A practical reference on heptapeptide: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-06-21 and is reviewed periodically as new material appears.
Verification of a supplied batch generally combines a certificate of analysis with independent testing, because certificates are self-reported documents. A typical package includes a chromatographic trace, a mass spectrum, and a stated water or counter-ion content. Batch-to-batch consistency matters more than a single purity figure when results are compared across experiments. No single mandatory standard governs research-grade peptide release, so laboratories are expected to define their own acceptance criteria. Residual trifluoroacetate from purification is a frequently overlooked counter-ion.
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.
各国监管态度分化明显。俄罗斯按处方药管理，部分东欧国家留有使用记录；欧盟与美国未批准其作为药物上市，市面流通品通常标注为研究用化学品。身份差异意味着标示含量、纯度与无菌性缺少统一核查。体育领域还牵涉反兴奋剂名录，跨境携带则受目的地药品法规约束。
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。
| Property | Value | Notes |
|---|---|---|
| Typical purity | 95% or higher | By reversed-phase HPLC area |
| Identity method | Electrospray mass spectrometry | Confirms molecular mass |
| Purity method | Reversed-phase HPLC | Detection near 214 nm |
| Primary degradation | Methionine oxidation | Sulfoxide product, +16 Da |
| Solution storage | 2-8 °C, short term | Aliquot to avoid freeze-thaw |
常规纯度与身份确认依赖反相高效液相色谱，并辅以质谱测定分子量。氨基酸组成分析可用于验证序列构成，肽图分析则能进一步定位修饰或降解产物。杂质谱通常关注缺失序列肽、截短片段和氧化产物。不同方法的检出限并不相同，因此各实验室报告的纯度数值不宜直接横向比较。
多数实验室与市售的 Semax 以冻干粉形式提供。冻干粉通常建议保存在 -20 °C 或更低温度下，同时避免光照与反复升温。短期运输有时采用冷藏条件，但长期保存仍以冷冻为主。分包操作应尽量减少开盖次数，以降低吸湿和微生物污染的风险。开封后若未一次用完，建议在干燥环境中密封并尽快放回低温储存。
溶液状态的稳定性明显低于冻干粉。肽类在水溶液中可能经历水解、氧化与聚集，其中甲硫氨酸和天冬酰胺等残基常是敏感位点。Semax 含有甲硫氨酸，因此氧化风险相对突出。工作液一般主张现配现用，或冷藏并在数日内用尽。缓冲液种类、pH 和离子强度都会影响降解速率，而关于最佳条件的公开数据并不统一。
The parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
Semax is a synthetic peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
Semax is normally supplied as a lyophilized powder, and that form is the most stable. Suppliers commonly recommend storage at -20 °C in a desiccated container protected from light, with short-term handling at room temperature limited to weighing and transfer. Powder that has absorbed moisture degrades faster, so vials should be warmed to ambient temperature before opening to prevent condensation on the contents. Hygroscopic behavior is typical of short hydrophilic peptides, and humidity control matters more than temperature alone for long-term retention.
Once dissolved, the peptide is considerably less stable than the solid. Aqueous solutions are usually prepared at neutral to slightly acidic pH, filtered, and divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are a common cause of avoidable loss and are best prevented by never refreezing a thawed aliquot. Adsorption to plastic and glass surfaces can lower the measured concentration of dilute solutions, particularly below roughly 0.1 mg/mL. Buffer choice, salt content, and container material all influence how much peptide remains detectable after storage.
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.
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.
== Etymology == The scientific name Crotalus is derived from Ancient Greek: κρόταλον, romanized: krótalon, lit. 'castanet'. The name Sistrurus is the Latinized form of the Greek for "tail rattler" (Σείστρουρος, Seístrouros) and shares its root with the ancient Egyptian musical instrument the sistrum, a type of rattle.
Her testimony contributed to UN Security Council sanctions being imposed on two Houthi security officials in February 2021. It was later alleged that she admitted some of her testimony was untrue, and she had embellished claims at the request of Saudi officials.
