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Melanotan II is a synthetic peptide analog modeled on alpha-melanocyte-stimulating hormone, a naturally occurring signaling peptide involved in pigmentation. Its structure is a cyclic heptapeptide containing two non-natural substitutions, norleucine at position four and D-phenylalanine at position seven. These modifications resist enzymatic breakdown and extend the molecule's activity relative to the native hormone. The compound binds melanocortin receptors and is studied mainly as a pharmacological tool rather than a therapeutic product. It has never received approval as a medicine in any major jurisdiction.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Belongs to the melanocortin agonist family |
| Key substitutions | Nle4 and D-Phe7 | Improve resistance to enzymatic degradation |
| Molecular formula | C50H69N15O9 | Approximately 1024 g/mol |
| Regulatory status | Not approved as a medicine | Distributed as a research chemical |
| Common synonyms | Melanotan II, MT-II, MT-2 | Spelling varies across sources |
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.
Melanotan-2 is a synthetic cyclic heptapeptide designed as a structural analogue of alpha-melanocyte-stimulating hormone, the endogenous tridecapeptide that regulates pigment production. Two modifications distinguish it from the natural hormone: norleucine replaces methionine at the N-terminus, which limits oxidation, and a D-phenylalanine substitution raises receptor affinity. The ring is closed through an aspartate-lysine lactam bridge, giving the molecule a constrained conformation. The free base has a molecular mass near 1024 daltons, and commercial material is usually supplied as an acetate salt. It appears in the literature as a research peptide rather than an approved therapeutic agent.
Receptor studies place melanotan-2 among non-selective melanocortin agonists, binding MC1R, MC3R, MC4R and MC5R rather than a single subtype. Activation of MC1R on cutaneous melanocytes raises tyrosinase activity and shifts pigment synthesis toward eumelanin, which is darker and more photostable than pheomelanin. Central receptors, particularly MC4R, are associated with appetite suppression and with reported effects on sexual function. Because subtype selectivity is low, the same molecule engages pigment, metabolic and vascular pathways at once, and this breadth is a common explanation offered for the range of adverse events described in user reports.
The entrance to the Cothon at Carthage was protected by a chain. The chain at Fort Blockhouse, protecting Portsmouth Harbour from 1431 to 1539. The Leonine Wall included a chain blocking the Tiber A chain spanned the Golden Horn A chain and boom blocked the River Medway during the Raid on the Medway Hudson River Chain The chain blocking the Parana River during the Battle of Vuelta de Obligado A chain was placed from Columbus, Kentucky across the Mississippi River to Missouri in order to block Union ships during the American Civil War Between the A Palma Castle in Mugardos and Saint Philip Castle, in ria of Ferrol, to defend the city and naval base.
In July, the chief administrator of the Environmental Protection Agency announced rescinding of the 2009 endangerment finding, which concluded that planet-warming greenhouse gases pose a threat to public health. (The endangerment finding is the scientific determination that underpins the federal government's legal authority to combat climate change.) In concurrence with the attempt to rollback the endangerment finding, Trump's Department of Energy released an assessment titled A Critical Review of Impacts of Greenhouse Gas Emissions on the U.S. Climate. The report was assembled by five climate science contrarians and was heavily criticized for cherry-picked evidence, falsehoods, and distortions. The Union of Concerned Scientists called it "deeply flawed [and] anti-science". Climate scientist Andrew Dessler called it "a mockery of science". On February 12, 2026, the EPA formally rescinded the Endangerment Finding. In August 2025, the Bureau of Land Management initiated a review of offshore wind energy regulations and revised its rules to favor fossil fuel production over renewables. On September 23, 2025, Trump told the United Nations General Assembly that climate change is "the greatest con job ever perpetrated on the world", that scientific predictions "were made by stupid people", and that renewable energy is a "scam". In October 2025, the Department of Energy cancelled 321 clean energy grants, totaling $7.56 billion, issued in the Biden administration.
Glaxo Laboratories was incorporated as a distinct subsidiary company in London in 1935. Joseph Nathan's shareholders reorganised the group's structure in 1947, making Glaxo the parent and obtained a listing on the London Stock Exchange. Glaxo acquired Allen & Hanburys in 1958. The Scottish pharmacologist David Jack was hired as a researcher for Allen & Hanburys a few years after Glaxo took it over; he went on to lead the company's research and development (R&D) until 1987. After Glaxo bought Meyer Laboratories in 1978, it began to play an important role in the US market. In 1983, the American arm, Glaxo Inc., moved to Research Triangle Park (US headquarters/research) and Zebulon (US manufacturing) in North Carolina.
