If you have been reading about cyclic heptapeptide 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 2025-12-06. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
Analytical confirmation of identity relies on mass spectrometry, most often coupled to liquid chromatography. Reversed-phase high-performance liquid chromatography separates the peptide from related impurities and provides a purity estimate based on peak area. Electrospray ionization mass spectrometry then confirms the expected molecular mass, while tandem mass spectrometry can map the fragment sequence. For research-grade material, these two techniques together form the standard minimum. Purity figures reported by vendors are frequently not traceable to an independent laboratory.
Independent verification is central to quality control because the compound is not produced under pharmaceutical manufacturing standards. Third-party laboratories can measure purity, identity, residual solvents, and microbial contamination, though the scope of testing varies between services. Reported analyses of vendor samples have shown batch-to-batch variation in peptide content and the presence of truncated or oxidized species. How much of this variation reflects synthesis conditions versus storage and shipping is not well characterized. No harmonized reference standard exists for the material as sold.
| Property | Value | Notes |
|---|---|---|
| Compound class | Synthetic cyclic heptapeptide | Alpha-MSH analogue containing a D-phenylalanine residue |
| Molecular formula | C50H69N15O9 | Average molecular mass approximately 1024.2 g/mol |
| Appearance | White to off-white lyophilised powder | Normally supplied as a freeze-dried solid in a sealed vial |
| Solubility | Freely soluble in water and polar solvents | Dissolves readily in aqueous buffers and in alcohol-water mixtures |
| Receptor targets | MC1R, MC3R, MC4R, MC5R | Acts as a non-selective melanocortin receptor agonist |
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.
Identity and purity are assessed mainly by reversed-phase high-performance liquid chromatography with ultraviolet detection, often paired with mass spectrometry. Retention time supports identity, while the mass spectrum confirms the molecular weight of the intact peptide. Purity is frequently reported as a percentage of total peak area, a figure that depends on the wavelength, column and gradient used. Impurity profiling may also look for truncated sequences, oxidised forms and residual counterions. Amino acid analysis and peptide mapping provide orthogonal confirmation when required.
Regulatory status varies by jurisdiction, and the substance is frequently described as unapproved for therapeutic use. Some authorities classify it alongside prescription-only medicines or controlled categories, while others address it through general consumer protection rules. Analytical surveys have reported mismatches between label claims and measured content in products sold online, although the scope of such testing is limited. Whether these discrepancies are widespread remains an open question. Discussion in the literature therefore tends to combine chemistry, supply-chain observation and policy analysis.
Worldwide or global organizations: Generally open to nations worldwide as long as certain criteria are met. This category includes the United Nations and its specialized agencies, World Health Organization, International Telecommunication Union, World Bank, and International Monetary Fund. It also includes globally operating intergovernmental organizations that are not an agency of the UN, including for example: the Hague Conference on Private International Law, an operating intergovernmental organization based in The Hague that pursues the progressive unification of private international law; the International Criminal Court that adjudicates crimes defined under the Rome Statute; and the CGIAR (formerly the Consultative Group for International Agricultural Research), a global partnership that unites intergovernmental organizations engaged in research for a food-secured future. Cultural, linguistic, ethnic, religious or historical organizations: Open to members based on some cultural, linguistic, ethnic, religious or historical link. Examples include the Commonwealth of Nations, Arab League, Organisation internationale de la Francophonie, Community of Portuguese Language Countries, Organization of Turkic States, International Organization of Turkic Culture, Organisation of Islamic Cooperation, and Commonwealth of Independent States (CIS). Economic organizations: Based on macro-economic policy goals. Some are dedicated to free trade and reduction of trade barriers, e.g. World Trade Organization, International Monetary Fund. Others are focused on international development.
== Use == Dehydroascorbic acid has been used as a vitamin C dietary supplement. As a cosmetic ingredient, dehydroascorbic acid is used to enhance the appearance of the skin. It may be used in a process for permanent waving of hair and in a process for sunless tanning of skin. In a cell culture growth medium, dehydroascorbic acid has been used to assure the uptake of vitamin C into cell types that do not contain ascorbic acid transporters. As a pharmaceutical agent, some research has suggested that administration of dehydroascorbic acid may confer protection from neuronal injury following an ischemic stroke. The literature contains many reports on the antiviral effects of vitamin C, and one study suggests dehydroascorbic acid has stronger antiviral effects and a different mechanism of action than ascorbic acid. Solutions in water containing ascorbic acid and copper ions and/or peroxide, resulting in rapid oxidation of ascorbic acid to dehydroascorbic acid, have been shown to possess powerful but short-lived antimicrobial, antifungal, and antiviral properties, and have been used to treat gingivitis, periodontal disease, and dental plaque. A pharmaceutical product named Ascoxal is an example of such a solution used as a mouth rinse as an oral mucolytic and prophylactic agent against gingivitis. Ascoxal solution has also been tested with positive results as a treatment for recurrent mucocutaneous herpes, and as a mucolytic agent in acute and chronic pulmonary disease such as emphysema, bronchitis, and asthma by aerosol inhalation.
