A practical reference on ACTH fragment: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
从分子层面看，Semax 是线性七肽，没有二硫键、糖基或脂链修饰，N 端为游离氨基，C 端为游离羧基。分子含组氨酸与谷氨酸侧链，因此在水和甲醇等极性溶剂中溶解良好，在非极性溶剂中溶解有限。计算分子量约为 814 Da，与其质子化离子的质荷比吻合，可用于质谱确认。
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。
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 |
|---|---|---|
| 分子式 | C37H51N9O10S | 游离碱形式 |
| 等电点 | 约 6.5 | 估算值，随缓冲体系变化 |
| 主要降解途径 | 水解与氧化 | 侧链氧化最为常见 |
| 溶液储存 | 2 至 8 摄氏度避光 | 避免反复冻融 |
| 常规分析手段 | 反相色谱与质谱联用 | 氨基酸分析辅助核对 |
The mechanisms attributed to semax are inferred from animal and cell studies rather than traced to one confirmed target. The most frequently cited pathway involves increased expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal and cortical tissue. Some work points to engagement of melanocortin receptors, particularly MC4, which the parent ACTH fragment can activate. Effects on dopaminergic and serotonergic signalling have also been reported. No single account explains all observed results, and the relative weight of each pathway remains unsettled.
Published studies examine a fairly narrow set of endpoints. Rodent experiments commonly measure maze learning, infarct volume after induced ischemia, and tissue levels of neurotrophic factors. Clinical reports from Russian centres describe attention, memory and recovery scores in patients after stroke or transient ischemic attack. Most of those human studies are small and few have been repeated by independent groups. Outcome measures differ between studies, which limits direct comparison.
Circulation time for the peptide is short because peptidases cleave it readily. The Pro-Gly-Pro tail is thought to slow breakdown compared with the bare ACTH fragment, but the gain appears modest. Absorption after intranasal dosing is limited, and only a fraction of a dose is expected to reach the central nervous system. Laboratory concentrations therefore sit well above levels achieved systemically, a gap that complicates translation from bench findings to clinical claims.
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.
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.
Lyophilized material is chemically stable for extended periods when kept dry, cold, and protected from light. The powder is hygroscopic, so vials should be warmed to room temperature before opening to reduce condensation on the contents. Once dissolved, the peptide is far less stable because peptide bonds are susceptible to hydrolysis and the methionine residue can oxidize. Solutions are typically aliquoted and held at 2-8 °C for short intervals or frozen for longer ones, and repeated freeze-thaw cycles should be avoided.
Routine characterization relies on reversed-phase high-performance liquid chromatography to establish purity and on mass spectrometry to confirm molecular identity. Electrospray ionization and matrix-assisted laser desorption ionization are both used for mass verification. Amino acid analysis and peptide mapping can detect sequence errors. Common impurities include truncated sequences, methionine sulfoxide formed by oxidation, and deamidated products. Chromatograms are usually recorded near 214 nm, where the peptide backbone absorbs, and purity is reported as the percentage area of the principal peak.
== Other uses == "Sip", a song from Joeboy Stranka Ivana Pernara, a Croatian political party Shelter-in-place, an emergency procedure Sip (kinship) Sip or Zip, one of the 18 months of the Haab', a part of the Maya calendric system SIP Grenade, self igniting phosphorus The Society of International Photographers, a not-for-profit organization founded in 1936 Soviet Interview Project, a research project conducted in the early 1980s Strangers in Paradise, an award-winning comic book State Implementation Plan, a United States state plan for complying with the federal Clean Air Act Sub-irrigated planter, a type of gardening container Sip as in SipSipStefan "Sip", a 2017 song by Chris Brown from Heartbreak on a Full Moon
Common barbiturate side effects include nausea, hypotension, headache, drowsiness, and skin rash. More serious side effects can include confusion, slow breathing, hallucination, fainting, and coma. Rare side effects may include agranulocytosis, liver injury, megaloblastic anemia, or Stevens-Johnson Syndrome.
