If you have been reading about counter-ion and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2026-04-17. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Calculated for the free peptide |
| Molar mass | 813.9 g/mol | Anhydrous free base |
| Peptide class | Synthetic heptapeptide | ACTH(4-10) analogue |
| Parent fragment | ACTH(4-10) | Adrenocorticotropic hormone segment |
| Developmental origin | Institute of Molecular Genetics, Moscow | Work began in the 1980s |
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。
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。
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.
Laboratory work points toward modulation of neurotrophic signaling, particularly expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal tissue. Studies also describe effects on monoamine turnover, inflammatory mediators, and oxidative markers. These observations come mainly from animal models and cultured cells, so the causal chain in humans is not firmly established. Whether the reported molecular changes translate into measurable clinical benefit is an open question. Reviews generally present the mechanism as plausible rather than demonstrated.
Clinical evidence consists largely of small trials with modest sample sizes, often without independent replication. Reported endpoints include cognitive scores, recovery after stroke, and visual function, but study designs vary widely and few trials meet contemporary reporting standards. Systematic reviewers have noted a high risk of bias in several of these reports. No large multicenter trial conducted outside Russia has been published. The compound is therefore best described as investigational in most jurisdictions, with its clinical role still unresolved.
Stability depends heavily on physical state. Lyophilized powder held dry, cold and dark retains its content over long periods, whereas dissolved peptide begins to change within days at room temperature. The most cited degradation route is oxidation of the methionine residue, which converts the peptide to a sulfoxide form that elutes differently on chromatography. Hydrolysis of amide bonds and adsorption onto container walls contribute smaller losses. Buffers that exclude oxygen from the headspace slow the oxidation pathway, but no single condition prevents all change indefinitely.
Practical handling follows from those properties. Bulk material is best divided into single-use portions soon after receipt, because each thaw exposes the whole container to moisture and temperature cycling. Vials should be allowed to reach room temperature before opening to prevent condensation on the powder. Low-binding plasticware reduces loss of dilute solutions, and sterile filtration is used when a preparation must remain free of microbial growth. Records of batch number, reconstitution date and storage history are what allow a later analytical result to be interpreted meaningfully.
Identity and purity of Semax are established mainly by reversed-phase high-performance liquid chromatography coupled with mass spectrometry. The chromatographic trace gives a purity estimate as a percentage of total peak area, while electrospray or matrix-assisted laser desorption ionization confirms the molecular mass against the calculated value. Amino acid analysis and sequence-specific fragmentation provide further confirmation when a supplier's chain of custody is unclear. Vendors frequently quote a purity figure without stating the detection wavelength or the integration method, which limits how far one number can be compared with another.
=== Copper binding === Replacement of histidine with other amino acids showed that the glycine residue plays major role in copper binding, whereas lysine can interact with copper only at alkaline pH. At physiological pH, lysine is able to interact with a cellular receptor. The ability of GHK to interact both with copper and with a cellular receptor may allow it to transfer copper into and from cells. The small size of GHK permits speedy traveling in extracellular space and its easy access to cellular receptors. The molecular structure of the GHK copper complex (GHK-Cu) has been determined by X-ray crystallography, EPR spectroscopy, X-ray absorption spectroscopy, NMR spectroscopy, as well as other methods such as titration. In the GHK-Cu complex, the Cu (II) ion is coordinated by the nitrogen from the imidazole side chain of the histidine, another nitrogen from the alpha-amino group of glycine and the deprotonated amide nitrogen of the glycine–histidine peptide bond. Since such a structure could not explain a high stability constant of the GHK-Cu complex (log 10 =16.44 vs. 8.68 of the GH copper complex, which is similar to the GHK-Cu structure), it was proposed that another amino group participates in the complex formation. Cu(II) is also coordinated by the oxygen from the carboxyl group of the lysine from the neighboring complex. Another carboxyl group of lysine from a neighboring complex provides the apical oxygen, resulting in the square-planar pyramid configuration.
Symptoms of intoxication from overdose include drowsiness, insomnia, stupor, agitation, coma, transient confusion, increased anxiety, ataxia, convulsions, oliguria, anuria, tachycardia or bradycardia, arrhythmia, AV block, hypotension, shock, respiratory depression, and, rarely, cardiac arrest.
