This is a working overview of Semax, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-08-10. Anything still debated is marked as such rather than presented as settled.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide (ACTH fragment analog) | Not a steroid; does not belong to the melanocortin agonist drugs by marketing category |
| Molecular formula | C37H51N9O10S (commonly cited) | Reported values vary slightly with salt and counter-ion content |
| Appearance | White to off-white lyophilized powder | A single batch may appear as a loose cake or fluffy solid |
| Solubility | Freely soluble in water and aqueous buffer | Stock solutions are usually prepared in sterile water or saline |
| Typical storage | −20 °C or below, desiccated and protected from light | Seal opened vials promptly to limit moisture uptake |
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.
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.
Identity and purity are commonly assessed by reversed-phase high-performance liquid chromatography, with ultraviolet detection near 214 nanometers for the peptide backbone. Mass spectrometry, either electrospray or matrix-assisted laser desorption, confirms molecular mass and detects truncation or modification products. Amino acid analysis can verify composition. Because the sequence contains no strongly absorbing aromatic residue apart from phenylalanine, detection wavelengths are chosen carefully. Purity values above 95 percent are typical for research-grade material.
Quality documentation for research-grade peptide usually includes a certificate of analysis stating purity, identity, and residual counterion content. Batch-to-batch variation in purity and salt form is a recognized issue, and comparisons across suppliers require attention to the exact counterion, for example acetate versus trifluoroacetate. Sequence verification by tandem mass spectrometry provides stronger evidence than a single mass measurement. For any study reporting biological results, the analytical method and the measured purity should be stated explicitly. Independent verification of supplier claims is considered good practice.
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.
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.
溶液状态的稳定性明显低于冻干粉。肽类在水溶液中可能经历水解、氧化与聚集，其中甲硫氨酸和天冬酰胺等残基常是敏感位点。Semax 含有甲硫氨酸，因此氧化风险相对突出。工作液一般主张现配现用，或冷藏并在数日内用尽。缓冲液种类、pH 和离子强度都会影响降解速率，而关于最佳条件的公开数据并不统一。
常规纯度与身份确认依赖反相高效液相色谱，并辅以质谱测定分子量。氨基酸组成分析可用于验证序列构成，肽图分析则能进一步定位修饰或降解产物。杂质谱通常关注缺失序列肽、截短片段和氧化产物。不同方法的检出限并不相同，因此各实验室报告的纯度数值不宜直接横向比较。
=== Microfractures of the fetal membranes === Throughout gestation the fetal membranes undergo remodeling to allow for the increase in size of the uterus. The remodeling of the fetal membranes occurs at both the level of the cells and the extracellular matrix (ECM). Structural abnormalities such as areas of where collagen has degraded, known as microfractures, have been observed in the amniotic membrane layer. Microfractures are characterised by:
=== USADA anti-doping partnership (2015–2024) === The UFC's partnership with USADA coming to an end in 2023, the UFC announced a new partnership with Drug Free Sport International, the same company that oversees the anti-doping programs of the NCAA, MLB, NFL, and NBA. This partnership is set to begin in 2024, after their current contract with USADA expired on December 31, 2023. The UFC announced that former FBI agent George Piro would serve as the independent administrator of the UFC's anti-doping program.
By replacing the gene with a new version fused to a green fluorescent protein marker or similar, expression may be directly quantified in live cells. This is done by imaging using a fluorescence microscope. It is very difficult to clone a GFP-fused protein into its native location in the genome without affecting expression levels, so this method often cannot be used to measure endogenous gene expression. It is, however, widely used to measure the expression of a gene artificially introduced into the cell, for example via an expression vector. By fusing a target protein to a fluorescent reporter, the protein's behavior, including its cellular localization and expression level, can be significantly changed. The enzyme-linked immunosorbent assay works by using antibodies immobilised on a microtiter plate to capture proteins of interest from samples added to the well. Using a detection antibody conjugated to an enzyme or fluorophore the quantity of bound protein can be accurately measured by fluorometric or colourimetric detection. The detection process is very similar to that of a Western blot, but by avoiding the gel steps more accurate quantification can be achieved.
=== Liquid biomolecular condensates === Liquid–liquid phase separation (LLPS) generates a subtype of colloid known as an emulsion that can coalesce to form large droplets within a liquid. Ordering of molecules during liquid–liquid phase separation can generate liquid crystals rather than emulsions. In cells, LLPS produces a liquid subclass of biomolecular condensate that can behave as either an emulsion or liquid crystal. The term biomolecular condensates was introduced in the context of intracellular assemblies as a convenient but non-exclusionary term to describe non-stoichiometric assemblies of biomolecules. The choice of language here is specific and important. It has been proposed that many biomolecular condensates form through liquid–liquid phase separation (LLPS) to form colloidal emulsions or liquid crystals in living organisms, as opposed to liquid–solid phase separation to form crystals/aggregates in gels, sols or suspensions within cells or extracellular secretions. However, unequivocally demonstrating that a cellular body forms through liquid–liquid phase separation is challenging, because different material states (liquid vs. gel vs. solid) are not always easy to distinguish in living cells. The term "biomolecular condensate" directly addresses this challenge by making no assumption regarding either the physical mechanism through which assembly is achieved, nor the material state of the resulting assembly.