Several articles demonstrate the efficacy of sugar application in the treatment of ulcers of diabetic origin, as well as necrotic wounds. A study of 50 leg ulcer patients demonstrated the efficacy of a weekly treatment consisting solely of a 60% / 40% glucose/vaseline mixture applied to the wound, without debridement. Complementary compression therapy is used to reduce the effects of venous insufficiency. There is uncertain evidence whether alginate dressing is effective in the healing of venous ulcers when compared to hydrocolloid dressing or plain non-adherent dressing. It is uncertain whether therapeutic ultrasound improves the healing of venous ulcers.
=== Directly affiliated public institutions === China Cooperative Times Management Cadre College Technology Promotion Center Vocational Skills Appraisal and Guidance Center Information Center Audiovisual Center Commercial Printing Center Nanjing Institute for Comprehensive Utilization of Wild Plants Jinan Fruit Research Institute Hangzhou Tea Research Institute Zhengzhou Cotton and Hemp Engineering Technology Design and Research Institute Beijing Institute of Commercial Machinery Tianjin Institute of Renewable Resources Kunming Edible Fungi Research Institute Xi'an Institute of Lacquer Coatings
Two-thirds of the increase in autism are estimated by an April 2025 Scientific American article to be due to better diagnosis and the desire of parents and schools to get started with early intervention. However, this same article estimates that one-third is due to an actual increase in autism from a variety of factors such as mothers in richer countries being older on average at childbirth, the ability to keep more premature children alive and healthy, and small-particle air pollution during the 3rd trimester which can cause an inflammatory response. On October 9, 2025, Trump and U.S. secretary of health and human services Robert Kennedy Jr. alleged a link between autism and circumcisions. Kennedy cited a 2015 Danish study to justify this claim. The validity of Kennedy's assertion about circumcisions being linked to autism has also been challenged by scientists and medical experts.
Sources: en.wikipedia.org
In 2012, under prosecution by the United States Department of Justice (DoJ) based on combined investigations of the Department of Health and Human Services (HHS-OIG), FDA and FBI, primarily concerning sales and marketing of the drugs Avandia, Paxil and Wellbutrin, GSK pleaded guilty to promotion of drugs for unapproved uses, failure to report safety data and kickbacks to physicians in the United States and agreed to pay a US$3 billion (£1.9bn) settlement. It was the largest health-care fraud case to date in the US and the largest settlement in the pharmaceutical industry.
=== Shortage === In the US, some compounding pharmacies prepare compounded versions of a drug on the FDA's drug shortages list if the compounded drug meets certain conditions detailed in federal law. The US Food and Drug Administration (FDA) declared a shortage of tirzepatide in December 2022. It declared the shortage over in October 2024, but enforcement was delayed until the end of 2024, after a lawsuit by compounding pharmacies challenged the declaration. The US National Association of Boards of Pharmacy says there are tens of thousands of online pharmacies operating out of compliance with state and federal regulations or the association's recommendations. The FDA has not evaluated these for safety and effectiveness and they are thus considered not to have been shown to be safe or effective.
Corneal opacification is a term used when the cornea of the eye loses its transparency. The term corneal opacity is used particularly for the loss of transparency of cornea due to scarring. Transparency of the cornea is dependent on the uniform diameter and the regular spacing and arrangement of the collagen fibrils within the stroma. Alterations in the spacing of collagen fibrils in a variety of conditions including corneal edema, scars, and macular corneal dystrophy is clinically manifested as corneal opacity. The term corneal blindness is commonly used to describe blindness due to corneal opacity. Keratoplasty also known as corneal transplantation is the main treatment option for visual improvement in corneal opacity. Other treatments which may improve visual outcome includes optical iridectomy, phototherapeutic keratectomy and keratoprosthesises. Corneal tattooing may be used for improving the cosmetic appearance of the opaque eye.
