synthetic heptapeptide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2025-10-07 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 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.
| 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. 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.
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.
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。
当时的短肽研究普遍关注能否穿越血脑屏障、在低剂量下产生中枢效应，Semax 属于这一路线。鼻内给药是其主要使用方式，俄语文献报道的适应症涵盖缺血性卒中、短暂性脑缺血发作、认知功能减退以及视神经病变。这些研究大多发表在当地期刊上，样本规模与终点设置同西方试验惯例存在差异，国际同行对其临床证据的强度看法不一。
Consider a natural analyte rich in isotope iA (denoted as A), and the same analyte, enriched in isotope jA (denoted as B). Then, the obtained mixture is analyzed for the isotopic composition of the analyte, RAB = n(iA)AB/n(jA)AB. If the amount of the isotopically enriched substance (nB) is known, the amount of substance in the sample (nA) can be obtained:
=== Mergers and acquisitions === In 1981, Tetra Pak relocated its corporate headquarters to Lausanne, Switzerland, for tax reasons, but retained all research in Lund, Sweden. For the equivalent of US$2.5 billion, Tetra Pak acquired Alfa-Laval AB in 1991, a Swedish company producing industrial and agricultural equipment and milk separators, world-leading in its industry, in what was at the time Sweden's largest takeover. Since the deal allowed Tetra Pak to integrate Alfa Laval processing know-how, the merger made it possible for Tetra Pak to offer packaging and processing solutions. The deal drew anti-competitive scrutiny from the European Commission, but it was approved after various concessions from both companies. After the merger with Alfa Laval, Tetra Pak announced plans to return its headquarters to Sweden, and in 1993 Tetra Laval Group was created with dual headquarters in Lund and Lausanne. Alfa Laval's liquid processing unit was absorbed into Tetra Pak and the unit specialising in dairy production machinery was organised separately as Alfa Laval Agri. Alfa Laval Agri was later renamed DeLaval, after Alfa Laval's founder Gustaf de Laval, and is still a part of the Tetra Laval group. The part of Alfa Laval that was not directly linked to Tetra Pak's activities – heat exchangers and separation equipment among others – was sold in 2000 to Swedish finance group Industri Kapital. In 2001, Tetra Laval acquired the French plastic packaging group Sidel.
==== Operation Juniper Shield ==== At some point in 2013, Operation Enduring Freedom – Trans Sahara was rebadged as Operation Juniper Shield. ABC News reported that the Green Berets are also advising and assisting Niger's military to build up their fighting capability to counter the terrorist groups like al-Qaeda and ISIS. In September 2014, the Huffington post reported that members of the 19th SFG were deployed to Camp Ram Ram in Morocco as part of Operation Juniper Shield. On July 1, 2015, Army Times reported that the 3rd SFG will begin shifting its area of operations to Africa, with its focus primarily on northern and western Africa, the group expects to complete its transition out of the Middle East and Central Asia by summer 2016, as the wars in Iraq and Afghanistan wind down. Colonel Robert Wilson, the group commander, said his group "will gradually replace 10th [SFG] mission on the continent." On February 2, 2017, during a “routine administrative movement,” a Green Beret from 1st Battalion, 3rd SFG was killed and another soldier injured in a vehicle accident in Niger; according to the Stars and Stripes report Niger is a hub for special operations forces to train partner nations in north and west Africa to counter extremist groups and militants such as Boko Haram in Nigeria. On October 4, 2017, Green Berets of the 3rd SFG were ambushed. Time reported that a joint team of 12 Green Berets and 30 Nigerien troops were conducting a two-day reconnaissance mission along the Niger-Mali border.
Sources: en.wikipedia.org
=== Tutorials and educational websites === "An Introduction to Proteins" from HOPES (Huntington's Disease Outreach Project for Education at Stanford) Proteins: Biogenesis to Degradation – The Virtual Library of Biochemistry and Cell Biology
There does appear to be a positive correlation between depression symptoms (measured by HAD-D) and degree of emotional blunting (measured by OQuESA), but more research is needed to clarify how much depression may contribute to this symptom. One possible explanation of this side effect of SSRIs and SNRIs is that they decrease the resting-state functional connectivity of the dorsal medial prefrontal cortex. As many as one-third of patients experiencing emotional blunting do not report it as a side effect to their physician.
