melanotan-2 is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2025-08-06. Numbers and descriptions here follow the published literature rather than marketing material.
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controlled human data on melanotan-2 remain sparse, and much of what circulates online derives from small studies or unpublished reports.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.
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.
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, 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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Alpha-MSH analogue with a lactam ring |
| Molecular formula | C50H69N15O9 | Commonly cited value for the neutral peptide |
| Molecular weight | 1024.18 g/mol | Calculated for the free molecule |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility | Soluble in water, DMSO and ethanol | Dissolution in pure water is often slow |
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.
Melanocortin receptors comprise five subtypes with distinct tissue distributions and functions. Melanotan-2 is described in the literature as a non-selective agonist that engages several of these subtypes, including MC1R, MC3R, MC4R, and MC5R. MC1R is the subtype most directly linked to melanin production in skin cells. Because the compound is not subtype-selective, its observed effects in experimental settings are generally attributed to activity across multiple receptor pathways rather than to a single target.
Melanotan-2 is a synthetic linear peptide built from seven amino acids arranged in a short chain. Its sequence is commonly written as Ac-Nle-Asp-His-D-Phe-Arg-Trp-Lys-NH2, which includes a modified N-terminus and an amidated C-terminus. The molecule belongs to the melanocortin family and acts as a receptor agonist. Structural features such as the D-phenylalanine residue and the Nle substitution are associated with increased stability against enzymatic degradation relative to the natural parent peptide.
== Scientific analysis == Sindonology (from the Greek σινδών—sindon, the word used in the Gospel of Mark to describe the type of the burial cloth of Jesus) is the formal study of the Shroud. The Oxford English Dictionary cites the first use of this word in 1964: "The investigation ... assumed the stature of a separate discipline and was given a name, sindonology", but also identifies the use of "sindonological" in 1950 and "sindonologist" in 1953. Secondo Pia's 1898 photographs of the shroud allowed the scientific community to begin to study it. A variety of scientific theories regarding the shroud have since been proposed, based on disciplines ranging from chemistry to biology and medical forensics to optical image analysis. The scientific approaches to the study of the Shroud fall into three groups: material analysis (both chemical and historical), biology and medical forensics and image analysis.
==== Immediately after the Japan bombings ==== After the successful Trinity nuclear test July 16, 1945, which was the very first nuclear detonation, the Manhattan Project lead manager J. Robert Oppenheimer recalled:
=== Systems biology and systems medicine === Beginning in the 1990s, Hood focused more on cross-disciplinary biology and systems biology. He established in 1992 the first cross-disciplinary biology department, the Molecular Biotechnology Department at the University of Washington. In 2000, he co-founded the Institute for Systems Biology (ISB) in Seattle, Washington to develop strategies and technologies for systems approaches to biology and medicine. He co-led the Hood-Price research lab at ISB with Nathan Price until Price left to join Center for Human Healthspan at the Buck Institute for Research on Aging. Hood pioneered the systems biology concept of considering human biology as a "network of networks." In this model, understanding how systems function requires knowledge of: (1) the components of each network (including genetic, molecular, cellular, organ networks), (2) how these networks inter- and intra-connect, (3) how the networks change over time and undergo perturbations, and (4) how function is achieved within these networks. At the ISB under Hood's direction, genomic, transcriptomic, metabolomic and proteomic technologies are used to understand the "network of networks" and are focused on diverse biological systems (e.g. yeast, mice and humans). Hood applies the notion of systems biology to the study of medicine, specifically to cancer and neurodegenerative disease.
== Synthesis == Numerous methods are available for the preparation of nitriles. These include Kolbe nitrile synthesis, dehydration of carboxylic acid amides and oximes, and oxidation of primary amines. Industrially, the main methods for producing nitriles are ammoxidation and hydrocyanation. Both routes are green in the sense that they do not generate stoichiometric amounts of salts.
