The short version of cyclic heptapeptide fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-07-21 and is reviewed periodically as new material appears.
Pharmacologically, melanotan-2 behaves as a non-selective agonist across the melanocortin receptor family. Binding at MC1R on dermal melanocytes promotes eumelanin synthesis, which underlies the tanning response described in early human work. Activity at the centrally expressed MC4R receptor is associated with reported effects on appetite and erectile function. Because the peptide does not discriminate strongly among receptor subtypes, attributing any single observed effect to one receptor pathway is generally not possible without selective antagonists or receptor knockout models.
Research interest has centred on photoprotection and pigmentation, with a smaller body of work on appetite and sexual function. Published human data remain limited to small, frequently uncontrolled studies, and the compound has never received marketing approval from a national medicines regulator. Most laboratory work treats it as a pharmacological tool for probing melanocortin signalling in cell culture or animal models. Whether pigmentation changes observed in people translate into measurable protection against ultraviolet-induced DNA damage remains an open question.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone, the naturally occurring peptide involved in pigmentation signalling. Its sequence is conventionally written as Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, with a lactam bridge joining the aspartate side chain to the lysine side chain. The empirical formula is C50H69N15O9 and the monoisotopic mass lies near 1023.5 daltons. N-terminal acetylation and the D-configured phenylalanine both increase resistance to enzymatic breakdown compared with the parent hormone.
Verification of a purchased sample requires documentation linking a batch to a certificate of analysis, and that document should be read for the methods used rather than the headline purity figure. A single chromatographic percentage does not establish identity. Independent laboratories can perform identity and content assays, but no such test establishes that a product is suitable for human use. Claims about efficacy rest largely on small, early studies rather than on replicated controlled trials, and that gap remains open.
Identity testing for a cyclic peptide of this size usually relies on reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The mass spectrum confirms molecular weight, while the chromatographic trace indicates the proportion of related impurities. Tandem mass spectrometry can provide sequence-level information when fragmentation data are compared against a reference standard. Nuclear magnetic resonance is sometimes used to confirm the lactam bridge, although it requires more material and greater operator expertise than routine chromatographic methods.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | Melanotan II; MT-II; N-acetyl-norleucyl-cyclo[Asp-His-D-Phe-Arg-Trp-Lys] amide | Naming follows peptide convention; the numeral distinguishes it from melanotan-1 |
| Molecular formula | C50H69N15O9 | Includes the lactam bridge; no counter-ion assumed |
| Monoisotopic mass | 1023.53 Da | Free base; salts and counter-ions shift the observed value |
| Appearance | White to off-white lyophilised powder | Batch-to-batch colour variation is not itself proof of impurity |
| Typical analytical method | RP-HPLC purity determination with ESI-MS identity confirmation | Retention time alone does not establish sequence identity |
Receptor binding at MC1R on melanocytes raises intracellular cyclic AMP and increases expression of tyrosinase and related enzymes. The downstream result is greater synthesis of eumelanin, the dark pigment, without ultraviolet exposure acting as the trigger. The compound is not selective, however, and also engages MC3R, MC4R and MC5R, which are expressed in the central nervous system and elsewhere. That lack of selectivity is the explanation usually offered for effects reported outside pigmentation, including appetite suppression and nausea. Selectivity remains a central theme in comparative studies of related peptides.
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.
Regulatory treatment varies by country. In the United States, melanotan-2 is not approved for any indication, and products marketed for human use fall outside the approved drug framework. Some other jurisdictions have placed it under prescription controls or listed it as a prohibited or restricted substance. Online listings frequently describe the material as a research chemical, a category that does not carry the same manufacturing and labelling requirements as approved medicines.
Solid peptide material is generally stable when kept cold and dry. Common practice is storage at -20 degrees Celsius or lower, with desiccant and protection from light. Repeated freeze-thaw cycles and exposure to moisture are associated with degradation, aggregation, or loss of material. Once dissolved, stability depends on solvent, concentration, and temperature, and solutions are usually treated as short-lived unless stability data support longer periods. Handling notes typically emphasise minimising time at ambient temperature.