The term "MPR vaccine" is also used to refer to this vaccine, whereas "P" refers to parotitis which is caused by mumps. Merck MMR II is supplied freeze-dried (lyophilized) and contains live viruses. Before injection, it is reconstituted with the solvent provided. According to a review published in 2018, the GlaxoSmithKline (GSK) MMR vaccine known as Pluserix "contains the Schwarz measles virus, the Jeryl Lynn–like mumps strain, and RA27/3 rubella virus". Pluserix was introduced in Hungary in 1999. Enders' Edmonston strain has been used since 1999 in Hungary in Merck MMR II product. GSK Priorix vaccine, which uses attenuated Schwarz Measles, was introduced in Hungary in 2003.
Sources: en.wikipedia.org
There is broad scientific consensus that the acids DHA and EPA (both of which are highly prevalent in seafood) are beneficial to neurodevelopment and cognition, especially at young ages. The United Nations' Food and Agriculture Organization has described fish as "nature's superfood". Seafood consumption is associated with improved neurodevelopment during pregnancy and early childhood. Fish consumption is associated with a decreased risk of dementia, lung cancer, and stroke, as well as a more tenuous link to reduced mortality from coronary heart disease. A 2020 umbrella review concluded that fish consumption reduces all-cause mortality, cancer, cardiovascular disease, stroke, and other outcomes, while suggesting that two to four servings per week is generally safe. However, two other umbrella reviews found no statistically significant association between fish consumption and cancer risks, and have cautioned researchers when it comes to interpreting this reported association as the quality of evidence is low. The parts of fish containing essential fats and micronutrients, often cited as the primary health benefits of eating seafood, are frequently discarded in the developed world. Micronutrients including calcium, iodine, potassium, selenium, and zinc are found in their highest concentrations in the head, intestines, bones, and scales of fish. Government recommendations promote moderate consumption of fish.
==== Emulsions ==== The so-called "oil" adjuvants are really oils intended to be made into an emulsion with water, either oil-in-water (O/W) or water-in-oil (W/O). They would not work when moved out of the droplet form. Freund's complete adjuvant is a solution of inactivated Mycobacterium tuberculosis in mineral oil and/or lanolin developed in 1930. It is used as water-in-oil, It is not safe enough for human use. A safer version without the bacteria is known as Freund's incomplete adjuvant, but its effect is weaker. In either case, the W/O structure probably helps vaccines release antigens for a longer time. Despite the side effects, its potential benefit has led to a few clinical trials, including a few attempts at adding other microbial-derived parts to balance safety and strength. (A common side effect for both versions is long-term retention of the oil in tissue.) All "oil" adjuvants approved for humans are oil-in-water. They adsorb antigens to their surface and induce immune cell recruitment. All of these human-approved O/W adjuvants use squalene, an oil produced by human liver and skin. MF59 is an oil-in-water emulsion of squalene adjuvant used in some human vaccines. As of 2021, over 22 million doses of one vaccine with squalene, FLUAD, have been administered with no severe adverse effects reported. In addition, squalene-based O/W emulsions have also been shown to stably incorporate small molecule TLR7/8 adjuvants (e.g. PVP-037) and lead to enhanced adjuvanticity via synergism. An interesting choice of oil in O/W emusions is vitamin E.
The jury acquitted Letby of the attempted murder on counts 9 (Baby G) and 10 (Baby H), and was unable to reach verdicts on counts 11 (Baby H), 13 (Baby J), 14, (Baby K), 18 and 19 (Baby N), and 22 (Baby Q). On 21 August 2023, Letby was sentenced to life imprisonment with a whole life order, the most severe penalty available under English law. She became the fourth woman in the UK to receive such a sentence. In his remarks, Goss described her actions as "a cruel, calculated and cynical campaign of child murder involving the smallest and most vulnerable of children", adding that "there was a deep malevolence bordering on sadism [...] you [Letby] have no remorse [...] there are no mitigating factors [...] the offences are of sufficient severity to require a whole life order." Letby chose not to attend the sentencing hearing and therefore did not hear the victim impact statements or the sentence being passed. In response, the Secretary of State for Justice, Alex Chalk, said the government would "look at options to change the law at the earliest opportunity" to require defendants to attend their sentencing. Following the trial, Letby was transferred to HMP Low Newton in County Durham. As of February 2025, she is held at HM Prison Bronzefield.
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.
The sequence is Met-Glu-His-Phe-Pro-Gly-Pro, a seven-residue peptide. The first four residues correspond to the ACTH(4-10) fragment, and Pro-Gly-Pro is added at the C-terminus. N-acetylated versions also appear in the literature and differ in mass.