The short version of Melanotan II fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-09-15 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.
Melanotan-2 appears on the World Anti-Doping Agency prohibited list within the peptide hormone class, and several national regulators treat it as an unapproved prescription substance. Some countries restrict importation or sale for personal use. Because the compound is widely traded as a research chemical, the practical legal picture differs between jurisdictions and shifts over time. Human safety data covering long periods are limited, and whether repeated pigmentation changes carry any lasting risk to melanocytes remains an open question.
Freeze-dried melanotan-2 is normally kept as a desiccated powder at minus twenty degrees Celsius or lower, shielded from light and moisture. Peptides of this size degrade through hydrolysis, oxidation and deamidation, and each pathway accelerates as temperature and water activity rise. Repeated freeze-thaw cycles promote aggregation and loss of material, so aliquoting a stock solution before freezing is standard laboratory practice. Once dissolved, the solution is markedly less stable than the powder. In laboratory work, solutions are generally refrigerated and used within days rather than kept for months.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, which separates the target peptide from truncated or oxidised impurities. Mass spectrometry, most often coupled to liquid chromatography, confirms molecular mass and detects substitutions that chromatography alone may miss. Amino acid analysis and peptide mapping supply additional structural evidence, while nuclear magnetic resonance is reserved for full structural confirmation. Laboratories that examine samples sold online report wide variation in actual content, with some vials containing little or none of the labelled material.
| 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 |
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.
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.
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.
Receptor-binding studies classify melanotan II as a non-selective melanocortin agonist. It interacts with MC1R, MC3R, MC4R and MC5R, with reported affinities in the low nanomolar range and no strong subtype preference. Activation of MC1R on dermal melanocytes shifts pigment synthesis toward eumelanin, the dark polymer deposited in melanosomes and transferred to keratinocytes. Because the same peptide engages MC4R in the hypothalamus, it also appears in animal work on food intake and erectile response, which is why it is discussed in both pigment and metabolic research. Which receptor populations dominate after systemic exposure in humans is not fully established.
Published pharmacokinetic information is limited and comes mainly from small studies rather than registrational trials. Plasma half-life is usually described as short, on the order of tens of minutes, followed by rapid tissue distribution and clearance of the intact peptide. Metabolites and low concentrations of parent compound have been reported in urine, a detail relevant to anti-doping and forensic testing. Whether repeated exposure changes receptor sensitivity or clearance over time remains an open question. Values differ noticeably between analytical assays, so published numbers should be read as approximate rather than definitive.
Because the substance circulates mainly through informal markets, verification is a recurring theme in technical discussion. Independent analyses have found that labeled content and actual content can diverge, and that purity varies between samples. Analytical laboratories use reversed-phase chromatography to separate components and mass spectrometry to confirm identity. Isotope-labeled internal standards improve quantification in complex matrices. Such methods describe what a sample contains but say nothing about its sterility, lawful status, or suitability for any use. Open questions remain about how consistently testing is applied across the supply chain.
Regulatory treatment of this peptide varies by country. It holds no marketing authorization as a medicine in the United States, the European Union, or most other jurisdictions. Some countries classify products containing it as prescription-only or unlicensed medicines, which restricts lawful supply. Authorities have issued public notices warning that unregulated products may contain undeclared or incorrect ingredients. The molecule also appears on prohibited lists for competitive sport. These measures address supply oversight rather than any approved therapeutic role.
Diseases of the endocrine system are common, including conditions such as diabetes mellitus, thyroid disease, and obesity. Endocrine disease is characterized by misregulated hormone release (a productive pituitary adenoma), inappropriate response to signaling (hypothyroidism), lack of a gland (diabetes mellitus type 1, diminished erythropoiesis in chronic kidney failure), or structural enlargement in a critical site such as the thyroid (toxic multinodular goitre). Hypofunction of endocrine glands can occur as a result of loss of reserve, hyposecretion, agenesis, atrophy, or active destruction. Hyperfunction can occur as a result of hypersecretion, loss of suppression, hyperplastic or neoplastic change, or hyperstimulation. Endocrinopathies are classified as primary, secondary, or tertiary. Primary endocrine disease inhibits the action of downstream glands. Secondary endocrine disease is indicative of a problem with the pituitary gland. Tertiary endocrine disease is associated with dysfunction of the hypothalamus and its releasing hormones. As the thyroid, and hormones have been implicated in signaling distant tissues to proliferate, for example, the estrogen receptor has been shown to be involved in certain breast cancers. Endocrine, paracrine, and autocrine signaling have all been implicated in proliferation, one of the required steps of oncogenesis. Other common diseases that result from endocrine dysfunction include Addison's disease, Cushing's disease and Graves' disease.
