heptapeptide is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-05-11. Where a claim depends on a specific study, the study is described rather than over-claimed.
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。
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It was derived from the ACTH(4-10) fragment, a short segment of adrenocorticotropic hormone that lacks the hormonal activity associated with the full-length peptide. Researchers at the Institute of Molecular Genetics in Moscow developed the compound during the 1980s. It has been registered as a pharmaceutical product in Russia and several neighbouring countries, where it is supplied as a nasal solution, and it is also sold internationally as a research chemical.
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.
| Property | Value | Notes |
|---|---|---|
| 结构类别 | 线性合成七肽 | 无环化结构，不含二硫键 |
| 氨基酸序列 | Met-Glu-His-Phe-Pro-Gly-Pro | N 端为甲硫氨酸 |
| 分子量 | 约 814 Da | 游离碱形式的计算值 |
| 外观 | 白色至类白色粉末 | 具吸湿性 |
| 溶解性 | 易溶于水 | 亦可溶于甲醇等极性溶剂 |
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its chain combines the first seven residues of corticotropin with a C-terminal proline-glycine-proline extension, a modification intended to slow enzymatic breakdown. The free peptide has a molecular mass near 813.9 daltons. It belongs to the class of ACTH-derived fragments studied for central nervous system activity rather than for adrenal steroid stimulation. This structural relationship to a natural hormone fragment is the usual starting point for describing the compound in the literature.
Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.
Pharmacological accounts link semax to melanocortin signalling and to modulation of neurotrophic factor expression, particularly brain-derived neurotrophic factor and nerve growth factor. Much of this evidence comes from rodent studies using intranasal delivery, a route chosen because it allows peptides to reach the central nervous system with limited systemic exposure. Whether the same mechanisms operate in humans at comparable magnitude remains an open question. The precise receptor or receptors responsible for the reported behavioural and neuroprotective effects have not been conclusively identified.
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 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.
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.
== Reactions == Compared to other heteroallenes, carbodiimides are very weak electrophiles and only react with nucleophiles in the presence of catalysts, such as acids. In this way, guanidines can be prepared. As weak bases, carbodiimides bind to Lewis acids to give adducts.
=== PDMS hydrogel === This method uses a hydrogel that is contained within a porous, silicone-based polymer called polydimethylsiloxane (PDMS). The polymer allows the hydrogel to withstand 14-19 times more force than it could on its own.
=== Use in the removal of phenolic compounds from wastewater === Researchers have found spongin to be useful in the photocatalytic degradation and removal of bisphenols (such as BPA) in wastewater. A heterogeneous catalyst consisting of a spongin scaffold for iron phthalocyanine (SFe) in conjunction with peroxide and UV radiation has been shown to remove phenolic wastes more quickly and efficiently than conventional methods. Other research using spongin scaffolds for the immobilization of Trametes versicolor Laccase has shown similar results in phenol degradation.
Sources: en.wikipedia.org
=== Pre-discovery === In the late 1940s to early 1960s, the early days of making heavier and heavier transuranic elements, it was predicted that since such elements did not occur naturally, they would have shorter and shorter spontaneous fission half-lives, until they stopped existing altogether around element 108 (now called hassium). Initial work in synthesizing the heavier actinides seemed to confirm this. But the nuclear shell model, introduced in 1949 and extensively developed in the late 1960s by William Myers and Władysław Świątecki, stated that protons and neutrons form shells within a nucleus, analogous to electron shells. Noble gases are unreactive due to a full electron shell; similarly, it was theorized that elements with full nuclear shells – those having "magic" numbers of protons or neutrons – would be stabilized against decay. A doubly magic isotope, with magic numbers of both protons and neutrons, would be especially stabilized. Heiner Meldner calculated in 1965 that the next doubly magic isotope after 208Pb was 298Fl with 114 protons and 184 neutrons, which would be the centre of an "island of stability". This island of stability, supposedly from copernicium (Z = 112) to oganesson (Z = 118), would come after a long "sea of instability" from mendelevium (Z = 101) to roentgenium (Z = 111), and the flerovium isotopes in it were speculated in 1966 to have half-lives over 108 years. These early predictions fascinated researchers, and led to the first attempt to make flerovium, in 1968 with the reaction 248Cm(40Ar,xn).
In the late 2010s, graphics processing units (GPUs) that were increasingly designed with AI-specific enhancements and used with specialised TensorFlow software had replaced previously used central processing unit (CPUs) as the dominant means for large-scale (commercial and academic) machine learning models' training. Specialised programming languages such as Prolog were used in early AI research, but general-purpose programming languages like Python have become predominant. The transistor density in integrated circuits has been observed to roughly double every 18 months—a trend known as Moore's law, named after the Intel co-founder Gordon Moore, who first identified it. Improvements in GPUs have been even faster, a trend sometimes called Huang's law, named after Nvidia co-founder and CEO Jensen Huang.