Melanocytes are the pigment-producing cells of the skin, and they carry melanocortin-1 receptors on their surface. When the receptor is activated, cyclic adenosine monophosphate rises inside the cell and raises the activity of enzymes such as tyrosinase, which increases melanin output. Melanotan-2 binds melanocortin-1 receptors in vitro and in animal models, and this binding is generally described as the basis for the tanning effect. Other receptors account for different effects: melanocortin-4 receptors contribute to appetite and erectile signalling, while melanocortin-3 and melanocortin-5 receptors contribute to energy balance and exocrine function.
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 has not received marketing authorisation from major regulatory agencies for any therapeutic indication. Several jurisdictions classify it as a prescription-only medicine or a controlled substance when supplied for human use. Because approved products do not exist, material sold online usually sits outside pharmaceutical supply chains and formal quality oversight. Regulators have issued public notices describing the compound as unapproved. Enforcement varies, and the legal position differs between countries, which complicates any single general statement about its status.
Scientific discussion of Melanotan-2 spans pharmacology, dermatology, and public-health literature. Laboratory studies examine its receptor binding and cellular effects, while clinical reports describe outcomes observed after unregulated use. These two bodies of work differ in rigour and intent. Peer-reviewed trials of the compound as a medicine are limited, so much of the available information comes from case reports and surveillance data. Authors frequently note the gap between experimental findings and real-world use.
According to the operators, the MIC tank pressure gauge had been malfunctioning for roughly a week. Other tanks were used, rather than repairing the gauge. The build-up in temperature and pressure is believed to have affected the magnitude of the gas release. UCC admitted in their own investigation report that most of the safety systems were not functioning on the night of 3 December 1984. The design of the MIC plant, following government guidelines, was "Indianized" by UCIL engineers to maximise the use of indigenous materials and products. Mumbai-based Humphreys and Glasgow Consultants Pvt. Ltd., were the main consultants, Larsen & Toubro fabricated the MIC storage tanks, and Taylor of India Ltd. provided the instrumentation. In 1998, during civil action suits in India, it emerged that the plant was not prepared for problems. No action plans had been established to cope with accidents of this magnitude. This included not informing local authorities of the quantities or dangers of chemicals used and manufactured at Bhopal.
=== Animals === Proteases are used throughout an organism for various metabolic processes. Acid proteases secreted into the stomach (such as pepsin) and serine proteases present in the duodenum (trypsin and chymotrypsin) enable the digestion of protein in food. Proteases present in blood serum (thrombin, plasmin, Hageman factor, etc.) play an important role in blood-clotting, as well as lysis of the clots, and the correct action of the immune system. Other proteases are present in leukocytes (elastase, cathepsin G) and play several different roles in metabolic control. Some snake venoms are also proteases, such as pit viper haemotoxin, which interferes with the victim's blood clotting cascade. Proteases determine the lifetime of other proteins playing important physiological roles like hormones, antibodies, or other enzymes. This is one of the fastest "switching on" and "switching off" regulatory mechanisms in the physiology of an organism. By a complex cooperative action, proteases can catalyze cascade reactions, which result in rapid and efficient amplification of an organism's response to a physiological signal.
Since the 18th century, critics have argued that slavery hinders technological advancement because the focus is on increasing the number of slaves doing simple tasks rather than upgrading their efficiency. For example, it is sometimes argued that, because of this narrow focus, technology in Greece – and later in Rome – was not applied to ease physical labour or improve manufacturing.