Pseudomonas syringae pv. tabaci, the causal agent of the wildfire of tobacco P. syringae pv. coronafaciens P. syringae pv. garcae P. syringae BR2, which causes a disease of bean (Phaseolus vulgaris) similar to tobacco wildfire. This organism is closely related to P. syringae pv. tabaci but cannot be classified in the pathovar tabaci because it is not pathogenic on tobacco. Tabtoxin is a dipeptide precursor to the biologically active form of TBL, differing by having an extra threonine attached by a peptide bond to the C terminus. Tabtoxin is required by BR2(R) for both chlorosis and lesion formation on bean. All mutations that affected tabtoxin production, whether spontaneous deletion or transposon-induced, also affected lesion formation, and in all cases, restoration of tabtoxin production also restored pathogenic symptoms. Other factors may be required for BR2 to be pathogenic on bean, but apparently these are in addition to tabtoxin production. This toxin is a irreversible inhibitor of glutamine synthetase.
Maximum speed: 440 mph (710 km/h, 383 kn) Cruise speed: 362 mph (583 km/h, 315 kn) Stall speed: 100 mph (160 km/h, 87 kn) Range: 1,650 mi (2,660 km, 1,434 nmi) with external tanks Service ceiling: 41,900 ft (12,800 m) Rate of climb: 3,200 ft/min (16 m/s) Lift-to-drag: 14.6 Wing loading: 39 lb/sq ft (190 kg/m2) Power/mass: 0.162 / 0.187 hp/lb (0.266 / 0.307 kW/kg) (without / with WEP) Recommended Mach limit 0.8 Armament
Mahathir was a prominent international advocate for Bosniaks in Bosnia and Herzegovina during his tenure. His government permitted Bosnians to come to Malaysia without a visa during the Bosnian War. He was influential in the establishment of an OIC summit in Karachi in 1993 to discuss the need for weapons for Bosnia during the War. Malaysia sent UN Peacekeeping forces to Bosnia and was part of the Contact Group advocating for Bosnia at the UN. In February 2007, Mahathir was nominated by four non-governmental organisations in Bosnia and Herzegovina for the Nobel Peace Prize that year. The nominations were made by the Serb Civic Council from Bosnia and Herzegovina, the Croat National Council, the Sarajevo School of Science and Technology, and the Congress of Bosnik Intellectuals.
To overcome this effect, a new index was created, named the Equatorial Southern Oscillation Index (EQSOI). To generate this index, two new regions, centered on the Equator, were defined. The western region is located over Indonesia and the eastern one over the equatorial Pacific, close to the South American coast. However, data on EQSOI goes back only to 1949. Sea surface height (SSH) changes up or down by several centimeters in Pacific equatorial region with the ENSO: El Niño causes a positive SSH anomaly (raised sea level) because of thermal expansion while La Niña causes a negative SSH anomaly (lowered sea level) via contraction.
Sources: en.wikipedia.org
== Recognition == In 2003, a GameSpy editorial cited Minh Le as the most important reason Half-Life was still popular five years after it was released. IGN ranked Jess Cliffe and Minh Le as number 14 in their "Top 100 Game Creators of All Time" list.
=== In diagnosis === Lactoferrin levels in tear fluid have been shown to decrease in dry eye diseases such as Sjögren's syndrome. A rapid, portable test utilizing microfluidic technology has been developed to enable measurement of lactoferrin levels in human tear fluid at the point-of-care with the aim of improving diagnosis of Sjögren's syndrome and other forms of dry eye disease.
Most commercially produced dog food is made with animal feed grade ingredients and comes dry in bags (also known in the US as kibble) or wet in cans. Dry food contains 6–10% moisture by volume, as compared to 60–90% in canned food. Semi-moist products typically run 25–35%. Isotopic analysis of dog food in the Brazilian market have found that they are basically made of maize and poultry by-products.
