ACTH analog 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 2026-05-20. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Semax is normally supplied as a lyophilized powder, and that form is the most stable. Suppliers commonly recommend storage at -20 °C in a desiccated container protected from light, with short-term handling at room temperature limited to weighing and transfer. Powder that has absorbed moisture degrades faster, so vials should be warmed to ambient temperature before opening to prevent condensation on the contents. Hygroscopic behavior is typical of short hydrophilic peptides, and humidity control matters more than temperature alone for long-term retention.
Once dissolved, the peptide is considerably less stable than the solid. Aqueous solutions are usually prepared at neutral to slightly acidic pH, filtered, and divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are a common cause of avoidable loss and are best prevented by never refreezing a thawed aliquot. Adsorption to plastic and glass surfaces can lower the measured concentration of dilute solutions, particularly below roughly 0.1 mg/mL. Buffer choice, salt content, and container material all influence how much peptide remains detectable after storage.
Identity and purity are established with standard peptide methods. Reversed-phase HPLC with ultraviolet detection near 214 nm resolves the parent peak from deletion and truncation byproducts, and reports typically quote a main-peak percentage. Mass spectrometry by electrospray or MALDI-TOF confirms the expected molecular mass, while amino acid analysis or peptide mapping can verify composition when the sequence itself is in question. A certificate of analysis that pairs a chromatogram with a mass spectrum is more informative than a purity figure alone. Counter-ion content and residual solvents are separate specifications and are frequently omitted.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Free acid form of the heptapeptide; depends on terminal groups |
| Molecular mass | About 813.9 g/mol | Average mass used for mass spectrometry confirmation |
| Appearance | White to off-white solid | Supplied as a lyophilised powder; hygroscopic |
| Solubility class | Freely soluble in aqueous media | Water, saline, and phosphate buffers; limited organic solubility |
| Typical storage temperature | -20 degrees Celsius | Long term and dry; short working periods may use 2 to 8 degrees Celsius |
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.
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.
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.
当时的短肽研究普遍关注能否穿越血脑屏障、在低剂量下产生中枢效应，Semax 属于这一路线。鼻内给药是其主要使用方式，俄语文献报道的适应症涵盖缺血性卒中、短暂性脑缺血发作、认知功能减退以及视神经病变。这些研究大多发表在当地期刊上，样本规模与终点设置同西方试验惯例存在差异，国际同行对其临床证据的强度看法不一。
各国监管态度分化明显。俄罗斯按处方药管理，部分东欧国家留有使用记录；欧盟与美国未批准其作为药物上市，市面流通品通常标注为研究用化学品。身份差异意味着标示含量、纯度与无菌性缺少统一核查。体育领域还牵涉反兴奋剂名录，跨境携带则受目的地药品法规约束。
Identity and purity of semax are established with reversed-phase high-performance liquid chromatography coupled to ultraviolet detection, usually at 214 nanometres. Mass spectrometry, most often electrospray ionisation in positive mode, confirms the molecular mass and reveals truncated sequences. Amino acid analysis and peptide mapping after enzymatic digestion provide additional structural confirmation. Laboratories typically report purity as the percentage area of the main peak, a figure that does not capture isomeric or oxidised variants unless the method resolves them.
The peptide is prone to several degradation pathways. Oxidation of the methionine residue produces a sulfoxide that elutes close to the parent peak in many chromatographic systems. Hydrolysis of peptide bonds and deamidation of susceptible residues in related sequences also reduce purity over time. Lyophilised material kept dry at minus twenty degrees Celsius and shielded from light is the most stable form commonly described in laboratory practice.
Material sold for laboratory use varies widely in stated purity and documentation. A certificate of analysis should list the analytical method, the column and detector used, and the observed purity value. Independent verification by an outside laboratory is the practical way to confirm identity when documentation is absent or internally inconsistent. Regulatory status differs by country, and a product legal in one jurisdiction may be unapproved or controlled in another.
