If you have been reading about Melanocortin receptor 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 2026-02-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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。
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。
| 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 |
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.
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
Semax is a synthetic peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
Clinical reports describe use in ischaemic stroke, transient ischaemic attack, optic nerve conditions, and cognitive complaints, but most of these studies are small and were conducted in a single region. Systematic reviews have generally described the evidence base as limited in size and variable in methodological quality. Randomised controlled data suitable for international regulatory assessment are scarce. As a result, major treatment guidelines outside Russia do not include the peptide, and interest in it remains largely research-driven rather than routine clinical.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
=== Physical activity === Physical inactivity of children has also shown to be a serious cause, and children who fail to engage in regular physical activity are at greater risk of obesity. Researchers studied the physical activity of 133 children over a three-week period using an accelerometer to measure each child's level of physical activity. They discovered the obese children were 35% less active on school days and 65% less active on weekends compared to non-obese children. Physical inactivity as a child could result in physical inactivity as an adult. In a fitness survey of 6,000 adults, researchers discovered that 25% of those who were considered active at ages 14 to 19 were also active adults, compared to 2% of those who were inactive at ages 14 to 19, who were now said to be active adults. Staying physically inactive leaves unused energy in the body, most of which is stored as fat. Researchers studied 16 men over a 14-day period and fed them 50% more of their energy required every day through fats and carbohydrates. They discovered that carbohydrate overfeeding produced 75–85% excess energy being stored as body fat and fat overfeeding produced 90–95% storage of excess energy as body fat. Many children fail to exercise because they spend long periods of time engaging in sedentary activities such as computer usage, playing video games or watching television. Technology usage may lead to reduced physical activity and is a risk factor for obesity; recreational screen time of 2 hours or more per day is associated with an increased risk of obesity.
==== Solid samples ==== Solid samples can be prepared in a variety of ways. One common method is to crush the sample with an oily mulling agent (usually mineral oil Nujol). A thin film of the mull is applied onto salt plates and measured. The second method is to grind a quantity of the sample with a specially purified salt (usually potassium bromide) finely (to remove scattering effects from large crystals). This powder mixture is then pressed in a mechanical press to form a translucent pellet through which the beam of the spectrometer can pass. A third technique is the "cast film" technique, which is used mainly for polymeric materials. The sample is first dissolved in a suitable, non-hygroscopic solvent. A drop of this solution is deposited on the surface of a KBr or NaCl cell. The solution is then evaporated to dryness and the film formed on the cell is analysed directly. Care is important to ensure that the film is not too thick otherwise light cannot pass through. This technique is suitable for qualitative analysis. The final method is to use microtomy to cut a thin (20–100 μm) film from a solid sample. This is one of the most important ways of analysing failed plastic products for example because the integrity of the solid is preserved. In photoacoustic spectroscopy the need for sample treatment is minimal. The sample, liquid or solid, is placed into the sample cup which is inserted into the photoacoustic cell which is then sealed for the measurement. The sample may be one solid piece, powder or basically in any form for the measurement.
A hot dog is a grilled, steamed, or boiled sausage served in the slit of a partially sliced bun. The term hot dog can also refer to the sausage itself. The sausage used is a wiener (Vienna sausage) or a frankfurter (Frankfurter Würstchen, also just called frank). The names of these sausages commonly refer to their assembled dish. Hot dog preparation and condiments vary worldwide. Common condiments include mustard, ketchup, relish, onions in tomato sauce, and cheese sauce. Other toppings include sauerkraut, jalapeños, chili, grated cheese, coleslaw, bacon and olives. Hot dog variants include the corn dog and pigs in a blanket. These types of sausages were culturally imported from Germany and became popular in the United States. It became a working-class street food in the U.S., sold at stands and carts. The hot dog has become closely associated with baseball and American culture. Although particularly connected with New York City and its cuisine, the hot dog eventually became ubiquitous throughout the US during the 20th century. Its preparation varies regionally in the country, emerging as an important part of other regional cuisines, including Chicago street cuisine.
