synthetic heptapeptide is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2025-08-23. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
| 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.
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.
=== Synthesis === Mescaline was the first ever psychedelic drug synthesized by chemists. Ernst Späth's 1919 total synthesis started from 3,4,5-trimethoxybenzoyl chloride. Several approaches using different starting materials have been developed since, including the following:
Atomic nuclei consist of protons and neutrons bound together by the residual strong force. Because protons are positively charged, they repel each other. Neutrons, which are electrically neutral, stabilize the nucleus in two ways. Their copresence pushes protons slightly apart, reducing the electrostatic repulsion between the protons, and they exert an attractive nuclear force on each other and on protons. For this reason, one or more neutrons are necessary for two or more protons to bind into a nucleus. As the number of protons increases, so does the ratio of neutrons to protons necessary to ensure a stable nucleus (see graph at right). For example, although the neutron:proton ratio of 32He is 1:2, the neutron:proton ratio of 23892U is greater than 3:2. A number of lighter elements have stable nuclides with the ratio 1:1 (Z = N). The nuclide 4020Ca (calcium-40) is observationally the heaviest stable nuclide with the same number of neutrons and protons. All stable nuclides heavier than calcium-40 contain more neutrons than protons.
== Toxicity == The recommended therapeutic dose is 80-100 mg/m2 body area. Optimal dosage is determined based on measurements of unbound platinum concentration following intravenous infusion, combined with rate of creatine clearance as an assessment of renal function using Ishibashi’s formula: DoseNDP = AUC × CLNDP, where CLNDP = 0.0738 × creatinine clearance + 4.47 The exact mechanism of uptake into the cell is unknown, with information being considerably less available compared to cisplatin. What is known is that nedaplatin does not interact with the Oct2 or apical multidrug and toxin extrusion transporter (MATE) transporters, potentially explaining the difference in nephrotoxicity due to reduced accumulation in the proximal tubules of the kidney. Toxicogenomics has helped elucidate some of the mechanisms behind nephrotoxicity, where oxidative stress has been shown to deregulate gene expression via Hmox1 and other genes.
== Commercial performance == Ellipse debuted at number 5 on the Billboard 200 chart and spent a total of 9 weeks on the chart, while also debuting at number 4 on the Billboard Canadian Albums chart and spending a total of 2 weeks on that chart. She also earned three more top 5 entries (including a chart topping entry) in other Billboard charts As of 2011, the album had sold 161,000 copies in the United States. The album sold 48,025 copies worldwide in its first week, which is the most copies Imogen has sold in a singular week.
Sources: en.wikipedia.org
The substrates of this enzyme are mevalonic acid, coenzyme A, and oxidised nicotinamide adenine dinucleotide (NAD+). Its products are 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA), reduced NADH, and two protons. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is (R)-mevalonate:NAD+ oxidoreductase (CoA-acylating). Other names in common use include beta-hydroxy-beta-methylglutaryl coenzyme A reductase, beta-hydroxy-beta-methylglutaryl CoA-reductase, 3-hydroxy-3-methylglutaryl coenzyme A reductase, and hydroxymethylglutaryl coenzyme A reductase.
These adenylyl cyclases are toxins secreted by pathogenic bacteria such as Bacillus anthracis, Bordetella pertussis, Pseudomonas aeruginosa, and Vibrio vulnificus during infections. These bacteria also secrete proteins that enable the AC-II to enter host cells, where the exogenous AC activity undermines normal cellular processes. The genes for Class II ACs are known as cyaA, one of which is anthrax toxin. Several crystal structures are known for AC-II enzymes.
==== Oceania ==== In 1967, the first 99mTc procedures were carried out in Auckland, New Zealand. 99Mo was initially supplied by Amersham, UK, then by the Australian Nuclear Science and Technology Organisation (ANSTO) in Lucas Heights, Australia.
== Mechanism == The underlying reason for its occurrence is unclear, though the syndrome appears similar to withdrawal from other psychotropic drugs such as benzodiazepines. For SSRIs, a tapered discontinuation results in less severe symptoms. There is also evidence that antidepressant discontinuation syndrome may be related to the biological half-life of both SSRIs and antidepressants in general. Antidepressants with a lower half-life, such as paroxetine, duloxetine, and venlafaxine, have been implicated in higher incidences of withdrawal symptoms and more severe withdrawal symptoms. The opposite association has been observed in antidepressants with relatively longer half lives, such as fluoxetine. With SSRIs, duration of treatment does not appear associated with the severity of withdrawal symptoms. One hypothesis is that after the antidepressant is discontinued, there is a temporary (but in some cases long-lasting) deficiency in the brain of one or more essential neurotransmitters that regulate mood, such as serotonin, dopamine, norepinephrine, and GABA (gamma-aminobutyric acid), and since neurotransmitters are an interrelated system, dysregulation of one affects the others. There may be a link between lower 5-hydroxytryptamine (5-HT, i.e. serotonin) receptor availability and symptoms of antidepressant discontinuation syndrome. Among antidepressants analyzed by Gastaldon et al. (2022), lofepramine, vortioxetine, mianserin, agomelatine, and esketamine are not associated with significantly disproportionate reporting of withdrawal syndrome.
