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Calculated for the free peptide |
| Molar mass | 813.9 g/mol | Anhydrous free base |
| Peptide class | Synthetic heptapeptide | ACTH(4-10) analogue |
| Parent fragment | ACTH(4-10) | Adrenocorticotropic hormone segment |
| Developmental origin | Institute of Molecular Genetics, Moscow | Work began in the 1980s |
该化合物于二十世纪八十年代在俄罗斯被开发，相关工作由俄罗斯科学院分子遗传学研究所的研究团队主导。开发目标并非复制 ACTH 的完整激素活性，而是寻找保留其神经作用方向、同时去除促肾上腺皮质激素释放效应的短肽片段。研究记录显示，这一方向促成了多个相关短肽的合成与筛选，而 Semax 是其中被研究最广泛的一个。当地文献常以 Семакс 这一名称指代它。
研究兴趣主要集中在神经营养因子相关的路径上，包括脑源性神经营养因子与神经生长因子的表达变化。部分实验报告称在特定条件下观察到这些因子的水平上升，但具体信号通路和剂量依赖关系仍未完全厘清。多数公开数据来自细胞模型和动物实验，人体对照研究数量有限。因此，该化合物的作用机制在文献中属于活跃讨论，而非已经确立的定论。
Verification of a supplied batch generally combines a certificate of analysis with independent testing, because certificates are self-reported documents. A typical package includes a chromatographic trace, a mass spectrum, and a stated water or counter-ion content. Batch-to-batch consistency matters more than a single purity figure when results are compared across experiments. No single mandatory standard governs research-grade peptide release, so laboratories are expected to define their own acceptance criteria. Residual trifluoroacetate from purification is a frequently overlooked counter-ion.
Lyophilized material is chemically stable for extended periods when kept dry, cold, and protected from light. The powder is hygroscopic, so vials should be warmed to room temperature before opening to reduce condensation on the contents. Once dissolved, the peptide is far less stable because peptide bonds are susceptible to hydrolysis and the methionine residue can oxidize. Solutions are typically aliquoted and held at 2-8 °C for short intervals or frozen for longer ones, and repeated freeze-thaw cycles should be avoided.
=== Saint Ansbert of Rouen === Earlier reports of stigmatics do exist, however there is a lack of consensus on how the concept of stigmata was understood pre-Saint Francis. St. Ansbert of Rouen (d. 695 AD) could be considered the earliest stigmatic due to the claims of witnesses following his death, first recorded by an anonymous monk in the mid-8th century AD in Vita Sancti Ansberti:
Carlos Outeiral, CASP14: what Google DeepMind's AlphaFold 2 really achieved, and what it means for protein folding, biology and bioinformatics, Oxford Protein Informatics Group. (3 December) Mohammed AlQuraishi, AlphaFold2 @ CASP14: "It feels like one's child has left home." (blog), 8 December 2020 Mohammed AlQuraishi, The AlphaFold2 Method Paper: A Fount of Good Ideas (blog), 25 July 2021 AlphaFold-3 web server AlphaFold v2.1 code and links to model on GitHub Open access to protein structure predictions for the human proteome and 20 other key organisms at European Bioinformatics Institute (AlphaFold Protein Structure Database) CASP 14 website AlphaFold: The making of a scientific breakthrough, DeepMind, via YouTube. ColabFold, version for homooligomeric prediction and complexes
This enzyme is the extracellular nuclease of Staphylococcus aureus. Two strains, V8 and Foggi, yield almost identical enzymes. A common source is E.coli cells carrying a cloned nuc gene encoding Staphylococcus aureus extracellular nuclease (micrococcal nuclease). The 3-dimensional structure of micrococcal nuclease (then called Staphyloccal nuclease) was solved very early in the history of protein crystallography, in 1969. Higher-resolution, more recent crystal structures are available for the apo form and for the thymidine-diphosphate-inhibited form. As seen in the ribbon diagram above, the nuclease molecule has 3 long alpha helices and a 5-stranded, barrel-shaped beta sheet, in an arrangement known as the OB-fold (for oligonucleotide-binding fold) as classified in the SCOP database.
=== Industrial and chemical === Technetium-99 decays almost entirely by beta decay, emitting beta particles with consistent low energies and no accompanying gamma rays. Moreover, its long half-life means that this emission decreases very slowly with time. It can also be extracted to a high chemical and isotopic purity from radioactive waste. For these reasons, it is a U.S. National Institute of Standards and Technology (NIST) standard beta emitter, and is used for equipment calibration. Technetium-99 has also been proposed for optoelectronic devices and nanoscale nuclear batteries. Like rhenium and palladium, technetium can serve as a catalyst. In processes such as the dehydrogenation of isopropyl alcohol, it is a far more effective catalyst than either rhenium or palladium. However, its radioactivity is a major problem in safe catalytic applications. When steel is immersed in water, adding a small concentration (55 ppm) of potassium pertechnetate(VII) to the water protects the steel from corrosion, even if the temperature is raised to 250 °C (523 K). For this reason, pertechnetate has been used as an anodic corrosion inhibitor for steel, although technetium's radioactivity poses problems that limit this application to self-contained systems. While (for example) CrO2−4 can also inhibit corrosion, it requires a concentration ten times as high. In one experiment, a specimen of carbon steel was kept in an aqueous solution of pertechnetate for 20 years and was still uncorroded.
