prohibited list raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-03-27 and is reviewed periodically as new material appears.
Reversed-phase high-performance liquid chromatography is the routine method for purity assessment. Peptides absorb near 214 nm because of the peptide bond, and a gradient of acetonitrile in water separates the intact peptide from deletion sequences, oxidised products, and earlier-eluting fragments at neutral pH. Electrospray ionisation mass spectrometry provides an orthogonal check: the measured mass must agree with the theoretical value. Amino acid analysis and peptide mapping confirm structure but are used less often. Reference standards remain scarce because the peptide is not described in any pharmacopoeia.
Regulatory treatment varies by country. In the United States the peptide is not approved as a medicine, and products offered for human use may be treated as unapproved new drugs; some states also restrict sale. Australia, the United Kingdom, and European Union member states apply comparable restrictions to unapproved peptide products. Border agencies have seized shipments labelled as research chemicals. Classification may change over time, and the legal position for personal importation is not clearly settled in most published guidance.
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.
Melanotan II is a synthetic cyclic heptapeptide with the sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, corresponding to a molecular formula of C50H69N15O9 and a monoisotopic mass near 1024 daltons. It was designed as a structural analogue of alpha-melanocyte-stimulating hormone, a peptide hormone produced by cleavage of proopiomelanocortin. A lactam bridge between the aspartate and lysine side chains closes the ring, and the C-terminal amide removes a free carboxyl group. Both modifications increase resistance to enzymatic degradation compared with the linear parent hormone. Four substitutions distinguish it from afamelanotide, the linear analogue studied under the name melanotan I.
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.
| Property | Value | Notes |
|---|---|---|
| Lyophilised storage | −20 °C, dry, protected from light | Vials are sealed and allowed to reach room temperature before opening |
| Reconstituted storage | 2 to 8 °C, protected from light | Short-term holding; avoid repeated freeze-thaw cycles |
| Reconstitution solvent | Water for injection or bacteriostatic water | Added slowly along the vial wall to reduce foaming and shear |
| Purity measurement | RP-HPLC with area normalisation | Acetonitrile-water gradient monitored at roughly 214 nm |
| Identity confirmation | Electrospray ionisation mass spectrometry | Observed mass compared against the calculated peptide mass |
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.
Melanotan II binds several melanocortin receptor subtypes rather than a single target. MC1R on melanocytes drives melanin synthesis, while MC3R and MC4R participate in energy balance, appetite, and sexual response pathways. This lack of selectivity explains why reported effects extend beyond skin darkening. Substitutions at positions four and seven, including norleucine and D-phenylalanine, increase potency and resistance to peptidases. Understanding which receptor mediates which effect remains an active area of investigation.
Published human data come mostly from small, short studies rather than large controlled trials. Reported outcomes include increased skin pigmentation and, in some reports, effects on appetite and libido, but sample sizes are small and follow-up is limited. Whether long-term use produces durable pigment changes or adverse effects is not established. Because products sold outside pharmacies are not standardized, the actual content of any given vial is often unknown. Independent testing of such material is uncommon.
Melanotan II is a synthetic cyclic heptapeptide analog derived from the core sequence of alpha-melanocyte-stimulating hormone. Researchers at the University of Arizona synthesized it during the 1980s while studying pigmentation and appetite signaling. The compound is not an approved medicine in any major jurisdiction and appears mainly in laboratory and research-chemical settings. Its structure incorporates a lactam bridge between side chains, which constrains the ring and slows enzymatic breakdown relative to the natural hormone.
=== Uniform === Until 1914 the distinguishing colour of the Don Cossack Host was red, worn on the cap bands and wide trouser stripes of a dark blue uniform of the loose-fitting cut common to the Steppe Cossacks. Tall lambskin hats were worn on occasion, with red cloth tops edged in white lace. Silver metal scrolls were worn on the headdress to denote the distinguished conduct of individual regiments. Officers had silver braiding on their collars and epaulettes, plus silver/black girdles. Shoulder-straps of other ranks were the same dark blue as the caftan (coat). A whip was used instead of spurs. Prior to 1908, individual cossacks from all Hosts were required to provide their own uniforms, together with horses and harness. The size and relative affluence of the Don Cossack Host permitted the setting up of communally owned clothing factories. In 1908, a khaki field tunic was adopted, replacing the dark blue coats or white summer blouses previously worn for ordinary duties. The blue riding breeches with broad red stripes long characteristic of the Don Host, continued to be worn even on active service during both World Wars. The Don Cossack Battery of the Imperial Guard wore a "Tsar's green" uniform, a dark shade common to the army, with the black and red distinctions of the artillery as a branch.
