If you have been reading about Melanocortin receptor and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Semax binds to melanocortin receptors and is thought to influence neuronal survival and plasticity rather than to act through the adrenal axis. Laboratory work has shown increased expression of brain-derived neurotrophic factor and nerve growth factor in treated tissue. Changes in c-Fos, a marker of neuronal activation, have also been reported. Because the peptide is rapidly degraded by peptidases, its effects are generally attributed to downstream signaling cascades rather than to sustained receptor occupancy.
| 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 |
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.
纯度评估以反相高效液相色谱为主，通过主峰面积百分比给出粗略结果，再配合电喷雾质谱核对分子量。氨基酸分析可验证组成比例，手性色谱或毛细管电泳用于检查残基构型。常见杂质包括缺失序列的短肽、氧化产物与二聚体。由于多数市售品不附带完整检验报告，独立第三方检测常被用来核实标称值。
从分子层面看，Semax 是线性七肽，没有二硫键、糖基或脂链修饰，N 端为游离氨基，C 端为游离羧基。分子含组氨酸与谷氨酸侧链，因此在水和甲醇等极性溶剂中溶解良好，在非极性溶剂中溶解有限。计算分子量约为 814 Da，与其质子化离子的质荷比吻合，可用于质谱确认。
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.
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.
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。
多数实验室与市售的 Semax 以冻干粉形式提供。冻干粉通常建议保存在 -20 °C 或更低温度下，同时避免光照与反复升温。短期运输有时采用冷藏条件，但长期保存仍以冷冻为主。分包操作应尽量减少开盖次数，以降低吸湿和微生物污染的风险。开封后若未一次用完，建议在干燥环境中密封并尽快放回低温储存。
== Laboratory use == Pentanes are relatively inexpensive and are the most volatile liquid alkanes at room temperature, so they are often used in the laboratory as solvents that can be conveniently and rapidly evaporated. However, because of their nonpolarity and lack of functionality, they dissolve only nonpolar and alkyl-rich compounds. Pentanes are miscible with most common nonpolar solvents such as chlorocarbons, aromatics, and ethers. They are often used in liquid chromatography.
In February 2011, the European Commission's Committee for Medicinal Products for Human Use approved the product for the treatment of Dupuytren's contracture in adults with a palpable cord by 'properly trained' doctors. Pfizer was reported to be working with Europe's national medicines regulatory bodies to launch the new treatment, hoping doctors could prescribe the treatment by late 2011. On November 7, 2012, BioSpecifics announced "BioSpecifics Technologies Corp. : Reports Third Quarter 2012 Financial Results". Auxilium's submission of a License Application to the FDA for Xiaflex for the potential treatment of Peyronie's disease, an excess of inelastic collagen causing penile curvature deformity. The FDA approved Xiaflex for the treatment of Peyronie’s disease in December 2013. Following this, Xiapex gained EU approval for the treatment of Peyronie’s disease in February 2015, making it the first and only biologic therapy indicated for the treatment of Peyronie's disease. Auxilium has also reported additional trials for potential use of Xiaflex are underway for the treatment of frozen shoulder, cellulite reductions and both human and canine lipomas. In March 2020, the Swedish manufacturer abruptly withdrew distribution of this drug in Europe for commercial reasons. Collagenase is no longer available on the National Health System except as part of a small clinical trial.
=== Physical therapy === Patients with chronic pain, including those with fibromyalgia, can benefit from techniques such as manual therapy, cryotherapy, and balneotherapy. These can lessen the experience of chronic pain and increase both the amount and quality of sleep. Patients' quality of life is also improved by decreasing pain mechanisms and increasing sleep quality, particularly during the REM phase, sleep efficiency, and alertness. A 2021 meta-analysis concluded that massage and myofascial release diminish pain in the medium term. As of 2015, there was no good evidence for the benefit of other mind-body therapies. A 2013 review found moderate-level evidence on the usage of acupuncture with electrical stimulation for improvement of overall well-being. Acupuncture alone will not have the same effects, but will enhance the influence of exercise and medication in pain and stiffness.