=== Type 2 diabetes === In the BEGIN Basal-Bolus Type 2 trial, insulin degludec was studied as an alternative to insulin glargine in participants with type 2 diabetes. 995 participants were randomized to receive either insulin degludec (n=755) or insulin glargine (n=251), in addition to either mealtime insulin aspart, metformin, and/or pioglitazone. Participants in this trial had an average HbA1c of 8.3–8.4%, and 49–50% were on a regimen consisting of basal-bolus insulin plus oral antidiabetic medications. After 52 weeks, insulin degludec was found to be noninferior to insulin glargine, providing a similar HbA1c lowering effect (−1.10 vs. −1.18%). Overall rates of hypoglycemia were significantly lower with insulin degludec (11.09 vs. 13.63%/yr, p=0.0359), including cases of nocturnal hypoglycemia (1.39 vs. 1.84%/yr, p=0.0399).
Sources: en.wikipedia.org
He commented on the blame for the war, "We might claim that Georgia initiated the war … but it appears at first impression more like a situation when somebody spits in your face twenty days on and finally you react by slapping that person back. Suddenly, the provocateur blames you for the overreaction and says, ‘I have only spit on you but I never hit you…." He further stated, "Russia was the first to breach the 1994 agreement that was negotiated. South Ossetia did not have right to keep heavy artillery on its territory under the terms of this agreement." In October 2008, Russian military expert Vladislav Shurygin wrote that Russia won the war because "the troops and headquarters were preparing for this war" since Spring 2008 when the General Staff began to plan an "operation to force Georgia to peace" and "these tasks were worked out in the spring and summer exercises of the North Caucasus Military District". He continued, "We won because at the staff offices of all levels, there were developed detailed plans in case of the outbreak of this war. [...] We won because in the chaos of muddle and confusion there were those who took responsibility. Who, in the absence of intelligible and clear instructions from Moscow, decided to begin to act according to the plans that were worked out." Shurygin concluded that "had we missed another 2-3 hours, Tskhinvali would have fallen, Georgians would cut off the Transcaucasian Highway".
==== Abnormal tongue motion ==== Abnormal tongue motion of infants is commonly caused by nipple confusion. When infants are given a rubber nipple and pacifier, they may sip at the maternal nipple as if it was a rubber nipple. The tongue movements used in breastfeeding and bottle-feeding are different: infants use a wave-like motion to remove breast milk in breastfeeding and thrusting action against the latex nipple to control milk flow in bottle-feeding. If the infant pinches and presses the nipple with the gums repeatedly, it creates a large friction and results in nipple soreness and bruising.
Before beginning the process of restoration of a herbarium sheet, best practices suggest that the original mounted specimen be photographed for reference to ensure a new sheet is as close to the original as possible. The original mounting sheet can be dried and flattened in the same manner as the plant to serve as a reference for positioning the specimen on a new sheet. Additionally, any labels or supplement information accompanying the plant should be placed in the same place.
=== Protein === Protein intake in vegetarian diets tends to be lower than in meat diets but can meet the daily requirements for most people. Studies at Harvard University as well as other studies conducted in the United States, United Kingdom, Canada, Australia, New Zealand, and various European countries, confirmed that vegetarian diets provide sufficient protein intake as long as a variety of plant sources are available and consumed.
Sources: en.wikipedia.org
Semax is based on the ACTH(4-10) fragment, a seven-amino-acid segment of adrenocorticotropic hormone. The synthetic peptide retains the core sequence while removing regions associated with endocrine activity. This modification is intended to isolate effects on the nervous system.
It is registered for clinical use in Russia and a few other countries, typically as a nasal drop formulation. It does not hold approval from the United States Food and Drug Administration or the European Medicines Agency. Outside those markets it is generally handled as a research chemical.
The compound was developed in Moscow and the earliest studies were conducted there, so the primary literature is largely in Russian-language journals. Translation and indexing have been incomplete, which limits access for outside researchers. Independent groups have since published some work, but the total volume remains modest.
It is associated with the melanocortin receptor family, particularly subtypes found in the central nervous system. This interaction is separate from the adrenal pathway activated by full-length ACTH.