If you have been reading about heptapeptide 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.
Last reviewed on 2025-10-27. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Published research covers ischemic stroke, traumatic brain injury, cognitive impairment, optic nerve conditions and attention-related measures. Much of the human evidence comes from small trials conducted in one country, which limits how far the results generalize. Animal models supply the larger share of the data, and effects seen in rodents do not transfer automatically to people. Reviews have noted that methodological reporting is often incomplete, making it difficult to pool results or compare treatment schedules across studies.
Pharmacokinetic accounts emphasize rapid breakdown. After intravenous dosing the intact peptide disappears from blood within minutes, and nasal delivery produces low but measurable concentrations. Metabolites rather than the parent molecule may account for part of the observed activity, although the relative contribution is unresolved. Dosing in the literature varies widely and no optimal schedule has been agreed. These gaps are regularly cited as a reason the findings have not produced broad clinical adoption beyond the original research setting.
Proposed mechanisms center on neurotrophic signaling rather than on classical melanocortin receptor activation. Rodent experiments have reported shifts in the expression of brain-derived neurotrophic factor and nerve growth factor after administration, together with changes in the associated receptor systems. Several authors argue that the peptide acts largely through its degradation products and their interaction with peptidergic pathways, but this remains a hypothesis rather than a settled finding. No single molecular target has been identified in a way that the field broadly accepts.
| 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 |
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.
Purity assessment relies mainly on reversed-phase high-performance liquid chromatography, which separates the target heptapeptide from truncated sequences, deletion analogues, and oxidised forms. Mass spectrometry, usually coupled to liquid chromatography, confirms identity through the expected molecular ion and reveals modifications such as methionine sulfoxide formation. Amino acid analysis can verify composition, and tandem mass spectrometry supports sequence confirmation. Ultraviolet detection near 254 to 280 nanometres is convenient because the phenylalanine and histidine residues absorb in that region. Nuclear magnetic resonance is rarely used for routine release testing.
Common degradation pathways include oxidation of the methionine side chain, hydrolysis of the peptide backbone, and aggregation under unfavourable pH or concentration. Stability studies typically monitor the main peak by chromatography and report total related substances as a percentage. Because no official monograph exists, acceptance criteria vary between laboratories, and reported purity values are not directly comparable across suppliers. Analysts therefore document the method, column, and detection wavelength alongside each result, and open questions remain about how much biological activity the oxidised forms retain.
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.
An ice road or ice bridge is a human-made structure that runs on a frozen water surface (a river, a lake or a sea water expanse). Ice roads are typically part of a winter road, but they can also be simple stand-alone structures, connecting two shorelines. Ice roads may be planned, built and maintained so as to remain safe and effective, and a number of guidelines have been published with information in these regards. An ice road may be constructed year after year, for instance to service community needs during the winter. It could also be for a single year or two, so as to supply particular operations, such as a hydroelectric project or offshore drill sites.
High potassium concentrations in the plasma cause depolarization of the zona glomerulosa cells' membranes in the outer layer of the adrenal cortex. This causes the release of aldosterone into the blood. Aldosterone acts primarily on the distal convoluted tubules and collecting ducts of the kidneys, stimulating the excretion of potassium ions into the urine. It does so, however, by activating the basolateral Na+/K+ pumps of the tubular epithelial cells. These sodium/potassium exchangers pump three sodium ions out of the cell, into the interstitial fluid and two potassium ions into the cell from the interstitial fluid. This creates an ionic concentration gradient which results in the reabsorption of sodium (Na+) ions from the tubular fluid into the blood, and secreting potassium (K+) ions from the blood into the urine (lumen of collecting duct).