Adopted the American Experience table at its sixth convention in Buffalo, New York, in September 1920, but it wasn't until 1923 that it was actuarially sound. Headquarters in Scranton. Local groups are called "branches", and regional groups are called "Districts". National convention meets quadrennially. 20,000 members in 1930, 32,142 in 247 branches in the mid-1960s, and 31,649 in 210 branches in 1979. 30,000 members in 1994. No ritual or secrecy, but there is a pledge. Open to both sexes 16 and up. The 1979 constitution didn't say anything about Polish ancestry. Purchased Sponjnia Farm in 1929 in Waymart, Pennsylvania, and developed it into a home for aged and sick members. Began Warsaw Village in Thornhurst Township, Pennsylvania, in 1948 as summer vacation area. Helped fund Church of Our Lady of Perpetual Help near Zarki, Poland. Their first constitution declared "Religious, political and social convictions may not hinder admission", but has nevertheless been tied to the Polish National Catholic Church. Polish Roman Catholic Union of America Polish Union of America - Founded in 1890. 10,000 members in 1979. 9,000 in 1994. Active in anti-defamation campaigns, provides scholarships, contributes to churches, charities, and educational foundations; also sponsors radio broadcast. Maintains library, museum, speakers bureau, ethnic awareness programs, and vocational placement services. Also runs White Eagle Young Adults Club.
(a) Medial canthus The skin between the nasal dorsum and the medial canthal tendon is uniquely suited to healing by secondary intention; the outcomes often are superior to what is achieved with either skin grafts or skin-flaps and tissue-flaps. Because the medial canthal tendon is affixed to the facial bone, it readily resists the forces of wound contracture; moreover, the animation (movement) of the medial brow also lends resistance to the forces of wound contracture. Furthermore, the medial canthal region is aesthetically hidden by the shadows of the nasal dorsum and of the supraorbital rim, thereby obscuring any differences in the quality of the color and of the texture of the replacement skin (epithelium). Healing by secondary intention (re-epithelialisation) occurs even when the wound extends to the nasal bone. Although the rate of healing depends upon the patient's wound-healing capacity, nasal wounds measuring up to 10 mm in diameter usually heal in at 4-weeks post-operative. Nonetheless, one potential, but rare, complication of this nasal correction approach is the formation of a medial canthal web, which can be corrected with two opposing Z-plasties, technique which relieves the disfiguring tensions exerted by the scar tissue's contracture, its shape, and location on the nose.
Sources: en.wikipedia.org
In March 2002, Yorkshire merged with Tricon Global Restaurants to form Yum! Brands. A few weeks later, Malaysian company KUB took over the franchises in Southeast Asia, aiming to restore its prestige in Malaysia alone and increasing its market share. Subsequently, in January 2003, Yum! announced that A&W and Long John Silver's would move their operational base from Lexington to Louisville, as operating the chains from Lexington was considered "impractical and cost-inefficient", preferring to operate all of its chains from Louisville. Under Yum's management, A&W added franchises with a nostalgic look and modern technology. They have a carhop design with drive-thrus, and some have picnic tables. The chain didn't seek to compete against McDonald's, instead preferring to carve up its own niche. 2004 saw the return of the Papa Burger brand at a restaurant in Dayton - the Burger Family brand originally retired in the United States in the 1980s, being replaced by the Deluxe Burgers - and was the only name of the old line that was reinstated, with the other burgers having new names. In September 2001 the Singapore branch was taken over by KUB, who also oversaw the restaurants in Malaysia. At the time of takeover, it had twelve restaurants, but by November 2002, the number had dwindled to eight. Its restaurants had already been downgraded: the Ang Mo Kio restaurant shut down, the Tampines restaurant refused to repair its air conditioning systems, and cable TV was switched off in all outlets. Food sales had decreased by about 5-12%.
