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.
Updated 2026-08-01. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
Solid semax is typically supplied as a lyophilised powder that is hygroscopic and sensitive to moisture, light, and repeated temperature cycling. Long-term storage of the dry peptide is generally recommended at approximately -20 degrees Celsius, while shorter working periods may use refrigeration at 2 to 8 degrees Celsius. Vials should remain tightly closed and desiccated when brought to room temperature, because condensation can damage the material before it is weighed. Dividing a batch into aliquots is preferable to thawing one container repeatedly.
Dissolution is normally performed in water, phosphate-buffered saline, or normal saline, since the peptide is freely soluble in aqueous media and is rarely handled with strong organic solvents. Solution pH should be kept near neutral, because extreme acidity or alkalinity accelerates backbone hydrolysis and encourages oxidation of the methionine side chain. Once dissolved, the material is less stable than the dry powder and is commonly divided into single-use portions and frozen. Buffers containing primary amines, such as Tris, are often avoided because of possible side reactions.
| 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 |
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.
Published studies are dominated by animal models of stroke, ischemia, and cognitive impairment, with a smaller number of human trials conducted in Russia. Many of the human reports are small, single-center, and published in Russian-language journals, which limits independent scrutiny. Outcome measures vary between studies and often rely on clinician-rated scales rather than objective biomarkers. Systematic reviews have noted the methodological weaknesses and called for larger, preregistered trials before firm conclusions can be drawn.
Claims about enhanced focus, memory, or mood in healthy people rest mostly on anecdotal reports and community discussion rather than on controlled data. It remains unclear whether any cognitive benefit observed in patients recovering from brain injury would extend to uninjured users. Dose-response relationships, long-term safety, and interactions with other drugs are not well characterized in the peer-reviewed literature. Questions about optimal route of administration and treatment duration likewise remain open.
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.
=== 18th–19th centuries === After 1786, the territory of the Don Cossacks was officially called Don Host Land, and was renamed Don Host Oblast in 1870 (presently part of the Rostov, Volgograd, and Voronezh regions of the Russian Federation as well as part of the Luhansk region of Ukraine). In 1805 the Don Cossack capital was shifted from Cherkassk to Novocherkassk (New Cherkassk).
Hydra ( HY-drə) is a genus of small freshwater hydrozoans in the phylum Cnidaria. They are solitary, carnivorous jellyfish-like animals, native to the temperate and tropical regions. The genus was named by Linnaeus in 1758 after the Hydra, the mythical many-headed beast that was defeated by Heracles, as when the animal has a part severed, it will regenerate much like the mythical Hydra's heads. Biologists are especially interested in Hydra because of their regenerative ability; they do not appear to die of old age, or to age at all.
== Limitations == Chemotherapy does not always work, and even when it is useful, it may not completely destroy the cancer. People frequently fail to understand its limitations. In one study of people who had been newly diagnosed with incurable, stage 4 cancer, more than two-thirds of people with lung cancer and more than four-fifths of people with colorectal cancer still believed that chemotherapy was likely to cure their cancer. The blood–brain barrier poses an obstacle to delivery of chemotherapy to the brain. This is because the brain has an extensive system in place to protect it from harmful chemicals. Drug transporters can pump out drugs from the brain and brain's blood vessel cells into the cerebrospinal fluid and blood circulation. These transporters pump out most chemotherapy drugs, which reduces their efficacy for treatment of brain tumors. Only small lipophilic alkylating agents such as lomustine or temozolomide are able to cross this blood–brain barrier. Blood vessels in tumors are very different from those seen in normal tissues. As a tumor grows, tumor cells furthest away from the blood vessels become low in oxygen (hypoxic). To counteract this they then signal for new blood vessels to grow. The newly formed tumor vasculature is poorly formed and does not deliver an adequate blood supply to all areas of the tumor. This leads to issues with drug delivery because many drugs will be delivered to the tumor by the circulatory system.
==== Negative ion formation ==== In negative-ion mode, the potential of the exit grid electrode can be set to negative potentials. Penning electrons undergo electron capture with atmospheric oxygen to produce O2−. The O2− will produce radical anions. Several reactions are possible, depending on the analyte.
