Melanocortin receptor 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.
Updated 2026-06-30. Numbers and descriptions here follow the published literature rather than marketing material.
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。
== Effectiveness == Most injector pens are designed for subcutaneous injection just under the skin, but some are designed for injection into muscle. The desired injection site and the skin profile at the injection site will determine what needle length is appropriate for a person to use. For products with included needles, such as epinephrine pens, different brands may have different included needle lengths, which must be taken into account. Multiple studies have shown that many people prefer the use of injector pens over other forms of injectable medication, such as vial and syringe. Injector pens in general have also been shown to be at least as effective therapeutically as other injection methods. One study of the use of injector pens for insulin administration found that the chance a person initiated on insulin continued therapy for at least 12 months was higher with insulin pens than with vial and syringe administration. The same study found that the increase in adherence to therapy resulted in increased short-term pharmacy costs (i.e. for the pens/needles) but resulted in an overall decrease in healthcare costs related to diabetes. Insulin pens have also been shown to provide a higher quality of life than traditional injection methods. A 2011 systematic review which examined preference of insulin pens over vial and syringe administration found that in almost all studies and surveys a majority of people preferred insulin pens. The effectiveness of an injector pen can also depend on the technique used to inject.
== Mechanisms of action and effects == There are many different mechanisms through which steroid hormones affect their target cells. All of these different pathways can be classified as having either a genomic effect or a non-genomic effect. Genomic pathways are slow and result in altering transcription levels of certain proteins in the cell; non-genomic pathways are much faster.
=== Names === Lidocaine is the International Nonproprietary Name (INN), British Approved Name (BAN), and Australian Approved Name (AAN), while lignocaine is the former BAN and AAN. Both the old and new names will be displayed on the product label in Australia until at least 2023. Xylocaine is a brand name, referring to the major synthetic building block 2,6-xylidine. The "ligno" prefix is chosen because "xylo" means wood in Greek while "ligno" means the same in Latin. The "lido" prefix instead refers to the fact that the drug is chemically related to acetanilide.
CoQ10 is a component of the mitochondrial electron transport chain (ETC), where it plays a role in oxidative phosphorylation, a process required for the biosynthesis of adenosine triphosphate, the primary energy source of cells. CoQ10 is a lipophilic molecule that is located in all biological membranes of the human body and is a component for the synthesis of ATP and a life-sustaining cofactor for the three complexes (complex I, complex II, and complex III) of the ETC in the mitochondria. CoQ10 has a role in the transport of protons across lysosomal membranes to regulate pH in lysosome functions. The mitochondrial oxidative phosphorylation process occurs in the inner mitochondrial membrane of eukaryotic cells. This membrane is highly folded into structures called cristae, which increase the surface area available for oxidative phosphorylation. CoQ10 plays a role in this process as an essential cofactor of the ETC located in the inner mitochondrial membrane and serves the following functions:
Sources: en.wikipedia.org
== Diagnosis == A combination of clinical findings and laboratory tests are used to diagnose the syndrome. Initially, individuals are screened for symptoms and have their blood sugar levels analyzed. The two principle tests used to determine insulin resistance are the fasting plasma glucose test (FPG) and the oral glucose tolerance test (GTT). Results from a patient with severe insulin resistance will show values exceeding healthy ranges (≤99 mg/dL for FPG and ≤139 mg/dL for GTT) by over 50 units. A genetic history is also established to determine risk of recurrence in the family. Based on the combination of these findings, an appropriate diagnosis is made. Rabson–Mendenhall syndrome is commonly associated with Donohue syndrome, also known as leprechaunism. Both diseases are autosomal recessive disorders caused by mutations on chromosome 19. Severe insulin resistance and an irregular enlargement of the genitalia are also overlapping symptoms.
Under this state, there was great religious freedom, and alongside the Norman nobles existed a meritocratic bureaucracy of Jews, Muslims and Christians, both Catholic and Eastern Orthodox. The Kingdom of Sicily thus became characterized by Norman, Byzantine, Greek, Arab, Lombard and "native" Sicilian populations living in harmony, and its Norman rulers fostered plans of establishing an empire that would have encompassed Fatimid Egypt as well as the crusader states in the Levant. One of the great geographical treatises of the Middle Ages, the "Tabula Rogeriana", was written by al-Idrisi for King Roger II of Sicily, and entitled "Kitab Rudjdjar" ("The Book of Roger").
Though some studies indeed find this correlation, the consistent correlation between ophthalmic acid increases and glutathione depletion does not exist. Compared to a healthy baseline, both can go up, both can go down, or ophthalmic acid can go up with no changes in glutathione. A study on circadian rhythm tracking both glutathione and ophthalmic acid levels determined that ophthalmic acid levels were rhythmic, while glutathione levels were not. Ophthalmic acid trends also differ wildly between different tissues in the same animal at the same timepoint, again dispelling the notion of a broader and consistent correlation. The meaning of "biomarker" is much more narrow in this context than many studies assume. Importantly, the Soga et al. study sees a correlation between depleting hepatic glutathione levels, and rising ophthalmic acid levels in plasma, in mice. It solves the practical problem of not being able to directly measure an established glutathione depletion in liver by measuring ophthalmic acid in plasma. However, subsequent studies often measure both glutathione and ophthalmic acid, and when glutathione shows no aberration, ophthalmic acid is used as a "marker" to still claim oxidative stress. There cannot be an appeal to a correlation when the data itself disproves that very correlation. Ophthalmic acid can be found in high concentrations in healthy tissues. For instance in the eye. It is not solely found in stressed or diseased states.
