nasal formulation raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-05-27. Anything still debated is marked as such rather than presented as settled.
Development is attributed to researchers at the Institute of Molecular Genetics in Moscow during the early 1980s, building on earlier Soviet work with ACTH fragments. Russian regulatory approval followed for intranasal use, and the compound has remained commercially available there for decades. Most published human data originate from Russian and, later, some Eastern European clinical reports, which are not always accessible in English translation. Outside that region the material is generally handled as a research chemical rather than a licensed medicine.
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
各国监管态度分化明显。俄罗斯按处方药管理，部分东欧国家留有使用记录；欧盟与美国未批准其作为药物上市，市面流通品通常标注为研究用化学品。身份差异意味着标示含量、纯度与无菌性缺少统一核查。体育领域还牵涉反兴奋剂名录，跨境携带则受目的地药品法规约束。
Semax 是人工设计的七肽，序列为 Met-Glu-His-Phe-Pro-Gly-Pro，骨架取自促肾上腺皮质激素片段 ACTH(4-10)。它于二十世纪八十年代在苏联的分子遗传学研究机构内合成。设计目标是保留该片段与注意力和记忆相关的活性，同时剔除促皮质激素释放等内分泌作用。此后俄罗斯将其登记为药品并进入临床使用。
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide (ACTH fragment analog) | Not a steroid; does not belong to the melanocortin agonist drugs by marketing category |
| Molecular formula | C37H51N9O10S (commonly cited) | Reported values vary slightly with salt and counter-ion content |
| Appearance | White to off-white lyophilized powder | A single batch may appear as a loose cake or fluffy solid |
| Solubility | Freely soluble in water and aqueous buffer | Stock solutions are usually prepared in sterile water or saline |
| Typical storage | −20 °C or below, desiccated and protected from light | Seal opened vials promptly to limit moisture uptake |
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.
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 was derived from the ACTH(4-10) fragment, a short segment of adrenocorticotropic hormone that lacks the hormonal activity associated with the full-length peptide. Researchers at the Institute of Molecular Genetics in Moscow developed the compound during the 1980s. It has been registered as a pharmaceutical product in Russia and several neighbouring countries, where it is supplied as a nasal solution, and it is also sold internationally as a research chemical.
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.
Semax 是一种人工合成的七肽，氨基酸序列为 Met-Glu-His-Phe-Pro-Gly-Pro，单字母缩写记作 MEHFPGP。它被归类为促肾上腺皮质激素片段 ACTH(4-10) 的结构类似物，但并不天然存在于生物体内。母体片段 ACTH(4-10) 的序列为 Met-Glu-His-Phe-Arg-Trp-Gly，Semax 替换了中间两个残基，并在羧基端延长了 Pro-Gly-Pro 三肽。这种延长被普遍认为能提升分子对肽酶的耐受性。
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。
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.
As of 2005, India was the only country producing licit opium (opium gum) for both domestic use and export. Licit opium was produced also in Democratic People's Republic of Korea for domestic use, and in Japan for maintenance of the pertinent technology (small quantities). Opium poppies were grown principally for extraction of alkaloids (from poppy straw) in nine other countries: Australia, China, France, Hungary, Slovakia, Spain, the Republic of Macedonia, Turkey, and the United Kingdom. China ceased producing licit opium after 2001. Opium poppies grown principally for the seed crop, with licit poppy straw as a by-product, were produced in the Czech Republic, Serbia and Montenegro. Another six countries cultivated opium poppies solely for the poppy seed or horticultural purposes, without extraction of alkaloids from poppy straw: Austria, Estonia, Germany, Netherlands, Poland, and Ukraine. Illicit production of Polish heroin and other products derived from poppy straw is an ongoing problem in Poland, although it isn't as serious as in the 1980s, after poppies containing high levels of opioid alkaloids were banned in 1990s. The production of licit opium in India was in accord with terms of the 1961 Single Convention on Narcotic Drugs. After the opium was harvested, the plants were allowed to mature and harvested for poppy seeds. The sale of poppy seeds delivered a significant proportion of the income from the licit opium crop. Unknown fractions of both the opium harvest and the poppy straw residue from the poppy seed harvest were diverted to illicit uses.
