The short version of melanocortin receptor fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-12-08 and is reviewed periodically as new material appears.
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.
Two structural changes distinguish the synthetic peptide from the natural hormone. A norleucine residue replaces methionine at one position, and a D-configured phenylalanine replaces the natural L-form at another. Both substitutions slow enzymatic breakdown, which extends the molecule's persistence relative to the parent hormone. The lactam bridge further constrains the backbone into a stable conformation. These features are standard design strategies in peptide chemistry and are not unique to this compound; they appear across many research peptides built for improved stability.
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.
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.
| 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 |
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.
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.
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.
Melanotan-2 is a synthetic linear peptide built from seven amino acids arranged in a short chain. Its sequence is commonly written as Ac-Nle-Asp-His-D-Phe-Arg-Trp-Lys-NH2, which includes a modified N-terminus and an amidated C-terminus. The molecule belongs to the melanocortin family and acts as a receptor agonist. Structural features such as the D-phenylalanine residue and the Nle substitution are associated with increased stability against enzymatic degradation relative to the natural parent peptide.
=== Inland taipan === The inland taipan (Oxyuranus microlepidotus) is considered the most venomous snake in the world with a murine LD50 value of 0.025 mg/kg SC. Ernst and Zug et al. 1996 list a value of 0.01 mg/kg SC, which makes it the most venomous snake in the world in their study too. They have an average venom yield of 44 mg. Bites from this species have a mortality rate of 80% if left untreated, although it is very rare for this species to bite. This species is known to be a very shy, reclusive and a laid-back snake that will nearly always slither away from disturbance. It is not an aggressive species and rarely strikes. No recorded incidents have been fatal since the advent of the monovalent (specific) antivenom therapy.
==== Intercity coaches ==== Intercity bus service to and from Penn Station is provided by Vamoose Bus, Tripper Bus, and Go Buses. Vamoose Bus runs buses from a stop near Penn Station to Bethesda, Maryland; Arlington, Virginia; and Lorton, Virginia. Tripper Bus runs buses from a stop near Penn Station to Bethesda, Maryland and Arlington, Virginia. Go Buses runs buses from a stop near Penn Station to Newton, Massachusetts and Cambridge, Massachusetts. In 2021, the private parking lot at 300 West 31st Street (the southwest corner of 8th Avenue) was established as a major Midtown Manhattan hub stop for FlixBus. Most intercity and commuter bus services to and from midtown Manhattan use the Port Authority Bus Terminal, located approximately 0.5 miles (0.8 kilometers) to the north of Penn Station.
intensive farming methods requires 214 liters (47 imp gal; 57 U.S. gal) of water; using hydroponics, 70 liters (15 imp gal; 18 U.S. gal); and only 20 liters (4.4 imp gal; 5.3 U.S. gal) using aeroponics. Hydroponic cultures lead to highest biomass and protein production compared to other growth substrates, of plants cultivated in the same environmental conditions and supplied with equal amounts of nutrients. Hydroponics is not only used on earth, but has also proven itself in plant production experiments in Earth orbit.
overseeing the performance of the National Government institutions; approving plans, programmes and policies of the National Government; approving budgets; ratifying international treaties, conventions and agreements; adopting resolutions on matters of public concern; summoning Ministers to answer questions of members of the Assembly on matters related to their ministries; interrogating Ministers about their performance or the performance of their ministries; approving appointments as required by the Transitional Constitution or the law; casting a vote of no confidence against the Vice President and any Minister; enacting legislation to regulate the conditions and terms of service of the Judiciary and its oversight mechanisms; and performing any other function as determined by the Transitional Constitution or the law.
Sources: en.wikipedia.org
In 1998, Firehouse Subs surpassed 10 locations, and later that year opened the first location outside of Florida. In 2000, the founders decided to take a different approach, using consultants to plan franchise growth. They were able to set up financing for potential franchisees. The second wave of franchising began in 2001. In 2011, Firehouse Subs opened its first franchises in the U.S. territory of Puerto Rico, via local franchisee Caribbean Restaurants. By 2012 the company reached 500 locations, ending the year with nearly 600. In July 2016, Firehouse Subs opened its 1,000th location. In 2015, Firehouse Subs opened its first locations in Canada, with its first location opening in Oshawa, Ontario in October with franchisee OnFire Restaurant Group. Currently, the group operates 50 Canadian restaurants, with plans to open a total of 90 in Ontario alone. The chain also launched a loyalty program. In June 2017, Firehouse Subs opened its first airport location at Jacksonville International. In December 2017, the brand's second airport location opened at Orlando International. In April 2018, the chain opened its first on-campus location at Western New England University. In 2020 the chain opened a location at Jacksonville's Baptist Medical Center. On November 15, 2021, Burger King parent Restaurant Brands International announced that it would acquire Firehouse Subs for $1 billion. The acquisition was completed on December 15, 2021. On June 22, 2023, Firehouse Subs opened its first location outside North America in Zurich, Switzerland.
