lyophilised powder is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-07-08. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Development of the compound took place in the Soviet Union during the 1980s, largely through peptide research groups affiliated with the Shemyakin-Ovchinnikov Institute and Moscow State University. Investigators screened fragments of adrenocorticotropic hormone for activity on the central nervous system while attempting to separate cognitive effects from hormonal ones. The shortened sequence was selected because it retained behavioral activity in animal models without stimulating corticosteroid release. Early publications described the molecule as an ACTH(4-10) analog.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Seven-residue peptide |
| Molecular mass | 813.9 Da | Monoisotopic value |
| Appearance | White to off-white powder | Lyophilized form |
| Solubility | Freely soluble in water | Also soluble in saline and polar solvents |
| Storage (dry) | -20 °C or lower | Desiccated, protected from light |
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.
Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.
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.
IUPAC made a recommendation in 1991 for the description and measurement of carryover effects in clinical chemistry. The carryover ratio is the percentage of H3 carry to L1 constituting the carryover portion "h". In a design of 3 high samples followed by 3 low samples, h can be calculated as (L1 - mean of L2&L3) / (H3 - mean of L2&L3) The carry-over ratio's acceptance criteria depend on the measurement and the laboratory concerned. For example, 1% carryover of plasma albumin would generally lead to a clinically insignificant effect, while 1% carryover of cardiac High sensitivity Troponin assay would be catastrophic.
Because of the rapid hydrolysis of the ester, the reaction should be carried out at pH 4.5, in buffered phosphoric acid the product can even be obtained in virtually quantitative yield. The compound can be purified by recrystallization from ethanol or ethyl acetate. Compared with the benzotriazole derivatives 1-hydroxybenzotriazole (HOBt) and 1-hydroxy-7-azabenzotriazole (HOAt) (which are widely used as peptide-linking reagents but are explosive), ethyl cyanohydroxyiminoacetate exhibits a markedly slowed thermal decomposition on heating.
However, there has been criticism where it favors the idea for lips, with the 2017 analytical study proposing that tyrannosaurids had large, flat scales on their snouts instead of lips, as modern crocodiles do. But crocodiles possess rather cracked keratinized skin, not flat scales; by observing the hummocky rugosity of tyrannosaurids, and comparing it to extant lizards, researchers have found that tyrannosaurids had squamose scales rather than a crocodillian-like skin. In 2023, Cullen and colleagues supported the idea that theropods like tyrannosaurids had lips based on anatomical patterns, such as those of the foramina on their face and jaws, more similar to those of modern squamates such as monitor lizards or marine iguanas than those of modern crocodilians like alligators. Comparison of the teeth of Daspletosaurus and American alligators shows that the enamel of tyrannosaurids had no significant wear and that the teeth of modern crocodilians were eroded on the labial side and were substantially worn. This suggests that it is likely that theropod teeth were kept wet by lips. On the basis of the relationship between hydration and wear resistance, the authors argued that it is unlikely that the teeth of theropods, including tyrannosaurids, would have remained unworn when exposed for a long time, because it would have been hard to maintain hydration.
== Medical uses == Vortioxetine is used as a treatment for major depressive disorder, with its effectiveness shown to be similar to other antidepressants and its effect size has been described as modest. Vortioxetine may be used when other treatments have failed. A 2017 Cochrane review on vortioxetine determined that its place in the treatment of severe depression is unclear due to low-quality evidence and that more studies comparing vortioxetine to selective serotonin reuptake inhibitors (SSRIs), the typical first-line treatments, are needed. Vortioxetine appears to work in depressed patients with anxiety. Vortioxetine is also used off label for anxiety. A 2016 review found it was not useful in generalized anxiety disorder at 2.5, 5.0, and 10 mg doses (15 and 20 mg doses were not tested). A 2019 meta-analysis found that vortioxetine did not produce statistically significant results over placebo in the symptoms, quality of life, and remission rates of generalized anxiety disorder, but it was well-tolerated. However, a 2018 meta-analysis supported use and efficacy of vortioxetine for generalized anxiety disorder, though stated that more research was necessary to strengthen the evidence. A 2021 systematic review and meta-analysis concluded that there was uncertainty about the effectiveness of vortioxetine for anxiety due to existing evidence being of very low-quality.
