This is a working overview of alpha-MSH analogue, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-05-06 and is reviewed periodically as new material appears.
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.
Melanotan-2, also written Melanotan II, is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone. Its sequence is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, and the lactam bridge between the aspartate and lysine side chains constrains the peptide into a ring. This structural change increases receptor affinity and metabolic stability relative to the native hormone. The compound was created in the 1980s as a research tool for studying pigmentation biology.
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.
| Property | Value | Notes |
|---|---|---|
| Compound class | Synthetic cyclic heptapeptide | Alpha-MSH analogue containing a D-phenylalanine residue |
| Molecular formula | C50H69N15O9 | Average molecular mass approximately 1024.2 g/mol |
| Appearance | White to off-white lyophilised powder | Normally supplied as a freeze-dried solid in a sealed vial |
| Solubility | Freely soluble in water and polar solvents | Dissolves readily in aqueous buffers and in alcohol-water mixtures |
| Receptor targets | MC1R, MC3R, MC4R, MC5R | Acts as a non-selective melanocortin receptor agonist |
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.
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.
Melanotan II is a synthetic peptide analog modeled on alpha-melanocyte-stimulating hormone, a naturally occurring signaling peptide involved in pigmentation. Its structure is a cyclic heptapeptide containing two non-natural substitutions, norleucine at position four and D-phenylalanine at position seven. These modifications resist enzymatic breakdown and extend the molecule's activity relative to the native hormone. The compound binds melanocortin receptors and is studied mainly as a pharmacological tool rather than a therapeutic product. It has never received approval as a medicine in any major jurisdiction.
The compound was developed in the late 1980s and 1990s by academic researchers investigating photoprotection. The rationale held that stimulating melanin production might reduce ultraviolet damage to skin and lower skin cancer risk. Early work examined receptor binding, pigment response, and short-term tolerability in small studies. That program did not produce an approved drug, and formal development stalled after early-phase trials. Whether induced pigmentation confers meaningful photoprotection remains an open question.
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.
=== Technical issues during the flight === On the 19th orbit, the first sign of trouble appeared when the spacecraft 0.05 g (0.5 m/s2) light came on. However, this turned out to be a faulty indicator, and the spacecraft was not reentering. On the 20th orbit, Cooper lost all attitude readings. The 21st orbit saw a short-circuit occur in the bus bar serving the 250 VA (115 V, 400 Hz) main inverter. This left the automatic stabilization and control system without electric power. On the 21st orbit, John Glenn on board the tracking ship Coastal Sentry Quebec near Kyushu, Japan, helped Cooper prepare a revised checklist for retrofire. Due to the system malfunctions, many of the steps would have to be done manually. Only Hawaii and Zanzibar were in radio range on this last orbit, but communications were good. Cooper noted that the carbon dioxide level was rising in the cabin and in his spacesuit. He told Carpenter as he passed over Zanzibar, "Things are beginning to stack up a little." Throughout the problems, Cooper remained cool, calm and collected. Cooper did not experience much of an appetite during the flight and ate only because it was scheduled. The food containers and water dispenser system proved unwieldy and he was not able to properly prepare freeze-dried food packages, so he limited his consumption to cubed food and bite-sized sandwiches. Cooper found the cubed food largely unpalatable, which contributed to his lack of eating.
In the United States, the term "nickel" or "nick" originally applied to the copper-nickel Flying Eagle cent, which replaced copper with 12% nickel 1857–58, then the Indian Head cent of the same alloy from 1859 to 1864. Still later, in 1865, the term designated the three-cent nickel, with nickel increased to 25%. In 1866, the five-cent shield nickel (25% nickel, 75% copper) appropriated the designation, which has been used ever since for the subsequent 5-cent pieces. This alloy proportion is not ferromagnetic. The US nickel coin contains 0.04 ounces (1.1 g) of nickel, which at the April 2007 price was worth 6.5 cents, along with 3.75 grams of copper worth about 3 cents, with a total metal value of more than 9 cents. Since the face value of a nickel is 5 cents, this made it an attractive target for melting by people wanting to sell the metals at a profit. The United States Mint, anticipating this practice, implemented new interim rules on December 14, 2006, subject to public comment for 30 days, which criminalized the melting and export of cents and nickels. Violators can be punished with a fine of up to $10,000 and/or a maximum of five years in prison. As of February 19, 2025, the melt value of a US nickel (copper and nickel included) is $0.054 (108% of the face value).
