Melanocortin receptor comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
The proposed mechanism centres on neurotrophic signalling rather than direct receptor activation. Semax is reported to increase expression of brain-derived neurotrophic factor and nerve growth factor in several brain regions, and to shift the balance between excitatory and inhibitory neurotransmitter systems. Interaction with melanocortin receptors has been suggested because of the parent ACTH fragment. Many of these findings come from rodent studies, and the extent to which they translate to human physiology remains an open question.
Scientific literature on semax is unevenly distributed. A substantial share of published work originates from a small number of laboratories in Russia, while independent replication elsewhere is limited. Human data consist mostly of small trials with short follow-up, and several reported outcomes rely on subjective rating scales. Questions about how much intact peptide reaches the central nervous system after nasal administration, and how long it persists there, are still unresolved. The compound is best described as an active research subject rather than a settled pharmacological agent.
Practical handling follows from those properties. Bulk material is best divided into single-use portions soon after receipt, because each thaw exposes the whole container to moisture and temperature cycling. Vials should be allowed to reach room temperature before opening to prevent condensation on the powder. Low-binding plasticware reduces loss of dilute solutions, and sterile filtration is used when a preparation must remain free of microbial growth. Records of batch number, reconstitution date and storage history are what allow a later analytical result to be interpreted meaningfully.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Calculated for the free peptide |
| Molar mass | 813.9 g/mol | Anhydrous free base |
| Peptide class | Synthetic heptapeptide | ACTH(4-10) analogue |
| Parent fragment | ACTH(4-10) | Adrenocorticotropic hormone segment |
| Developmental origin | Institute of Molecular Genetics, Moscow | Work began in the 1980s |
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.
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.
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 supplied as a lyophilized powder that appears white to off-white. It dissolves readily in water, phosphate-buffered saline, and other aqueous media, which simplifies preparation of working solutions for laboratory use. The nasal products registered in Russia are dilute aqueous solutions, typically around 0.1 percent peptide by weight. Organic solvents are rarely necessary and can complicate handling. Because the peptide is hygroscopic, weighing should be performed quickly and with minimal exposure to ambient humidity.
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。
Semax 是人工设计的七肽，序列为 Met-Glu-His-Phe-Pro-Gly-Pro，骨架取自促肾上腺皮质激素片段 ACTH(4-10)。它于二十世纪八十年代在苏联的分子遗传学研究机构内合成。设计目标是保留该片段与注意力和记忆相关的活性，同时剔除促皮质激素释放等内分泌作用。此后俄罗斯将其登记为药品并进入临床使用。
== In transplant rejection == In a transplant procedure, as of an organ or stem cells, MHC molecules themselves act as antigens and can provoke immune response in the recipient, thus causing transplant rejection. MHC molecules were identified and named after their role in transplant rejection between mice of different strains, though it took over 20 years to clarify MHC's role in presenting peptide antigens to cytotoxic T lymphocytes (CTLs). Each human cell expresses six MHC class I alleles (one HLA-A, -B, and -C allele from each parent) and six to eight MHC class II alleles (one HLA-DP and -DQ, and one or two HLA-DR from each parent, and combinations of these). The MHC variation in the human population is high, at least 350 alleles for HLA-A genes, 620 alleles for HLA-B, 400 alleles for DR, and 90 alleles for DQ. Any two individuals who are not identical twins, triplets, or higher order multiple births, will express differing MHC molecules. All MHC molecules can mediate transplant rejection, but HLA-C and HLA-DP, showing low polymorphism, seem least important. When maturing in the thymus, T lymphocytes are selected for their TCR incapacity to recognize self antigens, yet T lymphocytes can react against the donor MHC's peptide-binding groove, the variable region of MHC holding the presented antigen's epitope for recognition by TCR, the matching paratope. T lymphocytes of the recipient take the incompatible peptide-binding groove as nonself antigen. There are various types of transplant rejection that are known to be mediated by MHC (HLA):
The breast is an apocrine gland that produces the milk used to feed an infant. The nipple of the breast is surrounded by the areola (nipple-areola complex). The areola has many sebaceous glands, and the skin color varies from pink to dark brown. The basic units of the breast are the terminal duct lobular units (TDLUs), which produce the fatty breast milk. They give the breast its offspring-feeding functions as a mammary gland. They are distributed throughout the body of the breast. Approximately two-thirds of the lactiferous tissue is within 30 mm of the base of the nipple. The terminal lactiferous ducts drain the milk from TDLUs into 4–18 lactiferous ducts, which drain to the nipple. The milk-glands-to-fat ratio is 2:1 in a lactating woman, and 1:1 in a non-lactating woman. In addition to the milk glands, the breast is also composed of connective tissues (collagen, elastin), white fat, and the suspensory Cooper's ligaments. Sensation in the breast is provided by the peripheral nervous system innervation by means of the front (anterior) and side (lateral) cutaneous branches of the fourth-, fifth-, and sixth intercostal nerves. The T-4 nerve (Thoracic spinal nerve 4), which innervates the dermatomic area, supplies sensation to the nipple-areola complex.
