Everything below concerns alpha-MSH analogue. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-04-15. Where a claim depends on a specific study, the study is described rather than over-claimed.
Receptor binding at MC1R on melanocytes raises intracellular cyclic AMP and increases expression of tyrosinase and related enzymes. The downstream result is greater synthesis of eumelanin, the dark pigment, without ultraviolet exposure acting as the trigger. The compound is not selective, however, and also engages MC3R, MC4R and MC5R, which are expressed in the central nervous system and elsewhere. That lack of selectivity is the explanation usually offered for effects reported outside pigmentation, including appetite suppression and nausea. Selectivity remains a central theme in comparative studies of related peptides.
Human data remain limited and mostly short-term. Reports describe small trials and observational accounts rather than large controlled studies, so questions about dose-response relationships and long-term effects on melanocytes stay open. Whether repeated exposure alters naevus behaviour is not settled in the published record. Researchers also note that self-administered use outside clinical settings makes actual exposure difficult to quantify. Statements about efficacy and safety should therefore be read as preliminary rather than established.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone. Its sequence incorporates a lactam bridge that constrains the peptide into a ring, which increases resistance to enzymatic breakdown relative to the natural hormone. Researchers at the University of Arizona synthesised the compound in the late 1980s and early 1990s while studying pigmentation pathways. It has never received marketing approval from any national medicines regulator. In the scientific literature it is usually described as a laboratory research reagent rather than a therapeutic product.
The peptide acts as a non-selective agonist at melanocortin receptors, showing affinity for MC1R, MC3R, MC4R and MC5R. Activation of MC1R on melanocytes drives the conversion of tyrosine into melanin and shifts production toward the darker eumelanin form. MC4R signalling in the central nervous system is linked to appetite and energy balance, which helps explain why reduced food intake appeared in early human studies. Effects on MC4R and on vascular tone also account for the erectile responses recorded as unexpected findings in those same trials.
Melanotan-2 is frequently confused with afamelanotide, a linear analogue authorised in the European Union for erythropoietic protoporphyria. The two compounds differ in chain length, ring structure and receptor selectivity, so findings for one cannot be transferred directly to the other. Published controlled human data on melanotan-2 remain sparse, and much of what circulates online derives from small studies or unpublished reports. Questions about effect size, dose-response behaviour and long-term safety therefore remain unresolved.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Melanocortin receptor agonist |
| Molecular formula | C50H69N15O9 | Neutral form, mass near 1024.2 g/mol |
| Primary targets | MC1R, MC3R, MC4R, MC5R | Binding is non-selective across subtypes |
| Related compounds | Alpha-MSH, melanotan I, afamelanotide | Structurally or functionally related peptides |
| Common abbreviations | MT-II, MT-2 | Naming in the literature is not uniform |
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone, a naturally occurring peptide involved in pigmentation signalling. Its sequence incorporates modified residues that increase potency and extend biological activity relative to the native hormone. The compound binds receptors of the melanocortin family and is examined mainly in laboratory research. It does not occur naturally and exists only as a manufactured chemical entity produced by solid-phase synthesis.
The peptide was developed during the 1980s by researchers investigating melanocortin signalling and skin pigmentation pathways. Early work focused on analogues of alpha-melanocyte-stimulating hormone that would resist enzymatic breakdown more effectively than the parent molecule. Melanotan-2 emerged from that programme as a shortened, cyclised variant. Reports describing its synthesis and receptor activity later appeared in the scientific literature. Commercial availability grew through unregulated channels rather than through pharmaceutical approval.
Structurally, Melanotan-2 retains the core recognition motif of alpha-melanocyte-stimulating hormone while adding a lactam bridge that links two side chains and constrains the molecule into a ring. This modification lowers susceptibility to enzymatic degradation. The compound acts as an agonist at melanocortin receptors, particularly subtypes associated with melanin production. Because the same receptor family influences several physiological processes, researchers note that its activity is not confined to pigmentation alone. Receptor selectivity continues to be examined in published studies.
Activity is attributed to agonism at melanocortin receptors, particularly MC1R and MC4R. Activation of MC1R on melanocytes increases melanin synthesis, which underlies the reported tanning effect. MC4R engagement in the central nervous system is linked to appetite suppression and to effects on sexual arousal reported in early clinical studies. Those studies were small and were not designed to establish efficacy or long-term safety. Receptor selectivity among the melanocortin subtypes is not absolute, which complicates attribution of any effect to a single pathway.
Regulatory treatment varies between countries. Several national medicines agencies have classified the peptide as unapproved, and customs authorities in some jurisdictions seize shipments on that basis. A few jurisdictions channel supply through prescription-only frameworks that do not list the substance by name. Because the material circulates mainly through online vendors, composition and purity are rarely verified before sale. Surveys of unapproved peptide products have reported labels that did not match measured content in a substantial fraction of samples.
The primary purpose of packaging space food is preserving and containing the food. However, the packaging must also be light-weight, easy to dispose of and useful in the preparation of the food for consumption. The packaging also includes a bar-coded label, which allows for the tracking of an astronaut's diet. The labels also specify the food's preparation instructions in both English and Russian. Many foods from the Russian space program are packaged in cans and tins. These are heated through electro-resistive (ohmic) methods, opened with a can-opener, and the food inside consumed directly. Russian soups are hydrated and consumed directly from their packages. NASA space foods are packaged in retort pouches or employ freeze drying. They are also packaged in sealed containers which fit into trays to keep them in place. The trays include straps on the underside, allowing astronauts to attach the tray to an anchor point such as their legs or a wall surface and include clips for retaining a beverage pouch or utensils in the microgravity environment.
