If you have been reading about Neurotrophic signalling 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 2026-05-02. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
The compound was developed in the 1980s at the Institute of Molecular Genetics in Moscow, where it emerged from research on short ACTH fragments and their effects on the central nervous system. Russian pharmaceutical listings describe it as a nootropic and neuroprotective agent, most often formulated as nasal drops. It is not a marketed medicine in the United States or the European Union, and no pharmacopoeial monograph covers it. Consequently, most published clinical experience with the substance originates from a small number of research centres, mainly in Russia and neighbouring countries.
| 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 |
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.
The collapse of birthrates among blacks and (non-white) Hispanics, down 50%, was largely responsible for this development. However, their birthrates remained, on average, twice as high as those of their white counterparts. The birth rates of teenage Asians and Pacific Islanders were even lower, about half that of whites. In a 2014 paper, economists Melissa S. Kearney and Phillip B. Levine howed that popular TV programs depicting the reality of teenage parenthood, such as MTV's 16 and Pregnant and its Teen Mom sequels, have played a significant role in the reduction of teenage childbearing. Researchers from the Guttmacher Institute showed that the fall in teenage birthrates is likely not due to terminated pregnancies. The number of abortions remained the same or decreased in all U.S. states except for Vermont. This contradicts the historically negative correlation between birthrates and abortions. Modern youths also have better access to contraception than did their predecessors when they were at the same age. A CDC analysis found that the rates of teens using a long-acting and reversible method of contraception, such as an intrauterine device (IUD), jumped from 0.4% in 2005 to 7.1% in 2013. The teen birthrate continues to fall in the late 2010s, down to 17.4 births per 1000 in 2018. In 2022, it fell to 13.5, the lowest on record.
=== Herchel Smith Laboratory for Medicinal Chemistry === The Herchel Smith Laboratory for Medicinal Chemistry is a laboratory under the aegis of the Regius Professor of Physic in the School of Clinical Medicine.
=== Co-Precipitation === Actinide isolation by co-precipitation is frequently used for samples of relatively large volumes to concentrate analytes and remove interferences. Actinide carriers include iron hydroxides, lanthanide fluorides/hydroxides, manganese dioxide, and a few other species.
=== Pharmacodynamics === Loratadine is a tricyclic antihistamine, which acts as a selective inverse agonist of peripheral histamine H1 receptors. The potency of second generation histamine antagonists is (from strongest to weakest) desloratadine (Ki 0.4 nM) > levocetirizine (Ki 3 nM) > cetirizine (Ki 6 nM) > fexofenadine (Ki 10 nM) > terfenadine > loratadine. However, the onset of action varies significantly and clinical efficacy is not always directly related to only the H1 receptor potency, as the concentration of free drug at the receptor must also be considered. Loratadine also shows anti-inflammatory properties independent of H1 receptors. The effect is exhibited through suppression of the NF-κB pathway, and by regulating the release of cytokines and chemokines, thereby regulating the recruitment of inflammatory cells.
Sources: en.wikipedia.org
A firm can design any number of channels they require to reach customers efficiently and effectively. Channels can be distinguished by the number of intermediaries between producer and consumer. If there are no intermediaries then this is known as a zero-level distribution system or direct marketing. A level one (sometimes called one-tier) channel has a single intermediary. A level two (alternatively a two-tier) channel has two intermediaries, and so on. This flow is typically represented as being manufacturer to retailer to consumer, but may involve other types of intermediaries. In practice, distribution systems for perishable goods tend to be shorter - direct or single intermediary, because of the need to reduce the time a product spends in transit or in storage. In other cases, distribution systems can become quite complex involving many levels and different types of intermediaries.
=== Gastrointestinal system === Somatostatin is homologous with cortistatin (see somatostatin family) and suppresses the release of gastrointestinal hormones Decreases the rate of gastric emptying, and reduces smooth muscle contractions and blood flow within the intestine Inhibits adenylyl cyclase in parietal cells, thereby suppressing gastric acid secretion Suppresses the release of pancreatic hormones Somatostatin release is triggered by the beta cell peptide urocortin3 (Ucn3) to inhibit insulin release. Inhibits the release of glucagon Suppresses the exocrine secretory action of the pancreas
"...and much more likely to endure their miseries publicly; a tired walker, after all, merely sits down – a tired cyclist falls off and possibly brings others crashing down as well. That's much more fun". The fascination with six-day bicycle races spread across the Atlantic and appealed to the crowds in America as well. And the more spectators paid at the gate, the higher the prizes could be and the greater was the incentive of riders to stay awake—or be kept awake—to ride the greatest distance. Their exhaustion was countered by soigneurs (the French word for "healers"), helpers akin to seconds in boxing. Among the treatments they supplied was nitroglycerine, a drug used to stimulate the heart after cardiac attacks and which was credited with improving riders' breathing. Riders had hallucinations from the exhaustion and perhaps the drugs. The American champion Major Taylor refused to continue the New York race, saying: "I cannot go on with safety, for there is a man chasing me around the ring with a knife in his hand." Public reaction turned against such trials, whether individual races or in teams of two. One report said:
=== Past exposure to psychiatric medications theory === The past exposure theory suggests that exposure to psychiatric medication alters neural synapses, introducing an imbalance that was not previously present. Discontinuation of the drug is expected to result in symptoms of psychiatric illness which resolve once the drug is restarted. This theory suggests that while it may appear that the medication is working, it is only treating a disorder caused by the medication itself. New exposure to psychiatric medication may lead to heightened sensitivity to the effects of drugs such as alcohol, which has a deteriorating effect on the patient.
