synthetic heptapeptide 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.
Last reviewed on 2025-11-15. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
稳定性主要由水解与氧化两条路径支配。肽键在中性或弱酸性条件下相对稳定，遇到强碱或长时间高温则明显断裂；甲硫氨酸侧链容易被氧化成亚砜，使主峰前移并拉低实际含量。金属离子、光照和反复冻融会进一步促进降解或聚集。冻干粉在低温避光条件下可存放较长时间，配制后的水溶液通常需要冷藏并尽快用完。
纯度评估以反相高效液相色谱为主，通过主峰面积百分比给出粗略结果，再配合电喷雾质谱核对分子量。氨基酸分析可验证组成比例，手性色谱或毛细管电泳用于检查残基构型。常见杂质包括缺失序列的短肽、氧化产物与二聚体。由于多数市售品不附带完整检验报告，独立第三方检测常被用来核实标称值。
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Contains one methionine sulfur atom |
| Molecular mass | Approximately 814 Da | Consistent with a seven-residue peptide |
| Appearance | White to off-white powder | Typical lyophilized form |
| Solubility | Freely soluble in water | Also soluble in dimethyl sulfoxide |
| Typical storage | -20 °C, desiccated | Limits methionine oxidation |
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 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.
Claims about enhanced focus, memory, or mood in healthy people rest mostly on anecdotal reports and community discussion rather than on controlled data. It remains unclear whether any cognitive benefit observed in patients recovering from brain injury would extend to uninjured users. Dose-response relationships, long-term safety, and interactions with other drugs are not well characterized in the peer-reviewed literature. Questions about optimal route of administration and treatment duration likewise remain open.
Semax binds to melanocortin receptors and is thought to influence neuronal survival and plasticity rather than to act through the adrenal axis. Laboratory work has shown increased expression of brain-derived neurotrophic factor and nerve growth factor in treated tissue. Changes in c-Fos, a marker of neuronal activation, have also been reported. Because the peptide is rapidly degraded by peptidases, its effects are generally attributed to downstream signaling cascades rather than to sustained receptor occupancy.
Terminology around the compound varies by source. It appears in catalogues and papers as Semax, as the heptapeptide ACTH(4-7)-Pro-Gly-Pro, and under various alphanumeric laboratory codes used by individual suppliers. These names refer to the same sequence but may imply different salt forms, purity grades, or counter-ions. Peptide databases usually list the free base mass, while product descriptions sometimes report acetate or trifluoroacetate salts with a different formula weight. Because naming conventions for research peptides are not standardised across vendors, checking the declared sequence and measured mass is more reliable than relying on a trade name alone.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its design combines the ACTH(4-7) core fragment with a C-terminal Pro-Gly-Pro extension, a modification intended to improve stability and prolong activity. The molecule is hydrophilic, carries no lipid chains or glycosylation, and has a theoretical mass just over 810 daltons in its free form. All seven residues are proteinogenic amino acids, so no non-natural building blocks appear in the backbone. A free N-terminal methionine and C-terminal proline define the unmodified parent peptide.
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
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.
Dissolution is normally performed in water, phosphate-buffered saline, or normal saline, since the peptide is freely soluble in aqueous media and is rarely handled with strong organic solvents. Solution pH should be kept near neutral, because extreme acidity or alkalinity accelerates backbone hydrolysis and encourages oxidation of the methionine side chain. Once dissolved, the material is less stable than the dry powder and is commonly divided into single-use portions and frozen. Buffers containing primary amines, such as Tris, are often avoided because of possible side reactions.
There are as many mass-balance equations as there are reagents, A, B..., so if the equilibrium constant values are known, there are n mass-balance equations in n unknowns, [A], [B]..., the so-called free reagent concentrations. Solution of these equations gives all the information needed to calculate the concentrations of all the species. Thus, the importance of equilibrium constants lies in the fact that, once their values have been determined by experiment, they can be used to calculate the concentrations, known as the speciation, of mixtures that contain the relevant species.
==== Indoor air ==== Humans spend more and more time in a confined atmosphere (around 80-90% of the time in a building or vehicle). According to the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) and various actors in France, the CO2 rate in the indoor air of buildings (linked to human or animal occupancy and the presence of combustion installations), weighted by air renewal, is "usually between about 350 and 2,500 ppm". In homes, schools, nurseries and offices, there are no systematic relationships between the levels of CO2 and other pollutants, and indoor CO2 is statistically not a good predictor of pollutants linked to outdoor road (or air, etc.) traffic. CO2 is the parameter that changes the fastest (with hygrometry and oxygen levels when humans or animals are gathered in a closed or poorly ventilated room). In poor countries, many open hearths are sources of CO2 and CO emitted directly into the living environment.
