Alpha-MSH raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-09-18. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
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.
| 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 |
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.
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.
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.
Mummies, though typically thought of as an Egyptian phenomenon, exist in many cultures and have been found on nearly every continent. The word mummy can refer to both intentionally and naturally preserved bodies and is not limited to one geographic area or culture. Damage of mummified remains can be caused by several factors, including poor environmental conditions, physical damage, and improper methods of preservation. Controlling environmental conditions is highly important in preserving the integrity of mummies. Fungi, pests, and microorganisms that cause decay are some of the possible results of inadequate storage and environmental factors. There are a number of ways to mitigate the effects of improper conditions, however. Methods of stabilizing mummies and halting deterioration include inert gas control, where the mummy is placed in a chamber or bag into which fumigants are introduced; wet sterilization, where solutions are applied to the mummy to repel insects and the growth of fungi; controlled drying, which reduces the relative humidity in order to stop growth of microorganisms; and ultraviolet irradiation, which kills microorganisms. Some previous treatments which were thought to help preserve mummified remains but ultimately led to further damage include curing remains by smoking them and applying solutions of copper salts to exposed skin. The Artefact Lab at the University of Pennsylvania Museum of Archaeology and Anthropology (Penn Museum) provides examples and images of mummy preservation.
== External links == Media related to Protons at Wikimedia Commons Particle Data Group at LBL Large Hadron Collider Eaves, Laurence; Copeland, Ed; Padilla, Antonio (Tony) (2010). "The shrinking proton". Sixty Symbols. Brady Haran for the University of Nottingham. MIT proton visualization project: Inside the Proton, the 'Most Complicated Thing You Could Possibly Imagine', Quanta Magazine, Oct 19 2022 Visualizing the Proton, Arts at MIT, 2022
The Hong Kong Garrison of the People's Liberation Army is responsible for the region's defence. Although the Chairman of the Central Military Commission is supreme commander of the armed forces, the regional government may request assistance from the garrison. Hong Kong residents are not required to perform military service, and current law has no provision for local enlistment. The garrison is composed entirely of non-Hongkongers. The central government and Ministry of Foreign Affairs handle diplomatic matters, but Hong Kong retains the ability to maintain separate economic and cultural relations with foreign nations. The territory actively participates in the World Trade Organization, the Asia-Pacific Economic Cooperation forum, the International Olympic Committee, and many United Nations agencies. It holds membership in other international bodies including the World Health Organization. The regional government maintains trade offices in Greater China and other nations. The imposition of the Hong Kong national security law by the central government in Beijing in June 2020 resulted in the suspension of bilateral extradition treaties by the United Kingdom, Canada, Australia, New Zealand, Finland, and Ireland. The United States ended its preferential economic and trade treatment of Hong Kong in July 2020 because it was no longer able to distinguish Hong Kong as a separate entity from the People's Republic of China.
== Folk medicine == Cannabis tea was used for centuries in folk medicine as it was thought to be a treatment for rheumatism, cystitis, and various urinary diseases. In an article in Nature, it is projected that cannabis has been used medicinally for nearly 12,000 years. The oldest confirmed reference to medicinal cannabis is ~2700 BC, in Ancient China. There is ~190AD evidence that a Chinese physician, Hua T'o, used an emulsion of tea and wine to anesthetize a patient for surgery. According to a short communication published in the Journal of Ethnopharmacology, based on the research of Zias et al. regarding cannabis use in ancient childbirth, cannabis is said to have been used to assist women during childbirth. The communication is regarding an anthropological find of a birthing mother, dated to the 4th century AD., "We assume that the ashes found in the tomb were cannabis, burned in a vessel and administered to the young girl as an inhalant to facilitate the birth process." Cannabis tea has been traditionally used by Jamaican women as a remedy for morning sickness associated with pregnancy. There is no evidence that cannabis is an abortive medicine."
Sources: en.wikipedia.org
Choline is an essential nutrient. The cholines are a family of water-soluble quaternary ammonium compounds. Choline is the parent compound of the cholines class, consisting of ethanolamine having three methyl substituents attached to the amino function. Healthy humans fed artificially composed diets that are deficient in choline develop fatty liver, liver damage, and muscle damage. Choline was not initially classified as essential because the human body can produce choline in small amounts through phosphatidylcholine metabolism.
In addition to the PFC, there is moderate to high expression of serotonin 5-HT2A receptors in the primary visual cortex (V1), as well as expression of the serotonin 5-HT2A receptor in other visual areas, and activation of these receptors may contribute to or mediate the visual effects of serotonergic psychedelics. Serotonergic psychedelics also directly or indirectly modulate a variety of other brain areas, like the claustrum, and this may be involved in their effects as well. Psychedelics may work in part by disrupting the default mode network (DMN), a collection of interconnected brain areas which has high serotonin 5-HT2A receptor expression and is said to construct our sense of space, time, and self. The ego dissolution and altered time perception caused by psychedelics correlates with DMN desynchronization, whereas psychedelic visual imagery correlates with disruption in the visual cortex. Serotonin, as well as drugs that increase serotonin levels, like the serotonin precursor 5-hydroxytryptophan (5-HTP), serotonin reuptake inhibitors, and serotonin releasing agents, are non-hallucinogenic in humans despite increasing activation of serotonin 5-HT2A receptors. Serotonin is a hydrophilic molecule which cannot easily cross biological membranes without active transport, and the serotonin 5-HT2A receptor is usually expressed as a cell surface receptor that is readily accessible to extracellular serotonin.
