The short version of methionine sulfoxide fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-06-01 and is reviewed periodically as new material appears.
Published research has focused mainly on neurological and cognitive endpoints in animal models, with proposed mechanisms involving brain-derived neurotrophic factor and related signalling pathways. A substantial share of the human data originates from a limited number of research groups, and independent replication in other countries remains sparse. Regulatory status reflects that distribution: the peptide is registered as a medicine in Russia and appears in some neighbouring markets, while elsewhere it is handled as a research chemical without approved therapeutic labelling. Questions about dose-response relationships, long-term effects, and comparability across studies are still open.
Lyophilised powder is normally kept at -20 °C in a desiccated container, with some suppliers recommending -80 °C for long-term archival storage. Repeated freeze-thaw cycles are the most common cause of avoidable loss, so aliquoting before freezing reduces variability between working sessions. Dissolved peptide is far less stable than the dry solid and is usually prepared fresh or held briefly at 4 °C. Aqueous solutions support both hydrolysis of the backbone and oxidation of the N-terminal methionine, and these two routes dominate degradation under ordinary laboratory conditions.
Clinical reports describe use in ischaemic stroke, transient ischaemic attack, optic nerve conditions, and cognitive complaints, but most of these studies are small and were conducted in a single region. Systematic reviews have generally described the evidence base as limited in size and variable in methodological quality. Randomised controlled data suitable for international regulatory assessment are scarce. As a result, major treatment guidelines outside Russia do not include the peptide, and interest in it remains largely research-driven rather than routine clinical.
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.
| Property | Value | Notes |
|---|---|---|
| Purity assay | RP-HPLC, UV 214 nm | Typical research grade 95 percent or higher |
| Mass confirmation | ESI-MS or MALDI-TOF | Compared with theoretical value |
| Main degradation route | Methionine oxidation | Sulfoxide formation in solution |
| Powder storage | -20 °C, desiccated | Amber vial, minimal headspace |
| Working solution | Sterile water or saline | Prepare fresh; avoid repeated thawing |
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.
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.
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
Semax is a synthetic peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
The parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
Published studies examine a fairly narrow set of endpoints. Rodent experiments commonly measure maze learning, infarct volume after induced ischemia, and tissue levels of neurotrophic factors. Clinical reports from Russian centres describe attention, memory and recovery scores in patients after stroke or transient ischemic attack. Most of those human studies are small and few have been repeated by independent groups. Outcome measures differ between studies, which limits direct comparison.
Circulation time for the peptide is short because peptidases cleave it readily. The Pro-Gly-Pro tail is thought to slow breakdown compared with the bare ACTH fragment, but the gain appears modest. Absorption after intranasal dosing is limited, and only a fraction of a dose is expected to reach the central nervous system. Laboratory concentrations therefore sit well above levels achieved systemically, a gap that complicates translation from bench findings to clinical claims.
The mechanisms attributed to semax are inferred from animal and cell studies rather than traced to one confirmed target. The most frequently cited pathway involves increased expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal and cortical tissue. Some work points to engagement of melanocortin receptors, particularly MC4, which the parent ACTH fragment can activate. Effects on dopaminergic and serotonergic signalling have also been reported. No single account explains all observed results, and the relative weight of each pathway remains unsettled.
=== Recognition of scientific advances === Coleman and Friedman have been awarded numerous prizes acknowledging their roles in discovery of leptin, including the Gairdner Foundation International Award (2005), the Shaw Prize (2009), the Lasker Award, the BBVA Foundation Frontiers of Knowledge Award and the King Faisal International Prize, Leibel has not received the same level of recognition from the discovery because he was omitted as a co-author of a scientific paper published by Friedman that reported the discovery of the gene. The various theories surrounding Friedman's omission of Leibel and others as co-authors of this paper have been presented in a number of publications, including Ellen Ruppel Shell's 2002 book The Hungry Gene. The discovery of leptin also is documented in a series of books including Fat: Fighting the Obesity Epidemic by Robert Pool, The Hungry Gene by Ellen Ruppel Shell, and Rethinking Thin: The New Science of Weight Loss and the Myths and Realities of Dieting by Gina Kolata. Fat: Fighting the Obesity Epidemic and Rethinking Thin: The New Science of Weight Loss and the Myths and Realities of Dieting review the work in the Friedman laboratory that led to the cloning of the ob gene, while The Hungry Gene draws attention to the contributions of Leibel.