Sources: en.wikipedia.org
== Prognosis == Challenges presented to people affected by this condition include: psychologically coming to terms with the condition, difficulties with sexual function, infertility. Long-term studies indicate that with appropriate medical and psychological treatment, those with CAIS can be satisfied with their sexual function and psychosexual development. Individuals with this condition can lead active lives and expect a normal lifespan.
High temperature conditions during the initial stages of implantation will increase the impurity diffusion in the substrate and as a result limit the impinging ion saturation, which is required for nanoparticle nucleation. Both the implant temperature and ion beam current density are crucial to control in order to obtain a monodisperse nanoparticle size and depth distribution. A low current density may be used to counter the thermal agitation from the ion beam and a buildup of surface charge. After implantation on the surface, the beam currents may be raised as the surface conductivity will increase. The rate at which impurities diffuse drops quickly after the formation of the nanoparticles, which act as a mobile ion trap. This suggests that the beginning of the implantation process is critical for control of the spacing and depth of the resulting nanoparticles, as well as control of the substrate temperature and ion beam density. The presence and nature of these particles can be analyzed using numerous spectroscopy and microscopy instruments. Nanoparticles synthesized in the substrate exhibit surface plasmon resonances as evidenced by characteristic absorption bands; these features undergo spectral shifts depending on the nanoparticle size and surface asperities, however the optical properties also strongly depend on the substrate material of the composite.
The collapse of the Soviet Union eventually allowed the US and the newly reconstituted Russian Federation to end their Cold War competition also in space, by agreeing in 1993 on the Shuttle–Mir and International Space Station programs.
Sources: en.wikipedia.org
The stream of protonated water clusters acts as a secondary ionizing species and generates analytes ions by chemical ionization mechanisms at atmospheric pressure. Here protonation, deprotonation, direct charge transfer and adduct ion formation may occur.
== Adverse effects == Nephrotoxicity: Like cisplatin, nephrotoxicity, harm to the kidneys, is the primary dose-limiting factor. However, the nephrotoxicity of nedaplatin has been shown to be less severe than cisplatin. In rats, nedaplatin primarily affected the renal papilla, with papillary necrosis in severe cases. Neurotoxicity: Nedaplatin is widely reported to be neurotoxic, especially to the nerves of the ear. Causing symptoms like numbness and tingling in mild cases, or sensory ataxia in more severe cases. Nausea and vomiting: The emetogenic effects of nedaplatin are commonly managed with prophylactic antiemetics, such as duplex dexamethasone and ondansetron or triplex dexamethasone, ondansetron and aprepitant. Ototoxicity: Nedaplatin is toxic to the nerve and hair cells in the cochlea. In rats, nedaplatin was severely toxic to the nerve cells at a concentration of 10 μM, with damage to hair cells becoming more severe exceeding 100 μM. Neutropenia, leukopenia, anemia and thrombocytopenia (see "Aqupla アクプラ" in External Links): Nedaplatin is toxic to the hemopoietic cells of the bone marrow, combined with reduced levels of erythropoietin, leads to elevated incidence of bone marrow suppression compared to cisplatin. Incidence of severe grades of leukopenia and neutropenia are reported to be higher than cisplatin in treatment combined with radiotherapy. These haematological adverse effects are common in general.
=== Availability === Suvorexant has been marketed in the United States, Canada, Australia, Russia, and Japan. Although previously available, suvorexant appears to have been discontinued in Canada. It does not appear to be available in the United Kingdom or other European countries besides Russia.
Sources: en.wikipedia.org
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.
No regulatory agency has approved it for any indication. It is encountered as a research chemical sold outside pharmaceutical supply chains. Products marketed this way are not subject to the manufacturing and labeling requirements that apply to approved drugs.
Reports describe increased skin pigmentation as well as side effects such as nausea, flushing, and changes to existing moles. Much of the evidence comes from small studies and case reports rather than large trials. The long-term safety profile is therefore uncertain.
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.