Sources: en.wikipedia.org
== Synthesis == Cyclodextrins are prepared by enzymatic treatment of starch. Commonly cyclodextrin glycosyltransferase (CGTase) is employed along with α-amylase. First starch is liquified either by heat treatment or using α-amylase, then CGTase is added for the enzymatic conversion. CGTases produce mixtures of cyclodextrins, thus the product of the conversion results in a mixture of the three main types of cyclic molecules, in ratios that are strictly dependent on the enzyme used: each CGTase has its own characteristic α:β:γ synthesis ratio. Purification of the three types of cyclodextrins takes advantage of the different water solubility of the molecules: β-CD which is poorly water-soluble (18.5 g/L or 16.3 mM at 25 °C) can be easily retrieved through crystallization while the more soluble α- and γ-CDs (145 and 232 g/L respectively) are usually purified by means of expensive and time consuming chromatography techniques. As an alternative a "complexing agent" can be added during the enzymatic conversion step: such agents (usually organic solvents like toluene, acetone or ethanol) form a complex with the desired cyclodextrin which subsequently precipitates. The complex formation drives the conversion of starch towards the synthesis of the precipitated cyclodextrin, thus enriching its content in the final mixture of products. Some researchers have developed dedicated processes that can produce alpha-, beta- or gamma-cyclodextrin specifically.
Mucosal associated invariant T (MAIT) cells display innate, effector-like qualities. In humans, MAIT cells are found in the blood, liver, lungs, and mucosa, defending against microbial activity and infection. The MHC class I-like protein, MR1, is responsible for presenting bacterially-produced vitamin B metabolites to MAIT cells. After the presentation of foreign antigen by MR1, MAIT cells secrete pro-inflammatory cytokines and are capable of lysing bacterially-infected cells. MAIT cells can also be activated through MR1-independent signaling. In addition to possessing innate-like functions, this T cell subset supports the adaptive immune response and has a memory-like phenotype. Furthermore, MAIT cells are thought to play a role in autoimmune diseases, such as multiple sclerosis, arthritis and inflammatory bowel disease, although definitive evidence is yet to be published.
== History == The solution takes the name from British chemist Henry Drysdale Dakin (1880–1952) who developed it in 1916, during World War I, while he was stationed at a field hospital in Compiègne. He worked there in collaboration with French physician Alexis Carrel, and the particular use they made of the solution is known as the Carrel–Dakin method for wound treatment. Sodium hypochlorite solution had been developed as a bleaching agent around 1820 by the French chemist Antoine Labarraque, as a cheaper substitute for Claude Berthollet's potassium hypochlorite solution, produced as Eau de Javel since the late 18th century. Around that time, he also discovered the disinfectant properties of his Eau de Labarraque, which was quickly adopted for that purpose. His work greatly improved medical practice, public health, and the sanitary conditions in hospitals, slaughterhouses, and all industries dealing with animal products. However, those products were too concentrated and alkaline for use on wounds, as they strongly irritated healthy tissues. Almost a century later Carrel and Dakin observed that few doctors at the time practiced asepsis, and moreover there were no studies of the effectiveness of various antiseptics for wounds. They set out to look for a substance that did not irritate skin, yet had sufficient bactericidal power. Dakin tested more than 200 substances, measuring their action on tissues and bacteria.
Pennington was born on October 8, 1872, in Nashville, Tennessee, to Henry and Sarah Malony Pennington. Shortly after her birth, her parents moved to Philadelphia to be closer to her mother's Quaker relatives. She became interested in chemistry at the age of 12 after reading a library book on medicinal chemistry. She walked to the University of Pennsylvania and asked a professor for help with the terminology she did not understand. She was told to come back when she was older. She entered the University of Pennsylvania in 1890 and completed the requirements for a B.S. degree in chemistry with minors in botany and zoology in 1892. However, since the University of Pennsylvania did not grant degrees to women at this time, she was given a certificate of proficiency instead of a degree. Pennington received her Ph.D. from the University of Pennsylvania in 1895. Her thesis was entitled "Derivatives of Columbium and Tantalum." From 1895 to 1896, she was a university fellow in botany at the University of Pennsylvania. She was a fellow in physiological chemistry at Yale University from 1897 to 1899, and conducted research with Lafayette Mendel and Russell Henry Chittenden.