=== Gastrointestinal distress === Nausea, vomiting, anorexia, diarrhea, abdominal cramps, and constipation are common side-effects of chemotherapeutic medications that kill fast-dividing cells. Malnutrition and dehydration can result when the recipient does not eat or drink enough, or when the person vomits frequently, because of gastrointestinal damage. This can result in rapid weight loss, or occasionally in weight gain, if the person eats too much in an effort to allay nausea or heartburn. Weight gain can also be caused by some steroid medications. These side-effects can frequently be reduced or eliminated with antiemetic drugs. Low-certainty evidence also suggests that probiotics may have a preventative and treatment effect of diarrhoea related to chemotherapy alone and with radiotherapy. However, a high index of suspicion is appropriate, since diarrhoea and bloating are also symptoms of typhlitis, a very serious and potentially life-threatening medical emergency that requires immediate treatment.
=== In the brain === VIP is also found in the brain and some autonomic nerves: One region includes a specific area of the suprachiasmatic nuclei (SCN), the location of the 'master circadian pacemaker'. See SCN and circadian rhythm below. VIP in the pituitary helps to regulate prolactin secretion; it stimulates prolactin release in the domestic turkey. Additionally, the growth-hormone-releasing hormone (GH-RH) is a member of the VIP family and stimulates growth hormone secretion in the anterior pituitary gland. VIP is also expressed in a subtype of inhibitory interneuron in various regions of the brain.
Sources: en.wikipedia.org
=== Single Convention on Narcotic Drugs, 1961 === The adoption of this convention is regarded as a milestone in the history of the international drug ban. The Single Convention codified all existing multilateral treaties on drug control and extended the existing control systems to include the cultivation of plants that were grown as the raw material of narcotic drugs. The principal objectives of the convention are to limit the possession, use, trade, distribution, import, export, manufacture, and production of drugs exclusively for medical and scientific purposes, and to address drug trafficking through international cooperation to deter and discourage drug traffickers. The convention also established the International Narcotics Control Board, merging the Permanent Central Board and the Drug Supervisory Board. The 1961 Convention seeks to control over 116 drugs that it classifies as narcotic. These include:
=== Derivatives === A number of derivatives of 18-MC have been developed, with several of them being superior to 18-MC itself, the methoxyethyl congener ME-18-MC being more potent than 18-MC with similar efficacy, and the methylamino analogue 18-MAC being more effective than 18-MC with around the same potency. These compounds were also found to act as selective α3β4 nicotinic acetylcholine antagonists, with little or no effect on NMDA receptors.
Diets to promote weight loss can be divided into four categories: low-fat, low-carbohydrate, low-calorie, and very low calorie. Many dietary patterns are effective. A meta-analysis of six randomized controlled trials found no difference between three of the main diet types (low calorie, low carbohydrate and low fat), with a 2–4 kilograms (4.4–8.8 lb) weight loss in all studies. At two years these three methods resulted in similar weight loss irrespective of the macronutrients emphasized. High protein diets do not appear to make any difference. A diet high in added sugars such as those in soft drinks increases weight. There is evidence that dieting alone can be effective for weight loss and improving health for obese individuals. However, a large study of adults found that obesity was associated with differences in brain structure, largely due to shared genetic factors, suggesting that interventions for obesity should not focus solely on energy content, but also take into account the neurobehavioral profile that obesity is genetically associated with. Dieting for calorie restriction is advised for overweight individuals by the Dietary Guidelines for Americans and United Kingdom's NICE.
== Other reactions == Ornithine, through the action of ornithine decarboxylase (EC 4.1.1.17), serves as the starting point for the synthesis of polyamines such as putrescine. In bacteria such as E. coli, ornithine can be synthesized from L-glutamate.
=== Discovery of androgens === The use of gonadal steroids pre-dates their identification and isolation. Use of cow urine for treatment of ascites, heart failure, renal failure and vitiligo has been elaborately described in Sushruta Samhita, suggesting that ancient Indians had some understanding of steroidal properties of cow urine around 6th century BC. Extraction of hormones from urines began in China around 100 BC. Medical use of testicle extract began in the late 19th century while its effects on strength were still being studied. The isolation of gonadal steroids can be traced back to 1931, when Adolf Butenandt, a chemist in Marburg, purified 15 milligrams of the male hormone androstenone from tens of thousands of litres of urine. This steroid was subsequently synthesized in 1934 by Leopold Ružička, a chemist in Zurich. In the 1930s, it was already known that the testes contain a more powerful androgen than androstenone, and three groups of scientists, funded by competing pharmaceutical companies in the Netherlands, Germany, and Switzerland, raced to isolate it. This hormone was first identified by Karoly Gyula David, E. Dingemanse, J. Freud and Ernst Laqueur in a May 1935 paper "On Crystalline Male Hormone from Testicles (Testosterone)." They named the hormone testosterone, from the stems of testicle and sterol, and the suffix of ketone. The chemical synthesis of testosterone was achieved in August that year, when Butenandt and G.
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.