In a speech delivered in the Reichstag, Hitler stressed the military importance of occupation, noting that by occupying Czechoslovakia, Germany gained 2,175 field cannons, 469 tanks, 500 anti-aircraft artillery pieces, 43,000 machine guns, 1,090,000 military rifles, 114,000 pistols, about a billion rounds of ammunition and three million anti-aircraft shells. This amount of weaponry would be sufficient to arm about half of the then Wehrmacht. Czechoslovak weaponry later played a major part in the German conquests of Poland (1939) and France (1940). Heydrich during his time as Reichsprotektor brought about increases in rations for workers in the armaments industry, improved welfare services, free shoes and for a short time, a five-day work week as Saturday was made a holiday. The National Union of Employees was remolded in the style of the Nazi pseudo-union, the German Labour Front, to provide free sports events, films, concerts and plays for the workers. Heydrich sought to portray himself as the friend of the Czech working class, even meeting a group of selected Czech workers on 24 October 1941 in a photo-op to show his supposed concern for the Czech workers. Heydrich cynically called his policy "optical effects" as he believed that mere gestures such as free showings of films at the local cinemas and free sports matches could win the support of the working class and increase productivity in the war industries. However, inflation was rampant and wage increases failed to keep up with the cost of living, causing the workers to frequently grumble about their conditions.
Sources: en.wikipedia.org
Sarafotoxins (SRTXs) are a group of toxins present in the venom of Atractaspis engaddensis, and in clinical trials cause similar symptoms to patients diagnosed with acute giardiasis. Their etymology is from the name of the snake "שרף עין גדי" in Hebrew, pronounced "Saraf Ein Gedi" (meaning serpent of Ein Gedi). Together with endothelins (ETs), they form a homogenous family of strong vasoconstrictor isopeptides. Among them, a few slightly different substances can be named as SRTX-a, SRTX-b, SRTX-c, which were initially derived from A. engaddensis. Each one contains twenty-one amino acid residues that spontaneously fold into a defined tertiary structure, with two interchain-cysteine linkages (disulfide bonds) and a long hydrophobic tail. There are also other compounds, however, they are mostly derivations of previously mentioned ones. The main differences in the family of endothelin and sarafotoxins appear at N-terminal of peptides, as C-terminal in all of them is almost the same.
Panic disorder with or without agoraphobia. Body dysmorphic disorder Repetitive self-injurious/self-harming behaviours in those with intellectual disability specifically. The subtype of systemised paranoia characterised by somatic phenomena. Compulsive nail-biting (onychophagia). Cataplexy associated with narcolepsy. This is a TGA and MHRA-labeled indication for clomipramine. Self-bloodletting Premature ejaculation, where it may be more effective than paroxetine Depersonalization-derealization disorder Chronic pain with or without organic disease, particularly headache of the tension type. Developmental stuttering Sleep paralysis, with or without narcolepsy Enuresis (involuntary urinating in sleep) in children. The effect may not be sustained following treatment, and alarm therapy may be more effective in both the short-term and the long-term. Combining a tricyclic (such as clomipramine) with anticholinergic medication may be more effective for treating enuresis than the tricyclic alone. Trichotillomania In combination with lithium and tryptophan for severe, particularly treatment-resistant depression. This combination, in a similar vein, has also been used for clomipramine-resistant obsessive-compulsive disorder. When electro-convulsive therapy is performed alongside this treatment-regime (as may be the case in severe depression and accompanied with thyroxine,) however, great care must be taken with lithium. The overall risk of seizures may have to be weighted against the refractory severity of the current illness and necessity of the amalgamation of treatment(s).
=== Extrapulmonary === Very rarely, the primary site for small-cell carcinoma is outside of the lungs and pleural space; in these cases, it is referred to as extrapulmonary small-cell carcinoma (EPSCC). Outside of the respiratory tract, small-cell carcinoma can appear in the cervix, prostate, liver, pancreas, gastrointestinal tract, or bladder. It is estimated to account for 1,000 new cases a year in the U.S. Histologically similar to small-cell lung cancer, therapies for small-cell lung cancer are usually used to treat EPSCC. First-line treatment is usually with cisplatin and etoposide. In Japan, first-line treatment is shifting to irinotecan and cisplatin. When the primary site is in the skin, it is referred to as a Merkel-cell carcinoma.
Sources: en.wikipedia.org
不存在。它是依据 ACTH 的一段序列人工设计的分子，天然蛋白质中找不到与之完全相同的七肽。名称属于研究代号，而非天然物质名。
Semax 对应 ACTH 第 4 至第 10 位的片段，并在两端做了替换与延长，使其不再具备促肾上腺皮质激素的典型内分泌活性。这一改动同时改变了它在体内的稳定性与分布特征。
俄罗斯将其列为处方药物，需要医生开具处方。多数其他国家把它当作研究化合物，不能作为药品销售或宣称疗效。具体合法性取决于当地法规。
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.