Engineering is the process by which technology is developed. It often requires problem-solving under strict constraints. Technological development is "action-oriented", while scientific knowledge is fundamentally explanatory. Polish philosopher Henryk Skolimowski framed it like so: "science concerns itself with what is, technology with what is to be." The direction of causality between scientific discovery and technological innovation has been debated by scientists, philosophers and policymakers. Because innovation is often undertaken at the edge of scientific knowledge, most technologies are not derived from scientific knowledge, but instead from engineering, tinkering and chance. For example, in the 1940s and 1950s, when knowledge of turbulent combustion or fluid dynamics was still crude, jet engines were invented through "running the device to destruction, analyzing what broke [...] and repeating the process". Scientific explanations often follow technological developments rather than preceding them. Many discoveries also arose from pure chance, like the discovery of penicillin as a result of accidental lab contamination. Since the 1960s, the assumption that government funding of basic research would lead to the discovery of marketable technologies has lost credibility. Probabilist Nassim Taleb argues that national research programs that implement the notions of serendipity and convexity through frequent trial and error are more likely to lead to useful innovations than research that aims to reach specific outcomes.
==== Below 1% ==== There are few studies of the health effects of long-term continuous CO2 exposure on humans and animals at levels below 1%. Occupational CO2 exposure limits have been set in the United States at 0.5% (5000 ppm) for an eight-hour period. At this CO2 concentration, International Space Station crew experienced headaches, lethargy, mental slowness, emotional irritation, and sleep disruption. Studies in animals at 0.5% CO2 have demonstrated kidney calcification and bone loss after eight weeks of exposure. A study of humans exposed in 2.5 hour sessions demonstrated significant negative effects on cognitive abilities at concentrations as low as 0.1% (1000 ppm) CO2 likely due to CO2 induced increases in cerebral blood flow. Another study observed a decline in basic activity level and information usage at 1000 ppm, when compared to 500 ppm. However a review of the literature found that a reliable subset of studies on the phenomenon of carbon dioxide induced cognitive impairment to only show a small effect on high-level decision making (for concentrations below 5000 ppm). Most of the studies were confounded by inadequate study designs, environmental comfort, uncertainties in exposure doses and differing cognitive assessments used. Similarly a study on the effects of the concentration of CO2 in motorcycle helmets has been criticized for having dubious methodology in not noting the self-reports of motorcycle riders and taking measurements using mannequins.
shorter needles, as insulin injections are subcutaneous (under the skin) rather than intramuscular, finer gauge needles, for less pain, markings in insulin units to simplify drawing a measured dose of insulin, and low dead space to reduce complications caused by improper drawing order of different insulin strengths.
The neuroendocrine system is the mechanism by which the hypothalamus maintains homeostasis, regulating metabolism, reproduction, eating and drinking behaviour, energy utilization, osmolarity and blood pressure. The regulation of metabolism, is carried out by hypothalamic interconnections to other glands. Three endocrine glands of the hypothalamic–pituitary–gonadal axis (HPG axis) often work together and have important regulatory functions. Two other regulatory endocrine axes are the hypothalamic–pituitary–adrenal axis (HPA axis) and the hypothalamic–pituitary–thyroid axis (HPT axis). The liver also has many regulatory functions of the metabolism. An important function is the production and control of bile acids. Too much bile acid can be toxic to cells and its synthesis can be inhibited by activation of FXR a nuclear receptor.
Sources: en.wikipedia.org
The diagnosis of polyneuropathy begins with a history (anamnesis) and physical examination to ascertain the pattern of the disease process (such as arms, legs, distal, proximal), if they fluctuate, and what deficits and pain are involved. If pain is a factor, determining where and how long it has been present is important; one also needs to know what disorders are present within the family and what diseases the person may have. Although diseases often are suggested by the physical examination and history alone, tests that may be employed include electrodiagnostic testing, serum protein electrophoresis, nerve conduction studies, urinalysis, serum creatine kinase (CK) and antibody testing; nerve biopsy is done sometimes. Other tests may be used, especially tests for specific disorders associated with polyneuropathies; quality measures have been developed to diagnose patients with distal symmetrical polyneuropathy (DSP).
