If you have been reading about reversed-phase HPLC 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.
Updated 2026-06-08. Numbers and descriptions here follow the published literature rather than marketing material.
Published research on this peptide originates mainly from Russian laboratories, and the wider international literature is comparatively thin. Studies have used rodent models of stroke, hypoxia, and memory tasks, with a smaller number of human trials reported. Reported outcomes include changes in attention and memory measures, along with effects on neurotrophic factor expression in some experiments. Small sample sizes, inconsistent dosing protocols, and limited independent replication are widely noted limitations, so the strength of the clinical evidence remains an open question.
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.
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.
| 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.
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.
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.
Clinical evidence consists largely of small trials with modest sample sizes, often without independent replication. Reported endpoints include cognitive scores, recovery after stroke, and visual function, but study designs vary widely and few trials meet contemporary reporting standards. Systematic reviewers have noted a high risk of bias in several of these reports. No large multicenter trial conducted outside Russia has been published. The compound is therefore best described as investigational in most jurisdictions, with its clinical role still unresolved.
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。
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。
== Uses == Historically, shell cordovan was used for razor strops to hone razors in barber shops. It is used mostly in the manufacture of shoes, including high-end shoemaking, and is also used for wallets and watch straps due to its visual appeal and durability. In archery, it is used to protect the fingers and is considered smooth and durable, ideal for a finger tab. Outside leather crafting, "cordwain" denotes a leather-grain embossed cover paper used for folders, covers, and similar applications in commercial printing.
In the example of a snake bite, the use of anti-venom halts the spread of toxins whilst receiving antibiotics to impede infection. Even after the initial cause of the necrosis has been halted, the necrotic tissue will remain in the body. The body's immune response to apoptosis, which involves the automatic breaking down and recycling of cellular material, is not triggered by necrotic cell death due to the apoptotic pathway being disabled.
==== Neuromuscular fatigue ==== Nerves control the contraction of muscles by determining the number, sequence, and force of muscular contraction. When a nerve experiences synaptic fatigue it becomes unable to stimulate the muscle that it innervates. Most movements require a force far below what a muscle could potentially generate, and barring pathology, neuromuscular fatigue is seldom an issue. For extremely powerful contractions that are close to the upper limit of a muscle's ability to generate force, neuromuscular fatigue can become a limiting factor in untrained individuals. In novice strength trainers, the muscle's ability to generate force is most strongly limited by nerve's ability to sustain a high-frequency signal. After an extended period of maximum contraction, the nerve's signal reduces in frequency and the force generated by the contraction diminishes. There is no sensation of pain or discomfort, the muscle appears to simply 'stop listening' and gradually cease to move, often lengthening. As there is insufficient stress on the muscles and tendons, there will often be no delayed onset muscle soreness following the workout. Part of the process of strength training is increasing the nerve's ability to generate sustained, high frequency signals which allow a muscle to contract with their greatest force. It is this "neural training" that causes several weeks worth of rapid gains in strength, which level off once the nerve is generating maximum contractions and the muscle reaches its physiological limit.
=== Early history === Saints were recognised by popular veneration acclamation until the 12th century. After controversial cases, Pope Alexander III in 1170 required all candidates for beatification to be approved by the Holy See. The papacy took total authority over the process in the 17th century.
Sources: en.wikipedia.org
== Bonding == With two π electrons, the cyclopropenium cation class obeys Hückel’s rules of aromaticity for 4n + 2 electrons since, in this case, n = 0. Consistent with this prediction, the C3H3 core is planar and the C–C bonds are equivalent. In the case of the cation in [C3(SiMe3)3]+SbCl−6, the ring C–C distances range from 1.374(2) to 1.392(2) Å.
In the United States, all of the northern states had abolished slavery by 1804, with New Jersey being the last to act. Abolitionist pressure produced a series of small steps towards emancipation. After the Act Prohibiting Importation of Slaves went into effect on January 1, 1808, the importation of slaves into the United States was prohibited, but not the internal slave trade, nor involvement in the international slave trade externally. Legal slavery persisted outside the northern states, but abolitionists took an active role in opposing slavery by supporting the Underground Railroad, and violent clashes between anti-slavery and pro-slavery Americans occurred, including in Bleeding Kansas, a series of political and armed disputes in 1854–1858 as to whether Kansas would join the United States as a slave or free state. By 1860, the total number of slaves reached almost four million, and the American Civil War, beginning in 1861, led to the end of slavery in the United States. Slaves in areas controlled by the Confederacy were legally emancipated in 1863, when Lincoln issued the Emancipation Proclamation, and slavery was banned nationwide, except as punishment for a crime, in 1865, with the ratification of the 13th Amendment to the U.S. Constitution. Many of the freed slaves became sharecroppers and indentured servants.