== Veterinary uses == In 2019, GS-441524 was shown to have promise for treating feline infectious peritonitis caused by a coronavirus. It has not been evaluated or approved by the US Food and Drug Administration (FDA) for the treatment of feline coronavirus or feline infectious peritonitis but has been available since 2019, through websites and social media as an unregulated black market substance. Because GS-441524 is the main circulating metabolite of remdesivir and because GS-441524 has similar potency against SARS-CoV-2 in vitro, some researchers have argued for the direct administration of GS-441524 as a COVID‑19 treatment.
On 13 May 1983, two peat workers at Lindow Moss, Andy Mould and Stephen Dooley, noticed an unusual object—about the size of a football—on the elevator taking peat to the shredding machine. They removed the object for closer inspection, joking that it was a dinosaur egg. Once the peat had been removed, their discovery turned out to be a decomposing, incomplete human head with one eye and some hair intact. Forensics identified the skull as belonging to a European woman, probably aged 30–50. Police initially thought the skull was that of Malika Reyn-Bardt, who had disappeared in 1960 and was the subject of an ongoing investigation. While in prison on another charge, her husband, Peter Reyn-Bardt, had boasted that he had killed his wife and buried her in the back garden of their bungalow, which was on the edge of the area of mossland where peat was being dug. The garden had been examined but no body was found. When Reyn-Bardt was confronted with the discovery of the skull from Lindow Moss, he confessed to the murder of his wife. The skull was later radiocarbon dated, revealing it to be nearly 2,000 years old. "Lindow Woman", as it became known, dated from around 210 AD. This emerged shortly before Reyn-Bardt went to trial, but he was convicted on the evidence of his confession.
Formaldehyde ( for-MAL-di-hide, US also fər-) (systematic name methanal) is a pungent colorless gas mainly used in the production of industrial resins, such as for particle board, coatings, plastics, pulp, paper, synthetic fibers, and textiles. A ~5% solution in water of formaldehyde is used as a disinfectant and fumigant in industrial, agricultural, and healthcare settings, and a ~37% solution is used to preserve tissue samples in labs. In 2024, the global production of formaldehyde was estimated at 26 million tons per year, and is a precursor to many other materials and chemical compounds. It is an organic compound with the chemical formula CH2O and structure H2C=O. The gas spontaneously polymerizes into paraformaldehyde. It is stored as a ~37% aqueous solution known as formalin, which consists mainly of the hydrate CH2(OH)2. It is the simplest of the aldehydes (R−CHO). Formaldehyde also occurs naturally. It is derived from the degradation of serine, dimethylglycine, and lipids. Demethylases act by converting N-methyl groups to formaldehyde. Formaldehyde is classified as a group 1 carcinogen and can cause respiratory and skin irritation upon exposure.
==== Coffee substitute ==== Roasted and ground soybeans can be a caffeine-free substitute for coffee. After the soybeans are roasted and ground, they look similar to regular coffee beans or can be used as a powder similar to instant coffee, with the aroma and flavor of roasted soybeans.
Sources: en.wikipedia.org
Arrhenius acid Any substance that, when dissolved in water, increases the concentration of H+ ions, or, more correctly, of hydronium ions (H3O+), in the resulting aqueous solution. The definition is similar to that of a Brønsted–Lowry acid. Contrast Arrhenius base.
Internal aldimine formation: First, the ε-amino group of Lys258 forms a Schiff base linkage with the aldehyde carbon to generate an internal aldimine. Transaldimination: The internal aldimine then becomes an external aldimine when the ε-amino group of Lys258 is displaced by the amino group of aspartate. This transaldimination reaction occurs via a nucleophilic attack by the deprotonated amino group of Asp and proceeds through a tetrahedral intermediate. As this point, the carboxylate groups of Asp are stabilized by the guanidinium groups of the enzyme's Arg386 and Arg292 residues. Quinonoid formation: The hydrogen attached to the α-carbon of Asp is then abstracted (Lys258 is thought to be the proton acceptor) to form a quinonoid intermediate. Ketimine formation: The quinonoid is reprotonated, but now at the aldehyde carbon, to form the ketimine intermediate. Ketimine hydrolysis: Finally, the ketimine is hydrolyzed to form PMP and oxaloacetate. This mechanism is thought to have multiple partially rate-determining steps. However, it has been shown that the substrate binding step (transaldimination) drives the catalytic reaction forward.