== Genetics == The Sar1B GTPase is an enzyme located in epithelial cells of the gastrointestinal tract. These proteins are critical for release of chylomicrons in the body. Chylomicron retention disease is an autosomal homozygous recessive disorder arising from mutations in the gene encoding the Sar1B GTPase. The Sar1B gene is located at position 5q31.1 in the fifth chromosome and is composed of eight exons. Alternative splicing of the second exon results into two different splice isoforms for the Sar1B transcript RNA. In CMRD, a mutation of this genomic sequence affects the Sar1B enzyme's ability to interact with Guanine Exchange Factors (GEFs) and GTP-Activating Proteins (GAPs). The mutation of exon 6 of the sequence can eliminate the critical chain that is responsible for recognizing guanine. This strips the GTPase of its capability to hydrolyze GTP, its hallmark trait. This overall affects the ability of Sar1B GTPase to control chylomicron release. A third mutant allele containing a missense mutation has also been reported to cause CMRD. All three of these alleles display recessive inheritance, suggesting that they loss-of-function mutations cause the symptoms of CMRD.
Sources: en.wikipedia.org
== Contraindications == The substance is contraindicated in herpes simplex and most other viral eye infections, as well as mycobacterial, fungal and amoebal eye infections because it only reduces the inflammation but does not act against such microorganisms.
==== Huo and Wang ==== In 1989–1993, Huo and Wang (中国社会科学院考古研究所, Zhongguo shehui kexueyuan kaogu yanjiusuo) tested the following caves: 224, 76, 4, 8, 34, 68, 77, 98, 104, 114, 117, 118, 119, 125, 129, 135, 162, 171, 180, 189, 196, 198, 206, 212, 219, 227, 27, 39, 48, 60, 69, 84, 91, 92, 99, 123, 139, 161, 165, 178, 207. They proposed a chronology which has some significant differences with the chronology previously proposed by Su Bai. Japanese teams of Nagoya University (日本名古屋大学) tested in 1995, 1997, 1998 and 2011 the following caves: 8, 171, 224, 13, 67, 76, 77, 92, 205. Many of the results remain inconclusive, sometimes even contradictory, and the historical period in question is rather too short in relation to the uncertainty margin of Carbon 14 datation, to provide a meaningful segmentation of the caves. Most narrow Carbon dates given for the Kizil Caves refer to a 68% probability level (1σ), which implies a significant level of uncertainty, and when dates are adjusted to the 95% probability level (2σ) as standard archaeological practice requires, then the timespan between the earliest and lowest dates becomes so large (about 200 to 300 years), as to make individual comparisons between the caves meaningless. Most researchers now use an approach combining artistic and architectural analysis together with carbon-dating, as a way to approach a reliable nomenclature, as proposed by Marylin Martin Rhie from 2001.
Astatine was first produced by bombarding bismuth-209 with energetic alpha particles, and this is still the major route used to create the relatively long-lived isotopes astatine-209 through astatine-211. Astatine is only produced in minuscule quantities, with modern techniques allowing production runs of up to 6.6 gigabecquerels (about 86 nanograms or 2.47×1014 atoms). Synthesis of greater quantities of astatine using this method is constrained by the limited availability of suitable cyclotrons and the prospect of melting the target. Solvent radiolysis due to the cumulative effect of astatine decay is a related problem. With cryogenic technology, microgram quantities of astatine might be able to be generated via proton irradiation of thorium or uranium to yield radon-211, in turn decaying to astatine-211. Contamination with astatine-210 is expected to be a drawback of this method. The most important isotope is astatine-211, the only one in commercial use. To produce the bismuth target, the metal is sputtered onto a gold, copper, or aluminium surface at 50 to 100 milligrams per square centimeter. Bismuth oxide can be used instead; this is forcibly fused with a copper plate. The target is kept under a chemically neutral nitrogen atmosphere, and is cooled with water to prevent premature astatine vaporization. In a particle accelerator, such as a cyclotron, alpha particles are collided with the bismuth. Even though only one bismuth isotope is used (bismuth-209), the reaction may occur in three possible ways, producing astatine-209, astatine-210, or astatine-211.
As a result of canonical DNA sequence changes, directed evolution also enables the development of orthogonal ribosomes, which make it easier to incorporate XAAs into proteins or create "mirror life," or biological systems that contain biomolecules made up of enantiomers with different chiral orientations.
== Amino acid specificity == Many different amino acid side chains have been described as ADP-ribose acceptors. From a chemical perspective, this modification represents protein glycosylation: the transfer of ADP-ribose occurs onto amino acid side chains with a nucleophilic oxygen, nitrogen, or sulfur, resulting in N-, O-, or S-glycosidic linkage to the ribose of the ADP-ribose. Originally, acidic amino acids (glutamate and aspartate) were described as the main sites of ADP-ribosylation. However, many other ADP-ribose acceptor sites such as serine, arginine, cysteine, lysine, diphthamide, phosphoserine, and asparagine have been identified in subsequent works.