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
== History == In the 1960s, Werner Bollag of Roche Laboratories began studying 13-cis retinoic acid as a treatment for skin cancer. By 1971, Roche showed that the compound was likely ineffective against cancer but useful for treating acne. However, Roche abandoned the product after finding a likelihood that the compound could cause birth defects, as the thalidomide scandal had raised the public's fear of such side effects. In 1975, Gary Peck, a dermatologist at the National Cancer Institute, initiated a collaboration with Hoffmann-La Roche to evaluate the efficacy of isotretinoin for a number dermatological conditions previously managed with retinoic acids, including acne, psoriasis, genetic skin disorders, and skin cancer prevention. After Peck authored an article in 1979 reporting the drug's effectiveness against cystic and conglobate acne, Roche submitted a New Drug Application to the Food and Drug Administration (FDA). While admitting that isotretinoin caused birth defects in rabbits, Roche avoided regulatory scrutiny by excluding pregnant women from its clinical trials and secured FDA approval in 1982. Despite prior correlation of isotretinoin with birth defects, Accutane quickly became the dominant acne treatment prescribed by dermatologists and general practitioners alike. In 1983, the FDA made the unprecedented decision to warn blood banks against accepting the blood of donors taking isotretinoin and instruct women to begin taking contraceptives one month before use.
== Malignant neoplasm of digestive organs and peritoneum (150–159) == 150 Malignant neoplasm of esophagus 151 Malignant neoplasm of stomach 152 Malignant neoplasm of small intestine, including duodenum 153 Malignant neoplasm colon 154 Malignant neoplasm of rectum, rectosigmoid junction, and anus 155 Malignant neoplasm of liver and intrahepatic bile ducts 156 Malignant neoplasm of gallbladder and extrahepatic bile ducts 157 Malignant neoplasm of pancreas 158 Malignant neoplasm of retroperitoneum and peritoneum 159 Malignant neoplasm of other and ill-defined sites within the
The coexistence of intense, divergent moods within an individual was recognized by Homer, Hippocrates, and Aretaeus, the last describing the vacillating presence of impulsive anger, melancholia, and mania within a single person. Swiss physician Théophile Bonet revived the concept in 1684, and used the term folie maniaco-mélancolique to describe the phenomenon of unstable moods that followed an unpredictable course. Other writers noted the same pattern, including the American psychiatrist Charles H. Hughes in 1884 and J. C. Rosse in 1890, who called the disorder "borderline insanity". In 1921, Emil Kraepelin identified an "excitable personality" that closely parallels the borderline features outlined in the current concept of BPD. The idea that there were forms of disorder that were neither psychotic nor simply neurotic began to be discussed in psychoanalytic circles in the 1930s. The first formal definition of borderline disorder is widely acknowledged to have been written by Adolph Stern in 1938. He described a group of patients who he felt to be on the borderline between neurosis and psychosis, who often came from family backgrounds marked by trauma. He argued that such patients would often need more active support than that provided by classical psychoanalytic techniques. The 1960s and 1970s saw a shift from thinking of the condition as borderline schizophrenia to thinking of it as a borderline affective disorder (mood disorder), on the fringes of bipolar disorder, cyclothymia, and dysthymia.
=== Immuno-PET === The isotope 89Zr has been applied to the tracking and quantification of molecular antibodies with PET cameras (a method called "immuno-PET"). The biological half-life of antibodies is typically on the order of days, see daclizumab and erenumab by way of example. To visualize and quantify the distribution of such antibodies in the body, the PET isotope 89Zr is well suited because its physical half-life matches the typical biological half-life of antibodies, see table above. Immuno-PET can use both intact monoclonal antibodies and smaller antibody-derived constructs, including antibody fragments and nanobodies. The radionuclide is generally selected according to the pharmacokinetics of the antibody or antibody-derived construct. Intact antibodies circulate slowly and may therefore be labelled with radionuclides that permit imaging at later time points, including iodine-124, copper-64 and zirconium-89. By contrast, the faster clearance of smaller antibody-derived constructs allows the use of shorter-lived radionuclides, including gallium-68 and fluorine-18.
=== Available forms === Arsenic trioxide (ATO) is available in both intravenous (IV) and oral formulations for clinical use. The IV form is widely approved and used as the standard for treating acute promyelocytic leukemia (APL), requiring daily infusions. Recent advances have led to the development of oral formulations, including liquid and solid (tablet/pill) preparations, designed to provide comparable bioavailability and efficacy to IV ATO. Specific formulations include:
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.
The main proposal is modulation of neurotrophic factors such as brain-derived neurotrophic factor, supported largely by animal experiments. Receptor-level targets have not been firmly established. Most reviews describe the mechanism as only partially characterized.