ACTH fragment 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 2026-07-10. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Published research covers ischemic stroke, traumatic brain injury, cognitive impairment, optic nerve conditions and attention-related measures. Much of the human evidence comes from small trials conducted in one country, which limits how far the results generalize. Animal models supply the larger share of the data, and effects seen in rodents do not transfer automatically to people. Reviews have noted that methodological reporting is often incomplete, making it difficult to pool results or compare treatment schedules across studies.
Pharmacokinetic accounts emphasize rapid breakdown. After intravenous dosing the intact peptide disappears from blood within minutes, and nasal delivery produces low but measurable concentrations. Metabolites rather than the parent molecule may account for part of the observed activity, although the relative contribution is unresolved. Dosing in the literature varies widely and no optimal schedule has been agreed. These gaps are regularly cited as a reason the findings have not produced broad clinical adoption beyond the original research setting.
Proposed mechanisms center on neurotrophic signaling rather than on classical melanocortin receptor activation. Rodent experiments have reported shifts in the expression of brain-derived neurotrophic factor and nerve growth factor after administration, together with changes in the associated receptor systems. Several authors argue that the peptide acts largely through its degradation products and their interaction with peptidergic pathways, but this remains a hypothesis rather than a settled finding. No single molecular target has been identified in a way that the field broadly accepts.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Seven-residue peptide |
| Molecular mass | 813.9 Da | Monoisotopic value |
| Appearance | White to off-white powder | Lyophilized form |
| Solubility | Freely soluble in water | Also soluble in saline and polar solvents |
| Storage (dry) | -20 °C or lower | Desiccated, protected from light |
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。
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。
Common degradation pathways include oxidation of the methionine side chain, hydrolysis of the peptide backbone, and aggregation under unfavourable pH or concentration. Stability studies typically monitor the main peak by chromatography and report total related substances as a percentage. Because no official monograph exists, acceptance criteria vary between laboratories, and reported purity values are not directly comparable across suppliers. Analysts therefore document the method, column, and detection wavelength alongside each result, and open questions remain about how much biological activity the oxidised forms retain.
Solid semax is typically supplied as a lyophilised powder that is hygroscopic and sensitive to moisture, light, and repeated temperature cycling. Long-term storage of the dry peptide is generally recommended at approximately -20 degrees Celsius, while shorter working periods may use refrigeration at 2 to 8 degrees Celsius. Vials should remain tightly closed and desiccated when brought to room temperature, because condensation can damage the material before it is weighed. Dividing a batch into aliquots is preferable to thawing one container repeatedly.
== Commercialization == ChromaDex (now Niagen Bioscience) licensed patents for nicotinamide riboside from Dartmouth College, Cornell University, and Washington University in St. Louis in July 2012. The company developed a commercial production process for nicotinamide riboside chloride, trademarking the active ingredient as Niagen. ChromaDex has continued to expand using the brand name Tru Niagen globally while also supplying Niagen as an ingredient to other manufacturers. ChromaDex was in a patent dispute with Elysium Health over the rights to nicotinamide riboside supplements between 2016 and 2023. ChromaDex holds multiple patents related to nicotinamide riboside, including manufacturing methods, compositions, and uses. As of 2023, ChromaDex's patent portfolio for nicotinamide riboside includes 50+ granted patents and numerous pending patent applications worldwide. As of March 19, 2025, ChromaDex was renamed Niagen Bioscience, and now trades under the Ticker Symbol 'NAGE'.
=== In classical mechanics === In classical mechanics, discrete spectra are often associated to waves and oscillations in a bounded object or domain. Mathematically they can be identified with the eigenvalues of differential operators that describe the evolution of some continuous variable (such as strain or pressure) as a function of time and/or space. Discrete spectra are also produced by some non-linear oscillators where the relevant quantity has a non-sinusoidal waveform. Notable examples are the sound produced by the vocal cords of mammals. and the stridulation organs of crickets, whose spectrum shows a series of strong lines at frequencies that are integer multiples (harmonics) of the oscillation frequency. A related phenomenon is the appearance of strong harmonics when a sinusoidal signal (which has the ultimate "discrete spectrum", consisting of a single spectral line) is modified by a non-linear filter; for example, when a pure tone is played through an overloaded amplifier, or when an intense monochromatic laser beam goes through a non-linear medium. In the latter case, if two arbitrary sinusoidal signals with frequencies f and g are processed together, the output signal will generally have spectral lines at frequencies |mf + ng|, where m and n are any integers.
== Side effects == Side effects of doxylamine include dizziness, drowsiness, and dry mouth, among others. Doxylamine is a potent anticholinergic and has a side-effect profile common to such drugs, including blurred vision, dry mouth, constipation, muscle incoordination, urinary retention, mental confusion, and delirium. Because of its relatively long elimination half-life (10–12 hours), doxylamine is associated with next-day effects including sedation, drowsiness, grogginess, dry mouth, and tiredness when used as a hypnotic. This next-day sedation may be described as a "hangover effect". The shorter elimination half-life of diphenhydramine (4–8 hours) compared to doxylamine may give it an advantage over doxylamine as a sleep aid in this regard. Antihistamines like doxylamine are sedating initially but tolerance occurs with repeated use and can result in rebound insomnia upon discontinuation. Occasional case reports of coma and rhabdomyolysis have been reported with doxylamine overdose. This pattern is in contrast to diphenhydramine. Studies of doxylamine's carcinogenicity in mice and rats have produced positive results for both liver and thyroid cancer, especially in the mouse. The carcinogenicity of the drug in humans is not well-studied, and the International Agency for Research on Cancer lists the drug as "not classifiable as to its carcinogenicity to humans". Continuous and/or cumulative use of anticholinergic medications, including first-generation antihistamines, is associated with a higher risk of cognitive decline and dementia in older people.
