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.
Updated 2026-01-15. Numbers and descriptions here follow the published literature rather than marketing material.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its chain combines the first seven residues of corticotropin with a C-terminal proline-glycine-proline extension, a modification intended to slow enzymatic breakdown. The free peptide has a molecular mass near 813.9 daltons. It belongs to the class of ACTH-derived fragments studied for central nervous system activity rather than for adrenal steroid stimulation. This structural relationship to a natural hormone fragment is the usual starting point for describing the compound in the literature.
Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.
Russian regulatory authorities approved the peptide for nasal administration, and it remains listed in the national pharmacopoeia under several trade names. Documented indications include acute ischemic stroke, transient ischemic attacks, traumatic brain injury, and certain ophthalmological and neurological conditions. Physicians also prescribe it for cognitive complaints in older patients, although the evidence base for that use is thinner. Outside Russia and a few neighboring states, the substance is not an approved medicine and is sold instead as a research chemical.
Later generations of the molecule include an N-acetylated form and an amidated form, both marketed online alongside the parent peptide. These variants differ in terminal chemistry and stability, and they are frequently discussed in the same breath even though they have not been compared in controlled trials. Supply outside formal healthcare systems comes largely from laboratories that synthesize peptides to order. Purity and identity of these materials vary widely, and no single body oversees the international trade.
Semax is a synthetic heptapeptide developed in the Soviet Union during the 1980s by researchers at the Institute of Molecular Genetics in Moscow. It was designed as a truncated analog of adrenocorticotropic hormone, retaining only the fragment spanning residues four through ten. Investigators sought a peptide that would preserve the cognitive effects associated with ACTH while eliminating the hormonal stimulation of the adrenal cortex. The compound entered clinical use in Russia during the following decade.
| Property | Value | Notes |
|---|---|---|
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Heptapeptide; ACTH(4-10) analog extended at C-terminus |
| Molecular mass | ~813.9 Da | Free peptide, unmodified |
| Appearance | White to off-white powder | Typical lyophilized solid |
| Solubility | Soluble in water and saline | Also soluble in common aqueous buffers |
| Storage (solid) | -20 °C, desiccated | Protect from moisture and repeated thawing |
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 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.
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。
Several genera, including Asian coral snakes (Calliophis), burrowing asps (Atractaspis), and night adders (Causus), are remarkable for having exceptionally long venom glands, extending along each side of the body, in some cases extending posterially as far as the heart. Instead of the muscles of the temporal region serving to press out the venom into the duct, this action is performed by those of the side of the body. Considerable variability in biting behavior is seen among snakes. When biting, viperid snakes often strike quickly, discharging venom as the fangs penetrate the skin, and then immediately release. Alternatively, as in the case of a feeding response, some viperids (e.g. Lachesis) bite and hold. A proteroglyph or opisthoglyph may close its jaws and bite or chew firmly for a considerable time. Differences in fang length between the various venomous snakes are likely due to the evolution of different striking strategies. Additionally, it has been shown that the fangs of different species of venomous snakes have different sizes and shapes depending on the biomechanical properties of the snake's prey.
Saffron is not all of the same quality and strength. Strength is related to several factors, including age and the amount of yellow style picked relative to red stigma, as colour and flavour are concentrated in the latter. Saffron from Iran, Spain, and Kashmir is classified into various grades according to the proportion of stigma to style it contains. Grades of Iranian saffron are: sargol (Persian: سرگل, red stigma tips only, strongest grade), pushal or pushali (red stigmas plus some yellow style, lower strength), "bunch" saffron (red stigmas plus large amount of yellow style, presented in a tiny bundle like a miniature wheatsheaf) and konge (yellow style only, claimed to have aroma but with very little, if any, colouring potential). Grades of Spanish saffron are coupé (the strongest grade, like Iranian sargol), mancha (like Iranian pushal), and in order of further decreasing strength rio, standard and sierra saffron. The word mancha in the Spanish classification can have two meanings: a general grade of saffron or a very high quality Spanish-grown saffron from a specific geographical origin. Real Spanish-grown La Mancha saffron has PDO protected status, which is displayed on the product packaging. Spanish growers fought hard for Protected Status because they felt that imports of Iranian saffron re-packaged in Spain and sold as "Spanish Mancha saffron" were undermining the genuine La Mancha brand. Similar was the case in Kashmir where imported Iranian saffron is mixed with local saffron and sold as "Kashmir brand" at a higher price.