The siliceous frustules of diatoms accumulate in fresh and brackish wetlands and lakes. Some peats and mucks contain a sufficient abundance of frustules such that they can be mined. Most of Florida's diatomaceous earths have been found in the muck of wetlands or lakes. The American Diatomite Corporation, from 1935 to 1946, refined a maximum of 145 tons per year from their processing plant near Clermont, Florida. Muck from several locations in Lake County, Florida was dried and burned (calcined) to produce the diatomaceous earth. It was formerly extracted from Lake Mývatn in Iceland. The commercial deposits of diatomite are restricted to Tertiary or Quaternary periods. Older deposits from as early as the Cretaceous Period are known, but are of low quality. Diatomite deposits rich in fossils have been located in New Zealand, but mining of the Foulden Maar deposits on an industrial scale, for conversion to animal feed, has drawn strong opposition.
Sources: en.wikipedia.org
Cannabis (Cannabis sativa) [3.8–37.5% of cannabis flower essential oil] Black caraway (Carum nigrum) [7.8%] Cloves (Syzygium aromaticum) [1.7–19.5% of clove bud essential oil] Hops (Humulus lupulus) [5.1–14.5%] Basil (Ocimum spp.) [5.3–10.5% O. gratissimum; 4.0–19.8% O. micranthum] Oregano (Origanum vulgare) [4.9–15.7%] Black pepper (Piper nigrum) [7.29%] Lavender (Lavandula angustifolia) [4.62–7.55% of lavender oil] Rosemary (Rosmarinus officinalis) [0.1–8.3%] True cinnamon (Cinnamomum verum) [6.9–11.1%] Malabathrum (Cinnamomum tamala) [25.3%] Ylang-ylang (Cananga odorata) [3.1–10.7%] Copaiba oil (Copaifera)
On March 1, 2013, it was announced that trace amounts of horse meat from a European supplier had been found in various food products, including Taco Bell's beef in the UK. By August 2017, there were 17 Taco Bell branches in the United Kingdom, all of which were in England and outside of London. The first Scottish branch was opened in Glasgow in December 2017. As of June 2019 there are 39 branches in Scotland and England, including three in London. Beginning in October 2019, Taco Bell locations in the UK began serving Doritos Locos Tacos. On March 2, 2020, the first Welsh Taco Bell branch was opened in Cardiff. More recently, in November 2021, Taco Bell opened its 77th UK store, and a return to the British Midlands with a store in The Royal Town of Sutton Coldfield, Birmingham. In August 2022 a Taco Bell was opened in Torquay, Devon, the second in the county after Plymouth. As of 2024 there are now more than 130 locations in the UK.
=== Taxonomic qualification === The classification of Han Chinese has gone through numerous historical permutations. This, coupled with the loose terms of Han qualification, has led some modern academics to question its use both historically and modernly. It has been critiqued by some as being used similarly to the concept of "whiteness" in the Western tradition, expanding and contracting to include whoever is politically useful. This has led to a relatively recent resurgence in viewing the concept of Han Chinese through a critical lens. "Han Chinese, as a category, holds considerable commonality with the category of whiteness. Both are comparatively recent social constructions that fused together large subgroups of people, who themselves possessed their own distinct cultures and languages. Although Han Chinese as a defined ethno-racial category did not exist prior to the 20th century, 'the modern ethnonym builds on a much older historical formulation, one that informs the "cultural stuff" which defines the boundaries, symbols and sentiment of Han today'." – The operations of contemporary Han Chinese privilege, Reza Hasmath Contending that the development of Han as an ethnonym "owed much" to interactions between the nomadic and seminomadic Hu people and the Han dynasty, academic Mark Elliot states that the idea of Han Chinese is "more the product of repeated efforts to create and foster political unity than it is the source of that unity."
== Preparation == In addition to the original procedure shown above (which may have compatibility issues for sensitive substrates), Weinreb amides can be synthesized from a variety of acyl compounds. The vast majority of these procedures utilize the commercially available salt N,O-dimethylhydroxylamine hydrochloride [MeO(Me)NH•HCl], which is typically easier to handle than the free amine. Treatment of an ester or lactone with AlMe3 or AlMe2Cl affords the corresponding Weinreb amide in good yields. Alternatively, non-nucleophilic Grignard reagents such as isopropyl magnesium chloride can be used to activate the amine before addition of the ester.
== Adverse effects == Common side effects include headache, dizziness, feeling tired, cough, nausea, and rash. Serious side effects may include low blood pressure, liver problems, hyperkalemia, and angioedema. Use is not recommended during the entire duration of pregnancy as it may harm the baby.
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.
The lyophilised solid is best kept cold, dry and dark, typically at minus twenty degrees Celsius. Moisture and repeated warming cycles are the main causes of degradation. Solutions prepared from the powder are less stable and are normally used quickly.