If the buoyancy of an (unrestrained and unpowered) object exceeds its weight, it tends to rise. An object whose weight exceeds its buoyancy tends to sink. Calculation of the upwards force on a submerged object during its accelerating period cannot be done by the Archimedes principle alone; it is necessary to consider dynamics of an object involving buoyancy. Once it fully sinks to the floor of the fluid or rises to the surface and settles, Archimedes principle can be applied alone. For a floating object, only the submerged volume displaces water. For a sunken object, the entire volume displaces water, and there will be an additional force of reaction from the solid floor. In order for Archimedes' principle to be used alone, the object in question must be in equilibrium (the sum of the forces on the object must be zero), therefore;
During the Second World War penicillin became an important part of the Allied war effort, saving thousands of lives. Alexander Fleming, Howard Florey and Ernst Chain shared the 1945 Nobel Prize in Physiology or Medicine for the discovery and development of penicillin. After the end of the war in 1945, penicillin became widely available. Dorothy Hodgkin determined its chemical structure, one of the achievements for which she received the Nobel Prize in Chemistry in 1964. This led to the development of semisynthetic penicillins that were more potent and effective against a wider range of bacteria. The drug was synthesised in 1957, but cultivation of mould remains the primary means of production. It was discovered that adding penicillin to animal feed increased weight gain, improved feed-conversion efficiency, promoted more uniform growth and facilitated disease control. Agriculture became a major user of penicillin. Shortly after their discovery of penicillin, the Oxford team reported penicillin resistance in many bacteria. Research that aims to circumvent and understand the mechanisms of antibiotic resistance continues.
Sources: en.wikipedia.org
Pork heart can be stewed, poached, braised, or made into sausage. The Balinese oret is a sort of blood sausage made with pig heart and blood. A French recipe for cœur de porc à l'orange is made of braised heart with an orange sauce. Snake heart, called tim rắn in Vietnam, is sometimes a delicacy consumed in wine.
==== Sensitivity to erosion ==== Stream power has also been used as a criterion to determine whether a river is in a state of reshaping itself or whether it is stable. A value of unit stream power between 30 and 35 W m−2 in which this transition occurs has been found by multiple studies. Another technique gaining popularity is using a gradient of stream power by comparing the unit stream power upstream to the local unit stream power (
== Microscopic appearance == Melanin is brown, non-refractile, and finely granular, with individual granules having a diameter of less than 800 nanometers. This differentiates melanin from common blood breakdown pigments, which are larger, chunky, and refractile, and range in color from green to yellow or red-brown. In heavily pigmented lesions, dense aggregates of melanin can obscure histologic detail. A dilute solution of potassium permanganate is an effective melanin bleach.
Sources: en.wikipedia.org
It is a short synthetic peptide built from seven amino acids: methionine, glutamic acid, histidine, phenylalanine and three prolines. The sequence derives from the 4-10 fragment of adrenocorticotropic hormone with an added proline-glycine-proline tail. No plant or animal extract is involved; the material is produced by solid-phase peptide synthesis.
It was developed in the Soviet Union during the early 1980s by groups at the Institute of Molecular Genetics in Moscow. Russian approval for intranasal use followed, and it has been marketed there since. Western laboratories encountered it mainly through translated literature and, later, through online research-chemical trade.
It holds a Russian registration as a prescription nasal product but has no approval from the European Medicines Agency or the United States Food and Drug Administration. Buyers outside Russia usually receive material sold strictly for laboratory research. That distinction matters because research-grade and pharmaceutical-grade products carry different documentation and testing expectations.
不存在。它是依据 ACTH 的一段序列人工设计的分子，天然蛋白质中找不到与之完全相同的七肽。名称属于研究代号，而非天然物质名。