Many birds actively defend a territory from others of the same species during the breeding season; maintenance of territories protects the food source for their chicks. Species that are unable to defend feeding territories, such as seabirds and swifts, often breed in colonies instead; this is thought to offer protection from predators. Colonial breeders defend small nesting sites, and competition between and within species for nesting sites can be intense. All birds lay amniotic eggs with hard shells made mostly of calcium carbonate. Hole and burrow nesting species tend to lay white or pale eggs, while open nesters lay camouflaged eggs. There are many exceptions to this pattern, however; the ground-nesting nightjars have pale eggs, and camouflage is instead provided by their plumage. Species that are victims of brood parasites have varying egg colours to improve the chances of spotting a parasite's egg, which forces female parasites to match their eggs to those of their hosts.
Nature Communications, 6, 7564. https://doi.org/10.1038/ncomms8564 J. Su, P. Wang, W. Zhou, M. Peydayesh, J. Zhou, T. Jin, F. Donat, C. Jin, L. Xia, K. Wang, F. Ren, P. Van der Meeren, F. Pelayo García de Arquer & R. Mezzenga (2024). Single-site iron-anchored amyloid hydrogels as catalytic platforms for alcohol detoxification. Nature Nanotechnology, 19(8), 1168–1177. https://doi.org/10.1038/s41565-024-01657-7 J. Zhou, S. Gowachirapant, C. Zeder, A. Wieczorek, J. Guth, I. Kutzli, S. Siol, F. von Meyenn, M. B. Zimmermann & R. Mezzenga (2025). Oat protein nanofibril–iron hybrids offer a stable, high-absorption iron delivery platform for iron fortification. Nature Food, 6, 1164–1175. https://doi.org/10.1038/s43016-025-01260-6 J. Adamcik & R. Mezzenga (2018). Amyloid polymorphism in the protein folding and aggregation energy landscape. Angewandte Chemie International Edition, 57(28), 8370–8382. https://doi.org/10.1002/anie.201713416 D. Xu, J. Zhou, W.L. Soon, I. Kutzli, A. Molière, S. Diedrich, M. Radiom, S. Handschin, B. Li, L. Li, S. J. Sturla, C. Y. Ewald, R. Mezzenga (2023). Food amyloid fibrils are safe nutrition ingredients based on in-vitro and in-vivo assessment. Nature Communications, 14(1), 6806. https://doi.org/10.1038/s41467-023-42486-x
Sources: en.wikipedia.org
In December 2008, the 3d BCT deployed to Baghdad, Iraq and redeployed to Ft. Bragg in November 2009. In August 2009, 1st BCT deployed once again to Iraq and redeployed late July 2010. During the months of August and September 2009, 4th BCT deployed again to Afghanistan and returned in August 2010 having lost 38 soldiers. In May 2011 1–505 (Task Force 1 Panther) deployed to Afghanistan in support of Operation Enduring Freedom. Dispersed throughout the country, 1st battalion was attached to various Special Operations elements. 1st battalion redeployed to Fort Bragg, NC in February 2012 having lost two paratroopers. The 2d Brigade deployed to the Al Anbar Governorate in Iraq in May 2011, for the last time, as part of Operation New Dawn. Its mission was to advise, train and assist the Iraqi Armed Forces and Ministry of the Interior forces, as part of the withdrawal of United States Forces – Iraq. Elements of 2d Brigade were among the last US combat units to withdraw from Baghdad. The brigade suffered the loss of the last American service member in Iraq, SPC. David E. Hickman, on 14 November 2011. They were part of the long convoy of equipment and troops who exited Iraq into Kuwait as OIF came to an end.