== Taxonomy == The classification of corals has been discussed for millennia, owing to having similarities to both plants and animals. Aristotle's pupil Theophrastus described the red coral, korallion, in his book on stones, implying it was a mineral, but he described it as a deep-sea plant in his Enquiries on Plants, where he also mentions large stony plants that reveal bright flowers when under water in the Gulf of Heroes. Pliny the Elder stated boldly that several sea creatures including sea nettles and sponges "are neither animals nor plants, but are possessed of a third nature (tertia natura)". Petrus Gyllius copied Pliny, introducing the term zoophyta for this third group in his 1535 book On the French and Latin Names of the Fishes of the Marseilles Region; it is popularly but wrongly supposed that Aristotle created the term. Gyllius further noted, following Aristotle, how hard it was to define what was a plant and what was an animal. The Babylonian Talmud refers to coral among a list of types of trees, and the 11th-century French commentator Rashi describes it as "a type of tree (מין עץ) that grows underwater that goes by the (French) name 'coral'." The Persian polymath Al-Biruni (d.1048) classified sponges and corals as animals, arguing that they respond to touch. Nevertheless, people believed corals to be plants until the eighteenth century when William Herschel used a microscope to establish that coral had the characteristic thin cell membranes of an animal.
=== Empirical methods === A set of empirical rules relating the protein structure to the pKa values of ionizable residues have been developed by Li, Robertson, and Jensen. These rules form the basis for the web-accessible program called PROPKA for rapid predictions of pKa values. A recent empirical pKa prediction program was released by Tan KP et.al. with the online server DEPTH web server.
== In popular culture == British actor Bob Hoskins portrayed Manuel Noriega in the biographical 2000 American television movie Noriega: God's Favorite. Noriega was also depicted in the 2012 video game Call of Duty: Black Ops II. In July 2014, he filed a lawsuit against the game company Activision for depicting him and using his name without his permission. Noriega, who filed the suit while in prison for murder, claimed he was portrayed as "a kidnapper, murderer and enemy of the state". On October 28, 2014, the case against Activision was dismissed in California by Judge William H. Fahey.
== Treatment == Management of chronic granulomatous disease revolves around two goals: 1) diagnose the disease early so that antibiotic prophylaxis can be given to keep an infection from occurring, and 2) educate the patient about his or her condition so that prompt treatment can be given if an infection occurs.
Sources: en.wikipedia.org
=== Social sciences === Finance: a retirement fund will decay exponentially being subject to discrete payout amounts, usually monthly, and an input subject to a continuous interest rate. A differential equation dA/dt = input − output can be written and solved to find the time to reach any amount A, remaining in the fund. In simple glottochronology, the (debatable) assumption of a constant decay rate in languages allows one to estimate the age of single languages. (To compute the time of split between two languages requires additional assumptions, independent of exponential decay).
==== Kerogens and coals ==== The first stage that sedimentary organic matter (SOM) experiences after deposition is diagenesis. During diagenesis, biological decomposition can alter the DHR of organics. Several experimental studies have shown that some biodegraded materials become slightly enriched in D (less than 50‰). Most organics become kerogen by the end of diagenesis. Generally, δD of kerogen spans a wide range. Many factors contribute to the kerogen we observe in geologic records, including:
Judge Marino Barbero indicted 39 people, eight of whom would be sentenced in 1997 by the Supreme Court to sentences ranging from eleven years in prison to six months in prison. A third corruption case that splashed the PSOE was the "Ibercorp case", known in February 1992 and also uncovered by the newspaper El Mundo, and the one involving governor of the Bank of Spain Mariano Rubio which forced the former Minister of Economy and Finance Carlos Solchaga, who had appointed him, to resign as deputy. The PSOE was so questioned that it "exhibited an almost total lack of credibility" when it filed the denunciation of a corruption case involving the Popular Party, the "Naseiro case", by the name of the "treasurer" of the PP Rosendo Naseiro.
White coats which resemble lab coats are worn by students and teachers of most public primary schools as a daily uniform in countries like Argentina, Uruguay, Spain, Bolivia and Morocco, and in private schools in Colombia. It also was formerly worn during past decades in Paraguay and Chile.
== Total synthesis == Matinkhoo et al. devised strategies to surmount three synthetic hurdles to give α-amanitin in 2018. First, enantioselective synthesis of solid phase peptide synthesis-compatible (2S,3R,4R)-4,5-dihydroxyisoleucine was afforded in 11 steps from 2-(benzyloxy)acetaldehyde. Two key stereochemistry-defining steps include Brown crotylation at (3R,4R)-positions, and asymmetric Strecker amino acid synthesis at the (2S)-α carbon. Secondly, chemoselective inner ring closure by fluorocyclization between 6-hydroxytrytophan and cysteine was achieved by intra-annular Savige-Fontana reaction. This requires a solid phase peptide synthesis-compatible, and methyliminodiacetic acid (MIDA), a boron protecting group, orthogonal amino acid in 5 steps. As a final step, enantioselective oxidation at the tryptathionine linkage was achieved using a bulky organic oxidizing agent and an optimized solvent system to afford the desired bio-reactive (R)-enantiomer sulfoxide, completing the total synthesis.