Most newspapers in Hong Kong are written in Chinese. There are also English-language newspapers, the major one being the South China Morning Post, with The Standard serving as a business-oriented alternative. A variety of Chinese-language newspapers are published daily; the most prominent are Ming Pao and Oriental Daily News. Local publications are often partisan, with pro-Beijing or pro-democracy sympathies. The central government has a print-media presence in the territory through the state-owned Ta Kung Pao and Wen Wei Po. Several international publications have regional operations in Hong Kong, including The Wall Street Journal, the Financial Times, USA Today, TimeOut, The Nikkei and Vogue Hong Kong. Four free-to-air television broadcasters operate in the territory; TVB, HKTVE, HOY and Phoenix Television air eight digital channels. TVB, Hong Kong's dominant television network, has an 80% viewer share. Paid television services operated by PCCW offer hundreds of additional channels and cater to a variety of audiences. RTHK is the public broadcaster, providing seven radio channels and six free-to-air television channels. Ten non-domestic broadcasters air programming for the territory's foreign population. Access to media and information over the Internet is not subject to mainland Chinese regulations, including the Great Firewall, but local internet censorship applies.
=== Diagnostic tests === The initial tests for thalassemias are: Complete blood count (CBC): Checks the number, size, and maturity of blood cells. Hemoglobin of less than 10 g/dl may indicate a carrier, below 7 g/dl is indicative of thalassemia major. In thalassemia major, mean corpuscular volume (MCV) are less than 70 fl, in thalassemia intermedia, MCV levels are below 80 fl (The normal range for MCV is 80–100 fl). The Mentzer index can be a pointer for diagnosis of thalassemia; it can be calculated from a CBC report. Peripheral blood smear: A blood smear examined under a microscope can show red blood cells that are abnormal in shape (poikilocytosis or codocytes), color (hypochromic), or size (microcytic), as well as those with abnormal inclusions (Heinz bodies). Serum iron and ferritin: these tests are needed to rule out iron-deficiency anemia. For an exact diagnosis, the following tests can be performed:
Sources: en.wikipedia.org
The Centre Party (German: Zentrum, Z), officially the German Centre Party (German: Deutsche Zentrumspartei, DZP) and also known in English as the Catholic Centre Party, is a Christian democratic political party in Germany. It was most influential in the German Empire and Weimar Republic. Formed in 1870, it successfully battled the Kulturkampf waged by Chancellor Otto von Bismarck against the Catholic Church. It soon won a quarter of the seats in the Reichstag, and its middle position on most issues allowed it to play a decisive role in the formation of majorities. The party name Zentrum (Centre) originally came from the fact that Catholic representatives would take up the middle section of seats in parliament between the social democrats and the conservatives. For most of the Weimar Republic, the Centre Party was the third-largest party in the Reichstag and a bulwark of the Republic, participating in all governments until 1932. Following Adolf Hitler's rise to power in early 1933, the Centre Party was among the parties who voted for the Enabling Act, which granted legislative powers to Hitler's government. Nevertheless, the party was pressured into dissolving itself on 5 July, as the Nazi Party became the only legally permitted party in the country shortly thereafter. After World War II, the party was reconstituted, but could not rise again to its former importance, as most of its members joined the new interdenominational Christian Democratic Union (CDU) and, in Bavaria, the Christian Social Union (CSU).
