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 2026-06-23. 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 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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | ACTH(4-7) analogue |
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Free N terminus, unmodified side chains |
| Molecular weight | 813.9 Da | Free base; salt forms differ |
| Appearance | White to off-white powder | Lyophilised solid |
| Solubility | Freely soluble in water | Hydrophilic; polar solvents preferred |
The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It corresponds to the ACTH(4-7) fragment extended at the C-terminus by a Pro-Gly-Pro tripeptide, an addition intended to slow enzymatic breakdown. The molecular formula is C37H51N9O10S and the molecular mass is approximately 814 daltons. In the literature it is often described as an ACTH(4-10) analog, although that label reflects a naming convention as much as a precise structural relationship. The compound was developed in Russia and remains most closely associated with that research tradition.
Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.
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.
=== 22 January === German Foreign Minister Annalena Baerbock stated that Germany would not stand in the way if Poland or other countries provide Leopard 2 tanks. Russian state media reported that Russian forces advanced into Orikhiv and Huliaipole towns in Zaporizhzhia Oblast.
LLLT uses lasers, LEDs, or a combination of both to alter biological activity. The light sources expose cells to low-levels of red and near infrared light (compared to other forms of laser therapy). LLLT makes use of the Grotthuss-Draper law, the first law in photochemistry: light must be absorbed by a chemical substance in order for a photochemical reaction to take place. In the generally accepted LLLT theory that chemical substance is represented by the respiratory enzyme cytochrome c oxidase, which is involved in the electron transport chain in mitochondria. Administering LLLT below the dose range does not appear to be effective.
After the Christmas break, the Rhinos showed some strong performances, bolstered by Vusi Sibanda and Malcolm Waller, both of whom did not travel to the 2015 World Cup, but the One Day performances were abysmal. At the end of the season, the Rhinos won just 2 Pro50 matches but finished 2nd to Tuskers in the Logan Cup by only 3 points.
== History == The consumption of wheatgrass in the Western world began in the 1930s as a result of experiments conducted by Charles Schnabel in his attempts to popularize the plant. By 1940, cans of Schnabel's powdered grass were on sale in major drug stores throughout the United States and Canada. Ann Wigmore was also a strong advocate for the consumption of wheatgrass as a part of a raw food diet. Wigmore, founder of the Hippocrates Health Institute, believed that wheatgrass, as a part of a raw food diet, would cleanse the body of toxins while providing a proper balance of nutrients as a whole food. She also taught that wheatgrass could be used to treat those with serious disease. Both of these claims are believed by many reputable health institutes to be entirely unfounded by facts, and possibly dangerous.
Sources: en.wikipedia.org
In the case of compressed air, or nitrox mixtures, the exhaled gas is not valuable enough to justify the expense of recycling, but helium-based mixtures are considerably more expensive, and as the depth increases, the amount of gas used (in terms of mass, or number of molecules) increases in direct proportion to the ambient pressure. As a result, gas cost is a significant factor in deep open circuit diving with helium-based mixtures for long periods. By using a return line for the exhaled gas, it can be recompressed and used again, almost indefinitely. It is necessary to remove carbon dioxide from the reclaimed gas, but this is relatively cheap and uncomplicated. It is generally removed by a scrubber, which is a filter packed with a chemical which reacts with and removes the carbon dioxide from the gas. The reclaimed gas is also filtered to remove odour and microorganisms, and oxygen is added to the required concentration. The gas is compressed for storage between uses. Recovery of the exhaled gas requires special equipment. Simply venting it to a return hose through a non-return valve will not work, as the hose must be maintained at exactly the ambient pressure at the depth of the helmet, otherwise the gas from the helmet will either free-flow out under pressure, or not flow out at all because of back pressure.
== Research == It has been studied as a method to stimulate the immune system as part of the treatment of cancer. It has also shown some efficacy in the treatment of nephrotic syndrome in children. After being pulled from the market in the US and Canada in 1999 and 2003, respectively, levamisole has been tested in combination with fluorouracil to treat colon cancer. Evidence from clinical trials support its addition to fluorouracil therapy to benefit patients with colon cancer. In some of the leukemic cell line studies, both levamisole and tetramisole showed similar effect.
=== RNA sequencing === RNA sequencing was one of the earliest forms of nucleotide sequencing. The major landmark of RNA sequencing is the sequence of the first complete gene and the complete genome of Bacteriophage MS2, identified and published by Walter Fiers and his coworkers at the University of Ghent (Ghent, Belgium), in 1972 and 1976. Traditional RNA sequencing methods require the creation of a cDNA molecule which must be sequenced.
Along with Blount and McClung, those who purchased lots in the city included merchants Hugh Dunlap, Thomas Humes, and Nathaniel and Samuel Cowan, newspaper publisher George Roulstone, the Reverend Samuel Carrick, frontiersman John Adair (who had built a fort just to the north in what is now Fountain City), and tavern keeper John Chisholm.
