melanocortin receptor comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2025-12-19. 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.
| 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.
Outside regulated medicine, melanotan II circulates through online vendors as a research chemical, often marketed for tanning. Products sold this way vary widely in purity, concentration, and labeling accuracy, and independent testing has documented discrepancies. Published reports describe both pigment effects and adverse reactions, including nausea, flushing, and darkening of existing moles. Long-term safety data are sparse, and no large controlled trial has established a risk profile. Questions about cumulative effects on melanocytes remain unresolved in the literature.
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.
Phenibut is a derivative of the inhibitory neurotransmitter GABA. Hence, it is a GABA analogue. Phenibut is specifically the analogue of GABA with a phenyl ring substituted in at the β-position. As such, its chemical name is β-phenyl-γ-aminobutyric acid, which can be abbreviated as β-phenyl-GABA. The presence of the phenyl ring allows phenibut to cross the blood–brain barrier significantly, unlike GABA. Phenibut also contains the trace amine β-phenethylamine in its structure. Phenibut is closely related to a variety of other GABA analogues including baclofen (β-(4-chlorophenyl)-GABA), 4-fluorophenibut (β-(4-fluorophenyl)-GABA), tolibut (β-(4-methylphenyl)-GABA), pregabalin ((S)-β-isobutyl-GABA), gabapentin (1-(aminomethyl)cyclohexane acetic acid), and GABOB (β-hydroxy-GABA). It has almost the same chemical structure as baclofen, differing from it only in having a hydrogen atom instead of a chlorine atom at the para position of the phenyl ring. Phenibut is also close in structure to pregabalin, which has an isobutyl group at the β position instead of phenibut's phenyl ring. A glutamate-derivative analogue of phenibut is glufimet (dimethyl 3-phenylglutamate hydrochloride).
Of the 36 deep-water ports, Santos, Itajaí, Rio Grande, Paranaguá, Rio de Janeiro, Sepetiba, Vitória, Suape, Manaus and São Francisco do Sul are the most important. Bulk carriers have to wait up to 18 days before being serviced; container ships take 36.3 hours on average.
=== Civil society === Reactions also came from European civil society organisations. Transparency International described the incident as "the most egregious case" of alleged corruption the European Parliament has ever seen. The founder of the Good Lobby commented that "[w]hatever its final outcome, [the] Qatar 'corruption' scandal has unveiled an inconvenient, and for most Europeans already obvious, truth. Money does buy influence in the EU", and that "[t]he EU Parliament and most of its members have historically resisted stricter integrity rules and [an] effective enforcement system." As news broke of the investigation, the honorary board of the implicated NGO, Fight Impunity, resigned en masse. The board members included high-profile European policymakers including Federica Mogherini (former EU High Representative in the Juncker Commission), Bernard Cazeneuve (formerly Prime Minister of France), Dimitris Avramopoulos (former EU Commissioner for Migration, Home Affairs and Citizenship in the Juncker Commission), Cecilia Wikström (former MEP) and Emma Bonino (former EU Commissioner for Health and Consumer Protection in the Santer Commission). The honorary board has no executive or managerial role, so there is no suspicion or accusations against any member of the board. Visentini originally voluntarily stood down temporarily as president of the International Trade Union Congress but a specially convened Extraordinary Meeting of the General Council voted to suspend him of all of his duties.
The Leaning Tower of Pizza was a proposed 30-story slanted skyscraper that would have housed Domino's Pizza's operations at its Domino's Farms campus near Ann Arbor, Michigan. In the mid-1980s, Monaghan asked Taliesin Associated Architects, the inheritors of Frank Lloyd Wright's practice, to erect a structure based on an un-built tower that Wright designed in 1956 for Chicago called the Golden Beacon. Sometime during the planning of the tower, Monaghan and the Taliesin architects parted company, allegedly because both parties felt the project may have not served justice to the spirit of Wright's architecture. Monaghan then went to Gunnar Birkerts, the architect of Domino's unusual half-mile (800 m) long headquarters office building who came up with a design for a tower that would rise at a 15-degree angle with a swooping top reminiscent of the forms of Wright's late work. Birkerts' design, no doubt, had serious intent, but would immediately and forever be dubbed with the nickname "The Leaning Tower of Pizza" after Italy's Leaning Tower of Pisa. The structure was never built but a 50-foot (15 m) tall scale model stands at the proposed site on Domino Pizza headquarters in Ann Arbor Charter Township, Michigan, outside of Ann Arbor.