The mtFAS pathway takes place in the mitochondrial matrix and consists of at least six separate enzymes, each encoded by its own gene. This sets it apart from cytosolic fatty acid synthesis, where the multifunctional enzyme fatty acid synthase (FASN) contains all enzymatic activities within a single polypeptide chain and is encoded by a single gene. Despite this structural difference, mtFAS and cytosolic fatty acid synthesis use the same chemistry to build fatty acids. The mitochondrial acyl carrier protein (mtACP) serves as a scaffold for fatty acyl chains but requires prior phosphopantetheinylation by AASDHPPT to convert it from the inactive apo to the active holo form. This activation represents the first step of mtFAS and introduces a 4'-phosphopantetheine group, which provides the thiol group to which the fatty acyl chain is covalently attached and subsequently elongated, while also functioning as a flexible swinging arm. This allows the fatty acyl chain to swing out of its hydrophobic pocket within mtACP and enter those of interacting proteins. Malonyl-CoA provides the substrate for mtFAS and is generated in mitochondria from acetyl-CoA by mtACC1 (a mitochondrial isoform of acetyl-CoA carboxylase 1) and from malonate by acyl-CoA synthetase family member 3 (ACSF3). However, the precise mitochondrial source of malonyl-CoA remains under debate. The malonyl group is transferred from malonyl-CoA to mtACP by malonyl-CoA:ACP transacylase (MCAT), forming malonyl-mtACP.
Penicillamine, which contains nitrogen and sulphur donor atoms, is used as this type of ligand binds more strongly to copper ions than to calcium and magnesium ions. Treatment of poisoning by heavy metals such as lead and mercury is more problematical, because the ligands used do not have high specificity relative to calcium. For example, EDTA may be administered as a calcium salt to reduce the removal of calcium from bone together with the heavy metal. Factors determining selectivity for lead against zinc, cadmium and calcium have been reviewed.
Sources: en.wikipedia.org
Thioesters are prominent active esters, as illustrated by the esters of coenzyme A. Terpenes and terpenoids are generated from active esters. Some biosynthetically significant active esters include isopentenyl pyrophosphate, dimethylallyl pyrophosphate, and geranyl pyrophosphate.
== History == The first few amino acids were discovered in the early 1800s. In 1806, French chemists Louis-Nicolas Vauquelin and Pierre Jean Robiquet isolated a compound from asparagus that was subsequently named asparagine, the first amino acid to be discovered. Cystine was discovered in 1810, although its monomer, cysteine, remained undiscovered until 1884. Glycine and leucine were discovered in 1820. The last of the 20 common amino acids to be discovered was threonine in 1935 by William Cumming Rose, who also determined the essential amino acids and established the minimum daily requirements of all amino acids for optimal growth. The unity of the chemical category was recognized by Wurtz in 1865, but he gave no particular name to it. The first use of the term "amino acid" in the English language dates from 1898, while the German term, Aminosäure, was used earlier. Proteins were found to yield amino acids after enzymatic digestion or acid hydrolysis. In 1902, Emil Fischer and Franz Hofmeister independently proposed that proteins are formed from many amino acids, whereby bonds are formed between the amino group of one amino acid with the carboxyl group of another, resulting in a linear structure that Fischer termed "peptide".
=== Synthesis === A chemical synthesis of mirtazapine has been published. The first step of synthesis is a condensation reaction between 2-chloro-3-cyanopyridine (1) and 1-methyl-3-phenylpiperazine (2) to give cyano compound 3. Hydrolysis of the cyanide group to the corresponding carboxylic acid (4), reduction to the alcohol (5) allows for mirtazapine (6) to be synthesised via an acid mediated cyclisation.
Sources: en.wikipedia.org
== Membership == As of 2021, the organization had approximately 1200 members. Persons wishing to become members of the Society must be nominated for membership by two existing voting members. Membership then must be endorsed by the Chair of the jurisdictional Branch in which the applicant lives. In the case of overseas applicants, it is the role of the Council Executive to approve admission to the Society. Most members also belong to at least one of the five Special Interest Groups of the Society that represent members' primary field of practice in human genetics:
Conolidine has been discovered to bind to novel opioid receptor ACKR3 (CXCR7). By binding to this receptor, the endogenous opioid peptides (such as endorphins and enkephalins) cannot be trapped thus increasing availability of those peptides to their target sites.
=== Container Freight Stations (CFS) === GDL operates Container Freight Stations, located at major Indian ports such as Navi Mumbai, Chennai, Visakhapatanam, and Kochi. The stations offer container yards, general warehousing, bonded warehousing, empty handling and RFID technologies used for container tracking. GDL also has its own dedicated fleet of over 25 rakes and 265 trailers for first and last mile connectivity.
==== Kiln drying schedules ==== Satisfactory kiln drying can usually be accomplished by regulating the temperature and humidity of the circulating air to control the moisture content of the lumber at any given time. This condition is achieved by applying kiln-drying schedules. The desired objective of an appropriate schedule is to ensure drying lumber at the fastest possible rate without causing objectionable degrade. The following factors have a considerable bearing on the schedules.
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide and a non-selective melanocortin receptor agonist. Structurally it is modelled on alpha-melanocyte-stimulating hormone, a peptide that occurs naturally in the body.
Activation of MC1R increases pigment synthesis independently of ultraviolet exposure, which is the mechanism usually cited for darkening without sun exposure. Ultraviolet light still influences skin response through separate biological pathways.
Because the peptide binds several melanocortin receptor subtypes, its effects are not confined to pigmentation. This complicates interpretation of both intended and unintended outcomes reported in studies.
It is a synthetic cyclic heptapeptide modelled on alpha-melanocyte-stimulating hormone. A lactam bridge links two side chains, forming a ring that stabilises the molecule against proteolysis. It belongs to the broader melanocortin peptide family.