=== Helmut Kohl === In October 1982 the SPD–FDP coalition fell apart when the FDP joined forces with the CDU/CSU to elect CDU Chairman Helmut Kohl as Chancellor in a constructive vote of no confidence. Following national elections in March 1983, Kohl emerged in firm control of both the government and the CDU. The CDU/CSU fell just short of an absolute majority, due to the entry into the Bundestag of the Greens, who received 5.6% of the vote. In January 1987 the Kohl–Genscher government was returned to office, but the FDP and the Greens gained at the expense of the larger parties. Kohl's CDU and its Bavarian sister party, the CSU, slipped from 48.8% of the vote in 1983 to 44.3%. The SPD fell to 37%; long-time SPD Chairman Brandt subsequently resigned in April 1987 and was succeeded by Hans-Jochen Vogel. The FDP's share rose from 7% to 9.1%, its best showing since 1980. The Greens' share rose to 8.3% from their 1983 share of 5.6%.
In 2020, there were approximately 50 million people worldwide with Alzheimer's disease. The prevalence of AD in populations is dependent upon factors including incidence and survival. Since the incidence of AD increases with age, prevalence depends on the mean age of the population for which prevalence is given. Prevalence rates in less developed regions around the globe are lower. Both the prevalence and incidence rates of AD are steadily increasing, and the prevalence rate is estimated to triple by 2050 reaching 152 million, compared to the 50 million people with AD globally in 2020. Regarding incidence, where a disease-free population is followed over the years have shown rates between 10 and 15 per thousand person-years for all dementias and 5–8 for AD in Spain and Italy, which means that half of new dementia cases each year are Alzheimer's disease. Advancing age is a primary risk factor for the disease, and incidence rates are not equal for all ages: every 5 years after the age of 65, the risk of acquiring the disease approximately doubles, increasing from 3 to as much as 69 per thousand person-years.
In the treatment of polyneuropathies one must ascertain and manage the cause, among management activities are: weight decrease, use of a walking aid, and occupational therapist assistance. Additionally, BP control in those with diabetes is helpful, while intravenous immunoglobulin is used for multifocal motor neuropathy. According to Lopate, et al., methylprednisolone is a viable treatment for chronic inflammatory demyelinative polyneuropathy (which can also be treated with intravenous immunoglobulin). The authors also indicate that prednisone has greater adverse effects in such treatment, as opposed to intermittent (high-doses) of the aforementioned medication. According to Wu, et al., in critical illness polyneuropathy supportive and preventive therapy are important for the affected individual, as well as, avoiding (or limiting) corticosteroids.
Sources: en.wikipedia.org
The mechanism for the reaction is similar to that of other dioxygenases, and occurs in two distinct stages: In the first, a highly reactive Fe(IV)=O species is produced. Molecular oxygen is bound end-on in an axial position, producing a dioxygen unit. Nucleophilic attack on C2 generates a tetrahedral intermediate, with loss of the double bond in the dioxygen unit and bonds to iron and the alpha carbon of 2-oxoglutarate. Subsequent elimination of CO2 coincides with the formation of the Fe(IV)=O species. The second stage involves the abstraction of the pro-R hydrogen atom from C-4 of the proline substrate followed by radical combination, which yields hydroxyproline. As a consequence of the reaction mechanism, one molecule of 2-oxoglutarate is decarboxylated, forming succinate. This succinate is hydrolyzed and replaced with another 2-oxoglutarate after each reaction, and it has been concluded that in the presence of 2-oxoglutarate, enzyme-bound Fe2+ is rapidly converted to Fe3+, leading to inactivation of the enzyme. Ascorbate is utilized as a cofactor to reduce Fe3+ back to Fe2+.
In molecular biology, and more importantly high-throughput DNA sequencing, a chimera is a single DNA sequence originating when multiple transcripts or DNA sequences get joined. Chimeras can be considered artifacts and be filtered out from the data during processing to prevent spurious inferences of biological variation. However, chimeras should not be confused with chimeric reads, which are generally used by structural variant callers to detect structural variation events and are not always an indication of the presence of a chimeric transcript or gene. In a different context, the deliberate creation of artificial chimeras can also be a useful tool in molecular biology. For example, in protein engineering, "chimeragenesis" (forming chimeras between proteins that are encoded by homologous cDNAs) is one of the "two major techniques used to manipulate cDNA sequences". For gene fusions that occur through natural processes, see chimeric genes and fusion genes.
