The short version of analytical characterisation fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-09-19 and is reviewed periodically as new material appears.
Research interest has centred on photoprotection and pigmentation, with a smaller body of work on appetite and sexual function. Published human data remain limited to small, frequently uncontrolled studies, and the compound has never received marketing approval from a national medicines regulator. Most laboratory work treats it as a pharmacological tool for probing melanocortin signalling in cell culture or animal models. Whether pigmentation changes observed in people translate into measurable protection against ultraviolet-induced DNA damage remains an open question.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone, the naturally occurring peptide involved in pigmentation signalling. Its sequence is conventionally written as Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, with a lactam bridge joining the aspartate side chain to the lysine side chain. The empirical formula is C50H69N15O9 and the monoisotopic mass lies near 1023.5 daltons. N-terminal acetylation and the D-configured phenylalanine both increase resistance to enzymatic breakdown compared with the parent hormone.
Pharmacologically, melanotan-2 behaves as a non-selective agonist across the melanocortin receptor family. Binding at MC1R on dermal melanocytes promotes eumelanin synthesis, which underlies the tanning response described in early human work. Activity at the centrally expressed MC4R receptor is associated with reported effects on appetite and erectile function. Because the peptide does not discriminate strongly among receptor subtypes, attributing any single observed effect to one receptor pathway is generally not possible without selective antagonists or receptor knockout models.
Verification of a purchased sample requires documentation linking a batch to a certificate of analysis, and that document should be read for the methods used rather than the headline purity figure. A single chromatographic percentage does not establish identity. Independent laboratories can perform identity and content assays, but no such test establishes that a product is suitable for human use. Claims about efficacy rest largely on small, early studies rather than on replicated controlled trials, and that gap remains open.
Identity testing for a cyclic peptide of this size usually relies on reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The mass spectrum confirms molecular weight, while the chromatographic trace indicates the proportion of related impurities. Tandem mass spectrometry can provide sequence-level information when fragmentation data are compared against a reference standard. Nuclear magnetic resonance is sometimes used to confirm the lactam bridge, although it requires more material and greater operator expertise than routine chromatographic methods.
Lyophilised peptide powder is comparatively stable when kept dry, cold and protected from light. Once dissolved, the molecule is exposed to hydrolysis, oxidation and microbial growth, and degradation accelerates at higher temperatures and in alkaline solution. Repeated freeze-thaw cycles concentrate solutes and promote aggregation. Handling guidance for research peptides commonly clusters around freezer temperatures for powder and short refrigerated use for reconstituted solutions, with pH control and sterile technique applied throughout.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | Melanotan II; MT-II; N-acetyl-norleucyl-cyclo[Asp-His-D-Phe-Arg-Trp-Lys] amide | Naming follows peptide convention; the numeral distinguishes it from melanotan-1 |
| Molecular formula | C50H69N15O9 | Includes the lactam bridge; no counter-ion assumed |
| Monoisotopic mass | 1023.53 Da | Free base; salts and counter-ions shift the observed value |
| Appearance | White to off-white lyophilised powder | Batch-to-batch colour variation is not itself proof of impurity |
| Typical analytical method | RP-HPLC purity determination with ESI-MS identity confirmation | Retention time alone does not establish sequence identity |
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 II is a synthetic cyclic heptapeptide that acts as an agonist at melanocortin receptors. It was designed as a structural analogue of alpha-melanocyte-stimulating hormone, the endogenous peptide involved in pigment production. The analogue carries a lactam bridge that constrains the ring and slows enzymatic breakdown relative to the native hormone. In research literature it appears under several abbreviations, and naming conventions are not fully standardized. Published descriptions usually place it within the broader melanocortin agonist family.
Regulatory treatment varies by country. In the United States, melanotan-2 is not approved for any indication, and products marketed for human use fall outside the approved drug framework. Some other jurisdictions have placed it under prescription controls or listed it as a prohibited or restricted substance. Online listings frequently describe the material as a research chemical, a category that does not carry the same manufacturing and labelling requirements as approved medicines.
Solid peptide material is generally stable when kept cold and dry. Common practice is storage at -20 degrees Celsius or lower, with desiccant and protection from light. Repeated freeze-thaw cycles and exposure to moisture are associated with degradation, aggregation, or loss of material. Once dissolved, stability depends on solvent, concentration, and temperature, and solutions are usually treated as short-lived unless stability data support longer periods. Handling notes typically emphasise minimising time at ambient temperature.