== Problems faced in drug delivery == Other problems persist besides just simply getting through the blood–brain barrier. The first of these is that a lot of times, even if a compound transverses the barrier, it does not do it in a way that the drug is in a therapeutically relevant concentration. This can have many causes, the most simple being that the way the drug was produced only allows a small amount to pass through the barrier. Another cause of this would be the binding to other proteins in the body rendering the drug ineffective to either be therapeutically active or able to pass through the barrier with the adhered protein. Another problem that must be accounted for is the presence of enzymes in the brain tissue that could render the drug inactive. The drug may be able to pass through the membrane fine, but will be deconstructed once it is inside the brain tissue rendering it useless. All of these are problems that must be addressed and accounted for in trying to deliver effective drug solutions to the brain tissue.
As alternatives to pre-university education, however, courses are offered in other post-secondary education institutions, including at polytechnics and Institute of Technical Education (ITE) colleges. Singapore has six public universities, of which the National University of Singapore (NUS) and Nanyang Technological University (NTU) are among the top 20 universities in the world. National examinations are standardised across all schools, with a test taken after each stage. After the first six years of education, students take the Primary School Leaving Examination (PSLE), which determines their placement at secondary school. At the end of the secondary stage, GCE O-Level or GCE N-Level exams are taken; at the end of the following pre-university stage, the GCE A-Level exams are taken. Some schools have a degree of freedom in their curriculum and are known as autonomous schools, for secondary education level and above. Singapore is also an education hub, with more than 80,000 international students in 2006. 5,000 Malaysian students cross the Johor–Singapore Causeway daily to attend schools in Singapore. In 2009, 20% of all students in Singaporean universities were international students—the maximum cap allowed, a majority from ASEAN, China and India. Singapore students have excelled in many of the world education benchmarks in maths, science and reading. In 2015, both its primary and secondary students rank first in OECD's global school performance rankings across 76 countries—described as the most comprehensive map of education standards.
== Natural occurrence == Previously thought to be an exclusively synthetic compound, it has been reported to occur naturally in Argyreia nervosa (Hawaiian baby woodrose). The drug is on the World Health Organization's List of Essential Medicines.
Sources: en.wikipedia.org
Morea began his acting career with a role in the television series Captain Vyom, where he played the character Sonic. He made his film debut in Pyaar Mein Kabhi Kabhi (1999), opposite Rinke Khanna. The film was aimed at a young audience and earned him a nomination for the Zee Cine Award for Best Male Debut, although the award went to Aftab Shivdasani for Kasoor (2001). His breakthrough came with Rajiv Menon's Tamil-language film Kandukondain Kandukondain (2000), an adaptation of Jane Austen's Sense and Sensibility, where he appeared alongside an ensemble cast. In 2002, Morea starred in Raaz, a commercially and critically successful horror thriller directed by Vikram Bhatt. The film established Morea in the Hindi film industry. His portrayal of Aditya Dhanraj received positive reviews from the critics. Shah Rukh Khan praised Morea's performance and said "Your film is really doing well". He won a Zee Cine Award in the category of Dynamic Duo with Bipasha Basu. Raaz was both a commercial and critical success, and served as the best film of his career. His role as Aditya Dhanraj was noted in the media, and he received a Star Screen Award for Best Jodi along with co-star Bipasha Basu. That same year, he appeared in Gunaah, directed by Amol Shetge. The film was a commercial success, and Morea's performance received positive commentary in some reviews.
The AAA proteins contain two domains, an N-terminal alpha/beta domain that binds and hydrolyzes nucleotides (a Rossmann fold) and a C-terminal alpha-helical domain. The N-terminal domain is 200-250 amino acids long and contains Walker A and Walker B motifs, and is shared in common with other P-loop NTPases, the superfamily which includes the AAA family. Most AAA proteins have additional domains that are used for oligomerization, substrate binding and/or regulation. These domains can lie N- or C-terminal to the AAA module. Some classes of AAA proteins have an N-terminal non-ATPase domain which is followed by either one or two AAA domains (D1 and D2). In some proteins with two AAA domains, both are evolutionarily well conserved (like in Cdc48/p97). In others, either the D2 domain (like in Pex1p and Pex6p) or the D1 domain (in Sec18p/NSF) is better conserved in evolution. While the classical AAA family was based on motifs, the family has been expanded using structural information and is now termed the AAA family.