== Current research == In her Yale laboratory, Horsley has studied the cellular and molecular pathways involved in skin tissue development and maintenance, as well as the relationship between fat cells in the skin, wound healing, regeneration of hair follicles, and the formation of keratinocytes during embryonic development. Horsley currently studies adult stem cells in epithelial skin tissue and how these cells contribute to wound healing and the development of cancer, using the mouse as a genetic model system. Horsley revolutionized the field of epithelial stem cell biology by identifying skin adipocyte stem cells, establishing a major role for these progenitor cells in regulating turnover, rejuvenation and wound repair of the skin epidermis and hair follicles. She found that within epithelial tissues, cells tend to confine to distinct micro-environments. Mechanisms of adipocyte cells in tissue homeostasis and regeneration are not well understood. Horsley discovered the source of both fat cells and immune cells as local signals, as the hormone signal, prolactin, is responsible for stem cell activity and the regeneration of skin cells. Together, her laboratory also found that cell differentiation of adipocytes and hair growth occur simultaneously, and when the cell differentiation process (adipogenesis) ceases, hair growth stops and the follicles deteriorate. Her team identified specific adipose progenitors in the skin, which indicated the necessity of these cells to sufficiently induce hair follicle growth.
Sources: en.wikipedia.org
AMP + H2O + H+ → IMP + NH3 The second stage is the formation of adenylosuccinate from IMP and the amino acid aspartate, which is coupled to the energetically favourable hydrolysis of GTP, and catalysed by the enzyme adenylosuccinate synthetase:
Days after the strike had ended, the Governor Sir Tom Hickinbotham conferred with almost all of the tribal leaders from the Aden Protectorates, where broad agreement was reached that they should "seek some form of close association with each other". In May 1958 a state of emergency was declared and there were a number of bombings until the arrest of the principal instigators in July. However, in October 1958 there was a general strike, which was accompanied by widespread rioting and disorder which ended in the deportation of 240 Yemenis from Aden, as claimed by author Gillian King: "By ignoring the views of the local labour force, the British pushed much of the Arab population into opposition against their rule, who previously had been by no means captivated by Nasser". At the time much of the blame for these disturbances was placed on the broadcasts from Radio Cairo encouraged by Nasser's anti-imperialist and Arab Nationalist regime there, as claimed by author R. J. Gavin: "Radio Cairo began to speak in the tones of revolutionary Arab Nationalism. Men who had long lived in isolation now found a common political language and a breathtaking, liberating community of sentiment across the Arab world". In December 1963 there was a grenade attack by an unidentified assailant on the high commissioner who was unharmed; however, three bystanders were killed.
=== Models === A variety of theoretical frameworks exist to model optical, electronic, and structural properties of quantum dots. These may be broadly divided into quantum mechanical, semiclassical, and classical.
On the other hand, inside a population, the presence of many different alleles ensures there will always be an individual with a specific MHC molecule able to load the correct peptide to recognize a specific microbe. The evolution of the MHC polymorphism ensures that a population will not succumb to a new pathogen or a mutated one, because at least some individuals will be able to develop an adequate immune response to win over the pathogen. The variations in the MHC molecules (responsible for the polymorphism) are the result of the inheritance of different MHC molecules, and they are not induced by recombination, as it is the case for the antigen receptors. Because of the high levels of allelic diversity found within its genes, MHC has also attracted the attention of many evolutionary biologists, as well as disease specialists.
=== Cytokines === Cytokines can manipulate neurotransmissions creating sickness behavior, characterized by malaise and fatigue. In animal models, IL-1b stimulates serotonin release and increases activity of GABA. Lipopolysaccharide challenges also inhibit activity of histaminergic and dopaminergic neurons.
Sources: en.wikipedia.org
'Arctic Queen' or 'Polar bear' (double white) 'Clematis Josephine' or 'Clematis Evijohill' (pinkish-mauve) 'Marie Boisselot' (white) 'Miss Bateman' (white with red stamens) 'Nelly Moser' (white with pink stripes) 'Niobe' (maroon) 'The President' (blue) In the Clematis integrifolia group (or Integrifolia group) are non- or semi-climbing plants that flower on the current year's growth. These include the violet-pink 'Arabella'. In the late large-flowered group, which flower on the current year's growth, are:
GeV, predicting a longer proton lifetime. However, SUSY also introduces dimension 5 operators that can contribute to proton decay with much shorter decay times. To suppress these contributions extra symmetries are invoked, with the result that decays to quarks and leptons in other generation than (u, d, e,
=== Ancient Egypt === Over a dozen medical papyri have been preserved, most notably the Edwin Smith Papyrus (the oldest extant surgical handbook) and the Ebers Papyrus (a handbook of preparing and using materia medica for various diseases), both from around 1600 BCE. Ancient Egypt is also known for developing embalming, which was used for mummification, in order to preserve human remains and forestall decomposition.
When an organic compound is fermented, it is broken down to a simpler molecule and releases electrons. The electrons are transferred to a redox cofactor, which, in turn, transfers them to an organic compound. ATP is generated in the process, and it can be formed via substrate-level phosphorylation or by ATP synthase.
Sources: en.wikipedia.org
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.
The extension was introduced to slow enzymatic breakdown of the peptide in biological systems. Natural ACTH fragments are degraded rapidly by peptidases. Adding the tripeptide was intended to extend the window during which the molecule remains intact.
Most published work consists of animal experiments conducted in a small number of laboratories. Human data are limited in number and size. Whether the observed effects translate into reliable clinical benefit is still unresolved.
The main proposal is modulation of neurotrophic factors such as brain-derived neurotrophic factor, supported largely by animal experiments. Receptor-level targets have not been firmly established. Most reviews describe the mechanism as only partially characterized.