Sources: en.wikipedia.org
Due to the stabilization of 7s electronic orbitals and destabilization of 6d ones caused by relativistic effects, Cn2+ is likely to have a [Rn]5f146d87s2 electronic configuration, using the 6d orbitals before the 7s one, unlike its homologues. The fact that the 6d electrons participate more readily in chemical bonding means that once copernicium is ionized, it may behave more like a transition metal than its lighter homologues, especially in the possible +4 oxidation state. In aqueous solutions, copernicium may form the +2 and perhaps +4 oxidation states. The diatomic ion Hg2+2, featuring mercury in the +1 oxidation state, is well-known, but the Cn2+2 ion is predicted to be unstable or even non-existent. Copernicium(II) fluoride, CnF2, should be more unstable than the analogous mercury compound, mercury(II) fluoride (HgF2), and may even decompose spontaneously into its constituent elements. As the most electronegative reactive element, fluorine may be the only element able to oxidize copernicium even further to the +4 and even +6 oxidation states in CnF4 and CnF6; the latter may require matrix-isolation conditions to be detected, as in the disputed detection of HgF4. CnF4 should be more stable than CnF2. In polar solvents, copernicium is predicted to preferentially form the CnF−5 and CnF−3 anions rather than the analogous neutral fluorides (CnF4 and CnF2, respectively), although the analogous bromide or iodide ions may be more stable towards hydrolysis in aqueous solution. The anions CnCl2−4 and CnBr2−4 should also be able to exist in aqueous solution.
The MRGPRX2 activation pathway in humans involves four primate-specific families of MRGPRX genes (MRGPRX1-X4) as well as the MrgprD-H families, while the MrgprA, MrgprB and MrgprC families are specific to rodents. MRGPRX2 recognizes a wide variety of basic amino acids and low-molecular-weight compounds without amino acid sequence motifs. Mast cells (MCs) also have been shown to form mast cell extracellular traps (MCETs) to entrap and kill microbes. In a multistage process, MCs become activated, the nuclear membrane disintegrates, chromatin is released into the cytoplasm, cytoplasmic granules adhere to an emerging DNA web, and the complex is released into the extracellular space. Metabolic mechanisms in IgE mediated and non-IgE mediated MC activation are not well understood. Healthy mitochondrial respiration involves maximal production of adenosine triphosphate (ATP) and minimal production of reactive oxygen species (ROS).
== Biological activity == Protolichesterinic acid exhibits diverse biological activities, including antimicrobial, enzyme inhibitory, and anticancer properties. Studies with the compound isolated from Usnea albopunctata have demonstrated broad-spectrum antimicrobial activity. It shows strong antibacterial effects against Klebsiella pneumoniae (minimum inhibitory concentration 0.25 μg/mL) and Vibrio cholerae (0.5 μg/mL), exceeding the potency of ciprofloxacin. The compound is also active against methicillin-resistant Staphylococcus aureus (MRSA) and shows notable antifungal activity against Trichophyton rubrum, surpassing amphotericin B in potency. As an inhibitor, protolichesterinic acid selectively targets 5-lipoxygenase while showing minimal effect on cyclooxygenase. This selective inhibition suggests potential applications in treating inflammatory conditions, particularly those involving leukotriene bronchoconstrictors. Structure-activity studies indicate that while the stereospecific side chain and exocyclic double bond are not essential for activity, the carboxylic acid group plays a crucial role. The compound also inhibits the DNA polymerase activity of human immunodeficiency virus-1 reverse transcriptase (HIV-1 RT). Research has revealed that protolichesterinic acid affects cancer cell metabolism by disrupting mitochondrial function through inhibition of oxidative phosphorylation and enhancement of glycolysis. The compound undergoes cellular processing via the mercapturic pathway, forming conjugates with glutathione.
In prokaryotic cells, such as bacteria, which lack mitochondria, the citric acid cycle reaction sequence is performed in the cytosol with the proton gradient for ATP production being across the cell's surface (plasma membrane) rather than the inner membrane of the mitochondrion. For each pyruvate molecule (from glycolysis), the overall yield of energy-containing compounds from the citric acid cycle is three NADH, one FADH2, and one GTP or ATP.
=== Diplomatic means === A key element of US political, military and energy economic planning occurred in 1984. The Iran–Iraq war had been going on for five years and both had sustained casualties into the hundreds of thousands. Within President Ronald Reagan's National Security Council concern was growing war could spread beyond the two belligerents. A National Security Planning Group meeting was formed, chaired by then vice president George H. W. Bush, to review US options. It was determined that the conflict would likely spread into Saudi Arabia and other Gulf states, but the US had little capability to defend the region. A prolonged war in the region would induce much higher oil prices and threaten the recovery of the world economy, which was just beginning to gain momentum. In May 1984, President Reagan was briefed on the project conclusions by William Flynn Martin who had served as the head of the NSC staff that organized the study. The conclusions were: first, oil stocks needed to be increased among members of the International Energy Agency and, if necessary, released early if the oil market was disrupted; second, the US needed to strengthen the security of friendly Arab states in the region; and third, an embargo should be placed on sales of military equipment to Iran and Iraq. The plan was approved by Reagan and affirmed by the G7 leaders headed by the UK's prime minister, Margaret Thatcher, in the 10th G7 summit, held in London in June. The plan was implemented and became the basis for US preparedness to respond to the Iraqi occupation of Kuwait in 1991.
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.
Dry powder is usually kept at about -20 degrees Celsius for long-term storage and at 2 to 8 degrees Celsius for short working periods. Containers should stay sealed and protected from light and moisture to limit degradation.