=== Additional background === Before translation can begin, the process of binding a specific amino acid to its corresponding tRNA must occur. This reaction, called tRNA charging, is catalyzed by aminoacyl tRNA synthetase. A specific tRNA synthetase is responsible for recognizing and charging a particular amino acid. Furthermore, this enzyme has special discriminator regions to ensure the correct binding between tRNA and its cognate amino acid. The first step for joining an amino acid to its corresponding tRNA is the formation of aminoacyl-AMP:
On February 19, 2019, Sanders announced that he would seek the Democratic Party's 2020 nomination for president. He had declined the Vermont Democratic Party nomination for U.S. Senate in 2006, 2012, and 2018, which caused an unsuccessful legal challenge to his candidacy for the Democratic presidential nomination in 2016. Along with his 2019 campaign announcement, he said he would abide by a new Democratic Party rule for presidential candidates and that he would affirm his membership in that party. On March 5, 2019, he signed a formal statement, known as a "loyalty pledge", that he is a member of the Democratic Party and will serve as a Democrat if elected. News reports noted that the day before, he had signed paperwork to run as an independent for reelection to his Senate seat in 2024.
Sources: en.wikipedia.org
=== Next generation Mel's Drive-In === As of 2025, the next generation Mel's Drive-In chain has eight locations, four in San Francisco and four in the Los Angeles Area. Some Mel's Drive-In locations are not drive-ins but rather diners. For example, while founded in San Francisco, none of the locations in the city currently serve food to patrons' cars. The location near Downtown San Francisco, rechristened "Mel's Kitchen", has gone upscale, serving $12 cocktails, $16 burgers with locally sourced beef, ahi poke, acai smoothies, and avocado toast. That site was almost demolished in 2018 to build housing.
=== Vascular === Elabela is expressed by midline tissues (such as the notochord in zebrafish and neural tube in mammals) during organogenesis. There it serves as a chemoattractant to angioblasts expressing APLNR at their cell surface. This participates in the formation of the first and secondary vessels of the vascular system.
I cannot remember how they first came to be offered to us. But they were distributed in the dressing rooms. We didn't have to take them but most of the players did. The tablets were mostly white but once or twice they were yellow. They were used through the 1961–62 season and the championship season which followed it. Drug-taking had previously been virtually unnamed in the club. But once it had started we could have as many tablets as we liked. On match days they were handed out to most players as a matter of course. Soon some of the players could not do without the drugs. The club agreed that drugs had been used but that they "could not possibly have had any harmful effect." Dunlop, however, said he had become an addict. In November 1942, the Italian cyclist Fausto Coppi took "seven packets of amphetamine" to beat the world hour record on the track. In 1960, the Danish rider Knud Enemark Jensen collapsed during the 100 km team time trial at the Olympic Games in Rome and died later in hospital. The autopsy showed he had taken amphetamine and another drug, Ronicol, which dilates the blood vessels. The chairman of the Dutch cycling federation, Piet van Dijk, said of Rome that "dope – whole cartloads – [were] used in such royal quantities." The 1950s British cycling professional Jock Andrews would joke: "You need never go off-course chasing the peloton in a big race – just follow the trail of empty syringes and dope wrappers." The Dutch cycling team manager Kees Pellenaars told of a rider in his care:
== Coupled analysis == Following 2D SDS PAGE the proteins can be transferred to a polyvinylidene difluoride (PVDF) blotting membrane for further analysis. Edman degradations can be performed directly from a PVDF membrane. N-terminal residue sequencing resulting in five to ten amino acid may be sufficient to identify a Protein of Interest (POI).