The now elderly McCormick reunites with the also elderly Helen and asks her to marry him; she happily accepts, proving that true love does indeed last forever. McCormick introduces Nat to Helen, and the film ends with the three joining hands and going for a seaside stroll together.
Ketoacidosis Kussmaul breathing (deep, rapid breathing) Confusion or a decreased level of consciousness Dehydration due to glycosuria and osmotic diuresis Increased thirst 'Fruity' smelling breath odor Sweet sensation that is felt into the mouth without a reason Nausea and vomiting Abdominal pain Impairment of cognitive function, along with increased sadness and anxiety Weight loss Hyperglycemia causes a decrease in cognitive performance, specifically in processing speed, executive function, and performance. Decreased cognitive performance may cause forgetfulness and concentration loss.
=== Wilson's disease === Wilson's disease is a rare autosomal (chromosome 13) recessive genetic disorder of copper transport that causes an excess of copper to build up in the liver. This results in liver toxicity, among other symptoms. The disease is now treatable. Wilson's disease is produced by mutational defects of a protein that transports copper from the liver to the bile for excretion. The disease involves poor incorporation of copper into ceruloplasmin and impaired biliary copper excretion and is usually induced by mutations impairing the function of the Wilson copper ATPase. These genetic mutations produce copper toxicosis due to excess copper accumulation, predominantly in the liver and brain and, to a lesser extent, in kidneys, eyes, and other organs. The disease, which affects about 1/30,000 infants of both genders, may become clinically evident at any time from infancy through early adulthood. The age of onset of Wilson's disease ranges from 3 to 50 years of age. Initial symptoms include hepatic, neurologic, or psychiatric disorders and, rarely, kidney, skeletal, or endocrine symptomatology. The disease progresses with deepening jaundice and the development of encephalopathy, severe clotting abnormalities, occasionally associated with intravascular coagulation, and advanced chronic kidney disease. A peculiar type of tremor in the upper extremities, slowness of movement, and changes in temperament become apparent.
Sources: en.wikipedia.org
Language enhancements (including NULL, abstract classes and methods, covariants and finals, closures in tags, and more) Asynchronous programming, using Futures Command line REPL Auto lockdown capability Distributed cache support (Redis, memcached, JCS) REST playground capability Modernized Admin UI Performance Monitoring Toolset
== Role in the immune system == The proteasome plays a straightforward but critical role in the function of the adaptive immune system. Peptide antigens are displayed by the major histocompatibility complex class I (MHC) proteins on the surface of antigen-presenting cells. These peptides are products of proteasomal degradation of proteins originated by the invading pathogen. Although constitutively expressed proteasomes can participate in this process, a specialized complex composed of proteins, whose expression is induced by interferon gamma, are the primary producers of peptides which are optimal in size and composition for MHC binding. These proteins whose expression increases during the immune response include the 11S regulatory particle, whose main known biological role is regulating the production of MHC ligands, and specialized β subunits called β1i, β2i, and β5i with altered substrate specificity. The complex formed with the specialized β subunits is known as the immunoproteasome. Another β5i variant subunit, β5t, is expressed in the thymus, leading to a thymus-specific "thymoproteasome" whose function is as yet unclear. The strength of MHC class I ligand binding is dependent on the composition of the ligand C-terminus, as peptides bind by hydrogen bonding and by close contacts with a region called the "B pocket" on the MHC surface. Many MHC class I alleles prefer hydrophobic C-terminal residues, and the immunoproteasome complex is more likely to generate hydrophobic C-termini.
miscibility The tendency or capability of two or more substances to blend uniformly when combined (most commonly liquids, though the concept is also applicable to solids and gases), i.e. to dissolve in each other, forming a homogeneous mixture that exists in a single phase, without separation of phases, regardless of the proportions of each substance. Substances that do not mix uniformly in all proportions are said to be immiscible.
Wealth in the United States is highly concentrated; in 2011, the richest 10% of the adult population owned 72% of the country's household wealth, while the bottom 50% owned just 2%. U.S. wealth inequality increased substantially since the late 1980s, and income inequality in the U.S. reached a record high in 2019. In 2024, the country had some of the highest wealth and income inequality levels among OECD countries. Since the 1970s, there has been a decoupling of U.S. wage gains from worker productivity, while the economy has become more dominated by financial services and stock trading. In 2016, the top fifth of earners took home more than half of all income, giving the U.S. one of the widest income distributions among OECD countries. There were about 771,480 homeless persons in the U.S. on a single night in January 2024. In 2022, 6.4 million children experienced food insecurity. Feeding America estimates that around one in five, or approximately 13 million, children experience hunger in the U.S. and do not know where or when they will get their next meal. Also in 2022, about 37.9 million people, or 11.5% of the U.S. population, were living in poverty. The United States has a smaller welfare state and redistributes less income through government action than most other high-income countries. It is the only advanced economy that does not guarantee its workers paid vacation nationally and one of a few countries in the world without paid family leave as a legal right.
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.
No. No major regulatory agency has granted a marketing authorisation for melanotan II as a medicine. Products sold under this name are generally presented as laboratory reagents and are not subject to the batch-release testing applied to approved drugs.