Planar cell polarity (PCP) is a type of cell polarity in which the cells are oriented in a coordinated way across the plane of an epithelial tissue. The orientation is controlled by different cytoplasmic and transmembrane proteins concentrating on two opposite ends of the cells and forming dimers between neighboring cells. Common examples of PCP oriented tissue include animal fur, bird feathers, fish scales, wings of a fruit fly, and stereocilia in the inner ear. PCP also plays a major role in other biological processes, such as wound healing and embryonic development.
Sources: en.wikipedia.org
=== NAADP-selective physiology === Hardly surprisingly, the three major second messengers do not do the same thing and cannot always substitute for each other. The physiological consequences of Ca2+ release by each messenger may be different i.e. NAADP couples to downstream responses that cannot be mimicked by IP3 and cADPR. For example, NAADP selectively stimulates neuronal differentiation, or exocytosis in cytotoxic T-cells.
=== Austro-Prussian War and Province of Prussia === In 1866, the Austro-Prussian War broke out, in which Prussia quickly defeated Austria and its allies. In the 1866 Peace of Prague, Prussia gained Holstein in addition to Schleswig and Lauenburg. Contrary to the hopes of German Schleswig-Holsteiners, the area did not gain its independence, but was annexed to Prussia, becoming the Province of Schleswig-Holstein in 1868; Lauenburg remained a separate entity until it was incorporated as Kreis Herzogtum Lauenburg in 1876. The Peace of Prague also led to the dissolution of the loose (confederal) Austrian-led German Confederation and the establishment of the far more integrated (federal) Prussian-led North German Confederation, of which Schleswig-Holstein was now part as a Prussian Province; the North German Confederation became the German Empire in 1871. Section five of the Peace of Prague had also stipulated that the people of Northern Schleswig would be consulted in a referendum on whether to remain under Prussian rule or return to Danish rule. This condition, however, was never fulfilled by Prussia. During the decades of Prussian rule within the German Empire, authorities attempted a Germanisation policy in the northern part of Schleswig, which remained predominantly Danish. The period also meant increased industrialisation of Schleswig-Holstein and the use of Kiel and Flensburg as important Imperial German Navy locations. The northernmost part and the west coast of the province saw a wave of emigration to America, while some Danes of North Schleswig emigrated to Denmark.
The demand for indigo in the 19th century is indicated by the fact that in 1897, 7,000 km2 (2,700 sq mi) were dedicated to the cultivation of indican-producing plants, mainly in India. By comparison, the country of Luxembourg is 2,586 km2 (998 sq mi). In Europe, indigo remained a rare commodity throughout the Middle Ages. A chemically identical dye derived from the woad plant (Isatis tinctoria) was used instead. In the late 15th century, the Portuguese explorer Vasco da Gama discovered a sea route to India. This led to the establishment of direct trade with India, the Spice Islands, China, and Japan. Importers could now avoid the heavy duties imposed by Persian, Levantine, and Greek middlemen and the lengthy and dangerous land routes which had previously been used. Consequently, the importation and use of indigo in Europe rose significantly. Much European indigo from Asia arrived through ports in Portugal, the Netherlands, and England. Many indigo plantations were established by European powers in tropical climates. Spain imported the dye from its colonies in Central and South America, and it was a major crop in Haiti and Jamaica, with much or all of the labor performed by enslaved Africans and African Americans. Indigo plantations also thrived in the Virgin Islands. However, France and Germany outlawed imported indigo in the 16th century to protect the local woad dye industry. In central Europe, indigo resist dyeing is a centuries-old skill that has received UNESCO Intangible Cultural Heritage of Humanity recognition.
=== Major users' response === Beginning around 2000, as the scientific evidence and public concern about trans fat increased, major American users of trans fat began to switch to safer alternatives. The process received a large boost in 2003 when the FDA announced it would require trans fat labeling on packaged food starting in 2006. Packaged food companies then faced the choice of either eliminating trans fat from their products, or having to declare the trans fat on their nutrition label. Lawsuits in the U.S. against trans fat users also encouraged its removal. Major American fast food chains including McDonald's, Burger King, KFC and Wendy's reduced and then removed partially hydrogenated oils (containing artificial trans fats) by 2009. This was a major step toward trans fat removal, as french fries were one of the largest sources of trans fat in the American diet, with a large serving of fries typically having about 6 grams of trans fat until around 2007. Two other events were important in the removal of trans fat. First, in 2013 the FDA announced it planned to completely ban artificial trans fat in the form of partially hydrogenated oil. Second, soon after this, Walmart informed its suppliers they needed to remove trans fat by 2015 if they wanted to continue to sell their products at its stores. As Walmart is the largest brick-and-mortar retailer in the U.S., mainstream food brands had little choice but to comply.
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.
It is described as a synthetic analogue of the ACTH(4–10) fragment, a short segment of adrenocorticotropic hormone. Its sequence differs from that fragment and includes two proline residues, which influence stability and behaviour in solution.