Together with his Ph.D. student Hung Tung Tran Prof. Rode developed the practical and flexible visualization software Molvision® capable of interactively analyzing dynamic simulation data. In 2003 Dr. Tran was awarded with a European Innovation Award for the development of this program.
Stores that independently operate locations include Ahold Delhaize, Barnes & Noble, Target Corporation, Albertsons and, more recently, Publix stores. In the EMEA (Europe, Middle East, and Africa) markets, Starbucks operates a franchising program. Different from the licensing program in which existing corporations may apply to operate a Starbucks kiosk within an existing store, franchises can enable new, freestanding stores.
=== Sézary cells === Sézary cells are bigger than Lutzner cells, and have an overabundance of cellular folds in the membrane. They are also considered over pigmented and have large cerebriform nuclei with a small cytoplasm. Sézary cells are found in both mycosis fungoides and Sézary disease.
== In fiction == The atoms had begun to stack and lock—to freeze—in a different fashion. The liquid that was crystallizing hadn't changed, but the crystals it was forming were, as far as industrial applications went, pure junk... The seed, which had come from God-only-knows where, taught the atoms the novel way in which to stack and lock, to crystallize, to freeze. In the 1963 novel Cat's Cradle, by Kurt Vonnegut, the narrator learns about ice-nine, an alternative structure of water that is solid at room temperature and acts as a seed crystal upon contact with ordinary liquid water, causing that liquid water to instantly freeze and transform into more ice-nine. Later in the book, a character frozen in ice-nine falls into the sea. Instantly, all the water in the world's seas, rivers, and groundwater transforms into solid ice-nine, leading to a climatic doomsday scenario.
Sources: en.wikipedia.org
Isoguanine and isocytosine, which have their amine and ketone inverted compared to standard guanine and cytosine. They are not used probably as tautomers are problematic for base pairing, but isoC and isoG can be amplified correctly with PCR even in the presence of the 4 canonical bases. Diaminopyrimidine and xanthine, which bind like 2-aminoadenine and thymine but with inverted structures. This pair is not used as xanthine is a deamination product.
==== Thermoregulation ==== Hair length is not a factor in thermoregulation: for example, some tropical mammals such as sloths have the same length of fur length as some arctic mammals but with less insulation; and, conversely, other tropical mammals with short hair have the same insulating value as arctic mammals. The denseness of fur can increase an animal's insulation value, and arctic mammals especially have dense fur; for example, the musk ox has guard hairs measuring 30 cm (12 in) as well as a dense underfur, which forms an airtight coat, allowing them to survive in temperatures of −40 °C (−40 °F). Some desert mammals, such as camels, use dense fur to prevent solar heat from reaching their skin, allowing the animal to stay cool; a camel's fur may reach 70 °C (158 °F) in the summer, but the skin stays at 40 °C (104 °F). Aquatic mammals, conversely, trap air in their fur to conserve heat by keeping the skin dry.
== Further reading == Jablonski, S.; Leonard, R.M.; National Library of Medicine (U.S.) (1961). Russian Drug Index. Public Health Service publication. U.S. Department of Health, Education, and Welfare, Public Health Service. Retrieved 5 October 2024.
=== Vocals === Toufouti did not consider himself a singer when recording 2010's Leaving Paris. At that time, he was mainly inspired by voices he described as "a bit broken, a bit gravelly" over stoner and bluesy riffs, mentioning the band Down. On Hope /// Dope /// Rope, his bandmates encouraged him to abandon that vocal style and sing, telling him, "think crooner", which led him to learn to "desaturate" his voice. Toufouti felt that his voice retained a certain harshness on this album, though it was "clearer". On subsequent albums, he continued the improvements he had begun to reduce saturation as much as possible.
Many websites that allow explicit AI generated images or videos have been created, and this has been used to create illegal content, such as rape, child sexual abuse material, necrophilia, and zoophilia.
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.
It is a synthetic cyclic peptide designed as an analog of alpha-melanocyte-stimulating hormone. It acts on melanocortin receptors and is best known from research into pigmentation. It is not an approved pharmaceutical product.