neuropeptide comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-03-15. Numbers and descriptions here follow the published literature rather than marketing material.
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.
| 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。
== See also == List of Byzantine emperors Byzantine dress Family tree of Byzantine emperors List of Byzantine revolts and civil wars List of Byzantine wars List of Roman dynasties List of bishops and Ecumenical Patriarchs of Constantinople Outline of the Byzantine Empire
==== Antibody target for animal model of glomerulonephritis ==== Single tail vein intravenous injection of antibody (OX7 mouse monoclonal IgG) against Thy1.1 in rats is used as a standard animal model to produce experimental mesangioproliferative glomerulonephritis which is popularly known in the field of nephrology as antiThy1 GN.
=== Historical use by government agencies === Beginning in the 1950s, the US Central Intelligence Agency (CIA) began a research program code-named Project MKUltra. The CIA introduced LSD to the United States, purchasing the entire world's supply for $240,000 and propagating the LSD through CIA front organizations to American hospitals, clinics, prisons, and research centers. Experiments included administering LSD to CIA employees, military personnel, doctors, other government agents, prostitutes, mentally ill patients, and members of the general public to study their reactions (usually without the subjects' knowledge), the most well-known example of this being Operation Midnight Climax. The project was revealed in the US congressional Rockefeller Commission report in 1975. However, the extent of the experiments conducted under Project MKUltra are still mostly unknown, as acting CIA director Richard Helms destroyed many of the key documents related to MKUltra in 1973. According to declassified CIA documents, it's possible that the American agency spread LSD amongst civilians in Europe in the 1950s. LSD was also one of several psychoactive substances evaluated by the U.S. Army Chemical Corps as possible non-lethal incapacitants in the Edgewood Arsenal human experiments.
Sources: en.wikipedia.org
=== Ovarian cancer and other === In 2008, the submission was announced of a registration dossier to the European Medicines Agency and the FDA for Yondelis when administered in combination with pegylated liposomal doxorubicin (Doxil, Caelyx) for the treatment of women with relapsed ovarian cancer. In 2011, Johnson & Johnson voluntarily withdrew the submission in the United States following a request by the FDA for an additional phase III study to be done in support of the submission. Trabectedin is also in phase II trials for prostate, breast, and paediatric cancers.
=== AI Safety Summit and the AI Safety Institute (2023) === In November 2023, the UK hosted the inaugural global AI Safety Summit at Bletchley Park, the historic home of wartime codebreaking. The summit brought together representatives from 28 countries, major AI companies, and civil society organisations to address the risks posed by frontier AI systems through mandatory and voluntary regulatory frameworks.. The summit produced the Bletchley Declaration, a landmark international agreement recognising the potential for "catastrophic" harm from AI and committing signatories to cooperative risk assessment and safety research. The United Kingdom founded in April 2023 a safety organisation called Frontier AI Taskforce, with an initial budget of £100 million. In November 2023, it evolved into the AI Security Institute (AISI), and continued to be led by Ian Hogarth. The AISI is part of the United Kingdom's Department for Science, Innovation and Technology. The AISI's mandate encompasses developing and conducting evaluations on frontier AI models, driving foundational safety research, and equipping governments with empirical understanding of advanced AI risks.
=== Respiration === Earthworms have no special respiratory organs. Gases are exchanged through the moist skin and capillaries, where the oxygen is picked up by the haemoglobin dissolved in the blood plasma and carbon dioxide is released.
Sources: en.wikipedia.org
continuously collect small fractions of the effluent from 1D, ensuring that the separation is maintained in this dimension; focus or refocus the effluent of a narrow band; to quickly transfer the 2D fraction collected and focused as a narrow pulse. Taken together, these three steps are called modulation cycle, which is repeated throughout the chromatographic run.
In August 2025, the United States began a military buildup in the southern Caribbean, deploying warships and military personnel. The Central Intelligence Agency (CIA) sent a team into Venezuela that began tracking Maduro's movements, using a source close to the Venezuelan president, and plans were made for the capture of Maduro months in advance. The Delta Force and other participants in the operation erected a mockup of the safe house in which Maduro was believed to be hiding, described by Trump as a "very highly guarded ... fortress". In September, the United States Southern Command began conducting military strikes on vessels in the Caribbean Sea, alleging some were trafficking drugs on behalf of Venezuela. In November 2025, Venezuelan opposition leader María Corina Machado promised to open Venezuela's oil and gas reserves during a business meeting in Miami attended by Trump, and the Trump administration engaged in secret talks with Maduro's government about its oil reserves. In December 2025, this escalated to include seizures of sanctioned oil tankers carrying Venezuelan crude. These seizures formed part of the broader blockade on sanctioned oil preceding the January 2026 operation. The US also launched covert operations in Venezuela under the directive of the CIA in late December. On 2 January 2026, Trump announced that the US military would conduct strikes inside Venezuela. In the weeks preceding the operation, Trinidad and Tobago signed an agreement with the US to allow US military access to its airports.
is rather small, in the convenience of comparison between difference samples, the notation is define as a ratio minus 1 and expressed in permil (‰). The Δ notation is inherited from traditional δ notation. But the reference is not a physical reference material. Instead, the reference frame is defined as the stochastic distribution of isotopologues in the sample. It means the values of Δ are to denote the excess or deficit of the isotopologue relative to the amount expected if a material conforms to the stochastic distribution. The calculation of stochastic distribution of methane isotopologues:
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.