Sources: en.wikipedia.org
==== European guidelines for phenylketonuria ==== The consensus paper was picked up by the Scientific Advisory Committee of the E.S.PKU. The SAC launched an expert group, the creation the first European Guidelines for Phenylketonuria. This led to the first publication of the key statements in the lancet diabetes and endocrinology. By the end of the year, the complete guidelines were published in the Orphanet Journal of Rare Diseases. The publication also received some critical attention from other medical professionals. A second version of the guidelines is already been worked on.
For a soleus receptor, Houk and Simon obtain average values of K=57 pulses/sec/kg, A=0.31, a=0.22 sec−1, B=0.4, b=2.17 sec−1, C=2.5, c=36 sec−1 . When modeling a cat stretch reflex, Lin and Crago improved upon this model by adding a logarithmic nonlinearity before the Houk and Simon model and a threshold nonlinearity after.
=== Zeolitic imidazolate frameworks (ZIFs) === Several different mechanical phenomena have been observed in zeolitic imidazolate frameworks (ZIFs), the most widely studied MOF for mechanical properties due to their many similarities to zeolites. General trends for the ZIF family are the tendency of the Young's modulus and hardness of the ZIFs to decrease as the accessible pore volume increases. The bulk moduli of ZIF-62 series increase with the increasing of benzoimidazolate (bim−) concentration. ZIF-62 shows a continuous phase transition from open pore (op) to close pore (cp) phase when bim− concentration is over 0.35 per formular unit. The accessible pore size and volume of ZIF-62-bim0.35 can be precisely tuned by applying adequate pressures. Another study has shown that under hydrostatic loading in solvent the ZIF-8 material expands as opposed to contracting. This is a result of hyperfilling of the internal pores with solvent. A computational study demonstrated that ZIF-4 and ZIF-8 materials undergo a shear softening mechanism with amorphizing (at ~ 0.34 GPa) of the material under hydrostatic loading, while still possessing a bulk modulus on the order of 6.5 GPa. Additionally, the ZIF-4 and ZIF-8 MOFs are subject to many pressure dependent phase transitions.
Carbohydrates are compounds made up of types of sugar. Carbohydrates are classified according to their number of sugar units: monosaccharides (such as glucose and fructose), disaccharides (such as sucrose and lactose), oligosaccharides, and polysaccharides (such as starch, glycogen, and cellulose). Proteins are organic compounds that consist of amino acids joined by peptide bonds. Since the body cannot manufacture some of the amino acids (termed essential amino acids), the diet must supply them. Through digestion, proteins are broken down by proteases back into free amino acids. Fats consist of a glycerin molecule with three fatty acids attached. Fatty acid molecules contain a -COOH group attached to unbranched hydrocarbon chains connected by single bonds alone (saturated fatty acids) or by both double and single bonds (unsaturated fatty acids). Fats are needed for construction and maintenance of cell membranes, to maintain a stable body temperature, and to sustain the health of skin and hair. Because the body does not manufacture certain fatty acids (termed essential fatty acids), they must be obtained through one's diet.
Many Irish nationalists sympathised with the Boers as oppressed by British imperialism, much like they viewed themselves. Irish miners already in the Transvaal at the start of the war formed the nucleus of two Irish commandos. The Second Irish Brigade was headed by an Australian of Irish parents, Colonel Arthur Lynch. Groups of Irish volunteers went to fight with the Boers—despite the fact that there were many Irish troops fighting in the British army, including the Royal Dublin Fusiliers. In Britain, the "Pro-Boer" campaign expanded, with writers often idealising the Boer society. The war highlighted the dangers of Britain's policy of non-alignment and deepened her isolation. The 1900 UK general election, also known as the "Khaki election", was called by the Prime Minister, Lord Salisbury, on the back of British victories. There was much enthusiasm for the war at this point, resulting in a victory for the Conservative government. However, support waned as it became apparent the war would not be easy and it dragged on, partially contributing to the Conservatives' spectacular defeat in 1906. There was outrage at scorched earth tactics and conditions in the concentration camps. It became apparent there were serious problems with public health in Britain as up to 40% of recruits in Britain were unfit for conscription, and suffered from medical problems such as rickets and other poverty-related illnesses. This came at a time of increasing concern for the poor in Britain. 22,000 Empire troops were killed.