=== Pharmacodynamics === Mestanolone is an AAS, with both androgenic and anabolic effects. It is very similar in its effects to androstanolone (dihydrotestosterone; DHT), and can be thought of as an orally active version of this AAS. Due to inactivation by 3α-hydroxysteroid dehydrogenase (3α-HSD) in skeletal muscle, mestanolone is described as a very poor anabolic agent, similarly to androstanolone and mesterolone. As mestanolone is 5α-reduced, it cannot be aromatized and hence has no propensity for estrogenic side effects such as gynecomastia. The drug also has no progestogenic activity. Like other 17α-alkylated AAS, mestanolone is hepatotoxic.
c) Shows that it is more likely than not that Mr Galloway knew about and was complicit in what was happening. The Commissioner stated that he did not have "access to bank accounts held either solely by Mr Galloway or jointly by him with others".
Sources: en.wikipedia.org
January 14 The Senate is unable to pass a resolution which would bar the president from taking further military action in Venezuela without congressional approval after two Republicans switch their initial vote. A Verizon outage affects at least 175,000 people. January 17 – Trump confirms that European countries will be hit with a 10% tariff on "all or any goods" exported to the US from February 1, amid the dispute over Greenland. January 19 – The Indiana Hoosiers defeat the Miami Hurricanes 27–21 in the 2026 College Football Playoff National Championship, winning their first national title. January 20 – DHS launches "Operation Catch of the Day", a surge in immigration enforcement in Maine, primarily in the cities of Lewiston and Portland.
Synaptic degeneration and death of nerve cells are defining features of Alzheimer's disease (AD), the most prevalent age-related neurodegenerative disorders. In AD, neurons in the hippocampus and basal forebrain (brain regions that subserve learning and memory functions) are selectively vulnerable. Studies of postmortem brain tissue from AD people have provided evidence for increased levels of oxidative stress, mitochondrial dysfunction and impaired glucose uptake in vulnerable neuronal populations. Studies of animal and cell culture models of AD suggest that increased levels of oxidative stress (membrane lipid peroxidation, in particular) may disrupt neuronal energy metabolism and ion homeostasis, by impairing the function of membrane ion-motive ATPases, glucose and glutamate transporters. Such oxidative and metabolic compromise may thereby render neurons vulnerable to excitotoxicity and apoptosis. Recent studies suggest that AD can manifest systemic alterations in energy metabolism (e.g., increased insulin resistance and dysregulation of glucose metabolism). Emerging evidence that dietary restriction can forestall the development of AD is consistent with a major "metabolic" component to these disorders, and provides optimism that these devastating brain disorders of aging may be largely preventable.
Foot-and-mouth disease virus (FMDV) is a virus in the genus Aphthovirus that causes foot-and-mouth disease in cattle. As a member of the family Picornaviridae, FMDV is a positive-sense, single-stranded RNA virus. 2A is located between the capsid proteins and polymerases and proteases required for the capsid assembly in the late stages of the infection. The incomplete ribosomal skipping during the viral RNA translation mediated by the 2A results in "ribosome drop off" in some cases, after which the translation doesn't restart. This leads to a prevalence of the N-terminal proteins and allows for the increased production of the structural proteins relative to the non-structural proteins.
=== 1987 Goiânia, Goiás, Brazil === In the Goiânia accident of 1987, an improperly disposed of radiation therapy system from an abandoned clinic in Goiânia, Brazil, was removed, then cracked to be sold in junkyards. The glowing caesium salt was then sold to curious, unaware buyers. This led to four confirmed deaths and several serious injuries from radiation contamination.
== Manufacturing == Commercial preparations of lente insulin are standardized to 30% semilente (amorphous precipitates of insulin), and 70% ultralente (crystallized insulin). In early versions, the semilente insulin was extracted from pigs, and the ultralente insulin was extracted from cows.