=== Synthetic === The availability of synthetic toxin has allowed scientists to further explore the biological activity of the toxin, resulting in the observation that d-ACTX-Ar1a causes repetitive firing and prolongation of the action potential. These actions underlie the clinical symptoms seen following envenomation and further contribute to the understanding of the molecular basis for activity of this potent neurotoxin on voltage-gated sodium channels. Under voltage-clamp conditions in dorsal root ganglion (DRG) neurons it was found that the effects of the synthetic toxin on sodium currents were not significantly different from those previously reported for the native toxin. Neither native nor synthetic d-ACTX-Ar1a had any effect on TTX-resistant sodium currents, but both exerted a potent selective modulation of TTX-sensitive sodium currents consistent with actions on neurotoxin receptor site-3. This includes a slowing of the sodium-channel inactivation, a hyperpolarizing shift in the voltage-dependence of activation and a hyperpolarizing shift in the steady-state sodium-channel inactivation. d-ACTX-Ar1a causes a prolongation of action potential duration, accompanied by spontaneous repetitive firing, but does not depolarize the resting membrane potential. Effects on the autonomic nervous system, including vomiting, profuse sweating, salivation, lachrymation, marked hypertension followed by hypotension, together with effect on the somatic nervous system to cause muscle fasciculation and dyspnea (shortness of breath) are presumably due to excessive transmitter release.
Sources: en.wikipedia.org
No more than 5 hydrogen bond donors (the total number of nitrogen–hydrogen and oxygen–hydrogen bonds) No more than 10 hydrogen bond acceptors (all nitrogen or oxygen atoms) A molecular mass less than 500 daltons A calculated octanol-water partition coefficient (Clog P) that does not exceed 5 Note that all numbers are multiples of five, which is the origin of the rule's name. As with many other rules of thumb, such as Baldwin's rules for ring closure, there are many exceptions.
=== Mechanism of action === Avasimibe is a potent activator of the pregnane X receptor and, consequently, an indirect inducer of CYP3A4 and P-glycoprotein, as well as a potent inhibitor of several cytochrome P450 isoenzymes, including CYP1A2, CYP2C9, and CYP2C19; its spectrum of CYP induction and inhibition is similar to that of rifampicin.
== Epidemiology == The beta form of thalassemia is particularly prevalent among Mediterranean peoples, and this geographical association is responsible for its original name. Thalassemias resulted in 25,000 deaths in 2013, down from 36,000 deaths in 1990. In Europe, the highest concentrations of the disease are found in Greece, coastal regions in Turkey (particularly the Aegean Region such as İzmir, Balıkesir, Aydın, Muğla, and Mediterranean Region such as Antalya, Adana, Mersin), in southern Spain, in parts of Italy, particularly southern Italy. With the exception of the Balearics, the major Mediterranean Islands, such as Sicily, Sardinia, Malta, Corsica, Cyprus, and Crete are heavily affected. Other Mediterranean peoples, as well as those in the vicinity of the Mediterranean, also have high rates of thalassemia, including people from North Africa and West Asia. Far from the Mediterranean, South Asians are also affected, with the world's highest concentration of carriers (16–18% of the population) in the Maldives. The disease is also found in populations living in Africa, the Americas, and in Tharu people in the Terai region of Nepal and India. It is believed to account for much lower rates of malaria illnesses and deaths, accounting for the historic ability of Tharus to survive in areas with heavy malaria infestation while others could not. Thalassemias are particularly associated with people of Mediterranean origin, Arabs (especially Palestinians and people of Palestinian descent), and Asians.
== Applications == Ligand binding assays provide a measure of the interactions that occur between two molecules, such as protein-bindings, as well as the degree of affinity (weak, strong, or no connection) for which the reactants bind together. Essential aspects of binding assays include, but are not limited to, the concentration level of reactants or products (see radioactive section), maintaining the equilibrium constant of reactants throughout the assay, and the reliability and validity of linked reactions. Although binding assays are simple, they fail to provide information on whether or not the compound being tested affects the target's function.
Sources: en.wikipedia.org
Stationary phases can react with CDAs to form chiral stationary phases which can resolve chiral molecules. By reacting with alcohols on a silicate stationary phase, CDAs add a chiral center to the stationary phase, which allows for the separation of chiral molecules.
== Case against Stephen Dank == The AFL Tribunal heard cases against sports scientist Stephen Dank during the summer of 2014/15, and he was found guilty of ten charges. The charges upheld against Dank covered a wide range of illegal supplements that he trafficked in, attempted to traffic in, or was complicit in attempted trafficking when the AFL registered him. The upheld charges were:
== Cultivation == Many Japanese plant ashitaba in herb gardens, flower pots, and backyards. This is due to the modest conditions for cultivation and fast rate of growth. This is a cold hardy plant, with optimal temperatures ranging between 12 and 22 °C. Harvesting a leaf at the break of day often results in a new sprout growing overnight, being visible the following morning, hence the name "tomorrow's leaf".
Sources: en.wikipedia.org
It is a short synthetic peptide built from seven amino acids: methionine, glutamic acid, histidine, phenylalanine and three prolines. The sequence derives from the 4-10 fragment of adrenocorticotropic hormone with an added proline-glycine-proline tail. No plant or animal extract is involved; the material is produced by solid-phase peptide synthesis.
It was developed in the Soviet Union during the early 1980s by groups at the Institute of Molecular Genetics in Moscow. Russian approval for intranasal use followed, and it has been marketed there since. Western laboratories encountered it mainly through translated literature and, later, through online research-chemical trade.
It holds a Russian registration as a prescription nasal product but has no approval from the European Medicines Agency or the United States Food and Drug Administration. Buyers outside Russia usually receive material sold strictly for laboratory research. That distinction matters because research-grade and pharmaceutical-grade products carry different documentation and testing expectations.
It consists mainly of animal experiments and small clinical reports, with much of the clinical material published in Russian-language journals. Large independent trials are scarce. Separating reliable effects from chance findings is consequently difficult.