Sources: en.wikipedia.org
=== Other === There is evidence that some anticoagulants, particularly warfarin, which inhibit clot formation by interfering with Vitamin K metabolism, may promote arterial calcification in the long term despite reducing clot formation in the short term. Also, small molecules such as 3-hydroxybenzaldehyde and protocatechuic aldehyde have shown vasculoprotective effects to reduce risk of atherosclerosis.
==== Wars with Assyria and Babylonia ==== The Kingdom of Israel was conquered by the Neo-Assyrian Empire around 720 BCE. The records of Sargon II of Assyria indicate that he deported part of the population to Assyria. Some Israelites migrated to the southern kingdom of Judah, while those that remained in Samaria, concentrated mainly around Mount Gerizim, developed a new ethnic identity as Samaritans. Foreign groups were also settled by the Assyrians in the territories of the conquered kingdom. Research indicates that only a portion of the surviving Israelite population intermarried with Mesopotamian settlers. In their native Samaritan Hebrew, the Samaritans identify as "Israel", "B'nai Israel" or "Shamerim/Shomerim" (i.e. "Guardians/Keepers/Watchers"). Despite this, belief in the Ten Lost Tribes of Israel emerged because of the heavy assimilation faced by Samarian deportees. Towards the end of the same century, the Neo-Babylonian Empire emerged victorious over the Assyrians, leading to Judah's subjugation as a vassal state. In the early 6th century BC, a series of revolts in Judah prompted the Babylonian king Nebuchadnezzar II to lay siege to and destroy Jerusalem along with the First Temple, marking the kingdom's demise. Subsequently, a segment of the Judahite populace was exiled to Babylon in several waves. Judeans were progenitors of the Jewish people, who practised Second Temple Judaism during the Second Temple period.
Tris(hydroxymethyl)aminomethane (buffer) Sodium chloride (salt) Sucrose (sugar) Magnesium chloride hexahydrate Disodium EDTA dihydrate (a chelation ligand; sequestrant) Polysorbate 80 Ethanol 95% Water No adjuvants and no other components or ingredients should be included in the vaccine.
The first death row prisoner to be hanged in Singapore during the COVID-19 pandemic was 68-year-old Singaporean drug offender Abdul Kahar Othman on 30 March 2022, who had not appealed against his sentence and later executed as scheduled, therefore resuming executions in Singapore. By the time Abdul Kahar was executed, there were 62 prisoners on death row, awaiting execution (reduced to 61 with Nagaenthran's execution). Nagaenthran K. Dharmalingam was the second to be hanged on 27 April 2022 after Abdul Kahar. Datchinamurthy Kataiah was originally the third in line to be executed on 29 April 2022 after Nagaenthran before his execution was postponed due to an appeal. On 7 July 2022, Kalwant Singh Jogindar Singh and Norasharee Gous became the third and fourth convicts to be hanged in Singapore in 2022. In the same month, Nazeri Lajim was executed 15 days after Kalwant and Norasharee. Three more hangings - one on 26 July and two (Malaysian Rahmat Karimon and his accomplice Zainal Hamad) on 2 August - were conducted after Nazeri's execution. On 5 August 2022, 45-year-old Singaporean Abdul Rahim Shapiee and his 49-year-old accomplice Ong Seow Ping were the ninth and tenth to be executed. A 55-year-old Singaporean, whose name is unknown, was the eleventh to be executed for a drug charge on 7 October 2022. In total, eleven executions, all for drug trafficking, took place in the year 2022. In 2023, the first execution was carried out on 26 April 2023, when a 46-year-old Singaporean Tangaraju Suppiah, who was convicted in 2018 of marijuana trafficking, was hanged at dawn.
Sources: en.wikipedia.org
Low temperature slows hydrolysis and oxidation, the two main routes by which the peptide backbone and side chains are modified. A lyophilised powder stored at −20 °C is more stable than one kept at room temperature, and once the material is dissolved the degradation rate rises, making refrigeration more important.
Liquid chromatography coupled to mass spectrometry is the most common approach because it combines a retention time with a mass measurement. A chromatographic peak alone cannot establish which peptide is present, so mass determination or amino acid analysis is used as an orthogonal confirmation alongside the separation.
This depends on buffer, pH, and concentration, and published stability data for this peptide are limited. In practice laboratories work through a refrigerated solution within a few weeks and discard samples that show cloudiness or visible particles. Freezing and thawing repeatedly is generally discouraged.
No. It is a synthetic analogue carrying four amino acid changes, a lactam ring and an amidated C-terminus. The natural hormone is a linear thirteen-amino-acid peptide processed from proopiomelanocortin.