Sources: en.wikipedia.org
=== Gardening === Nolina lindheimeriana, like other species of Nolina, are favored for their extreme drought resistance, deer resistance, and their rosettes' attractive grassy texture; rosettes may clump into groups. The plants can be quite attractive when in flower or fruit, with the inflorescences rising about three meters tall (10 feet). However, because of the cutting leaf margins, plants shouldn't be placed near walkways. It is reported as cold tolerant, not needing much watering, and preferring locations in full or partial sunlight. It grows in various kinds of limestone-based loam soils, including caliche type. Also, true to its desert origins, the species can be a bit slow growing.
==== Public relations ==== On 26 September 2008, in order to quell the disquiet over the speech by Zhu Yonglan of the CGOSFSC regarding leaders' insulation from the food-security issues faced by the general population, Xinhua issued a brief statement, in Chinese, denying the existence of the centre, the award, or any person named Zhu Yonglan, saying these were "purely rumours". On 16 September, the AQSIQ tests on baby milk powder produced by 109 companies showed 69 batches from 22 companies to be melamine-contaminated; the State Council attempted to reassure that formula produced by most companies in China was safe. It said: "the number of companies with melamine-tainted milk accounted for 20.18% of the total of powdered milk companies in China; the number of tainted batches accounted for 14.05% of the total batches tested." On 30 September, the AQSIQ said its tests on 265 batches from 154 companies showed that "only 18%" had tested positive for melamine: "of the 290 dairies nationwide 154 dairies, representing 87% market share, 134 of these dairies had tested negative for melamine." On 16 September, the AQSIQ published results of tests on 408 liquid milk producers, and found "most dairy products were safe to drink", although the test results showed nearly 10 percent of batches from Mengniu, Yili and Bright were contaminated.
== Additional application == Acetoacetyl-CoA also behaves as a product of acetoacetyl-CoA synthetase (AACS) within the cytosol, using acetoacetate as the substrate, the reaction provides acetyl groups for lipogenesis. Understanding acetoacetyl-CoA is important in cholesterol development and lipogenesis and Acetoacetyl-CoA synthetase playing a role in its development, it also plays a significant role within the brain. Cholesterol and fats have been observed in high concentrations within neuronal tissue, as well as high AACS mRNA expression levels within cells of the hippocampus and cortical region. In addition, they play a significant role in neuronal development during the early embryonic and fetal developmental stages.
A protein phosphatase is a phosphatase enzyme that removes a phosphate group from the phosphorylated amino acid residue of its substrate protein. Protein phosphorylation is one of the most common forms of reversible protein posttranslational modification (PTM), with up to 30% of all proteins being phosphorylated at any given time. Protein kinases (PKs) are the effectors of phosphorylation and catalyse the transfer of a γ-phosphate from ATP to specific amino acids on proteins. Several hundred PKs exist in mammals and are classified into distinct super-families. Proteins are phosphorylated predominantly on Ser, Thr and Tyr residues, which account for 79.3, 16.9 and 3.8% respectively of the phosphoproteome, at least in mammals. In contrast, protein phosphatases (PPs) are the primary effectors of dephosphorylation and can be grouped into three main classes based on sequence, structure and catalytic function. The largest class of PPs is the phosphoprotein phosphatase (PPP) family comprising PP1, PP2A, PP2B, PP4, PP5, PP6 and PP7, and the protein phosphatase Mg2+- or Mn2+-dependent (PPM) family, composed primarily of PP2C. The protein Tyr phosphatase (PTP) super-family forms the second group, and the aspartate-based protein phosphatases the third. The protein pseudophosphatases form part of the larger phosphatase family, and in most cases are thought to be catalytically inert, instead functioning as phosphate-binding proteins, integrators of signalling or subcellular traps.
Sources: en.wikipedia.org
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.
The extension was introduced to slow enzymatic breakdown of the peptide in biological systems. Natural ACTH fragments are degraded rapidly by peptidases. Adding the tripeptide was intended to extend the window during which the molecule remains intact.
Most published work consists of animal experiments conducted in a small number of laboratories. Human data are limited in number and size. Whether the observed effects translate into reliable clinical benefit is still unresolved.
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.