Furthermore, these findings emphasize the dual role of RAGE in both EV biogenesis and as a mediator of inflammation through vesicular cross-talk, which has implications for targeting RAGE-EV interactions in therapeutic strategies aimed at mitigating inflammatory diseases.
A number of Singaporean writers such as Tan Swie Hian and Kuo Pao Kun have contributed work in more than one language. Singapore has a diverse music culture that ranges from pop and rock, to folk and classical. Western classical music plays a significant role in the cultural life in Singapore, with the Singapore Symphony Orchestra (SSO) instituted in 1979. Other notable western orchestras in Singapore include Singapore National Youth Orchestra and the community-based Braddell Heights Symphony Orchestra. Many orchestras and ensembles are also found in secondary schools and junior colleges. Various communities have their own distinct ethnic musical traditions: Chinese, Malays, Indians, and Eurasians. With their traditional forms of music and various modern musical styles, the fusion of different forms account for the musical diversity in the country. The nation's lively urban musical scene has made it a centre for international performances and festivals in the region. Some of Singapore's best known pop singers include Stefanie Sun, JJ Lin, Liang Wern Fook, Taufik Batisah and Dick Lee, who is famous for composing National Day theme songs, including Home.
Sources: en.wikipedia.org
Muscular dystrophy (MD) is a genetically and clinically heterogeneous group of rare neuromuscular diseases that cause progressive weakness and breakdown of skeletal muscles over time. The disorders differ as to which muscles are primarily affected, the degree of weakness, how fast they worsen, and when symptoms begin. Some types are also associated with problems in other organs. Over 30 different disorders are classified as muscular dystrophies. Of those, Duchenne muscular dystrophy (DMD) accounts for approximately 50% of cases and affects males beginning around the age of four. Other relatively common muscular dystrophies include Becker muscular dystrophy, facioscapulohumeral muscular dystrophy, and myotonic dystrophy, whereas limb–girdle muscular dystrophy and congenital muscular dystrophy are themselves groups of several – usually extremely rare – genetic disorders. Muscular dystrophies are caused by mutations in genes, usually those involved in making muscle proteins. The muscle protein dystrophin is in most muscle cells and works to strengthen the muscle fibers and protect them from injury as muscles contract and relax. It links the muscle membrane to the thin muscular filaments within the cell. Dystrophin is an integral part of the muscular structure. An absence of dystrophin can cause impairments: healthy muscle tissue can be replaced by fibrous tissue and fat, causing an inability to generate force. Respiratory and cardiac complications can occur as well. These mutations are either inherited from parents or may occur spontaneously during early development.
== History == Strychnine was the first alkaloid to be identified in plants of the genus Strychnos, family Loganiaceae. Strychnos, named by Carl Linnaeus in 1753, is a genus of trees and climbing shrubs of the Gentianales order. The genus contains 196 various species and is distributed throughout the warm regions of Asia (58 species), America (64 species), and Africa (75 species). The seeds and bark of many plants in this genus contain strychnine. The toxic and medicinal effects of Strychnos nux-vomica have been well known from the times of ancient India, although the chemical compound itself was not identified and characterized until the 19th century. The inhabitants of these countries had historical knowledge of the species Strychnos nux-vomica and Saint-Ignatius' bean (Strychnos ignatii). Strychnos nux-vomica is a tree native to the tropical forests on the Malabar Coast in Southern India, Sri Lanka and Indonesia, which attains a height of about 12 metres (39 ft). The tree has a crooked, short, thick trunk and the wood is close grained and very durable. The fruit has an orange color and is about the size of a large apple with a hard rind and contains five seeds, which are covered with a soft wool-like substance. The ripe seeds look like flattened disks, which are very hard. These seeds are the chief commercial source of strychnine and were first imported to and marketed in Europe as a poison to kill rodents and small predators. Strychnos ignatii is a woody climbing shrub of the Philippines.
