MC1R is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-01-24. Where a claim depends on a specific study, the study is described rather than over-claimed.
The compound was developed in the late 1980s and early 1990s by academic researchers investigating melanocortin signaling and pigmentation. Early work explored whether synthetic analogs could reproduce effects of the natural hormone under controlled conditions. The molecule never advanced through the full regulatory pathway required for approval as a medicine. From the mid-2000s onward it appeared in unregulated consumer markets, often distributed through informal channels. That gap between research origins and commercial availability shapes how the compound is discussed today.
Melanotan-2 is a synthetic peptide designed as an analog of alpha-melanocyte-stimulating hormone, a signaling molecule produced in the pituitary and skin. Its structure is a linear chain of seven amino acids that folds into a ring through an internal lactam bridge joining two side chains. The compound is sometimes written as MT-II or MEL-2 in informal and commercial contexts. It belongs to the melanocortin peptide family, a group of short signaling molecules that share a conserved core sequence recognized by melanocortin receptors.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic cyclic heptapeptide | Analog of alpha-MSH with an internal lactam bridge |
| Molecular weight | Approximately 1024 daltons | Free base value; salt forms differ |
| Appearance | White to off-white powder | Usually supplied as a lyophilized solid |
| Solubility | Freely soluble in water | Poorly soluble in nonpolar solvents |
| Typical storage | −20 °C, dry, protected from light | Repeated freeze-thaw cycles degrade peptides |
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-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone. Its sequence incorporates a lactam bridge that constrains the peptide into a ring, which increases resistance to enzymatic breakdown relative to the natural hormone. Researchers at the University of Arizona synthesised the compound in the late 1980s and early 1990s while studying pigmentation pathways. It has never received marketing approval from any national medicines regulator. In the scientific literature it is usually described as a laboratory research reagent rather than a therapeutic product.
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.
). The alternative notation also makes it straightforward to see how the GTR model can be applied to biological alphabets with a larger state-space (e.g., amino acids or codons). It is possible to write a set of equilibrium state frequencies as
In statistics, describes a mathematical measure of difference between groups. The difference is said to be significant if it is greater than what might be expected to happen by chance alone. Also called statistically significant. (NCI) Single blind study
=== Phylogenetic relationships and molecular studies === Modern taxonomy places X. parietina in the family Teloschistaceae, order Teloschistales, within the class Lecanoromycetes (lichenized Ascomycota). It is closely related to other orange lichens such as those in the genera Caloplaca, Teloschistes, and other members of the Xanthorioid clade of the Teloschistaceae. Molecular studies have helped clarify its phylogenetic relationships. For example, DNA sequence analyses provided evidence that X. parietina is genetically distinct from Xanthoria aureola, another yellow coastal lichen that had sometimes been considered merely a variety or form of X. parietina. Their study confirmed that X. aureola is a separate species, not conspecific with X. parietina. Microscopic studies have established Xanthoria parietina as the prototype species for the "Teloschistes-type" ascus, a structural category characterized by an apically thickened, strongly amyloid outer layer and a dome-like apex that splits longitudinally during spore release. This ascus type, originally described in members of Xanthoria, Teloschistes, and related genera, differs from the "Lecanora-type" by lacking a specialized discharge mechanism and instead relying on simple rupture for ascospore release. Early electron microscopy investigations of X. parietina helped clarify the functional nature of this ascus and its distinction from other ascus types found in lichenized fungi.
Clinafloxacin is an investigational fluoroquinolone antibiotic. Despite its promising antibiotic activity, the clinical development of clinafloxacin has been hampered by its risk for inducing serious side effects.
Sources: en.wikipedia.org
Technetium-99 produces the largest amount of LLFP radioactivity. It emits beta particles of low to medium energy but no gamma rays, so has little hazard on external exposure, but only if ingested. However, technetium's chemistry allows it to form anions (pertechnetate, TcO4−) that are relatively mobile in the environment. Tin-126 has a large decay energy (due to its following short half-life decay product) and is the only LLFP that emits energetic gamma radiation, which is an external exposure hazard. However, this isotope is produced in very small quantities in fission by thermal neutrons, so the energy per unit time from 126Sn is only about 5% as much as from 99Tc for U-235 fission, or 20% as much for 65% U-235+35% Pu-239. Fast fission may produce higher yields. Tin is an inert metal with little mobility in the environment, helping to limit health risks from its radiation. Selenium-79 is produced at low yields and emits only weak radiation. Its decay energy per unit time should be only about 0.2% that of Tc-99. Zirconium-93 is produced at a relatively high yield of about 6%, but its decay is 7.5 times slower than Tc-99, and its decay energy is only 30% as great; therefore its energy production is initially only 4% as great as Tc-99, though this fraction will increase as the Tc-99 decays. 93Zr does produce gamma radiation, but of a very low energy, and zirconium is relatively inert in the environment.