Historically, the birth rate of teenagers peaked in the late 1950s and early 1960s. However, at that time, most teenage parents were married. In the early twenty-first century, nine in ten births to the age group 15-19 are to unmarried mothers. Social norms have changed; it is now not unusual for teenagers to delay or avoid sexual intercourse altogether. Younger teenagers are more likely to practice abstinence than their older counterparts. A report published by the Center for Disease Control and Prevention (CDC) in early 2018 found the number of high school students who have had sex fell from 47% in 2005 down to 41% in 2015, with the most dramatic drop taking place between 2013 and 2015. On top of that, among never-married teens who have had sex, overwhelming majorities reported they used contraception the first time they did it. There are a few reasons for this. First, Millennials and Generation Z are more focused on the consequences of sex than their predecessors were. Second, there has been growing concern over unwanted sexual advances, especially in the wake of the Me-too movement. Writing for The Spectator, Douglas Murray dubbed this the "sexual counter-revolution." Third, as a consequence of the precarious contemporary economy, young adults today are more likely to be living with their parents rather than on their own, with a romantic partner, or a spouse. A 2016 analysis by the CDC discovered that teenage birthrates nosedived between 1991, when they reached a crisis point, and 2014, when they dropped by 60%, a record low.
== Professional organizations for clinical data management == International Network of Clinical Data Management Associations (INCDMA) aims at the promotion of collaboration among clinical data management groups around the world. It is an international forum for discussion of and feedback on current topics of relevance to the discipline of CDM. It is composed of members the boards of the SCDM, ACDM, DMB (France), PSDM (The Netherlands) who participate in the INCDMA proceedings and funding. It also regroups DM leaders and subject matter experts from Europe, North America, Israel, Japan, China and Australia. The Association for Clinical Data Management (ACDM) is a global organization founded in 1987 and is Empowering Excellence in Clinical Data Management. The ACDM represents a vibrant community of dedicated clinical research professionals who are passionate about enhancing the drug development process through fostering an environment that encourages continuous learning and the practical application of modern Clinical Data Management practices. With over 35 years of service to the data management community, the ACDM's unwavering commitment is to provide clear and effective platforms for its members to network, share experiences, and stay abreast of the latest regulations and standards in Clinical Data Management. Along with supporting members on their professional development journeys, offering opportunities to gain the skills and insights needed to excel in their careers and shape the future of data management.
Below about 100 °C, volatiles, including some water, evaporate. Heat-sensitive substances, such as vitamin C and proteins, may partially change or decompose already at this stage. At about 100 °C or slightly higher, any remaining water that is merely absorbed in the material is driven off. This process consumes a lot of energy, so the temperature may stop rising until all water has evaporated. Water trapped in crystal structure of hydrates may come off at somewhat higher temperatures. Some solid substances, like fats, waxes, and sugars, may melt and separate. Between 100 and 500 °C, many common organic molecules break down. Most sugars start decomposing at 160–180 °C. Cellulose, a major component of wood, paper, and cotton fabrics, decomposes at about 350 °C. Lignin, another major wood component, starts decomposing at about 350 °C, but continues releasing volatile products up to 500 °C. The decomposition products usually include water, carbon monoxide CO and/or carbon dioxide CO2, as well as a large number of organic compounds. Gases and volatile products leave the sample, and some of them may condense again as smoke. Generally, this process also absorbs energy. Some volatiles may ignite and burn, creating a visible flame. The non-volatile residues typically become richer in carbon and form large disordered molecules, with colors ranging between brown and black. At this point the matter is said to have been "charred" or "carbonized".
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone, containing seven amino acids with a lactam ring and a D-configured phenylalanine residue. It is supplied as a lyophilised powder for laboratory research.
The natural hormone is a linear tridecapeptide that is rapidly degraded in circulation. Melanotan-2 is shortened, cyclised, N-terminally acetylated, and carries a D-amino acid substitution, all of which slow enzymatic breakdown.
No national medicines regulator has approved melanotan-2 for therapeutic or cosmetic use. In several jurisdictions it is treated as an unapproved prescription medicine, and its legal classification differs from country to country.
Mass spectrometry combined with liquid chromatography provides both molecular weight confirmation and a measure of related impurities. Tandem mass spectrometry adds sequence information. A purity percentage reported without a mass measurement does not confirm what the material is.