Melanocytes are the pigment-producing cells of the skin, and they carry melanocortin-1 receptors on their surface. When the receptor is activated, cyclic adenosine monophosphate rises inside the cell and raises the activity of enzymes such as tyrosinase, which increases melanin output. Melanotan-2 binds melanocortin-1 receptors in vitro and in animal models, and this binding is generally described as the basis for the tanning effect. Other receptors account for different effects: melanocortin-4 receptors contribute to appetite and erectile signalling, while melanocortin-3 and melanocortin-5 receptors contribute to energy balance and exocrine function.
Early published reports described melanotan-2 as a tanning agent without sun protection, which means darkening is not the same as protection against ultraviolet radiation. Later studies explored the peptide in erectile dysfunction, hemorrhagic shock, and some skin conditions. No regulator in the United States or Europe has approved it for clinical use. Many products labelled melanotan-2 are sold without approval and their identity and purity are unverified. Its long-term safety in humans remains an open question.
Reported observations after unregulated use include shifts in skin pigmentation and, in some accounts, unintended changes to moles and other lesions. Whether these outcomes are causally linked to the compound, and how often they occur, remain open questions because controlled data are scarce. The absence of standardised dosing and verified product purity complicates interpretation. Researchers have called for better surveillance and analytical characterisation of samples obtained outside regulated channels. Conclusions drawn from anecdotal evidence should be treated as provisional.
Melanotan-2 has not received marketing authorisation from major regulatory agencies for any therapeutic indication. Several jurisdictions classify it as a prescription-only medicine or a controlled substance when supplied for human use. Because approved products do not exist, material sold online usually sits outside pharmaceutical supply chains and formal quality oversight. Regulators have issued public notices describing the compound as unapproved. Enforcement varies, and the legal position differs between countries, which complicates any single general statement about its status.
==== Stable isotope paleoaltimetry ==== The possibility of using water isotope depletion with elevation to reconstruct paleoaltimetry was demonstrated as early as the late 1960s, when Caltech geochemist Samuel Epstein tried to collect rainwater at different elevations in a single storm. The δ18O and δD lapse rates vary within -1 to -5‰/km and -10 to -40‰/km respectively, but can vary with locations and seasons, and are not exactly linear with altitude. One of the first studies in stable isotope paleoaltimetry demonstrated a meteoric water δD signature of -90 to -139‰ in fluid inclusions in quartz and adularia in an epithermal gold-silver deposit in Nevada, and suggested the applicability of stable isotopes in reconstruction of ancient topography in the Great Basin. The hydrogen and oxygen isotopes of hydrous silicate minerals have since then been used to reconstruct topographic histories in mountain ranges across the world, including the North American Cordillera, the Rocky Mountains, the Himalayas, the European Alps, and Southern Alps in New Zealand. Lab experiments with clay minerals have shown that the hydrogen and oxygen isotope compositions are relatively resistant to alteration at moderate temperature (<100°C), and can preserve the original meteoric water signal. One important effect of mountain ranges on rainfall stable isotopes is the rain shadow effect, in which an isotopic depletion happens in precipitation on the leeward side compared to the windward side.
An urgent issue that had to be addressed was the economic crisis that began in 1974. Minister of Economy Fuentes Quintana proposed the signing of a great "social pact" that would "compensate" the harsh adjustment measures that had to be taken through social improvements and some juridical-political reforms. This led to the Moncloa Pacts signed on October 27, 1977, which succeeded in stabilizing the economy and controlling inflation ─ from 26.4% in 1977 to 16.5 the following year ─ and social spending was increased in return ─ unemployment benefits, pensions, education and health spending ─ thanks to the tax reform implemented by Minister Francisco Fernández Ordóñez. Another pressing matter was the "regional question", since the demands for self-government on the part of Catalonia and the Basque Country did not admit any further delay. In the case of Catalonia, the restoration of the Statute of Autonomy approved by the Republic was demanded, but Suárez opted to approve a decree-law of September 29, 1977, which "provisionally" restored the Generalitat although without reference to the 1932 Statute which allowed the return from exile of the "president" Josep Tarradellas. For the Basque Country, the Basque General Council was constituted in December 1977 under the presidency of the socialist Ramón Rubial, but as in the case of Catalonia, the Statute of Autonomy approved by the Republic was not reestablished either.