Overall, there are various non-selective calcium channel blockers that help alleviate symptoms of hypertension, schizophrenia, cardiac arrhythmia, epilepsy, pain, asthma, bradycardia, angina pectoris and Alzheimer's disease. Although many of the therapeutic compounds' main target is not P-type channels, further research needs to determine if the clinical effects of these compounds are also influenced by the P-type channel blockage.
Sources: en.wikipedia.org
Kiggans announced on January 7, 2024, that she would run for reelection in the 2024 election—a race targeted by the Democratic Congressional Campaign Committee. In June 2024, she participated in a rally with former president Donald Trump and incumbent governor Glenn Youngkin in Chesapeake after the first presidential debate. Kiggans faced Democratic nominee Missy Cotter Smasal, a fellow Navy veteran. Kiggans campaigned on support for a Mexico–United States border wall and lowering inflation occurring under the Biden administration. The Cook Political Report rated the election as "Lean Republican" by November 1, 2024. Kiggans defeated Smasal by a 4-point margin in the general election, larger than her 3-point margin in the 2022 election.
== Bibliography == Bogle, James and Joanna. (1990). A Heart for Europe: The Lives of Emperor Charles and Empress Zita of Austria-Hungary, Fowler Wright, 1990, ISBN 0-85244-173-8 Brook-Shepherd, Gordon. (1991). The Last Empress: The Life and Times of Zita of Austria-Hungary 1893–1989. Harper-Collins. ISBN 0-00-215861-2 Harding, Bertita. (1939). Imperial Twilight: The Story of Karl and Zita of Hungary. Bobbs-Merrill Company Publishers. ASIN: B000J0DDQO (in German) Bernhard A. Macek: Kaiser Karl I. Der letzte Kaiser Österreichs. Ein biografischer Bilderbogen, Sutton Verlag, Erfurt 2012, ISBN 978-3-9540-0076-0 (in French) Debris, Cyrille. (2013). Zita, Portrait intime d'une imperatrice. Cerf, Paris, 2013, ISBN 978-2-204-10085-4
The control of enzymatic browning has always been a challenge for the food industry. A variety of approaches are used to prevent or slow down enzymatic browning of foods, each method aimed at targeting specific steps of the chemical reaction. The different types of enzymatic browning control can be classified into two large groups: physical and chemical. Usually, multiple methods are used. The use of sulfites (powerful anti-browning chemicals) have been reconsidered due to the potential hazards that it causes along with its activity. Much research has been conducted regarding the exact types of control mechanisms that take place when confronted with the enzymatic process. Besides prevention, control over browning also includes measures intended to recover the food color after its browning. For instance, ion exchange filtration or ultrafiltration can be used in winemaking to remove the brown color sediments in the solution.
===== Impact on impoverished communities ===== In countries where cocaine is illicitly produced, an intermediate product known as cocaine paste—often referred to as "poor man's cocaine"—is frequently smoked in impoverished communities. This substance is favored in these areas primarily because it is inexpensive and more accessible than refined cocaine. However, the use of cocaine paste poses severe health risks. During its production, various toxic chemicals are used to extract coca alkaloids from the coca leaves. Many of these hazardous substances, such as solvents and acids, remain in the paste after processing. When the paste is smoked, individuals are exposed not only to the addictive effects of the drug itself but also to the dangerous residual chemicals, which can cause significant harm to the lungs, nervous system, and overall health. This combination of affordability, accessibility, and toxicity makes cocaine paste particularly damaging to vulnerable populations in cocaine-producing regions.
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.