== Bibliography == Cotton, F. Albert; Wilkinson, Geoffrey; Murillo, Carlos A.; Bochmann, Manfred (1999). Advanced Inorganic Chemistry (6th ed.). John Wiley & Sons. ISBN 978-0-471-19957-1. Cunningham, B. B. (1968). "Californium". In Hampel, Clifford A. (ed.). The Encyclopedia of the Chemical Elements. Reinhold Book Corporation. LCCN 68029938. Emsley, John (1998). The Elements. Oxford University Press. ISBN 978-0-19-855818-7. Emsley, John (2001). "Californium". Nature's Building Blocks: An A-Z Guide to the Elements. Oxford University Press. ISBN 978-0-19-850340-8. Greenwood, N. N.; Earnshaw, A. (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-7506-3365-9. Haire, Richard G. (2006). "Californium". In Morss, Lester R.; Edelstein, Norman M.; Fuger, Jean (eds.). The Chemistry of the Actinide and Transactinide Elements (3rd ed.). Springer Science+Business Media. ISBN 978-1-4020-3555-5. Heiserman, David L. (1992). "Element 98: Californium". Exploring Chemical Elements and their Compounds. TAB Books. ISBN 978-0-8306-3018-9. Jakubke, Hans-Dieter; Jeschkeit, Hans, eds. (1994). Concise Encyclopedia Chemistry. trans. rev. Eagleson, Mary. Walter de Gruyter. ISBN 978-3-11-011451-5. Krebs, Robert (2006). The History and Use of our Earth's Chemical Elements: A Reference Guide. Greenwood Publishing Group. ISBN 978-0-313-33438-2. Lide, David R., ed. (2006). Handbook of Chemistry and Physics (87th ed.). CRC Press, Taylor & Francis Group. ISBN 978-0-8493-0487-3. National Research Council (U.S.). Committee on Radiation Source Use and Replacement (2008).
Newer varieties are now pending regulatory approval in the US which are designed to work rapidly, but retain the same genetic structure as regular human insulin. Short-acting insulin includes regular insulin, which begins working within 30 minutes and is active about 5 to 8 hours. Intermediate-acting insulin includes NPH insulin, which begins working in 1 to 3 hours and is active for 16 to 24 hours. Long-acting insulin includes the analogues glargine U100 and detemir, each of which begins working within 1 to 2 hours and continues to be active, without major peaks or dips, for about 24 hours, although this varies in many individuals. Ultra-long acting insulin includes the analogues insulin glargine U300 and degludec, which begin working within 30 to 90 minutes and continues to be active for greater than 24 hours. Newer long-acting insulins, like insulin icodec and insulin efsitora alfa, are designed for once-weekly use. Studies show they provide similar blood sugar control to daily insulins, with a comparable risk of hypoglycemia, while offering a simpler dosing routine. Combination insulin products combine fast- and short-acting insulin with a longer-acting insulin like NPH insulin. The combination products begin to work with the shorter-acting insulin (5–15 minutes for fast-acting, and 30 minutes for short-acting), and remain active for 16–24 hours. There are several variations with different proportions of the mixed insulins (e.g., Novolog Mix 70/30 contains 70% aspart protamine [akin to NPH], and 30% aspart).
Sources: en.wikipedia.org
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.
It is registered for clinical use in Russia and a few other countries, typically as a nasal drop formulation. It does not hold approval from the United States Food and Drug Administration or the European Medicines Agency. Outside those markets it is generally handled as a research chemical.
The compound was developed in Moscow and the earliest studies were conducted there, so the primary literature is largely in Russian-language journals. Translation and indexing have been incomplete, which limits access for outside researchers. Independent groups have since published some work, but the total volume remains modest.
It is associated with the melanocortin receptor family, particularly subtypes found in the central nervous system. This interaction is separate from the adrenal pathway activated by full-length ACTH.