If you have been reading about Melanotan II and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2025-08-02. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Melanotan II is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone, a naturally occurring peptide involved in pigmentation signalling. Its structure substitutes a lactam bridge between side chains to increase stability relative to the native hormone. The compound is also known by the shorthand MT-II and by several non-proprietary synonyms used in research catalogues. It is not an approved therapeutic product in any major jurisdiction; material sold under this name is typically offered as a laboratory reagent rather than as a medicine.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Cyclic heptapeptide, C-terminally amidated |
| Approximate molecular mass | 1024 Da | Monoisotopic mass of the free peptide |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility class | Soluble in water and polar solvents | Also dissolves in neutral aqueous buffer |
| Common synonyms | Melanotan II, MT-II, MT-2 | Described as a melanocortin agonist in early literature |
The compound emerged from research programs in the 1980s that examined analogues of alpha-melanocyte-stimulating hormone for pigmentation and photoprotection. Investigators modified the native sequence to extend activity duration and potency. A related analogue, afamelanotide, was developed within the same broad line of inquiry and eventually gained approval in certain jurisdictions for a rare light-sensitivity condition. Melanotan-2 itself did not progress through the same regulatory route and has no approved therapeutic indication.
Melanocortin receptors comprise five subtypes with distinct tissue distributions and functions. Melanotan-2 is described in the literature as a non-selective agonist that engages several of these subtypes, including MC1R, MC3R, MC4R, and MC5R. MC1R is the subtype most directly linked to melanin production in skin cells. Because the compound is not subtype-selective, its observed effects in experimental settings are generally attributed to activity across multiple receptor pathways rather than to a single target.
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.
Tetracyclines are antibiotics that also exhibit MMP inhibitory activity. They chelate Zn2+ ion, thereby inhibiting MMP activity. It is believed that tetracyclines also effect MMP expression and proteolytic activity.
Increased rates of immune system disorders and other wide-ranging symptoms, including chronic pain, fatigue and memory loss, have been reported in over one quarter of combat veterans of the 1991 Gulf War. Combustion products from depleted uranium munitions are being considered as one of the potential causes by the Research Advisory Committee on Gulf War Veterans' Illnesses, as DU was used in 30 mm and 25 mm cannon rounds on a large scale for the first time in the Gulf War. Veterans of the conflicts in the Persian Gulf, Bosnia and Kosovo have been found to have up to 14 times the usual level of chromosome abnormalities in their genes. Serum-soluble genotoxic teratogens produce congenital disorders, and in white blood cells causes immune system damage. A 2005 epidemiology review concluded: "In aggregate the human epidemiological evidence is consistent with increased risk of birth defects in offspring of persons exposed to DU." A 2001 study of 15,000 February 1991 U.S. Gulf War combat veterans and 15,000 control veterans found that the Gulf War veterans were 1.8 (fathers) to 2.8 (mothers) times as likely to have children with birth defects. After examination of children's medical records two years later, the birth defect rate increased by more than 20%:
== Legal status == As of May 2013, Boehringer and Lilly had submitted applications for marketing approval to the European Medicines Agency (EMA) and the US Food and Drug Administration (FDA). Empagliflozin was approved in the European Union in May 2014, and was approved in the United States in August 2014. The FDA required four postmarketing studies: a cardiovascular outcomes trial, two studies in children, and a toxicity study in animals related to the pediatric trials. After the patent expired in 2025, about 37 companies began producing generic empagliflozin in India.
== Narcotics corruption == Drug-related corruption reportedly began to take a firm hold within Bolivia's military and security services under General Banzer's rule (1971–78). In 1980 the Junta of Commanders headed by Luis García Meza Tejada forced a violent coup d'etat—sometimes referred to as the Cocaine Coup - on 17 July. The García Meza regime (1980–81) was one of Bolivia's most flagrant examples of narcotics corruption. García Meza's so-called cocaine coup was itself generally believed to have been financed by the cocaine "mafia," which bribed certain military officers. García Meza reportedly ruled with an "inner cabinet" of leading civilians and military officers involved in the cocaine trade. Two of his ministers—Colonel Ariel Coca and Colonel Luis Arce Gómez—were well-known "godfathers" of the industry. By 1982 approximately 4,500 prosecutions were under way in connection with the embezzlement of state funds by civil servants, said to amount to a total of US$100 million. Garcia Meza's rule was so violent, and his regime so internationally isolated due to his drug trafficking, that he was forced to resign in 1981. His main collaborator, Colonel Luis Arce Gómez, was extradited to the United States, where he served a jail sentence for drug trafficking. In early 1986, Congress charged García Meza and fifty-five of his former colleagues with sedition, armed uprising, treason, genocide, murder, torture, fraud against the state, drug trafficking, crimes against the Constitution, and other crimes.