Actuation (推动; 推動; tuīdòng) – of all physical processes in the body, especially the circulation of all body fluids such as blood in their vessels. This includes actuation of the functions of the zang-fu organs and meridians. Warming (温煦; 溫煦; wēnxù) – the body, especially the limbs. Defense (防御; fángyù) – against Exogenous Pathogenic Factors Containment (固摄; 固攝; gùshè) – of body fluids, i.e., keeping blood, sweat, urine, semen, etc. from leakage or excessive emission. Inter-transformationel (气化; 氣化; qìhuà) – of food, drink, and breath into qi, xue (blood), and jinye ("fluids"), and/or transformation of all of the latter into each other. A lack of qi will be characterized especially by pale complexion, lassitude of spirit, lack of strength, spontaneous sweating, laziness to speak, non-digestion of food, shortness of breath (especially on exertion), and a pale and enlarged tongue. Qi is believed to be partially generated from food and drink, and partially from air (by breathing). Another considerable part of it is inherited from the parents and will be consumed in the course of life. TCM uses special terms for qi running inside of the blood vessels and for qi that is distributed in the skin, muscles, and tissues between them. The former is called yingqi (营气; 營氣; yíngqì); its function is to complement xuè and its nature has a strong yin aspect (although qi in general is considered to be yang). The latter is called weiqi (卫气; 衛氣; weìqì); its main function is defence and it has pronounced yang nature. Qi is said to circulate in the meridians.
He was less successful militarily: an invasion of Sicily was decisively defeated by King William I in 1156, leading to tensions with Frederick Barbarossa, the Holy Roman Emperor; two decades later, an invasion of Anatolia was defeated at the Battle of Myriokephalon.
=== Thyroid hormone uptake === Thyroid hormone uptake (Tuptake or T3 uptake) is a measure of the unbound thyroxine binding globulins in the blood, that is, the TBG that is unsaturated with thyroid hormone. Unsaturated TBG increases with decreased levels of thyroid hormones. It is not directly related to triiodothyronine, despite the name T3 uptake. Reference ranges:
Substrate + NADPH + H+ → 5α-substrate + NADP+ Beyond being a catalyst in the rate-limiting step in testosterone reduction, 5α-reductase isoforms I and II reduce progesterone to 5α-dihydroprogesterone (5α-DHP) and deoxycorticosterone to dihydrodeoxycorticosterone (DHDOC). In vitro and animal models suggest subsequent 3α-reduction of DHT, 5α-DHP and DHDOC lead to neurosteroid metabolites with effect on cerebral function. These neurosteroids, which include allopregnanolone, tetrahydrodeoxycorticosterone (THDOC), and 3α-androstanediol, act as potent positive allosteric modulators of GABAA receptors, and have antidepressant, anxiolytic, prosexual, and anticonvulsant effects. 5α-Dihydrocortisol is present in the aqueous humor of the eye, is synthesized in the lens, and might help make the aqueous humor itself. 5α-Dihydroaldosterone is a potent antinatriuretic agent, although different from aldosterone. Its formation in the kidney is enhanced by restriction of dietary salt, suggesting it may help retain sodium. 5α-DHP is a major hormone in circulation of normal cycling and pregnant women. Other enzymes compensate to a degree for the absent conversion of 5α-reductase, specifically with local expression at the skin of reductive 17β-hydroxysteroid dehydrogenase, and oxidative 3α-hydroxysteroid dehydrogenase and 3β-hydroxysteroid dehydrogenase enzymes. In BPH, DHT acts as a potent cellular androgen and promotes prostate growth; therefore, DHT blockers inhibit and alleviate symptoms of BPH.
Sources: en.wikipedia.org
Semax is a synthetic seven-amino-acid peptide derived from a fragment of corticotropin. It is used in Russia as a nasal preparation, while elsewhere it is studied as a research compound. It is not approved as a medicine in most countries.
Its sequence corresponds to the 4-10 region of corticotropin extended by three residues. This fragment lacks the region responsible for adrenal steroid release, so it is explored for neural rather than hormonal effects. The relationship explains the compound's classification among ACTH-derived peptides.
It holds approval in Russia for several neurological indications as a nasal spray or drop formulation. Regulatory agencies in the United States and the European Union have not approved it. Products sold elsewhere are generally labeled for research use only.
It originated at the Institute of Molecular Genetics in Moscow during the 1980s. The work was carried out by a Russian research group that specialized in peptide neuropharmacology.