A practical reference on heptapeptide: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-03-27 and is reviewed periodically as new material appears.
The C-terminal Pro-Gly-Pro extension is not incidental. Proline-rich tails are known to resist several common peptidases, and the published literature attributes the longer half-life of Semax, relative to unmodified ACTH fragments, to this feature. The modification also removes the melanocyte-stimulating and corticosteroidogenic activity that characterizes longer ACTH-derived sequences. Because the molecule is small and hydrophilic, it is typically formulated as an aqueous solution for intranasal or parenteral delivery. Acetylation or amidation at the termini appears in closely related research peptides and shifts the mass by a fixed increment.
Reported pharmacological work centers on neurotrophic signaling, including changes in BDNF and NGF expression in hippocampal tissue in animal models. Human data come largely from studies conducted in Russia, and how well those results generalize to other populations remains an open question. Regulatory status differs sharply by jurisdiction: Semax is a registered prescription medicine in Russia, while it holds no approved marketing status in the United States or the European Union. Outside such jurisdictions it is generally handled as a research chemical, which affects both documentation and quality expectations.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. It was developed as a fragment analog of adrenocorticotropic hormone, modeled specifically on the ACTH(4-10) region. The first four residues reproduce that fragment, while a Pro-Gly-Pro tripeptide is appended at the C-terminus. Work on the compound originated in Russia, where it entered clinical use as an intranasal preparation. Its sequence places it among short regulatory peptides studied for effects on the central nervous system rather than on the adrenal axis.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular weight | ~813.9 Da (free heptapeptide) | N-acetylated form is about 42 Da heavier |
| Residue count | 7 (heptapeptide) | Four residues from ACTH(4-10), three added |
| Appearance | White to off-white powder | Usually supplied lyophilized |
| Solubility class | Freely soluble in water | Also dissolves in DMSO and polar organic solvents |
| Related parent fragment | ACTH(4-10) | Parent motif is Met-Glu-His-Phe |
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
The compound was developed in the 1980s at the Institute of Molecular Genetics in Moscow, where it emerged from research on short ACTH fragments and their effects on the central nervous system. Russian pharmaceutical listings describe it as a nootropic and neuroprotective agent, most often formulated as nasal drops. It is not a marketed medicine in the United States or the European Union, and no pharmacopoeial monograph covers it. Consequently, most published clinical experience with the substance originates from a small number of research centres, mainly in Russia and neighbouring countries.
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
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.
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.
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.
C6H5HgCl + CCl2 → C6H5HgCCl3, reversed with heat. Organomercury halides react with hydride sources to give organomercury hydrides. Those compounds have an exceptionally weak C−Hg bond, and readily cleave to alkyl radicals.
Russian officials claimed that one person was killed in a Ukrainian drone strike in Belgorod Oblast. Canada imposed new sanctions on Russian individuals and entities for facilitating the illegal transfer of North Korean weapons, including ballistic missiles, for use in the invasion of Ukraine. The EU agreed to allow Ukraine to use the interest earned from seized Russian assets, totalling approximately 2.5 billion to 3 billion euros ($2.7 billion to $3.3 billion) annually, disbursed twice per year. Institutions will keep all interest earned between February 2022 and February 2024, possibly for reconstruction purposes, according to European Commission sources. More than 3,000 Ukrainian prisoners have applied to join the Ukrainian military.
=== Maximum depositional age === Some of the most important information we can get from detrital zircon ages is the maximum depositional age of the referring sedimentary unit. The sedimentary unit cannot be older than the youngest age of the analyzed detrital zircons because the zircon should have existed before the rock formation. This provides useful age information to rock strata where fossils are unavailable, such as the terrestrial successions during Precambrian or pre-Devonian times. Practically, maximum depositional age is averaged from a cluster of youngest age data or the peak in age probability because the youngest U-Pb age within a sample is almost always younger with uncertainty.