As a result, a reactor operating at constant power has a fixed steady-state equilibrium concentration, but when lowering reactor power, the 135Xe concentration can increase enough to effectively shut down the reactor. Without enough neutrons to offset their absorption by 135Xe, nor to burn the built-up xenon, the reactor has to be kept in shutdown state for 1–2 days until enough of the 135Xe decays. 135Xe beta-decays with half-life of 9.2 hours to 135Cs; a poisoned core will spontaneously recover after several half-lives. After about 3 days of shutdown, the core can be assumed to be free of 135Xe, without it introducing errors into the reactivity calculations. The inability of the reactor to be restarted in such state is called xenon precluded start up or dropping into an iodine pit; the duration of this situation is known as xenon dead time, poison outage, or iodine pit depth. Due to the risk of such situations, in the early Soviet nuclear industry, many servicing operations were performed on running reactors, as downtimes longer than an hour led to xenon buildup that could keep the reactor offline for significant time, lower the production of 239Pu, required for nuclear weapons, and would lead to investigations and punishment of the reactor operators.
Sources: en.wikipedia.org
=== Hypersensitivity === Hypersensitivity is a rarely described but significant complication of parenteral nutrition therapy. First reported in 1965, the incidence of these reactions is speculated to be around one in 1.5 million patients who are provided parenteral nutrition. There is a wide range in how and when these reactions manifest. Cutaneous manifestations are the most common presentation. Hypersensitivity is thought to occur to the individual components of TPN, with the intravenous lipid emulsion being the most frequently implicated component, followed by the multivitamin solution and the amino acid solution. Medications Patients who are receiving intravenous parenteral nutrition may also need to receive intravenous medications as well using the same Y-site. It is important to assess the compatibility of the medications with the nutrition components. Incompatibilities can be observed physically through discoloration, phase separation, or precipitation.
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== Glutathione == As the key substrate in GST-mediated reactions, glutathione is one of the most conserved reducing agents in bacterial cells. In its reduced form, glutathione plays a key role in the regulation of reactive oxygen species (ROS) in the cell. ROS are specific to aerobic cells and are usually produced in their metabolic processes. They function to maintain a dynamic balance under normal conditions, acting as intracellular and extracellular signaling molecules. The regulation of levels of ROS, levels of oxidized and reduced glutathione and other thiols, and antioxidant enzymes (such as GSTs and glutathione reductase) are important in determination of the most stable conditions for redox control, or for activation of apoptosis. Glutathione reductase is another enzyme that helps maintain cellular redox homeostasis by maintaining the supply of reduced glutathione. Without glutathione in its reduced form, glutathione transferases are not able to utilize it as a substrate in redox reactions. Glutathione contains a significant amount of cysteine residues, which contributes to its nature of being readily oxidized. The -SH groups on these residues act as strong nucleophiles, which can conjugate with a variety of molecules, including other glutathione molecules. Sulfur itself is able to exist in several different oxidation states; this redox flexibility combined with its strong nucleophilic properties allows glutathione to oxidize/readily pick up electrons from reactive oxygen species. Glutathione transferases play a key role in catalyzing such reactions.
Sources: en.wikipedia.org
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.
It appears in Russian pharmaceutical listings as a nasal formulation, but it is not an authorised medicine in the United States or the European Union. Outside those markets it is normally encountered as a research chemical rather than a prescription product.
Laboratory and animal work points to melanocortin signalling and changes in neurotrophic factor levels, especially brain-derived neurotrophic factor. The exact receptor targets and the degree to which these findings transfer to humans are still unresolved.
Each freeze-thaw cycle can degrade a fraction of the peptide and promote aggregation. Dividing a stock solution into single-use volumes removes repeated cycling as a variable. It also limits the time a thawed solution spends at room temperature.