It is unlikely that chocolate consumption in small amounts causes lead poisoning. Some studies have shown that lead may bind to cocoa shells, and contamination may occur during the manufacturing process. One study showed the mean lead level in milk chocolate candy bars was 0.027 μg lead per gram of candy. Another study found that some chocolate purchased at U.S. supermarkets contained up to 0.965 μg per gram, close to the international (voluntary) standard limit for lead in cocoa powder or beans, which is 1 μg of lead per gram. In 2006, the U.S. FDA lowered by one-fifth the amount of lead permissible in candy, but compliance is only voluntary. Studies concluded that "children, who are big consumers of chocolates, may be at risk of exceeding the daily limit of lead, [as] one 10 g cube of dark chocolate may contain as much as 20% of the daily lead oral limit. Moreover chocolate may not be the only source of lead in their nutrition" and "chocolate might be a significant source of cadmium and lead ingestion, particularly for children." According to a 2005 study, the average lead concentration of cocoa beans is ≤ 0.5 ng/g, which is one of the lowest reported values for a natural food. However, during cultivation and production, chocolate may absorb lead from the environment (such as in atmospheric emissions of now unused leaded gasoline). The European Food Safety Authority recommended a tolerable weekly intake for cadmium of 2.5 micrograms per kg of body weight for Europeans, indicating that consuming chocolate products caused exposure of about 4% among all foods eaten.
The dominions and colonies provided 57 contingents, overwhelmingly of volunteer forces as none had a substantial full-time force; those from Canada alone numbered some 7,400 Altogether, Britain and her empire deployed some half a million soldiers. After the South African War, the Conservative government embarked on a series of reorganisations that had a negative impact on all the auxiliary forces. The Militia was heavily understrength and disorganised, whilst the number of recruits for the Volunteers was falling off and it was becoming apparent that many Volunteer Corps were headed towards financial collapse unless some action was taken. The Territorial Force was created by the Secretary of State for War, Richard Burdon Haldane, following the enactment of the Territorial and Reserve Forces Act 1907 which combined and re-organised the old Volunteer Force with the Yeomanry. As part of the same process, the remaining units of militia were converted to the Special Reserve. Most Volunteer infantry units had unique identities, but lost these in the reorganisation, becoming Territorial battalions of Regular Army infantry regiments. Only one infantry unit, the London Regiment, has maintained a separate identity. The TF was formed on 1 April 1908 and contained fourteen infantry divisions, and fourteen mounted yeomanry brigades. It had an overall strength of approximately 269,000. Haldane designed it to provide a much larger second line for the six divisions of the Expeditionary Force which he was establishing as the centerpiece of the Regular Army.
At the beginning of Hong Kong's opening up, Western medicine was not yet popular, and Western medicine doctors were mostly foreigners; local residents mostly relied on Chinese medicine practitioners. In 1841, the British government of Hong Kong issued an announcement pledging to govern Hong Kong residents in accordance with all the original rituals, customs and private legal property rights. As traditional Chinese medicine had always been used in China, the use of traditional Chinese medicine was not regulated. The establishment in 1870 of the Tung Wah Hospital was the first use of Chinese medicine for the treatment in Chinese hospitals providing free medical services. As the promotion of Western medicine by the British government started from 1940, Western medicine started being popular among Hong Kong population. In 1959, Hong Kong had researched the use of traditional Chinese medicine to replace Western medicine.
Sources: en.wikipedia.org
Church records of christenings, marriages and burials Voter or citizenship rolls Records of wills and deceased estates Land tenure records Tax lists Muster lists for militia service The internet has stimulated amateur one-place studies, especially in England, since websites allow large volumes of historic material to be published easily. One-place studies of urban parishes are less common, since urban populations were migratory and analysis is more difficult when few of the families remain present for the whole period under study.
Thy-1 or CD90 (Cluster of Differentiation 90) is a 25–37 kDa heavily N-glycosylated, glycophosphatidylinositol (GPI) anchored conserved cell surface protein with a single V-like immunoglobulin domain, originally discovered as a thymocyte antigen. Thy-1 can be used as a marker for a variety of stem cells and for the axonal processes of mature neurons. Structural study of Thy-1 led to the foundation of the Immunoglobulin superfamily, of which it is the smallest member, and led to some of the initial biochemical description and characterization of a vertebrate GPI anchor and also the first demonstration of tissue specific differential glycosylation.
=== Preclinical === Acne vaccine – immunostimulant ADA-308 – antiandrogen (androgen receptor antagonist) Research programme: acne vulgaris therapeutics - Attillaps Pharmaceuticals – acetylcholinesterase inhibitors
Spencer RL, Preiss J (1967). "Biosynthesis of diphosphopyridine nucleotide. The purification and the properties of diphospyridine nucleotide synthetase from Escherichia coli b". J. Biol. Chem. 242 (3): 385–92. doi:10.1016/S0021-9258(18)96282-4. PMID 4290215.
Sources: en.wikipedia.org
Semax is based on the ACTH(4-10) fragment, a seven-amino-acid segment of adrenocorticotropic hormone. The synthetic peptide retains the core sequence while removing regions associated with endocrine activity. This modification is intended to isolate effects on the nervous system.
It is registered for clinical use in Russia and a few other countries, typically as a nasal drop formulation. It does not hold approval from the United States Food and Drug Administration or the European Medicines Agency. Outside those markets it is generally handled as a research chemical.
The compound was developed in Moscow and the earliest studies were conducted there, so the primary literature is largely in Russian-language journals. Translation and indexing have been incomplete, which limits access for outside researchers. Independent groups have since published some work, but the total volume remains modest.
Suppliers normally quote a percentage of total chromatographic peak area, most often from reversed-phase HPLC. That figure says nothing about what the remaining percentage contains, and it depends on the detection wavelength used. A mass spectrometry result is a separate and stronger check on identity.