Expectations diminished as a result of numerous failed replications, the retraction of several previously reported positive replications, and the identification of methodological flaws and experimental errors in the original study. By late 1989, most scientists considered cold fusion claims dead, and cold fusion subsequently gained a reputation as pathological science. In 1989 the United States Department of Energy (DOE) concluded that the reported results of excess heat did not present convincing evidence of a useful source of energy and decided against allocating funding specifically for cold fusion. A second DOE review in 2004, which looked at new research, reached similar conclusions and did not result in DOE funding of cold fusion. Presently, since articles about cold fusion are rarely published in peer-reviewed mainstream scientific journals, they do not attract the level of scrutiny expected for mainstream scientific publications. Some interest in cold fusion has continued through the decades—for example, a Google-funded failed replication attempt was published in a 2019 issue of Nature. A small community of researchers continues to investigate it, often under the alternative designations low-energy nuclear reactions (LENR) or condensed matter nuclear science (CMNS).
=== Patenting === In the U.S., efforts into creating a chimeric entity appeared to be legal when the topic first came up. Developmental biologist Stuart Newman, a professor at New York Medical College in Valhalla, N.Y., applied for a patent on a human-animal chimera in 1997 as a challenge to the U.S. Patent and Trademark Office and the U.S. Congress, motivated by his moral and scientific opposition to the notion that living things can be patented at all. Prior legal precedent had established that genetically engineered entities, in general, could be patented, even if they were based on beings occurring in nature. After a seven-year process, Newman's patent finally received a flat rejection. The legal process had created a paper trail of arguments, giving Newman what he claimed was a victory. The Washington Post ran an article on the controversy that stated that it had raised "profound questions about the differences—and similarities—between humans and other animals, and the limits of treating animals as property."
Sources: en.wikipedia.org
All-cause mortality is higher above 64 mmol/mol (8.0 DCCT%) HbA1c as well as below 42 mmol/mol (6.0 DCCT %) in diabetic patients, and above 42 mmol/mol (6.0 DCCT %) as well as below 31 mmol/mol (5.0 DCCT %) in non-diabetic persons, indicating the risks of hyperglycemia and hypoglycemia, respectively. Similar risk results are seen for cardiovascular disease. The 2022 ADA guidelines reaffirmed the recommendation that HbA1c should be maintained below 7.0% for most patients. Higher target values are appropriate for children and adolescents, patients with extensive co-morbid illness and those with a history of severe hypoglycemia. More stringent targets (<6.0%) are preferred for pregnant patients if this can be achieved without significant hypoglycemia.
hydroxylation Proline residues may be hydroxylated at either of two atoms, as can lysine (at one atom). Hydroxyproline is a critical component of collagen, which becomes unstable upon its loss. The hydroxylation reaction is catalyzed by an enzyme that requires ascorbic acid (vitamin C), deficiencies in which lead to many connective-tissue diseases such as scurvy. methylation Several protein residues can be methylated, most notably the positive groups of lysine and arginine. Arginine residues interact with the nucleic acid phosphate backbone and commonly form hydrogen bonds with the base residues, particularly guanine, in protein–DNA complexes. Lysine residues can be singly, doubly and even triply methylated. Methylation does not alter the positive charge on the side chain, however. acetylation Acetylation of the lysine amino groups is chemically analogous to the acetylation of the N-terminus. Functionally, however, the acetylation of lysine residues is used to regulate the binding of proteins to nucleic acids. The cancellation of the positive charge on the lysine weakens the electrostatic attraction for the (negatively charged) nucleic acids. sulfation Tyrosines may become sulfated on their
=== Availability === Phenibut is approved in Russia, Ukraine, Belarus, Georgia and Latvia for medical use. It is not approved or available as a medication in other countries in the European Union, the United States, or Australia. In countries where phenibut is not a licensed pharmaceutical drug, it is sold online without a prescription as a "nutritional supplement". It is often used as a form of self-medication for social anxiety.
The package aimed to raise $739 billion and authorize $370 billion in spending on energy and climate change, $300 billion in deficit reduction, three years of Affordable Care Act subsidies, prescription drug reform to lower prices, and tax reform. According to an analysis by the Rhodium Group, the bill will lower U.S. greenhouse gas emissions between 31 percent and 44 percent below 2005 levels by 2030. On August 7, 2022, the Senate passed the bill (as amended) on a 51–50 vote, with all Democrats voting in favor, all Republicans opposed, and Vice President Kamala Harris breaking the tie. Biden signed the bill on August 16. Before and during the 2021 United Nations Climate Change Conference (COP26), Biden promoted an agreement that the U.S. and the European Union cut methane emissions by a third by 2030 and tried to add dozens of other countries to the effort. Biden pledged to double climate funding to developing countries by 2024. Also at COP26, the U.S. and China reached a deal on greenhouse gas emission reduction. The two countries are responsible for 40 percent of global emissions. In July 2023, when heat waves hit the United States, Biden announced measures to protect the population and said the heat waves were linked to climate change. In April 2024, he unveiled a plan to protect and restore natural water sources (3.2 million hectares of wetlands and 161,000 km of waterways). Biden protected 674 million acres of land and ocean from natural resource exploitation, more than any other president.