Libya had long supported the FROLINAT militia in neighbouring Chad, but FROLINAT became divided over its ties to Libya in 1976. In January 1978, the anti-Libya faction within FROLINAT, led by Hissène Habré, switched sides and allied with Chadian President Félix Malloum. Meanwhile, the pro-Libya faction within FROLINAT, led by Goukouni Oueddei, renamed itself People's Armed Forces (FAP). In December 1980, Gaddafi reinvaded Chad at the request of the FAP-controlled GUNT government to aid in the civil war; in January 1981, Gaddafi suggested a political merger. The Organisation of African Unity (OAU) rejected this and called for a Libyan withdrawal, which came in November 1981. The civil war resumed, and Libya sent troops back in. In 1982, the GUNT government was overthrown by Habré's forces and Oueddei fled to Libya, where Gaddafi provided him with arms to continue to guerrilla war against Habré. In November 1984, Gaddafi met with French President François Mitterrand; both agreed to withdraw from Chad. Oueddei broke with Gaddafi in 1985 due to the former's intentions to negotiate a truce with Habré. Consequently, he was placed under house arrest by Gaddafi and allegedly arrested by Libyan police and shot in the stomach. Oueddei survived the shooting and fled to Algeria, but continued to claim he and Gaddafi enjoyed a good relationship. When Gaddafi ordered the remnant of GUNT to attack Habré in February 1986 in violation of his agreement with Mitterrand, France launched Operation Épervier, which escalated into the Toyota War.
Sources: en.wikipedia.org
==== Lipofection ==== In lipofection, the gene is injected with the help of liposomes. The DNA sequence is encapsulated in a liposome with the same composition as the cell membrane. This method allows it to directly fuse with the membrane, or be endocytosed, which then releases the DNA into the cell. Lipofection is often used because it works with many different cell types, is highly reproducible, and is a fast method for both stable and transient expression.
10 Ca(OH)2 + 6 H3PO4 → Ca10(PO4)6(OH)2 + 18 H2O The ability to synthetically replicate hydroxyapatite has invaluable clinical implications, especially in dentistry. Each technique yields hydroxyapatite crystals of varied characteristics, such as size and shape. These variations have a marked effect on the biological and mechanical properties of the compound, and therefore these hydroxyapatite products have different clinical uses.
== State and local government == Several states have proposed and passed laws that regulate AI models and AI-generated content, including impersonations, chatbot disclosures, and synthetic political content.
The laboratory industry is a part of the broader healthcare and health technology industry. Companies exist at various levels, including clinical laboratory services, suppliers of instrumentation equipment and consumable materials, and suppliers and developers of diagnostic tests themselves (often by biotechnology companies). Clinical laboratory services includes large multinational corporations such LabCorp, Quest Diagnostics, and Sonic Healthcare but a significant portion of revenue, estimated at 60% in the United States, is generated by hospital labs. In 2018, the total global revenue for these companies was estimated to reach $146 billion by 2024. Another estimate places the market size at $205 billion, reaching $333 billion by 2023. The American Association for Clinical Chemistry (AACC) represents professionals in the field. Clinical laboratories are supplied by other multinational companies which focus on materials and equipment, which can be used for both scientific research and medical testing. The largest of these is Thermo Fisher Scientific. In 2016, global life sciences instrumentation sales were around $47 billion, not including consumables, software, and services. In general, laboratory equipment includes lab centrifuges, transfection solutions, water purification systems, extraction techniques, gas generators, concentrators and evaporators, fume hoods, incubators, biological safety cabinets, bioreactors and fermenters, microwave-assisted chemistry, lab washers, and shakers and stirrers.
Sources: en.wikipedia.org
No. It is a laboratory-made peptide, while the natural hormone is alpha-melanocyte-stimulating hormone, a longer peptide produced by the pituitary gland and by skin cells. Melanotan-2 mimics only a short active region of that hormone and contains non-natural residues such as D-phenylalanine.
No approved regulatory indication exists in major markets. An approval exists for a different peptide, afamelanotide, which is used for a rare photosensitivity disorder called erythropoietic protoporphyria. Melanotan-2 itself remains a research compound with no cleared clinical role.
Melanocortin-1 receptors on melanocytes are the receptor most closely linked to pigment production. The peptide is not selective, however, and also activates melanocortin-3, melanocortin-4, and melanocortin-5 receptors. That lack of selectivity is the usual explanation offered for both its range of observed effects and its off-target effects.
The lyophilized powder is generally held at minus twenty degrees Celsius or below, away from light and moisture. Reconstituted solutions are typically refrigerated and used quickly. These practices derive from general peptide handling rather than a formal stability study.