A practical reference on melanocortin signalling: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-03-26 and is reviewed periodically as new material appears.
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.
The compound was developed in the 1980s at the Institute of Molecular Genetics in Moscow, where it emerged from research on short ACTH fragments and their effects on the central nervous system. Russian pharmaceutical listings describe it as a nootropic and neuroprotective agent, most often formulated as nasal drops. It is not a marketed medicine in the United States or the European Union, and no pharmacopoeial monograph covers it. Consequently, most published clinical experience with the substance originates from a small number of research centres, mainly in Russia and neighbouring countries.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Free acid form of the heptapeptide; depends on terminal groups |
| Molecular mass | About 813.9 g/mol | Average mass used for mass spectrometry confirmation |
| Appearance | White to off-white solid | Supplied as a lyophilised powder; hygroscopic |
| Solubility class | Freely soluble in aqueous media | Water, saline, and phosphate buffers; limited organic solubility |
| Typical storage temperature | -20 degrees Celsius | Long term and dry; short working periods may use 2 to 8 degrees Celsius |
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. It was developed as a fragment analog of adrenocorticotropic hormone, modeled specifically on the ACTH(4-10) region. The first four residues reproduce that fragment, while a Pro-Gly-Pro tripeptide is appended at the C-terminus. Work on the compound originated in Russia, where it entered clinical use as an intranasal preparation. Its sequence places it among short regulatory peptides studied for effects on the central nervous system rather than on the adrenal axis.
The C-terminal Pro-Gly-Pro extension is not incidental. Proline-rich tails are known to resist several common peptidases, and the published literature attributes the longer half-life of Semax, relative to unmodified ACTH fragments, to this feature. The modification also removes the melanocyte-stimulating and corticosteroidogenic activity that characterizes longer ACTH-derived sequences. Because the molecule is small and hydrophilic, it is typically formulated as an aqueous solution for intranasal or parenteral delivery. Acetylation or amidation at the termini appears in closely related research peptides and shifts the mass by a fixed increment.
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。
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.
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 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.
The parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
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.
=== Menstruation and fertility === The first menstrual bleeding is referred to as menarche, and typically occurs about two years after thelarche. The average age of menarche is 12½ in the United States. Most American females experience their first period at 11, 12 or 13, but some experience it earlier than their 11th birthday and others after their 14th birthday. In fact, anytime between 8 and 16 is normal. In Canada, the average age of menarche is 12.72, and in the United Kingdom it is 12.9. The time between menstrual periods (menses) is not always regular in the first two years after menarche. Ovulation is necessary for fertility, but may or may not accompany the earliest menses. In postmenarchal females, about 80% of the cycles were anovulatory in the first year after menarche, 50% in the third year and 10% in the sixth year. Initiation of ovulation after menarche is not inevitable. A high proportion of females with continued irregularity in the menstrual cycle several years from menarche will continue to have prolonged irregularity and anovulation, and are at higher risk for reduced fertility.
=== Stadtholderate under the House of Orange-Nassau === The political origins of the Dutch monarchy dates back to 1559, when Philip II of Spain appointed William I, Prince of Orange as stadtholder of Holland, Zeeland and Utrecht. Following his dismissal by the Spanish King Philip II for his leadership in the Dutch Revolt, the States-General reinstated him as stadtholder of the rebelling provinces in 1572. Due to his foundational role in the uprising, he became revered as the Pater Patriae ("Father of the Fatherland"). When the United Provinces formally severed ties with the Spanish Crown through the Act of Abjuration in 1581, the traditional role of stadtholder underwent a radical transformation. Since the feudal lord had been abjured, the representative function of the office became obsolete. Rather than being abolished, the office was adapted by the newly formed Republic of the Seven United Netherlands; the stadtholder was reconstituted as the highest executive official and military commander, formally appointed by and serving at the pleasure of the sovereign States of each individual province.
One study estimated that 10 square meters of oyster reef could enhance an ecosystem's biomass by 2.57 kg Herbivore shellfish will also be preyed on. This moves energy directly from primary producers to higher trophic levels potentially skipping out on multiple energetically costly trophic jumps which would increase biomass in the ecosystem. Seaweed farming is a carbon negative crop, with a high potential for climate change mitigation. The IPCC Special Report on the Ocean and Cryosphere in a Changing Climate recommends "further research attention" as a mitigation tactic. Regenerative ocean farming is a polyculture farming system that grows a mix of seaweeds and shellfish while sequestering carbon, decreasing nitrogen in the water and increasing oxygen, helping to regenerate and restore local habitat like reef ecosystems.