=== Extrapolation === Retrograde extrapolation is the mathematical process by which someone's blood alcohol concentration at the time of driving is estimated by projecting backwards from a later chemical test. This involves estimating the absorption and elimination of alcohol in the interim between driving and testing. The rate of elimination in the average person is commonly estimated at 0.015 to 0.020 grams per deciliter per hour (g/dL/h), although again this can vary from person to person and in a given person from one moment to another. Metabolism can be affected by numerous factors, including such things as body temperature, the type of alcoholic beverage consumed, and the amount and type of food consumed. In an increasing number of states, laws have been enacted to facilitate this speculative task: the blood alcohol content at the time of driving is legally presumed to be the same as when later tested. There are usually time limits put on this presumption, commonly two or three hours, and the defendant is permitted to offer evidence to rebut this presumption. Forward extrapolation can also be attempted. If the amount of alcohol consumed is known, along with such variables as the weight and sex of the subject and period and rate of consumption, the blood alcohol level can be estimated by extrapolating forward. Although subject to the same infirmities as retrograde extrapolation—guessing based upon averages and unknown variables—this can be relevant in estimating BAC when driving and/or corroborating or contradicting the results of a later chemical test.
Sources: en.wikipedia.org
A similar role has been suggested for clays, though this speculation has not been supported through experimental evidence. The prebiotic synthesis of peptides from simpler molecules such as CO, NH3 and C, skipping the step of amino acid formation, is also very efficient.
== Dosage comparison == For constant pain, the relieving effect of extended-release morphine given once (for Kadian) or twice (for MS Contin) every 24 hours is roughly the same as multiple administrations of immediate release (or "regular") morphine. Morphine sulfate pentahydrate (trade names including Dolcontin) has a higher molecular mass than morphine base, and therefore 10 mg morphine sulfate pentahydrate contains approximatively 7.5 mg of morphine free base. Extended-release morphine can be administered together with "rescue doses" of immediate-release morphine pro re nata in case of breakthrough pain, each generally consisting of 5% to 15% of the 24-hour extended-release dosage.
Henning Genz (2001). Nothingness: The Science Of Empty Space. Da Capo Press. ISBN 978-0-7382-0610-3. Luciano Boi (2011). The Quantum Vacuum: A Scientific and Philosophical Concept, from Electrodynamics to String Theory and the Geometry of the Microscopic World. Johns Hopkins University Press. ISBN 978-1-4214-0247-5.
The recommended safe daily dose of cannabidiol (CBD) is lowered by the Food Standards Agency, following concerns that long-term use might cause liver and other health problems. Downing Street announces that the UK will send surveillance aircraft and two Royal Navy ships to the eastern Mediterranean to support Israel. The Royal Mint unveils a new set of coins bearing the portrait of Charles III which will go into circulation at the end of the year. 13 October The Competition and Markets Authority approves Microsoft's £59bn takeover of Call of Duty-maker Activision Blizzard, the largest ever deal in video game history. The United Kingdom begins evacuating British citizens from Israel. The Metropolitan Police reports a "massive increase" in the number of antisemitic incidents in London between 30 September and 13 October, with 105 incidents and 75 offences, compared to 14 incidents and 12 offences during the same period of 2022. Sunak describes the increase as "disgusting". 14 October Michael Caine announces his retirement from acting at the age of 90, following the recent launch of his final film, The Great Escaper. Pro-Palestinian protests take place in cities across the UK, including London and Manchester, with police warning that anyone showing support for Hamas faces arrest. Red paint is sprayed over the BBC headquarters in central London. A pro-Palestinian group claims responsibility, citing the broadcaster's coverage of the Israel-Hamas war, but the Metropolitan police denies the incident is linked to a protest group and says no arrests have been made.
Sources: en.wikipedia.org
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.
Afamelanotide is the linear analogue [Nle4-D-Phe7]-alpha-MSH, sometimes called melanotan I, while melanotan II is cyclic and carries three further substitutions. The two are distinct molecules and are not interchangeable in analytical testing.
Binding to the four melanocortin receptor subtypes is well documented in vitro. The relative contribution of each subtype to whole-body effects in humans is far less certain.
No. No major regulatory agency has granted a marketing authorisation for melanotan II as a medicine. Products sold under this name are generally presented as laboratory reagents and are not subject to the batch-release testing applied to approved drugs.