== Products and services == GeneDx offers genetic testing services with a primary focus on whole genome sequencing (WGS) and whole exome sequencing (WES). WGS provides a comprehensive analysis of an individual's entire genome, while WES focuses on protein-coding regions called exons, which contain a majority of known disease-related genetic variants. The company's tests are used in clinical diagnostics, research, and precision medicine by geneticists, genetic counselors, neonatologists, pediatric specialists, and pediatricians. GeneDx offers testing for conditions including rare diseases, autism spectrum disorders, epilepsy, neurodevelopmental disorders, cardiomyopathies, and inherited conditions affecting vision, the immune system, muscles, hearing, metabolism, neurology, and mitochondrial diseases. GeneDx also offers rapid sequencing options intended for critically ill pediatric and neonatal patients where timely results may influence acute medical management. GeneDx continues to develop genetic testing technologies and expand access to genomic information for clinical use in pediatric, adult, and newborn populations. Professional guidelines from organizations such as the American College of Medical Genetics and Genomics (ACMG) and the American Academy of Pediatrics (AAP) support the use of exome or genome sequencing as first-line or early diagnostic tests in selected patient populations.
== External links == Space filling 3D model and ball & stick 3D model full motion animated rotating of Acetorphine/Acetyletorphine 2D nonanimated/nonmoving rendering of Acetorphine/Acetyletorphine as a flat diagram
== See also == Substituted methoxyphenethylamine Scaline § Related compounds Dimethoxyphenethylamine 3-Methoxytyramine Mescaline 3-Methoxy-4-ethoxyphenethylamine (MEPEA; 3-desmethoxyescaline) 3-Methoxy-4-allyloxyphenethylamine (MAPEA; 3-desmethoxyallylescaline) Pachycereus pringlei § Constituents and effects
Sources: en.wikipedia.org
As a small open economy, Denmark is very dependent on its foreign trade. In 2017, the value of total exports of goods and services made up 55% of GDP, whereas the value of total imports amounted to 47% of GDP. Trade in goods made up slightly more than 60% of both exports and imports, and trade in services the remaining close to 40%. Machinery, chemicals and related products like medicine and agricultural products were the largest groups of export goods in 2017. Service exports were dominated by freight sea transport services from the Danish merchant navy. Most of Denmark's most important trading partners are neighbouring countries. The five main importers of Danish goods and services in 2017 were Germany, Sweden, United Kingdom, United States and Norway. The five countries from which Denmark imported most goods and services in 2017 were Germany, Sweden, the Netherlands, China and United Kingdom. After having almost consistently an external balance of payments current account deficit since the beginning of the 1960s, Denmark has maintained a surplus on its BOP current account for every year since 1990, with the single exception of 1998. In 2017, the current account surplus amounted to approximately 8% of GDP. Consequently, Denmark has changed from a net debtor to a net creditor country. By 1 July 2018, the net foreign wealth or net international investment position of Denmark was equal to 64.6% of GDP, Denmark thus having the largest net foreign wealth relative to GDP of any EU country.
=== Novel applications === Due to the versatility of SPR instrumentation, this technique pairs well with other approaches, leading to novel applications in various fields, such as biomedical and environmental studies. When coupled with nanotechnology, SPR biosensors can use nanoparticles as carriers for therapeutic implants. For instance, in the treatment of Alzheimer's disease, nanoparticles can be used to deliver therapeutic molecules in targeted ways. In general, SPR biosensing is demonstrating advantages over other approaches in the biomedical field due to this technique being label-free, lower in costs, applicable in point-of-care settings, and capable of producing faster results for smaller research cohorts. In the study of environmental pollutants, SPR instrumentation can be used as a replacement for former chromatography-based techniques. Current pollution research relies on chromatography to monitor increases in pollution in an ecosystem over time. When SPR instrumentation with a Kretschmann prism configuration was used in the detection of chlorophene, an emerging pollutant, it was demonstrated that SPR has similar precision and accuracy levels as chromatography techniques. Furthermore, SPR sensing surpasses chromatography techniques through its high-speed, straightforward analysis.