=== School lunches === The reaction against the product has also been partially credited to a Change.org petition that has landed over a quarter million signatures to ban it in school meals. After some parents and consumer advocates insisted the product be removed from public schools, the USDA indicated, beginning in fall 2012, that it would give school districts the choice between ground beef with or without LFTB. CBS News reported that Chicago Public schools may have served "pink slime" in school lunches. While some school districts have their own suppliers, many school districts purchase beef directly from the USDA and do not know what is in the beef. For the year 2012, the USDA planned on purchasing 7 million pounds of lean beef trimmings for the U.S. national school lunch program. USDA spokesman Mike Jarvis stated that of the 117 million pounds of beef ordered nationally for the school lunch program in the past year, 6% was LFTB. An analysis of California Department of Education data indicated that "anywhere from none to nearly 3 million pounds of beef from the USDA that was served in California schools last year could have contained lean finely textured beef". According to the USDA, the cost differential between ground beef with and without the additive has been estimated at approximately 3%.
Sources: en.wikipedia.org
Physician self-referral is the practice of a physician referring a patient to a medical facility in which the physician has a financial interest, be it ownership, investment, or a structured compensation arrangement. Critics argue that this practice is an inherent conflict of interest, because the physician benefits from the physician's own referral. They suggest that such arrangements may encourage overutilization of services, in turn driving up health care costs. In addition, they believe that it would create a captive referral system, which limits competition by other providers. Those who defend the practice contend that these problems are not widespread. They argue that physicians who own, invest in, or operate medical facilities are responding to a need for medical services which would otherwise not be met, particularly in medically under-served areas. In addition, it is often the case that physician owned entities present a lower-cost alternative to the facilities that are located at hospitals. This is due mostly to higher overhead costs that hospitals must pass down to their services.
CPA is widely available throughout the world, and is marketed in almost every developed country, with the notable major exceptions of the United States and Japan. In almost all countries in which CPA is marketed, it is available both alone and in combination with an estrogen in birth control pills. CPA is marketed widely in combination with both ethinylestradiol and estradiol valerate. CPA-containing birth control pills are available in South Korea, but CPA as a standalone medication is not marketed in this country. In Japan and South Korea, the closely related antiandrogen and progestin chlormadinone acetate, as well as other medications, are used instead of CPA. Specific places in which CPA is marketed include the United Kingdom, elsewhere throughout Europe, Canada, Australia, New Zealand, South Africa, Latin America, and Asia. CPA is not marketed in most of Africa and the Middle East. It has been said that the lack of availability of CPA in the United States explains why there are relatively few studies of it in the treatment of androgen-dependent conditions such as hyperandrogenism and hirsutism in women.
==== Oral testosterone undecanoate ==== Instead of in its free unesterified form, testosterone is used by oral administration in the form of testosterone undecanoate. Due to the unique chemical properties afforded by its long fatty acid ester chain, this testosterone ester is partially absorbed from the gastrointestinal tract into the lymphatic system, thereby bypassing a portion of first-pass metabolism in the liver and producing measurable increases in testosterone levels at much lower doses than free testosterone. Of oral testosterone undecanoate that reaches circulation, 90 to 100% is transported lymphatically. However, its duration remains short, with an elimination half-life of 1.6 hours and a mean residence time of 3.7 hours. Oral testosterone undecanoate is provided as 40 mg oil-filled capsules and requires administration 2 to 4 times per day (i.e., 80 to 160 mg/day) for substitution in men. It must be taken with food containing at least a moderate or "normal" amount of fat in order to achieve adequate absorption. In addition, there is very high interindividual variability in levels of testosterone with oral testosterone undecanoate. The bioavailability of oral testosterone undecanoate taken with food is 3 to 7%. Inappropriately high levels of testosterone have been observed with 10 to 40 mg/day oral testosterone undecanoate in women. The oral bioavailability of testosterone undecanoate in young women after a single 40 mg dose was found to be 6.8 ± 3.3%.
Sources: en.wikipedia.org
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。
甲硫氨酸侧链含硫醚，在氧气、光照或金属离子存在时容易被氧化。氧化产物极性略增，常在色谱图上表现为主峰之前的肩峰或前伸峰。
通常建议冷藏避光，并在较短时间内使用。不存在适用于所有配方的统一期限，具体取决于浓度、缓冲体系与容器材质。
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.