The short version of methionine sulfoxide fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-12-04. Anything still debated is marked as such rather than presented as settled.
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.
Stability depends heavily on physical state. Lyophilized powder held dry, cold and dark retains its content over long periods, whereas dissolved peptide begins to change within days at room temperature. The most cited degradation route is oxidation of the methionine residue, which converts the peptide to a sulfoxide form that elutes differently on chromatography. Hydrolysis of amide bonds and adsorption onto container walls contribute smaller losses. Buffers that exclude oxygen from the headspace slow the oxidation pathway, but no single condition prevents all change indefinitely.
Practical handling follows from those properties. Bulk material is best divided into single-use portions soon after receipt, because each thaw exposes the whole container to moisture and temperature cycling. Vials should be allowed to reach room temperature before opening to prevent condensation on the powder. Low-binding plasticware reduces loss of dilute solutions, and sterile filtration is used when a preparation must remain free of microbial growth. Records of batch number, reconstitution date and storage history are what allow a later analytical result to be interpreted meaningfully.
Identity and purity of Semax are established mainly by reversed-phase high-performance liquid chromatography coupled with mass spectrometry. The chromatographic trace gives a purity estimate as a percentage of total peak area, while electrospray or matrix-assisted laser desorption ionization confirms the molecular mass against the calculated value. Amino acid analysis and sequence-specific fragmentation provide further confirmation when a supplier's chain of custody is unclear. Vendors frequently quote a purity figure without stating the detection wavelength or the integration method, which limits how far one number can be compared with another.
| 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 |
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.
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.
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.
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.
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.
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.
Vitarine Pharmaceuticals of New York, which sought approval of a generic version of the drug Dyazide, a medication for high blood pressure, submitted Dyazide, rather than its generic version, for the FDA tests. In April 1989, the FDA investigated 11 manufacturers for irregularities; and later brought that number up to 13. Dozens of drugs were eventually suspended or recalled by manufacturers. In the early 1990s, the U.S. Securities and Exchange Commission filed securities fraud charges against the Bolar Pharmaceutical Company, a major generic manufacturer based in Long Island, New York.
However, all annealing based assembly methods require the primers to be mixed together in one tube. In this case, shorter overlaps do not always allow precise and specific annealing of complementary primers, resulting in the inhibition of full length product formation. Manual design of oligonucleotides is a laborious procedure and does not guarantee the successful synthesis of the desired gene. For optimal performance of almost all annealing based methods, the melting temperatures of the overlapping regions are supposed to be similar for all oligonucleotides. The necessary primer optimisation should be performed using specialized oligonucleotide design programs. Several solutions for automated primer design for gene synthesis have been presented so far.
=== Neuropathic pain === The European Federation of Neurological Societies recommends pregabalin as a first-line agent for the treatment of pain associated with diabetic neuropathy, post-herpetic neuralgia, and central neuropathic pain. A minority obtain substantial benefit, and a larger number obtain moderate benefit. It is given equal weight as gabapentin and tricyclic antidepressants as a first-line agent, though the latter are less expensive as of 2010. Pregabalin is as effective at relieving pain as duloxetine and amitriptyline. Combination treatment of pregabalin and amitriptyline or duloxetine offers additional pain relief for people whose pain is not adequately controlled with one medication and is safe. Studies have shown that higher doses of pregabalin are associated with greater efficacy. Pregabalin's use in cancer-associated neuropathic pain is controversial, though such use is common. It has been examined for the prevention of post-surgical chronic pain, but its utility for this purpose is controversial. Pregabalin is generally not regarded as efficacious in the treatment of acute pain. In trials examining the utility of pregabalin for the treatment of acute post-surgical pain, no effect on overall pain levels was observed, but people did require less morphine and had fewer opioid-related side effects. Several possible mechanisms for pain improvement have been discussed.
=== DEA classification === Vicoprofen was initially scheduled as a schedule III drug, but was later reclassified to a schedule II drug based on the DEA reclassification of products containing hydrocodone, effective October 2014.
Sources: en.wikipedia.org
==== Colourants and pigments ==== In addition to the uses described above, the European Union Observatory for Nanomaterials (EUON) has highlighted that silver nanoparticles are used in colourants in cosmetics, as well as pigments. A recently published study by the EUON has illustrated the existence of knowledge gaps regarding the safety of nanoparticles in pigments.
==== Soviet secrecy and obfuscation ==== On August 30, 1955, Sergei Korolev succeeded in convincing the Soviet Academy of Sciences to establish a commission dedicated to achieving the goal of launching a satellite into Earth orbit before the United States, this can be viewed as the de facto start date of the space race. The Council of Ministers of the Soviet Union began a policy of treating development of its space program as top-secret. When the Sputnik project was first approved, one of the immediate courses of action the Politburo took was to consider what to announce to the world regarding their event. The Telegraph Agency of the Soviet Union (TASS) established precedents for all official announcements on the Soviet space program. The information eventually released did not offer details on who built and launched the satellite or why it was launched. The Soviet space program's use of secrecy served as both a tool to prevent the leaking of classified information between countries, and to avoid revealing specifics to the Soviet populace in regards to their short and long term goals; the program's nature embodied ambiguous messages concerning its goals, successes, and values. Launches were not announced until they took place, cosmonaut names were not released until they flew, and outside observers did not know the size or shape of their rockets or cabins of most of their spaceships, except for the first Sputniks, lunar probes, and Venus probe.
Clinical identification of P. aeruginosa may include identifying the production of both pyocyanin and fluorescein, as well as its ability to grow at 42 °C. P. aeruginosa is capable of growth in diesel and jet fuels, where it is known as a hydrocarbon-using microorganism, causing microbial corrosion. It creates dark, gellish mats sometimes improperly called "algae" because of their appearance.
The word "parsley" is a merger of Old English petersilie (which is identical to the contemporary German word for parsley: Petersilie) and the Old French peresil. Both of these names are derived from Medieval Latin petrosilium, from Latin petroselinum, which is the latinization of the Greek πετροσέλινον, petroselinon, 'rock-celery', from πέτρα, petra, 'rock, stone' and σέλινον, selinon, 'celery'. Mycenaean Greek se-ri-no, in Linear B, is the earliest attested form of the word selinon.
Autoimmune estrogen dermatitis Autoimmune progesterone dermatitis Autosensitization dermatitis Breast eczema (nipple eczema) Chronic vesiculobullous hand eczema Circumostomy eczema Dyshidrosis (acute vesiculobullous hand eczema, cheiropompholyx, dyshidrotic eczema, pompholyx, podopompholyx) Ear eczema Eyelid dermatitis Hand eczema Hyperkeratotic hand dermatitis Id reaction (disseminated eczema, generalized eczema) Irritant diaper dermatitis (diaper dermatitis, napkin dermatitis) Juvenile plantar dermatosis (atopic winter feet, dermatitis plantaris sicca, forefoot dermatitis, moon-boot foot syndrome, sweaty sock dermatitis) Molluscum dermatitis Nummular dermatitis (discoid eczema, microbial eczema, nummular eczema, nummular neurodermatitis) Nutritional deficiency eczema Sulzberger–Garbe syndrome (oid-oid disease) Xerotic eczema (asteatotic eczema, desiccation dermatitis, eczema craquelé, pruritus hiemalis, winter eczema, winter itch)
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.
Suppliers normally quote a percentage of total chromatographic peak area, most often from reversed-phase HPLC. That figure says nothing about what the remaining percentage contains, and it depends on the detection wavelength used. A mass spectrometry result is a separate and stronger check on identity.