Sources: en.wikipedia.org
Prenatal vitamins are dietary supplements commonly given to pregnant women to supply nutrients that may reduce health complications for the mother and fetus. Although prenatal vitamins are not meant to substitute for dietary nutrition, prenatal supplementation may be beneficial for pregnant women at risk of nutrient deficiencies because of diet limitations or restrictions. The most common components in prenatal vitamins include vitamins B6, folate, B12, C, D, E, iron and calcium. Sufficient intake of vitamin B6 can lower the risk of early pregnancy loss and relieve symptoms of morning sickness. Folate is also an essential nutrient for pregnant women to prevent neural tube defects. In 2006, the World Health Organization endorsed the recommendation for women of child-bearing age to consume 400 micrograms of folate through the diet daily if planning a pregnancy. A 2013 review found folic acid supplementation during pregnancy did not affect the mother's health other than a risk reduction on low pre-delivery serum folate and megaloblastic anemia. There is little evidence to suggest that vitamin D supplementation improves prenatal outcomes in hypertensive disorders and gestational diabetes. Evidence does not support the routine use of vitamin E supplementation during pregnancy to prevent adverse events, such as preterm birth, fetal or neonatal death, or maternal hypertensive disorders. Iron supplementation can lower the risk of iron deficiency anemia for pregnant women.
From 1878 to 1955 the Third Avenue El ran above the Bowery, further darkening its streets, populated largely by men. "It is filled with employment agencies, cheap clothing and knickknack stores, cheap moving-picture shows, cheap lodging-houses, cheap eating-houses, cheap saloons", writers in The Century Magazine found it in 1919. "Here, too, by the thousands come sailors on shore leave, – notice the 'studios' of the tattoo artists, – and here most in evidence are the 'down and outs'". Prohibition eliminated the Bowery's numerous saloons: One Mile House, the "stately old tavern... replaced by a cheap saloon" at the southeast corner of Rivington Street, named for the battered milestone across the way, where the politicians of the East Side had made informal arrangements for the city's governance, was renovated for retail space in 1921, "obliterating all vestiges of its former appearance", The New York Times reported. Restaurant supply stores were among the businesses that had come to the Bowery, and many remain to this day. Pressure for a new name after World War I came to naught and in the 1920s and 1930s, it was an impoverished area. From the 1940s through the 1970s, the Bowery was New York City's "Skid Row," notable for "Bowery Bums" (disaffected alcoholics and homeless persons). Among those who wrote about Bowery personalities was New Yorker staff member Joseph Mitchell (1908–1996).
=== Excitotoxicity and glutamate receptors === Excitotoxicity is phenomenon in which glutamate receptors are inappropriately activated. It can be caused by prolonged excitatory synaptic transmission in which high levels of glutamate neurotransmitter cause excessive activation in a postsynaptic neuron that can result in the death of the postsynaptic neuron. Following brain injury (such as from ischemia), it has been found that excitotoxicity is a significant cause of neuronal damage. This can be understandable in the case where sudden perfusion of blood after reduced blood flow to the brain can result in excessive synaptic activity caused by the presence of increased glutamate and aspartate during the period of ischemia.
An antiscalant is a chemical or pre-treatment chemical that prevents the formation of scale, or crystallized mineral salts, commonly used in water purification systems, pipelines, and cooling tower applications. Antiscalants are also known as scale inhibitor agents. Scale formation occurs when the concentration of dissolved salts in water exceeds their solubility limits, leading to the precipitation of these salts onto surfaces as hard deposits. Antiscalants dissolve the substances accumulated near the membrane surface and reduce the rate of fouling. They play a crucial role in preventing scale formation, thus improving the efficiency and longevity of industrial equipment and processes.
== Industrial functionality == A number of halogenated compounds are environmentally toxic industrial by-products, and it has been suggested that haloalkane dehalogenases may be useful catalysts for their biodegradation, with potential applications in bioremediation. In biocatalysis, there is a standing interest in these enzymes, particularly for the production of optically pure alcohols. Therefore, the identification of dehalogenating enzymes with appropriate selectivity patterns is very important in terms of their industrial utility.
Sources: en.wikipedia.org
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.
Most published work uses intranasal administration, matching the route of the registered Russian formulation. Some animal experiments use intravenous or intraperitoneal injection. The route matters because the intact peptide is cleared rapidly from blood, so exposure differs between methods.
A purity value describes the share of the powder accounted for by the target peptide, usually by high-performance liquid chromatography. It does not confirm that the sequence is correct, which requires mass spectrometry or amino acid analysis. Purity and identity are separate checks.
电喷雾或基质辅助激光解吸电离质谱是常用手段，测得的质子化离子质荷比可换算为分子量。结果与理论值落在合理误差内，才支持结构一致的判断。