The ribbons' conductance exceeds predictions by a factor of 10. The ribbons can function more like optical waveguides or quantum dots, allowing electrons to flow smoothly along the ribbon edges. In copper, resistance increases proportionally with length as electrons encounter impurities. Transport is dominated by two modes: one ballistic and temperature-independent, and the other thermally activated. Ballistic electrons resemble those in cylindrical carbon nanotubes. At room temperature, resistance increases abruptly at a specific length—the ballistic mode at 16 micrometers and the thermally activated mode at 160 nanometers (1% of the former length). Graphene electrons can traverse micrometer distances without scattering, even at room temperature.
Sources: en.wikipedia.org
Karen M. Frank is an American clinical pathologist and microbiologist researching the pathogenesis of Staphylococcus aureus pneumonia and resistant gram-negative bacteria. She is a senior clinician, principal investigator, and chief of laboratory medicine at the National Institutes of Health Clinical Center.
The first example of the practical application of this FAB was the elucidation of the amino acid sequence of the oligopeptide efrapeptin D. This contained a variety of very unusual amino acid residues. The sequence was shown to be: N-acetyl-L-pip-AIB-L-pip-AIB-AIB-L-leu-beta-ala-gly-AIB-AIB-L-pip-AIB-gly-L-leu-L-iva-AIB-X. PIP = pipecolic acid, AIB = alpha-amino-isobutyric acid, leu = leucine, iva = isovaline, gly = glycine. This is a potent inhibitor of mitochondrial ATPase activity. Another application of FAB includes its original use for the analysis of condensed-phase samples. FAB can be use for measurements of the molecular weight of samples below 5000 Da, as well as their structural characteristics. FAB can be paired with various mass spectrometers for data analysis, such as with a quadrupole mass analyzer, liquid chromatography–mass spectrometry, and more.
== History == On 28 November 2016, the university came into existence via Haryana Vidhan Sabha legislature. On 18 April 2017, Chief Minister Manohar Lal Khattar's administration renamed it after the Maharana Pratap.
The structure of the U.S. healthcare system, in which people not qualifying for government programs are required to obtain private insurance, favors prescribing drugs over more expensive therapies. According to Professor Judith Feinberg, "Most insurance, especially for poor people, won't pay for anything but a pill." While the rates of opioid prescriptions increased between 2001 and 2010, the prescription of non-opioid pain relievers (aspirin, ibuprofen, etc.) decreased from 38% to 29% of ambulatory visits in the same period. The annual opioid prescribing rates have been slowly decreasing since 2012, but the number is still high. There were about 58 opioid prescriptions per 100 Americans in 2017. Characteristics of jurisdictions with a greater number of opioid prescriptions per resident include small cities or large towns, cities with more dentists and primary care doctors per capita, cities with a higher percentage of white residents, cities with a higher uninsured/unemployment rate, and cities with more residents who have diabetes, arthritis, or a disability. Studies have been conducted to find out how opioids were primarily acquired. A 2013 national survey indicated that 74% of people who recreationally use opioids acquired their opioids directly from a single doctor, friend, or relative, who received their opioids from a clinician. Among pharmacies, the most prolific distributor was Walgreens, which bought 13 billion oxycodone and hydrocodone pills from 2006 to 2012, about twenty percent of all such pills in US pharmacies.
==== Pregnancy ==== Many women with MS who become pregnant experience lower symptoms during pregnancy, especially in the third trimester. During the period directly after delivery, the risk increases. Overall, pregnancy does not seem to influence long-term disability.
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide modelled on alpha-melanocyte-stimulating hormone. A lactam bridge links two side chains, forming a ring that stabilises the molecule against proteolysis. It belongs to the broader melanocortin peptide family.
No national medicines agency has approved melanotan-2 for clinical use. Afamelanotide, a related but distinct peptide, holds a marketing authorisation in the European Union for a rare photosensitivity disorder. Melanotan-2 itself is handled as a laboratory chemical.
Its broad activity across melanocortin receptors makes it a tool for probing pigmentation, appetite and vascular signalling. Early trials recorded skin darkening and other effects that were not the original focus of the work. Those observations generated hypotheses that later studies have examined.
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.