Sources: en.wikipedia.org
=== Blood sugar and insulin levels === Erythritol has no effect on blood sugar or blood insulin levels, and therefore may be used as a sugar substitute by people with type 2 diabetes. The glycemic index (GI) of erythritol is 0% of the GI for glucose and the insulin index (II) is 2% of the II for glucose.
He recommended that the diets of the pregnant and nursing females and the weaned cubs be switched from lean horse meat to goat – including calcium- and phosphorus-containing bones – and cod liver oil, solving the problem. Subsequently, researchers realized that animal models such as dogs and rats could be used for rickets research, leading to the identification and naming of the responsible vitamin in 1922. In 1914, American researchers Elmer McCollum and Marguerite Davis had discovered a substance in cod liver oil which later was named "vitamin A". Edward Mellanby, a British researcher, observed that dogs that were fed cod liver oil did not develop rickets, and (wrongly) concluded that vitamin A could prevent the disease. In 1922, McCollum tested modified cod liver oil in which the vitamin A had been destroyed. The modified oil cured the sick dogs, so McCollum concluded the factor in cod liver oil which cured rickets was distinct from vitamin A. He called it vitamin D because it was the fourth vitamin to be named. In 1925, it was established that when 7-dehydrocholesterol is irradiated with light, a form of a fat-soluble substance is produced, now known as vitamin D3. Adolf Windaus, at the University of Göttingen in Germany, received the Nobel Prize in Chemistry in 1928 "for the services rendered through his research into the constitution of the sterols and their connection with the vitamins".
=== Treatment === The development of the science of microsurgery over the last 40 years has provided several treatment options for a traumatic amputation, depending on the patient's specific trauma and clinical situation:
=== Cryogenic refrigeration === The Topeka, Kansas shops of the Santa Fe Railway built five experimental refrigerator cars employing liquid nitrogen as the cooling agent in 1965. A mist induced by liquefied nitrogen was released throughout the car if the temperature rose above a pre-determined level. Each car carried 3,000 pounds (1,400 kg) of refrigerant and could maintain a temperature of minus 20 degrees Fahrenheit (−30 °C). During the 1990s, a few railcar manufacturers experimented with using liquid carbon dioxide (CO2) as a cooling agent. The move was in response to rising fuel costs and aimed to eliminate standard mechanical refrigeration systems that required periodic maintenance. The CO2 system can keep the cargo frozen solid for 14 to 16 days. Several hundred "cryogenic" refrigerator cars were placed in service to transport frozen foodstuffs. However, they failed to gain wide acceptance (due in part to the rising cost of liquid carbon dioxide).
Vacuum deaerator Composite plastic moulding processes; Production of most types of electric lamps, vacuum tubes, and CRTs where the device is either left evacuated or re-filled with a specific gas or gas mixture; Semiconductor processing, notably ion implantation, dry etch and PVD, ALD, PECVD and CVD deposition and so on in photolithography; Electron microscopy; Medical processes that require suction; Uranium enrichment; Medical applications such as radiotherapy, radiosurgery and radiopharmacy; Analytical instrumentation to analyse gas, liquid, solid, surface and bio materials; Mass spectrometers to create a high vacuum between the ion source and the detector; Vacuum coating on glass, metal and plastics for decoration, for durability and for energy saving, such as low-emissivity glass, hard coating for engine components (as in Formula One), ophthalmic coating, milking machines and other equipment in dairy sheds; Vacuum impregnation of porous products such as wood or electric motor windings; Air conditioning service (removing all contaminants from the system before charging with refrigerant); Trash compactor; Vacuum engineering; Sewage systems (see EN1091:1997 standards); Freeze drying; and Fusion research. In the field of oil regeneration and re-refining, vacuum pumps create a low vacuum for oil dehydration and a high vacuum for oil purification. A vacuum may be used to power, or provide assistance to mechanical devices. In hybrid and diesel engine motor vehicles, a pump fitted on the engine (usually on the camshaft) is used to produce a vacuum.
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.
It is associated with the melanocortin receptor family, particularly subtypes found in the central nervous system. This interaction is separate from the adrenal pathway activated by full-length ACTH.