Sources: en.wikipedia.org
Ibotenic acid, or ibotenate, also known as premuscimol or as (S)-2-amino-2-(3-hydroxyisoxazol-5-yl)acetic acid, is a naturally occurring α-amino acid found in certain Amanita mushrooms such as Amanita muscaria. It acts primarily as a potent glutamate receptor agonist and produces neurological effects. The compound is used as a brain-lesioning agent in scientific research. Ibotenic acid is a conformationally-restricted analogue of the excitatory neurotransmitter glutamate which acts as a non-selective agonist of glutamate receptors, strongly activating NMDA, group I and II metabotropic glutamate receptors, and weakly activating AMPA and kainate receptors. Taken systemically, it is a prodrug of muscimol, broken down by the liver into this more stable compound, which acts as a potent GABAA and GABAA-ρ receptor agonist. Although the compound's psychoactive effects are not well-understood, some researchers speculate that ibotenic acid itself may have stimulant-like properties. Ibotenic acid is biosynthesized from glutamic acid by hydroxylation catalyzed by an Fe(II)/2-oxoglutarate-dependent oxygenase, with subsequent conversion steps carried out by enzymes encoded within a linked biosynthetic gene cluster. Ibotenic acid is commonly used in research to create site-specific hippocampal brain lesions in rats, allowing for task relearning due to its interaction with glutamate receptors, and is favored over other agents for its selectivity and long-term stability in saline solution.
=== UFC Que Choisir v. Valve Corporation === Consumer rights group UFC Que Choisir, based in France, filed a lawsuit against Valve in December 2015, claiming users should be able to resell their software. The High Court of Paris ruled in favor of UFC Que Choisir in September 2019, stating that Valve must allow the resale of Steam games. Valve stated it will appeal the decision. In 2022, the Court of Appeal of Paris overturned the lower court's decision, ruling in Valve's favour. In 2024, The French Supreme Court later confirmed this ruling, citing the EU Copyright and Information Society Directive 2001.
=== Multi-locus sequence typing === Multilocus sequence typing (MLST) is the sequencing of numerous loci to diagnose an organism by comparing DNA sequences to a database of known organisms. This method is often used to compare isolates or strains of the same species to see if they are indistinguishable or different from each other. This is common for tracking food-borne illnesses and public health outbreaks. Most MLST assays are published in scientific journals so consistent methods are used worldwide. There are also public databases available for tracking and comparisons.
Sources: en.wikipedia.org
Hydrophobins have been found to be structurally and functionally similar to cerato-platanins, another group of small cysteine-rich proteins, which also contain a high percentage of hydrophobic amino acids, and are also associated with hyphal growth. This family of proteins includes the rodlet proteins of Neurospora crassa (gene eas) and Emericella nidulans (gene rodA), these proteins are the main component of the hydrophobic sheath covering the surface of many fungal spores. Genomic sequencing of two fungi from dry or salty environments (Wallemia sebi and W. ichthyophaga) revealed that these species contain predicted hydrophobins with unusually high proportion of acidic amino acids and therefore with potentially novel characteristics. High proportion of acidic amino acids is thought to be an adaptation of proteins to high concentrations of salt.
== Use in production engines == UK company RCV Engines Ltd uses rotating cylinder liner technology as a specialized form of rotary valve in some of their four-stroke model engine and small-engine line-up. RCV also use horizontal and vertical rotary valves in four-stroke engines in their current range of engines. Piccard-Pictet in Switzerland patented a Rotary Valve, GB118407, basically a turning cylinder liner, different to Burt-McCollum Single Sleeve valve that both oscilates and turns, in an ellipsoid way RCV have developed a 125cc rotating cylinder liner engine, incorporating a rotating valve in the cylinder liner, for scooter applications. PGO Scooters of Taiwan were working with RCV in developing the engine for their applications. The Suzuki RG500 "Gamma" was powered by a two-stroke, rotary valve, twin crank, square four engine displacing 498 cubic centimeters. The power output was 93.7 brake horsepower (69.9 kW) at 9,500 RPM.
In 2005, he introduced an algorithm for computing the absolute partitioning free energies of unfolded peptides into the phosphatidylcholine bilayer interface. In his studies, he also described how partitioning of membrane-active oligopeptides into membrane interfaces plays a significant role in terms of promoting the formation of secondary structure. Focusing on the partitioning of two series of small model peptides into the interfaces of neutral (zwitterionic) phospholipid membranes, he determined a complete interfacial hydrophobicity scale that includes the contribution of the peptide bond. His study with von Heijne based on the recognition of transmembrane helices by the endoplasmic reticulum translocon introduced a new dimension to the problem of predicting transmembrane helices from amino acid sequences, as well as showing that direct protein–lipid interactions are critical during translocon-mediated membrane insertion. White studied the preference of tryptophan and tyrosine residues for membrane interfaces as significant features of membrane proteins. He explored several possibilities for tryptophan's interfacial preference. Most recently, his lab developed methods for studying membrane protein biogenesis and folding in E. coli using chimeric single-span membrane proteins. White was part of a consortium of scientists that developed a comprehensive classification system for lipids.
Sources: en.wikipedia.org
It is described as a synthetic analogue of the ACTH(4–10) fragment, a short segment of adrenocorticotropic hormone. Its sequence differs from that fragment and includes two proline residues, which influence stability and behaviour in solution.
It appears in Russian pharmaceutical listings as a nasal formulation, but it is not an authorised medicine in the United States or the European Union. Outside those markets it is normally encountered as a research chemical rather than a prescription product.
Laboratory and animal work points to melanocortin signalling and changes in neurotrophic factor levels, especially brain-derived neurotrophic factor. The exact receptor targets and the degree to which these findings transfer to humans are still unresolved.
It is registered as a pharmaceutical product in Russia, where it is typically supplied as a nasal solution. In most other countries it is not an approved drug and is traded as a research chemical instead. Approval status depends entirely on the jurisdiction involved.