There are colloidal methods to produce many different semiconductors. Typical dots are made of binary compounds such as lead sulfide, lead selenide, cadmium selenide, cadmium sulfide, cadmium telluride, indium arsenide, and indium phosphide. Dots may also be made from ternary compounds such as cadmium selenide sulfide. Further, recent advances have been made which allow for synthesis of colloidal perovskite quantum dots. These quantum dots can contain as few as 100 to 100,000 atoms within the quantum dot volume, with a diameter of approximately 10 to 50 atom diameters. This corresponds to about 2 to 10 nanometers, and at 10 nm in diameter, nearly 3 million quantum dots could be lined up end to end and fit within the width of a human thumb.
There was a prosecutor that asked for an authorization for a prisoner to be freed that guaranteed that he knew where Rui Pedro was. The result: the prisoner went missing. Was not it. It's clear isn't it? They gave the prisoner credit cards. They gave the prisoner a car, gave money and (...) [everything went missing] If that was a lie I would be arrested, because it's easy to arrest journalists, working is hard.The journalist also critiqued the law for having allowed for Mendonça's grandfather to have the role that the Portuguese State had spending money on the Madeleine McCann case. However, Mendonça's grandfather spent his fortune falling for all kinds of scams while searching for the boy. He also questioned the PJ's high rate of success in solving missing children cases, but this one went through three teams of investigation without success. In another interview, he said that the Portuguese State should be on the defendant's bench in Dias' trial, for having left in the open who was, or were the defendants through the fourteen years, which could have affected the testimony of the witnesses in the court.
=== Vaccination === By 2006, China has successfully immunised 11.1 million children living in the country's poorest provinces against hepatitis B according to the Chinese health ministry, and the Global Alliance for Vaccines and Immunization (GAVI). However, China still has a long way to go before immunisation levels reach a percentage able to limit the spread of hepatitis B. China's health minister, Gao Qiang told a Beijing press conference that the project, while effective, has covered only one third of all children born in China since the project began in 2002. This does not mean the rest of China's children went unvaccinated. However, even within the project's target area, over one million newborns went unvaccinated each year because of access issues; health-care costs, lack of birth attendants, and the remoteness of their birthplaces, such as herder's huts, mountain villages, and remote farms. Until 2005, when a law banning the practice was passed, parents were charged fees for the administration of the vaccine. Even though the GAVI alliance (whose partners include UNICEF and the WHO), and Chinese government were providing the vaccine and one-use needles free of charge, health-care workers charged fees that parents were unwilling or unable to pay. Based on a 1992 epidemiological survey, the disease burden of those who are chronically infected with hepatitis B in China is estimated to be at 120 million, one third of the overall burden (360 million) as estimated by the WHO. China's national target is to reach greater than 85% vaccination.
== Research == Studies performed by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), found that two specific polymorphisms in the MC3R gene may be associated with pediatric obesity and greater body mass because of greater energy intake. Children who were homozygous for C17A + G241A consumed approximately 38% more than those who did not contain aforementioned polymorphisms. The study concluded that these genetic variants did not affect energy expenditure.
Sources: en.wikipedia.org
No. It is a laboratory-made peptide, while the natural hormone is alpha-melanocyte-stimulating hormone, a longer peptide produced by the pituitary gland and by skin cells. Melanotan-2 mimics only a short active region of that hormone and contains non-natural residues such as D-phenylalanine.
No approved regulatory indication exists in major markets. An approval exists for a different peptide, afamelanotide, which is used for a rare photosensitivity disorder called erythropoietic protoporphyria. Melanotan-2 itself remains a research compound with no cleared clinical role.
Melanocortin-1 receptors on melanocytes are the receptor most closely linked to pigment production. The peptide is not selective, however, and also activates melanocortin-3, melanocortin-4, and melanocortin-5 receptors. That lack of selectivity is the usual explanation offered for both its range of observed effects and its off-target effects.
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.