Sources: en.wikipedia.org
=== On Mars === Thiophene derivatives have been detected at nanomole levels in 3.5 billions year old Martian soil sediments (Murray Formation, Pahrump Hills) by the rover Curiosity at Gale crater (Mars) between 2012 and 2017.
On 2 September 2025, Trump said that the US had struck a boat carrying unspecified illegal drugs, alleging it was operated by the Tren de Aragua. Trump said that the strike killed 11 "narcoterrorists". On 28 November, it was revealed that two men who survived the initial strike were killed in subsequent strikes. A second strike occurred on 15 September, killing three. The US government did not provide evidence that those killed in either strike were narco-trafficking. In a third strike on 19 September that killed three, the Dominican Republic later stated it had cooperated with the US Navy in a first-ever joint operation to locate the boat and salvage 377 packages of cocaine, weighing 1,000 kilograms (2,200 lb). On 3 October, a strike on a vessel near the coast of Venezuela killed four; anonymous US officials later declared that there were Colombians on at least one of the boats. Trump stated on 14 October that six more were killed in a strike near the coast of Venezuela. Reuters reported that another previously unannounced strike on 16 October had killed two and included two survivors who were being held on a Navy ship. By 19 October, both were repatriated to their respective countries of origin, Colombia and Ecuador. On 17 October, three were killed in a strike on an alleged drug vessel operated by the National Liberation Army (ELN) of Colombia. The ELN denied involvement in any drug boat trafficking. The first strike at night, on 24 October against an alleged drug vessel operated by Tren de Aragua in the Caribbean, killed six.
Bacitracin is a polypeptide antibiotic. It is a mixture of related cyclic peptides produced by Bacillus licheniformis bacteria, that was first isolated from the variety "Tracy I" (ATCC 10716) in 1945. These peptides disrupt Gram-positive bacteria by interfering with cell wall and peptidoglycan synthesis. Bacitracin is primarily used as a topical preparation, as it can cause kidney damage when used internally. It is generally safe when used topically, but in rare cases may cause hypersensitivity, allergic or anaphylactic reactions, especially in people allergic to neomycin. In 2023, it was the 323rd most commonly prescribed medication in the United States, with more than 100,000 prescriptions.
Based on the size and histological staining characteristics of the fibrils, it is likely that at least in part they are composed of type III collagen (reticulin). An in vitro study with native collagen demonstrated that fibronectin binds to type III collagen rather than other types.
== Risk factors == Glaucoma can affect anyone. Some people have a higher risk or susceptibility to develop glaucoma due to certain risk factors, including increasing age, high intraocular pressure, a family history of glaucoma, and use of steroid medications.
Sources: en.wikipedia.org
The sequence is Met-Glu-His-Phe-Pro-Gly-Pro, a seven-residue peptide. The first four residues correspond to the ACTH(4-10) fragment, and Pro-Gly-Pro is added at the C-terminus. N-acetylated versions also appear in the literature and differ in mass.
Semax is a synthetic analog of the ACTH(4-10) fragment rather than a copy of the full hormone. Truncation plus the added tail removes the steroidogenic portion of ACTH. That distinction explains why it is studied for nervous-system effects instead of adrenal stimulation.
It is registered as a prescription product in Russia and has been used there clinically, chiefly by the intranasal route. No approval exists in the United States or the European Union. Availability elsewhere typically falls under research-chemical distribution, with varying purity documentation.
It is registered as a pharmaceutical product in Russia, where it is typically supplied as a nasal solution. In most other countries it is not an approved drug and is traded as a research chemical instead. Approval status depends entirely on the jurisdiction involved.