== History == Methaqualone was first synthesized in India in 1951 by Indra Kishore Kacker and Syed Husain Zaheer, who were conducting research on finding new antimalarial medications. In 1962, methaqualone was patented in the United States by Wallace and Tiernan. By 1965, it was the most commonly prescribed sedative in Britain, where it has been sold legally under the names Malsed, Malsedin, and Renoval. In 1965, a methaqualone/antihistamine combination was sold as the sedative drug Mandrax in Europe, by Roussel Laboratories (now part of Sanofi S.A.). In 1972, it was the sixth-bestselling sedative in the US, where it was legal under the brand name Quaalude. Sold in the United States under the brand name Quaalude, methaqualone was moved to Schedule I in 1984 after prescription controls failed to curb diversion. Quaalude in the United States was originally manufactured in 1965 by the pharmaceutical firm William H. Rorer, Inc., based in Fort Washington, Pennsylvania. The drug name "Quaalude" is a portmanteau, combining the words "quiet interlude" and shared a stylistic reference to another drug marketed by the firm, Maalox. In 1978, Rorer sold the rights to manufacture Quaalude to the Lemmon Company of Sellersville, Pennsylvania. At that time, Rorer chairman John Eckman commented on Quaalude's bad reputation stemming from illegal manufacture and use of methaqualone, and illegal sale and use of legally prescribed Quaalude: "Quaalude accounted for less than 2% of our sales, but created 98% of our headaches." Both companies still regarded Quaalude as an excellent sleeping drug.
Amikacin Amoxicillin/clavulanic acid (amoxicillin + clavulanic acid) Bedaquiline Clofazimine Cycloserine Delamanid Ethambutol Ethambutol/isoniazid/pyrazinamide/rifampicin (ethambutol + isoniazid + pyrazinamide + rifampicin) Ethambutol/isoniazid/rifampicin (ethambutol + isoniazid + rifampicin) Ethionamide Isoniazid Isoniazid/pyrazinamide/rifampicin (isoniazid + pyrazinamide + rifampicin) Isoniazid/rifampicin (isoniazid + rifampicin) Isoniazid/rifapentine (isoniazid + rifapentine) Levofloxacin Linezolid Meropenem Moxifloxacin P-aminosalicylic acid (p-aminosalicylate sodium) Pretomanid Pyrazinamide Rifabutin Rifampicin Rifapentine Streptomycin
Trent Reznor of Nine Inch Nails said in the 2010 documentary Rush: Beyond the Lighted Stage that Rush is one of his favourite bands, and he has also cited the band's early 1980s period in particular as a major influence on him in regard to incorporating keyboards and synthesizers into hard rock. Rush had been eligible for nomination into the Rock and Roll Hall of Fame since 1998. The band was nominated for entry in 2012, and their induction was announced on December 11, 2012. A reason for their previous exclusion may have been their genre. USA Today writer Edna Gundersen criticized the Hall of Fame for excluding some genres, including progressive rock. Supporters cited the band's accomplishments, including longevity, proficiency, and influence, as well as commercial sales figures and RIAA certifications. In the years before induction, Lifeson expressed his indifference toward the perceived slight, saying, "I couldn't care less. Look who's up for induction; it's a joke". In his acceptance speech on the occasion of Rush's induction into the Roll Hall of Fame on April 18, 2013, Lifeson spontaneously recited his prepared text in "blah blah blah" speech, annoying his band fellows and confusing the audience. On April 24, 2010, the documentary Rush: Beyond the Lighted Stage, directed by Scot McFadyen and Sam Dunn, premiered at the Tribeca Film Festival. It received the Tribeca Film Festival Audience Award. The film was nominated for Best Long Form Music Video at the 53rd Grammy Awards, losing to When You're Strange, a documentary about The Doors.
On 24 December 1944, the 82nd Airborne Division with an official strength of 8,520 men was facing off against a vastly superior combined force of 43,000 men and over 1,200 armored fighting and artillery vehicles and pieces. Due to these circumstances, the 82nd Airborne Division was forced to withdrawal for the first time in its combat history. The Germans pursued their retreat with the 2nd and 9th SS Panzer Divisions. The 2nd SS Panzer Division Das Reich engaged the 82nd until 28 December when it and what was left of the 1st SS Panzer Division Leibstandarte were ordered to move south to meet General George Patton's forces attacking in the area of Bastogne. Some units of the 9th SS Panzer including the 19th Panzer Grenadier Regiment stayed and fought the 82nd. They were joined by the 62nd Volksgrenadier Division. The 9th SS Panzer tried to breakthrough by attacking the 508 and 504 PIR positions, but ultimately failed. The failure of the 9th and 2nd SS Panzer Divisions to break through the 82nd lines marked the end of the German offensive in the northern shoulder of the Bulge. The German objective now became one of defense.