=== Pharmacokinetics === Gabapentin is absorbed from the intestines by an active transport process mediated via an amino acid transporter, presumably, LAT2. As a result, the pharmacokinetics of gabapentin is dose-dependent, with diminished bioavailability and delayed peak levels at higher doses. The oral bioavailability of gabapentin is approximately 80% at 100 mg administered three times daily once every 8 hours, but decreases to 60% at 300 mg, 47% at 400 mg, 34% at 800 mg, 33% at 1,200 mg, and 27% at 1,600 mg, all with the same dosing schedule. Drugs that increase the transit time of gabapentin in the small intestine can increase its oral bioavailability; when gabapentin was co-administered with oral morphine, the oral bioavailability of a 600 mg dose of gabapentin increased by 50%. Gabapentin at a low dose of 100 mg has a Tmax (time to peak levels) of approximately 1.7 hours, while the Tmax increases to 3 to 4 hours at higher doses. Food does not significantly affect the Tmax of gabapentin and increases the Cmax and area-under-curve levels of gabapentin by approximately 10%. Gabapentin can cross the blood–brain barrier and enter the central nervous system. Gabapentin concentration in cerebrospinal fluid is approximately 9–14% of its blood plasma concentration. Due to its low lipophilicity, gabapentin requires active transport across the blood–brain barrier. The LAT1 is highly expressed at the blood–brain barrier and transports gabapentin across into the brain.
The starting material is 5-aminoimidazole ribotide, which undergoes a rearrangement reaction via radical intermediates which incorporate the blue, green and red fragments shown into the product. The thiazole ring is formed in a reaction catalysed by thiazole synthase (EC 2.8.1.10). The ultimate precursors are 1-deoxy-D-xylulose 5-phosphate, 2-iminoacetate and a sulfur carrier protein called ThiS. An additional protein, ThiG, is also required to bring together all the components of the ring at the enzyme active site.
Sources: en.wikipedia.org
Also because it was expected to obtain the support of Sucre and the Bolivian state, together with the support of Gran Colombia, for the War in Brazil, even if that was at the expense of Peruvian interests.
Endothelial progenitor cell (or EPC) is a term that has been applied to multiple different cell types that play roles in the regeneration of the endothelial lining of blood vessels. Outgrowth endothelial cells are an EPC subtype committed to endothelial cell formation. Despite the history and controversy, the EPC in all its forms remains a promising target of regenerative medicine research.
==== Illegal water extraction ==== Illegal water extraction in Iran is a significant issue, contributing to the country's water scarcity. Many influential figures, including local officials and powerful business interests, operate unauthorized wells and exploit groundwater reserves beyond legal limits. Despite regulations to control water use, enforcement is weak, leading to the depletion of critical aquifers, land subsidence, and desertification, especially in agricultural regions like Fars and Khorasan. The problem is compounded by corruption, as those with political connections often evade penalties, further undermining sustainable water management efforts. According to Mohammad Hajrasouliha, the managing director of Iran Water Resources Management Company, there are almost 320,000 illegal wells, and between 13,000 and 14,000 illegal wells are sealed yearly. The fees for water are another factor causing misuse of water.
=== June 2025 military parade and "No Kings" protests === On June 14, the Trump administration held the U.S. Army 250th Anniversary Parade in Washington, D.C., to celebrate the 250th anniversary of the U.S. Army. The parade is estimated to have cost somewhere between $25 and $45 million. In protest, 50501, Indivisible, and other organizations organized No Kings protests in many American cities. Millions attended what was then the largest protest since Trump was re-elected. Two follow up No Kings protests (also referred to as No Kings 2 and No Kings 3) took place across the United States and cities abroad in October 2025 and March 2026. The October protests took place in some 2,700 locations across the country, and drew an estimated 7 million attendees, The March 2026 protests, held in response to the killings of Alex Pretti and Renée Good, as well as the 2026 Minnesota general strike, drew even more participants. The organizers claim the No Kings 3 protests took place in 3,300 locations and drew an estimated eight to nine million protestors, which would make it the largest single-day protest in American history.
Sources: en.wikipedia.org
Dry powder is normally held at -20 °C or lower, away from light and moisture. Sealed vials can also be kept at 2-8 °C for shorter intervals. Warming to room temperature before opening prevents condensation.
In solution, hydrolysis of peptide bonds and oxidation of the methionine residue are the principal concerns. Oxidation converts methionine to its sulfoxide form, shifting the mass by sixteen daltons. Both processes are slowed by cold storage and by avoiding alkaline conditions.
A certificate documents what the supplier measured on a specific lot, not how a laboratory will use the material. Independent verification of identity and purity is common practice. Acceptance criteria should be defined before a batch is ordered.
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。