== Publications == AMP co-owns The Journal of Molecular Diagnostics (JMD) with the American Society for Investigative Pathology. First published in 1999, JMD is the highest ranked journal in its field, with an Impact Factor rating of 5.341 in 2021. Its focus includes original research on advances in molecular diagnostic medicine in oncology, infectious diseases, hematopathology, inherited diseases, clinical informatics, as well as review articles. AMP members receive complementary online access to the journal with their membership, discounts on publication fees, and AMP makes its practice guidelines available free of charge. In addition, AMP working groups also collaborate with colleagues from other scholarly societies on reports appearing in publications other than JMD.
Sources: en.wikipedia.org
=== Semi-synthetic and synthetic opioids === Synthetic opioids were invented, and biological mechanisms for their actions discovered, in the 20th century. Scientists have searched for non-addictive forms of opioids, but have created stronger ones instead. In England Charles Romley Alder Wright developed hundreds of opiate compounds in his search for a nonaddictive opium derivative. In 1874 he became the first person to synthesize diamorphine (heroin), using a process called acetylation which involved boiling morphine with acetic anhydride for several hours. Heroin received little attention until it was independently synthesized by Felix Hoffmann (1868–1946), working for Heinrich Dreser (1860–1924) at Bayer Laboratories. Dreser brought the new drug to market as an analgesic and a cough treatment for tuberculosis, bronchitis, and asthma in 1898. Bayer ceased production in 1913, after heroin's addictive potential was recognized. Several semi-synthetic opioids were developed in Germany in the 1910s. The first, oxymorphone, was synthesized from thebaine, an opioid alkaloid in opium poppies, in 1914. Next, Martin Freund and Edmund Speyer developed oxycodone, also from thebaine, at the University of Frankfurt in 1916. In 1920, hydrocodone was prepared by Carl Mannich and Helene Löwenheim, deriving it from codeine. In 1924, hydromorphone was synthesized by adding hydrogen to morphine. Etorphine was synthesized in 1960, from the oripavine in opium poppy straw. Buprenorphine was discovered in 1972.
=== Presence in ecstasy === In his 1993 book E for Ecstasy examining the uses of the street drug ecstasy in the United Kingdom, the writer, activist, and ecstasy advocate Nicholas Saunders highlighted test results showing that certain consignments of the drug also contained selegiline. Consignments of ecstasy known as "Strawberry" contained what Saunders described as a "potentially dangerous combination of ketamine, ephedrine and selegiline," as did a consignment of "Sitting Duck" Ecstasy tablets.
The wavelength, localization technique, laser intensity, and irradiation period are determined based on the individual phototherapeutic agent, as these factors can vary greatly from compound to compound. Topical applications may be through the incorporation of the phototherapeutic agent with a hydrogel that will slowly leech the compound into the wound, allowing for a more controlled production of ROS and/or heat.
Floating villi float freely in the intervillous space. They exhibit a bi-layered epithelium consisting of cytotrophoblasts with overlaying syncytium (syncytiotrophoblast). Anchoring (stem) villi stabilize the mechanical integrity of the placental-maternal interface.
Firstly, ATP is needed for transport proteins to actively transport calcium ions into the sarcoplasmic reticulum (SR) of the muscle cell between muscle contractions. Afterwards, when a nerve signal is received, calcium channels in the SR open briefly and calcium rushes into the cytosol by selective diffusion (which does not use ATP) in what is called a "calcium spark." The diffusion of calcium ions into the cytosol causes the myosin strands of the myofibril to become exposed, and the myosin strands pull the actin microfilaments together. The muscle begins to contract. Secondly, ATP is needed to allow the myosin to release and pull again, so that the muscle can contract further in what is known as the sliding filament model. ATP is consumed at a high rate by contracting muscles. The need for ATP in muscle cells is illustrated by the phenomenon of Rigor mortis, which is the muscle rigidity that occurs in dead bodies for a short time after death. In these muscles, all the ATP has been used up and in the absence of further ATP being generated, the calcium transport proteins stop pumping calcium ions into the sarcoplasmic reticulum and the calcium ions gradually leak out. This causes the myosin proteins to grab the actin and pull once, but without further supply of ATP, cannot release and pull again. The muscles therefore remain rigid in the position at death until the binding of myosin to actin begins to break down and they become loose again.
Sources: en.wikipedia.org
It is a synthetic seven-amino-acid peptide built from the ACTH(4-7) sequence plus a Pro-Gly-Pro tail. It belongs to the family of short ACTH fragments studied for nervous-system effects. Its backbone contains only standard amino acids.
It contains the 4-7 fragment of adrenocorticotropic hormone extended at the C terminus. That truncation removes the region associated with steroidogenic activity. The design intent was to keep neurotrophic properties while avoiding full hormonal effects.
No natural source of the intact heptapeptide is known. It is produced by solid-phase peptide synthesis. Some related ACTH fragments arise as hormone processing products, but the Pro-Gly-Pro extension is a designed addition rather than a natural sequence.
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.