Sources: en.wikipedia.org
The UCIL factory was built in 1969 to produce the pesticide Sevin (UCC's brand name for carbaryl) using methyl isocyanate (MIC) as an intermediate. An MIC production plant was added to the UCIL site in 1979. The chemical process employed in the Bhopal plant had methylamine reacting with phosgene to form MIC, which was in turn reacted with 1-naphthol to form the final product, carbaryl. Another manufacturer, Bayer, also used this MIC-intermediate process at the chemical plant once owned by UCC at Institute, West Virginia in the United States. After the Bhopal plant was built, other manufacturers (including Bayer) produced carbaryl without MIC, though at a greater manufacturing cost. UCIL's process differed from the MIC-free routes used elsewhere, in which the same raw materials were combined in a different manufacturing order, with phosgene initially reacting with 1-naphthol to form a chloroformate ester, which was later reacted with methylamine. In the early 1980s, although the demand for pesticides had fallen, production continued leading to an accumulation of unused MIC at the Bhopal site.
=== Neurodegenerative disorders === Huntington disease. No reliable conclusion could be drawn regarding the effectiveness of THC or oral cannabis extract in treating the symptoms of Huntington disease as the available trials were too small to reliably detect any difference Parkinson's disease. Based on a single study, oral CBD extract was rated probably ineffective in treating levodopa-induced dyskinesia in Parkinson's disease. Alzheimer's disease. A 2009 Cochrane Review found insufficient evidence to conclude whether cannabis products have any utility in the treatment of Alzheimer's disease.
=== Investment costs === Investment costs for multipurpose plants are high in comparison with product output. However, they vary considerably, depending on the location, size of equipment and degree of sophistication (e.g., automation, containment, quality of equipment, complexity of infrastructure). An example for a cGMP multipurpose plant built in the US is shown in Table 9. The investment cost of $21 million comprises just the equipment and installation. The building, property and external services are excluded. For comparison purposes, the investment cost per m3 reactor volume is used. In this case, it is $0.9 million. The amount includes the cost of the reaction vessel itself plus an equitable part of the ancillary equipment, like feeding tanks, piping, pumps & process control. If larger or smaller reactors were installed, the unit cost per m3 would decrease or decrease with the exponent 0.5, respectively. Hence, by increasing the equipment size, manufacturing costs on a per kilogram (kg−1) basis typically decrease substantially. Costs for a plant that is used for the production of only non regulated intermediates would be substantially lower. Pharma companies tend to spend up to ten times more for a plant with the same capacity. In contrast, investment costs in developing countries, particularly in India or China, are considerably lower.
== External links == "Carol Robinson's Interview with Denis Noble". YouTube. voicesfromoxfordUK. 18 December 2013. (See Denis Noble.) "A New Phase for Structural Biology – with Carol Robinson". YouTube. The Royal Institution. 6 July 2016. "Mass spectrometry: From ribosomes to receptors | Prof Dame Carol Robinson DBE FRS FMedSci". YouTube. Cambridge SciSoc. 26 March 2021. "Carol Vivien, DBE, FRS, FMedSci ~ 10/14/2020 – Physiology Bashour Speaker". YouTube. UTSW Department of Physiology. 29 March 2021. "JACS in Conversation with Professor Dame V. Robinson". YouTube. ACS Productions. 7 September 2021. (interview conducted by Erick M. Carreira)
Adrenodoxin-NADP+ reductase (EC 1.18.1.6, adrenodoxin reductase, nicotinamide adenine dinucleotide phosphate-adrenodoxin reductase, ADR, NADPH:adrenal ferredoxin oxidoreductase) is an enzyme with systematic name adrendoxin:NADP+ oxidoreductase. This enzyme catalyses the following chemical reaction
Sources: en.wikipedia.org
It is a synthetic seven-amino-acid peptide modeled on alpha-melanocyte-stimulating hormone. It carries two non-natural substitutions and a cyclic bridge that increase its stability relative to the natural hormone. It circulates as a research chemical and is not an approved medicine.
Melanotan-1, also called afamelanotide, is a shorter linear analog with a different amino acid sequence and no lactam ring. It has been evaluated in formal clinical programs, while melanotan-2 has not. The two are distinct molecules and are not interchangeable.
No. Bremelanotide is a related but distinct cyclic peptide that reached approved status for one specific clinical indication. Melanotan-2 is a separate molecule with its own sequence and properties. Shared ancestry in the melanocortin family does not make them the same substance.
No. Melanotan-2 is manufactured synthetically. The naturally occurring peptide in the same family is alpha-melanocyte-stimulating hormone, which the body produces as part of normal endocrine and neural signalling.