=== EC 1.8.5 With a quinone or similar compound as acceptor === EC 1.8.5.1: glutathione dehydrogenase (ascorbate) EC 1.8.5.2: thiosulfate dehydrogenase (quinone) EC 1.8.5.3: respiratory dimethylsulfoxide reductase EC 1.8.5.4: bacterial sulfide:quinone reductase EC 1.8.5.5: thiosulfate reductase (quinone) EC 1.8.5.6: sulfite dehydrogenase (quinone) EC 1.8.5.7: glutathionyl-hydroquinone reductase EC 1.8.5.8: eukaryotic sulfide quinone oxidoreductase EC 1.8.5.9: protein dithiol:quinone oxidoreductase DsbB EC 1.8.5.10: DsrC-trisulfide reductase
=== Biological slug mucus === Mucus from gastropods is composed of a combination of water and glycoproteins, enzymes, and trace amounts of metal ions. Mucin glycoproteins, like achacin and glycosaminoglycans (GAGs) like hyaluronic acid are the primary components of mucus, contributing to its antimicrobial properties. Amino groups interact with the sulfate and carboxyl groups found in the glycosaminoglycans to promote bonding and hydrophobic interactions during gel formations. Other molecules like allantoin, or 5-ureidohyantoin, can be found in slug mucus to prompt cell proliferation and wound healing, as well as collagen synthesis, respectively. Significant amounts of zinc, iron, copper, and manganese metal ions are typically found in the chemical composition of slug mucus.
Sources: en.wikipedia.org
== Misattributed == Teleny, or The Reverse of the Medal (Paris, 1893) has been attributed to Wilde, but its authorship is unclear. One theory is that it was a combined effort by several of Wilde's friends, which he may have edited. Constance – On September 14, 2011, Wilde's grandson Merlin Holland contested Wilde's claimed authorship of this play entitled Constance, scheduled to open that week in the King's Head Theatre. It was not, in fact, "Oscar Wilde's final play," as its producers were claiming. Holland said Wilde did sketch out the play's scenario in 1894, but "never wrote a word" of it, and that "it is dishonest to foist this on the public." The artistic director Adam Spreadbury-Maher of the King's Head Theatre and producer of Constance pointed out that Wilde's son, Vyvyan Holland, wrote, in 1954, "a significant amount of the dialogue (of Constance) bears the authentic stamp of my father's hand". There is further proof that the developed scenario that Constance was reconstituted from was written by Wilde between 1897 and his death in 1900, rather than the 1894 George Alexander scenario which Merlin Holland quotes.
=== Reversal potential === Even if both K+ and Na+ ions have the same charge, they can still have very different equilibrium potentials for both outside and/or inside concentrations. The sodium-potassium pump moves toward a nonequilibrium state with the relative concentrations of Na+ and K+ for both inside and outside of cell. For instance, the concentration of K+ in cytosol is 100-140 mM, whereas the concentration of Na+ is 5-15 mM. On the other hand, in extracellular space, the usual concentration range of K+ is about 3.5-5 mM, whereas the concentration of Na+ is about 135-145 mM.
== Epidemiology == The prevalence of PAH is estimated to be 25 cases per 1 million people in Western countries. PAH is more common in women, the ratio of females to males affected by PAH is 1.7 to 1. Others have estimated that the prevalence of PAH related to congenital heart disease is 25 cases per 1 million people.
== Mode of action == The toxin binding site on the channels has high affinity for the toxins when they are closed and low affinity when channels are activated. As a result, the toxin preferentially binds to the closed channels. It binds at a region which contains the voltage-sensing domains. When bound, the toxin makes it more difficult for channels to be opened by depolarization, so much larger depolarizations are required for channel activation. Grammotoxin also binds to potassium channels but with lower affinity than to the calcium channels.
== Discovery and name == Taurine was first isolated from ox bile in 1827 by German scientists Friedrich Tiedemann and Leopold Gmelin. Another German scientist Von H. Demarcay first used its common chemical name Taurine in 1838, derived from the Latin taurus (cognate to Ancient Greek ταῦρος, taûros) meaning bull or ox. It was subsequently identified in human bile in 1846 by Edmund Ronalds.
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone, containing seven amino acids with a lactam ring and a D-configured phenylalanine residue. It is supplied as a lyophilised powder for laboratory research.
The natural hormone is a linear tridecapeptide that is rapidly degraded in circulation. Melanotan-2 is shortened, cyclised, N-terminally acetylated, and carries a D-amino acid substitution, all of which slow enzymatic breakdown.
No national medicines regulator has approved melanotan-2 for therapeutic or cosmetic use. In several jurisdictions it is treated as an unapproved prescription medicine, and its legal classification differs from country to country.
Mass spectrometry combined with liquid chromatography provides both molecular weight confirmation and a measure of related impurities. Tandem mass spectrometry adds sequence information. A purity percentage reported without a mass measurement does not confirm what the material is.