Ninnu Kori (transl. Wanting you) is a 2017 Indian Telugu-language romantic comedy drama film directed by debutant Shiva Nirvana from a screenplay written by Kona Venkat. Produced by DVV Danayya under DVV Entertainments, the film stars Nani, Nivetha Thomas and Aadhi Pinisetty while Murali Sharma and Tanikella Bharani play supporting roles. Gopi Sunder composed the music. Prawin Pudi and Karthik Ghattamaneni are the editor and cinematographer of the film respectively. The plot revolves around Uma (Nani), Pallavi (Thomas), and Arun (Pinisetty). When Uma declines her proposal to elope, Pallavi marries Arun and emigrates to the US. Uma who still is in love with Pallavi also lands up in the US a year later in the hope of getting her back. The film was commercially successful, grossing over ₹52 crore at the box office. A Tamil-language remake titled Thalli Pogathey was released in 2021.
Gunshot residue (GSR), also known as cartridge discharge residue (CDR), gunfire residue (GFR), or firearm discharge residue (FDR), consists of all of the particles that are expelled from the muzzle of a gun following the discharge of a bullet. It is principally composed of burnt and unburnt particles from the explosive primer, the propellant (gunpowder), stabilisers and other additives. The act of firing a bullet incites a highly pressurised, explosive reaction that is contained within the barrel of the firearm, which expels the bullet. This can cause the bullet, the barrel, or the cartridge to become damaged, meaning gunshot residue may also include metallic particles from the cartridge casing, the bullet jacket, as well as any other dirt or residue contained within the barrel that could have become dislodged. Law enforcement commonly use swabbing, adhesives and vacuums with very fine filters to collect GSR. They commonly swab the web of the non-firing hand to look for gunshot residue if they are suspected to have discharged a firearm themselves or were in close contact with one at the time of discharge. Hair and clothing also accumulate GSR; typically a double-sided adhesive is used to sample areas that may have been exposed to such residue. It is also possible to use a swab moistened with 5% nitric acid for collection.
genetic code A set of rules by which information encoded within nucleic acids is translated into proteins by living cells. These rules define how sequences of three consecutive nucleotides called codons specify which amino acid will be added next during protein synthesis. The vast majority of living organisms use the same genetic code (sometimes referred to as the "standard" genetic code) but variant codes do exist.
In November 1965, when asked to comment by Time after the number of Americans killed in Vietnam passed 1,000, Kissinger praised Johnson for having to make "difficult and lonely decisions". Kissinger compared Johnson to the sheriff played by Gary Cooper in the 1952 film High Noon, depicting Johnson as a heroic figure making necessary, but unpopular decisions. In a 1967 peace initiative, he would mediate between Washington and Hanoi. In June 1967, at an academic conference in Paris, Kissinger met a French biologist, Herbert Marcovitch, who mentioned that one of his friends was Raymond Aubrac, a Communist hero of the French resistance, who in turn was one of the few Westerners who were friends with Ho Chi Minh. Ho had something of an aversion to Westerners and tried to avoid meeting them as much as possible, and Aubrac was unique in being allowed to correspond with Ho. Wanting to play a role in diplomacy, Kissinger contacted the State Department with a plan for Marovitch and Aubrac to go to Hanoi with a peace offer. The Secretary of State, Dean Rusk, was opposed to Kissinger's plan. However, W. Averell Harriman of the "peace shop" was interested and got President Johnson to approve the approach, which was code-named Operation Pennsylvania. In July 1967, Aubrac and Marcovitch went to Hanoi to see Ho, who told him that he was willing to open peace talks with the United States, provided that the Americans "unconditionally" stopped bombing North Vietnam.
Sources: en.wikipedia.org
Reversed-phase HPLC gives the main purity figure, most often with UV detection near 214 nanometres. Mass spectrometry then confirms the molecular mass. Together the two methods distinguish a correct sequence from a closely related impurity.
The main chemical risks are methionine oxidation and backbone hydrolysis in solution. Moisture and repeated temperature cycling accelerate both processes. Dry powder held cold and desiccated is considerably more stable than any reconstituted preparation.
It holds a medicine registration in Russia, where it has been used clinically for decades. In most other countries it is treated as a research chemical. That split explains the uneven distribution of clinical literature.
It is described as a synthetic analogue of the ACTH(4–10) fragment, a short segment of adrenocorticotropic hormone. Its sequence differs from that fragment and includes two proline residues, which influence stability and behaviour in solution.