If you have been reading about MC1R 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.
Updated 2026-01-16. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Human data remain limited and mostly short-term. Reports describe small trials and observational accounts rather than large controlled studies, so questions about dose-response relationships and long-term effects on melanocytes stay open. Whether repeated exposure alters naevus behaviour is not settled in the published record. Researchers also note that self-administered use outside clinical settings makes actual exposure difficult to quantify. Statements about efficacy and safety should therefore be read as preliminary rather than established.
Melanotan II is a synthetic cyclic heptapeptide that acts as an agonist at melanocortin receptors. It was designed as a structural analogue of alpha-melanocyte-stimulating hormone, the endogenous peptide involved in pigment production. The analogue carries a lactam bridge that constrains the ring and slows enzymatic breakdown relative to the native hormone. In research literature it appears under several abbreviations, and naming conventions are not fully standardized. Published descriptions usually place it within the broader melanocortin agonist family.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Analog of alpha-melanocyte-stimulating hormone |
| Primary receptor family | Melanocortin receptors MC1R through MC5R | Binding is not subtype-selective |
| Development period | 1980s | Synthesized during pigmentation and appetite research |
| Regulatory status | Not an approved medicine | No major regulator has authorized human use |
| Related compound | Afamelanotide | Linear analog studied for photoprotection |
The peptide acts as a non-selective agonist at melanocortin receptors, showing affinity for MC1R, MC3R, MC4R and MC5R. Activation of MC1R on melanocytes drives the conversion of tyrosine into melanin and shifts production toward the darker eumelanin form. MC4R signalling in the central nervous system is linked to appetite and energy balance, which helps explain why reduced food intake appeared in early human studies. Effects on MC4R and on vascular tone also account for the erectile responses recorded as unexpected findings in those same trials.
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.
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.
The peptide was developed during the 1980s by researchers investigating melanocortin signalling and skin pigmentation pathways. Early work focused on analogues of alpha-melanocyte-stimulating hormone that would resist enzymatic breakdown more effectively than the parent molecule. Melanotan-2 emerged from that programme as a shortened, cyclised variant. Reports describing its synthesis and receptor activity later appeared in the scientific literature. Commercial availability grew through unregulated channels rather than through pharmaceutical approval.
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.
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.
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 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.
In February 1946, he also forced the French to surrender all of their concessions and ports in China, including Shanghai, in exchange for Chinese troops withdrawing from northern Indochina and allowing French troops to reoccupy the region starting in March 1946. This left the VNQDĐ without support, and they were suppressed by Việt Minh and French troops. The Việt Minh massacred thousands of VNQDĐ members and other nationalists in a large-scale purge.
== Bibliography == Pirie, N. W (1971). "Leaf protein:its agronomy, preparation, quality and use". IBP Handbook. Vol. 20. Blackwell Scientific Publications. Pirie, N. W (1975). "Leaf protein: a beneficiary of tribulations". Nature. 253 (5489): 239–241. Bibcode:1975Natur.253..239P. doi:10.1038/253239a0. S2CID 4196894.
The company also announced in March 2020 a partnership with Welldoc to integrate G6 CGM data with BlueStar, a digital platform for diabetes management. In November 2024, Dexcom announced a "strategic partnership" and data exchange with Oura.
==== Humidifier ==== A humidifier can be used to prevent low indoor humidity during winter (especially with indoor heating), and dry season. Commonly, patients with seborrhoeic dermatitis experience mild redness, scaly skin lesions and in some cases hair loss. Low humidity can cause adverse health effects and may cause atopic dermatitis, and seborrhoeic dermatitis.
In 1984, Applied Biosystems sales revenue tripled to over US$18 million, with a second yearly profit, and with over 200 employees. Services included synthesizing custom DNA and protein fragments, and the sequencing of protein samples submitted from customers. The third major instrument made by Applied, the Model 430A Peptide Synthesizer, was introduced. In 1985, Applied Biosystems sales revenue grew nearly 70% to over US$35 million, with a third yearly profit. Two new products included the Model 380B DNA Synthesizer and the 381A DNA Synthesizer. That year the company went international for the first time, when it established a wholly owned subsidiary in Great Britain to save shipping costs on chemical sales, which overall by then accounted for 17% of sales. Also in 1985, Applied Biosystems acquired Brownlee Labs, a manufacturer of columns and pumps for high-performance liquid chromatography (HPLC) systems, after its founder, Robert Brownlee was diagnosed with AIDS-related complex in 1984. Brownlee's technology brought the new on-line 120A PTH Amino Acid Analyzer. However, Brownlee then began a new company, which was viewed by Applied as a competitor. In 1989 Applied and Brownlee settled in a lawsuit over the conflict. As late as 1990, Brownlee publicly discussed what had been his contributions in the rocky relationship with Applied, before he died early the next year. In 1986, Andre Marion became president and chief executive officer. Sales revenue increased by 45% to nearly US$52 million. The company introduced six new products, totalling eleven automated instruments.