== Role in protection against oxidative stress == Aerobic bacteria inevitably are prone to the formation of reactive oxygen species due to the nature of their respiration processes. Under normal conditions these ROS strive to maintain a dynamic balance; however, this balance can often be disrupted by biotic or abiotic stressors such as superoxide radicals, endogenous lipids, DNA hydroperoxides, hydrogen peroxide, hydroxyl radicals, and hydroxy alkenals. Therefore, these susceptible organisms have intrinsic mechanisms to protect from oxidative damage; glutathione plays a key role in most of these antioxidant mechanisms. Once reduced, glutathione interacts with these reactive oxygen and nitrogen species. This interaction is catalyzed by GSTs and their involvement is vital for successful oxidation of glutathione. GSTs bind the ROS substrate at its hydrophobic alpha-helical C-terminal domain, as well as reduced glutathione to its glutathione-binding site on the N-terminal domain. These two domains are adjacent to each other on the enzyme, and together form the active site of the GST where the redox reaction occurs. Once both substrates are bound at the enzyme's active site, the monomeric GST interacts with another substrate-bound GST monomer and catalyzes a disulphide bridge between the two glutathione molecules. This yields the active dimeric enzyme structure. The reactive oxygen species then donates one electron to a glutathione molecule, completing the oxidation-reduction reaction and rendering it unable to perform oxidative damage to the cell.
Alitretinoin, or 9-cis-retinoic acid, is a form of vitamin A. It is also used in medicine as an antineoplastic (anti-cancer) agent developed by Ligand Pharmaceuticals. It is a first generation retinoid. Ligand gained Food and Drug Administration (FDA) approval for alitretinoin in February 1999.
Sources: en.wikipedia.org
The group released several reports on these effects as a cover story, claiming that their ionospheric studies had been interfering with the other experiments at the RRS at Slough, and expressing their gratitude that the Air Ministry had granted them access to unused land at Orfordness to continue their efforts. Bowen continued increasing the voltage in the transmitter, starting with the 5000 volt maximum suggested by the Navy, but increasing in steps over several months to 12,000 V, which produced pulses of 200 kW. Arcing between the valves required the transmitter to be rebuilt with more room between them, while arcing on the antenna was solved by hanging copper balls from the dipole to reduce corona discharge. By June the system was working well, although Bainbridge-Bell proved to be so skeptical of success that Watt eventually returned him to the RRS and replaced him with Nick Carter. The Tizard Committee visited the site on 15 June to examine the team's progress. Watt secretly arranged for a Vickers Valentia to fly nearby, and years later insisted that he saw the echoes on the display, but no one else recalls seeing these. Watt decided not to return to the RRS with the rest of the Tizard group and stayed with the team for another day. With no changes made to the equipment, on 17 June the system was turned on and immediately provided returns from an object at 17 mi (27 km). After tracking it for some time, they watched it fly off to the south and disappear.
With a population of 84.7 million according to the 2023 German census, Germany is the most populous member state of the European Union, the second-most populous country in Europe after Russia, and the nineteenth-most populous country in the world. Its population density stands at 236 inhabitants per square kilometre (610 inhabitants/mi2). The fertility rate of 1.36 children born per woman (2024 estimates) is below the replacement rate of 2.1, but slightly above the EU average of 1.34. Since the 1970s, Germany's death rate has exceeded its birth rate. However, the country is witnessing increased birth and migration rates since the early 2010s. Germany has the fourth oldest population in the world, with an average age of 47.8 years.
==== Rocker Deformity ==== When operating on the upper vault of the nose, osteotomies may be performed to mobilize the nasal bones. These osteotomies should ideally have their superior limit at the nasofrontal suture, which is approximated by the medial canthus. If the osteotomy is carried too far superiorly into the frontal bone, a Rocker deformity may result, wherein the upper portion of the mobile bone flares outwards (or "rocks") when the inferior portion is medialized. Correction of a Rocker deformity would involve a transverse percutaneous osteotomy.
==== NAD ==== Evolutionary conserved protein domain corresponding to oxidoreductase activity. NAD binding catalyzes redox reactions to alter the oxidation state of metal ions, using NADP+ as an electron acceptor.
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.
不是。Semax 是完全人工合成的七肽，自然界中没有对应的已知肽段。它的设计灵感来自促肾上腺皮质激素片段 ACTH(4-10)，但序列经过了替换和延长。