== Crime == Number of intentional homicides committed with a firearm that were recorded in criminal (police) statistics: Ranked 3rd for the year 2000 among the 92 countries that responded to the survey (behind #1 South Africa and #2 Colombia).
== Surgery == Antiseptic practices evolved in the 19th century through multiple individuals. Ignaz Semmelweis showed already in 1847-1848 that hand washing prior to delivery reduced puerperal fever. Despite this, many hospitals continued to practice surgery in unsanitary conditions, with some surgeons taking pride in their bloodstained operating gowns.Only a decade later the situation started to change, when some French surgeons started to adopt carbolic acid as an antiseptic, reducing surgical infection rates, followed by their Italian colleagues in the 1860s. In 1867 Joseph Lister published seminal paper Antiseptic Principle of the Practice of Surgery, where he explained this reduction in terms of Louis Pasteur's germ theory. Thus he was able to popularize the antiseptic surgical methods in the English-speaking world. Some of this work was anticipated by:
The foursubstrates of this enzyme are 3-hydroxybenzoic acid, reduced nicotinamide adenine dinucleotide phosphate (NADPH), oxygen, and a proton. Its products are protocatechuic acid, oxidised NADP+, and water. The enzyme is a flavin-containing monooxygenase that uses molecular oxygen as oxidant and incorporates one of its atoms into the starting material. The systematic name of this enzyme class is 3-hydroxybenzoate,NADPH:oxygen oxidoreductase (4-hydroxylating). It is also called 3-hydroxybenzoate 4-hydroxylase. It participates in benzoate degradation via hydroxylation and uses flavin adenine dinucleotide as a cofactor.
Sources: en.wikipedia.org
Sudanese Sovereignty Council (1955–1958) Armed Forces Supreme Council (Sudan) (1958–1964); see 1958 Sudanese coup d'état Sudanese Sovereignty Council (1964–1965) Sudanese Sovereignty Council (1965–1969) National Revolutionary Command Council (Sudan) (1969–1971) Transitional Military Council (1985) (1985–1986) Transitional Military Council (2019) Transitional Sovereignty Council (2019–2021, 2021–present)
The Original Chubby Burger which is made on sesame seed bun, and comes with Chubby Mayo (Hellmann's Mayo), and lettuce. The Spicy Habanero Chicken Burger is made on a seeded bun with a spicy chicken portion, and comes with jalapeño aioli, lettuce and tomato. BLT Chubby Burger is made on a 7-grain bun, and comes with Chubby Mayo (Hellmann's Mayo), two slices of bacon, lettuce, and tomato. These can be ordered by themselves, or in combos. They also offer all white-meat chicken strips which come in either 3 or 5, by themselves, or in combos. The chicken strips may also be ordered in wraps such as the "Chipotle Chicken wrap" and the "Bacon Ranch wrap". Some locations used to offer fried chicken bone-in pieces however, the bone in chicken was discontinued as an optional item in 2020.
In Australia, New Zealand, and the United States, it is considered an analog of other illegal drugs and can be controlled under laws similar to the US Federal Analog Act. In September 2011, the US temporarily classified mephedrone as a Schedule I drug, with the classification taking effect in October 2011. This was made permanent in July 2012 with the passage of the Synthetic Drug Abuse Prevention Act (SDAPA).
Oparin was born in Uglich in 1894 into a merchant family. He and his parents soon moved to Kokayevo, a nearby village. Oparin had an older brother, Dmitry, who became an economist. Oparin graduated from the Moscow State University in 1917 and became a professor of biochemistry there in 1927. Many of his early papers were about plant enzymes and their role in metabolism. His first experimental studies were devoted to the chemistry of respiration. In them, he showed that chlorogenic acid is an essential component of redox reactions in the cell. In 1924 he put forward a hypothesis suggesting that life on Earth developed through a gradual chemical evolution of carbon-based molecules in the Earth's primordial soup. In 1935, along with academician Aleksei Bach, he founded the Biochemistry Institute of the Soviet Academy of Sciences. In 1939, Oparin became a Corresponding Member of the Academy, and, in 1946, a full member. In 1937, he organized the Department of Technical Biochemistry at the Moscow Technological Institute of Food Industry. In 1940s and 1950s, Oparin supported the theories of Trofim Lysenko and Olga Lepeshinskaya, who made claims about "the origin of cells from noncellular matter". "Taking the party line" helped advance his career. However, according to cytologist Vladimir Alexandrov:
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.