Sources: en.wikipedia.org
=== Business === Suga is also a founder of PeptiDream Inc. Tokyo, a publicly traded biopharmaceutical start-up company responsible for discovering and developing non-standard peptide therapeutics in addition to addressing unmet medical needs as well as investigating peptide drug conjugates (PDC), peptides, and small molecule-based drugs. It is traded publicly on the Tokyo First Stock Exchange Market (the market capitalization is over JY 600 billions), which has many partnerships with pharmaceutical companies in worldwide. Suga is chair of the editorial board at RSC Chemical Biology and associate editor at Angewandte Chemie.
== Pathology == When initially identified, camptocormia was classified as a psychogenic disease. Although the condition is sometimes a psychogenic manifestation, camptocormia typically originates from either muscular or neurological diseases. However, due to the wide variety of pathologies resulting in camptocormia, there is no singular cause that is most influential for the condition.
Appearing to meet the concern, in Überseering BV v Nordic Construction GmbH the Court of Justice held that a German court could not deny a Dutch building company the right to enforce a contract in Germany, simply because it was not validly incorporated in Germany. Restrictions on freedom of establishment could be justified by creditor protection, labour rights to participate in work, or the public interest in collecting taxes. But in this case denial of capacity went too far: it was an "outright negation" of the right of establishment. Setting a further limit, in Cartesio Oktató és Szolgáltató bt the Court of Justice held that because corporations are created by law, they must be subject to any rules for formation that a state of incorporation wishes to impose. This meant the Hungarian authorities could prevent a company from shifting its central administration to Italy, while it still operated and was incorporated in Hungary. Thus, the court draws a distinction between the right of establishment for foreign companies (where restrictions must be justified), and the right of the state to determine conditions for companies incorporated in its territory, although it is not entirely clear why.
The administration of feed supplements based on Chinese rhubarb or with prebiotics and probiotics had no discernible effect in clinical studies; there is only one small manufacturer's study on the activated charcoal-based absorber for indole in the large intestine (trade name Porus one), but this did not include any cats with kidney disease.
Sources: en.wikipedia.org
The agreement specified that this agreement was only with Amat-Mamu, and no other person could lay claim to Belessunu's estate by providing for her. Two years after the agreement was made, two of Belessunu's cousins and fellow nadītus—Amat-Šamaš and Nīši-īnīšu—laid claim to the fields. The mayor of Sippar, Zimri-Erah, ruled that the inheritance was rightfully Belessunu's. The cousins were penalized for making a false claim over property, and they were forced to give Amat-Mamu a tablet that relinquished their claims. Professor Rivkah Harris speculated that Belessunu passed over her cousins in favor of Amat-Mamu because Amat-Mamu was a member of a wealthy family and therefore better able to support Belessunu during her life.
== Administrative division == The Russian Empire divided the former territories of the Commonwealth it obtained (Rech Pospolitaya in Russian) by creating or enlarging the following guberniyas (Tsarist governorates, or provinces).
In 2005, Neptune Resources NL, a mineral exploration company, applied for and was granted 35,000 km2 of exploration rights over the Kermadec Arc in New Zealand's Exclusive Economic Zone to explore for seafloor massive sulfide deposits, a potential new source of lead-zinc-copper sulfides formed from modern hydrothermal vent fields. The discovery of a vent in the Pacific Ocean offshore of Costa Rica, named the Medusa hydrothermal vent field (after the serpent-haired Medusa of Greek mythology), was announced in April 2007. The Ashadze hydrothermal field (13°N on the Mid-Atlantic Ridge, elevation -4200 m) was the deepest known high-temperature hydrothermal field until 2010, when a hydrothermal plume emanating from the Beebe site (18°33′N 81°43′W, elevation -5000 m) was detected by a group of scientists from NASA Jet Propulsion Laboratory and Woods Hole Oceanographic Institution. This site is located on the 110 km long, ultraslow spreading Mid-Cayman Rise within the Cayman Trough. In early 2013, the deepest known hydrothermal vents were discovered in the Caribbean Sea at a depth of almost 5,000 metres (16,000 ft). Oceanographers are studying the volcanoes and hydrothermal vents of the Juan de Fuca mid ocean ridge where tectonic plates are moving away from each other. Hydrothermal vents and other geothermal manifestations are currently being explored in the Bahía de Concepción, Baja California Sur, Mexico.
Sources: en.wikipedia.org
No regulator in a major market has approved it for human use. It appears in research settings and in products marketed outside pharmacy channels. Legal status for personal possession varies by country.
Afamelanotide is a linear analog that has received approval in some jurisdictions for a specific photoprotection indication. Melanotan II is cyclic and less selective across melanocortin receptors. The two are related but are not interchangeable in regulatory or clinical terms.
A compound that activates several receptor subtypes may produce effects beyond pigmentation. Selectivity influences which tissues respond and shapes the side-effect profile described in reports. Designing subtype-selective analogs is a stated goal of melanocortin research.
It is a synthetic cyclic heptapeptide and a non-selective melanocortin receptor agonist. Structurally it is modelled on alpha-melanocyte-stimulating hormone, a peptide that occurs naturally in the body.