A sphinx ( SFINKS; Ancient Greek: σφίγξ, pronounced [spʰíŋks]; pl. sphinxes or sphinges ) is a mythical creature with the head of a human, the body of a lion, and the wings of an eagle. In Greek tradition, the sphinx is a treacherous and merciless being with the head of a woman, the haunches of a lion, and the wings of a bird. According to Greek myth, she challenges those who encounter her to answer a riddle, and kills and eats them when they fail to solve the riddle. This deadly version of a sphinx appears in the myth and drama of Oedipus. In Egyptian mythology, in contrast, the sphinx is typically depicted as a man (an androsphinx (Ancient Greek: ἀνδρόσφιγξ)), and is seen as a benevolent representation of strength and ferocity, usually of a pharaoh. Unlike Greek or Levantine/Mesopotamian ones, Egyptian sphinxes were not winged. Both the Greek and Egyptian sphinxes were thought of as guardians, and statues of them often flank the entrances to temples. During the Renaissance, the sphinx enjoyed a major revival in European decorative art. During this period, images of the sphinx were initially similar to the ancient Egyptian version, but when later exported to other cultures, the sphinx was often conceived of quite differently, partly due to varied translations of descriptions of the originals, and partly through the evolution of the concept as it was integrated into other cultural traditions. However, depictions of the sphinx are generally associated with grand architectural structures, such as royal tombs or religious temples.
Sources: en.wikipedia.org
Pain and stiffness (moderate to severe) in the neck, shoulders, upper arms, thighs, and hips, which inhibits activity, especially in the morning, but which usually persists to some degree throughout the day. Pain can also occur in the groin area and in the buttocks. The pain can be limited to one of these areas as well. It is a disease of the "girdles" meaning shoulder girdle or pelvic girdle. Fatigue and lack of appetite (possibly leading to weight loss) Anemia An overall feeling of illness or flu-like symptoms. Low-grade (mild) fever or abnormal temperature is sometimes present. High or spiking fevers may occur in patients who also have giant cell arteritis. Generalized weakness Note that this is generalized weakness, not muscle weakness. The presence of muscle weakness likely indicates a different diagnosis. Inflammatory swelling and pain of wrists and/or knees (only ~25% of cases) Pitting edema (non-inflammatory swelling) of wrists, ankles, hands, and feet (only ~10% of cases)
==== Countercurrent flow examples ==== In a countercurrent heat exchanger, the hot fluid becomes cold, and the cold fluid becomes hot. In this example, hot water at 60 °C (140 °F) enters the top pipe. It warms water in the bottom pipe which has been warmed up along the way, to almost 60 °C (140 °F). A minute but existing heat difference still exists, and a small amount of heat is transferred, so that the water leaving the bottom pipe is at close to 60 °C (140 °F). Because the hot input is at its maximum temperature of 60 °C (140 °F), and the exiting water at the bottom pipe is nearly at that temperature but not quite, the water in the top pipe can warm the one in the bottom pipe to nearly its own temperature. At the cold end—the water exit from the top pipe, because the cold water entering the bottom pipe is still cold at 20 °C (68 °F), it can extract the last of the heat from the now-cooled hot water in the top pipe, bringing its temperature down nearly to the level of the cold input fluid (21 °C (70 °F)). The result is that the top pipe which received hot water, now has cold water leaving it at 20 °C (68 °F), while the bottom pipe which received cold water, is now emitting hot water at close to 60 °C (140 °F). In effect, most of the heat was transferred.
=== Twin amino acid stereocentres === A subset of L-α-amino acids are ambiguous as to which of two ends is the α-carbon. In proteins a cysteine residue can form a disulfide bond with another cysteine residue, thus crosslinking the protein. Two crosslinked cysteines form a cystine molecule. Cysteine and methionine are generally produced by direct sulfurylation, but in some species they can be produced by transsulfuration, where the activated homoserine or serine is fused to a cysteine or homocysteine forming cystathionine. A similar compound is lanthionine, which can be seen as two alanine molecules joined via a thioether bond and is found in various organisms. Similarly, djenkolic acid, a plant toxin from jengkol beans, is composed of two cysteines connected by a methylene group. Diaminopimelic acid is both used as a bridge in peptidoglycan and is used a precursor to lysine (via its decarboxylation).
=== Engineering strain === Engineering strain, also known as Cauchy strain, is expressed as the ratio of total deformation to the initial dimension of the material body on which forces are applied. In the case of a material line element or fiber axially loaded, its elongation gives rise to an engineering normal strain or engineering extensional strain e, which equals the relative elongation or the change in length ΔL per unit of the original length L of the line element or fibers (in meters per meter). The normal strain is positive if the material fibers are stretched and negative if they are compressed. Thus, we have
=== 19th century === Originally a farmer from Iowa, Abner Hackleman arrived as the first European American settler in 1845. Taking up a land claim for himself, Hackleman asked Hiram N. Smead to hold another for him until his son arrived from Iowa. In 1846, a year after arriving in Oregon, Hackleman died while returning to Iowa to fetch his family. In 1847 a pair of brothers, Walter and Thomas Monteith, settled in the area, after traveling by ox team along the Oregon Trail from their native state of New York. They were a family of early prominence in the area; in 1848, they bought a claim of 320 acres (1.3 km2) from Hiram Smead for $400 and a horse; they plotted out 60 acres (240,000 m2) for the town site. They named the city "Albany" after their hometown of Albany in New York. During the same period, Hackleman's son Abram reached his father's original land claim and built a log house in an oak grove still known as Hackleman's Grove. He later built a house, which still stands at the corner of Fifth and Jackson. The small settlement that formed on the Hackleman land became known as the community of Takenah in 1849.
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.