melanocortin receptor 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 2026-05-02. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
| 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 |
Melanotan II binds several melanocortin receptor subtypes rather than a single target. MC1R on melanocytes drives melanin synthesis, while MC3R and MC4R participate in energy balance, appetite, and sexual response pathways. This lack of selectivity explains why reported effects extend beyond skin darkening. Substitutions at positions four and seven, including norleucine and D-phenylalanine, increase potency and resistance to peptidases. Understanding which receptor mediates which effect remains an active area of investigation.
Published human data come mostly from small, short studies rather than large controlled trials. Reported outcomes include increased skin pigmentation and, in some reports, effects on appetite and libido, but sample sizes are small and follow-up is limited. Whether long-term use produces durable pigment changes or adverse effects is not established. Because products sold outside pharmacies are not standardized, the actual content of any given vial is often unknown. Independent testing of such material is uncommon.
Melanotan-2 appears on the World Anti-Doping Agency prohibited list within the peptide hormone class, and several national regulators treat it as an unapproved prescription substance. Some countries restrict importation or sale for personal use. Because the compound is widely traded as a research chemical, the practical legal picture differs between jurisdictions and shifts over time. Human safety data covering long periods are limited, and whether repeated pigmentation changes carry any lasting risk to melanocytes remains an open question.
Freeze-dried melanotan-2 is normally kept as a desiccated powder at minus twenty degrees Celsius or lower, shielded from light and moisture. Peptides of this size degrade through hydrolysis, oxidation and deamidation, and each pathway accelerates as temperature and water activity rise. Repeated freeze-thaw cycles promote aggregation and loss of material, so aliquoting a stock solution before freezing is standard laboratory practice. Once dissolved, the solution is markedly less stable than the powder. In laboratory work, solutions are generally refrigerated and used within days rather than kept for months.
Receptor-binding studies classify melanotan II as a non-selective melanocortin agonist. It interacts with MC1R, MC3R, MC4R and MC5R, with reported affinities in the low nanomolar range and no strong subtype preference. Activation of MC1R on dermal melanocytes shifts pigment synthesis toward eumelanin, the dark polymer deposited in melanosomes and transferred to keratinocytes. Because the same peptide engages MC4R in the hypothalamus, it also appears in animal work on food intake and erectile response, which is why it is discussed in both pigment and metabolic research. Which receptor populations dominate after systemic exposure in humans is not fully established.
Published pharmacokinetic information is limited and comes mainly from small studies rather than registrational trials. Plasma half-life is usually described as short, on the order of tens of minutes, followed by rapid tissue distribution and clearance of the intact peptide. Metabolites and low concentrations of parent compound have been reported in urine, a detail relevant to anti-doping and forensic testing. Whether repeated exposure changes receptor sensitivity or clearance over time remains an open question. Values differ noticeably between analytical assays, so published numbers should be read as approximate rather than definitive.
Regulatory treatment varies by country. In the United States the peptide is not approved as a medicine, and products offered for human use may be treated as unapproved new drugs; some states also restrict sale. Australia, the United Kingdom, and European Union member states apply comparable restrictions to unapproved peptide products. Border agencies have seized shipments labelled as research chemicals. Classification may change over time, and the legal position for personal importation is not clearly settled in most published guidance.
Lyophilised melanotan-2 is supplied as a solid, which is more stable than a solution. The material is hygroscopic, so weighing is done quickly, in low humidity, with the container kept sealed. Reconstitution usually uses water for injection or bacteriostatic water, added down the wall of the vial to limit foaming. A reconstituted solution is held at 2 to 8 °C and kept away from light. Repeated freezing and thawing of the same vial is avoided because ice crystal formation and concentration effects degrade the peptide.
β-catenin binds to transcription factors such as the protein TCF4 and in combination the molecules activate the necessary genes. LF3 strongly inhibits this binding in vitro, in cell lines and reduced tumor growth in mouse models. It prevented replication and reduced their ability to migrate, all without affecting healthy cells. No cancer stem cells remained after treatment. The discovery was the product of "rational drug design", involving AlphaScreens and ELISA technologies.
== Origin == Whenever muscles and joints are moved this also exerts mechanical strain on related fascia. The general assumption in sports science had therefore been that muscle strength exercises as well as cardiovascular training would be sufficient for an optimal training of the associate fibrous connective tissues. However, recent ultrasound-based research revealed that the mechanical threshold for a training effect on tendinous tissues tends to be significantly higher than for muscle fibers. This insight happened roughly during the same time in which the field of fascia research attracted major attention by showing that fascial tissues are much more than passive transmitters of muscular tension (years 2007 – 2010). Both influences together triggered an increasing attention in sports science towards the question whether and how fascial tissues can be specifically stimulated with active exercises. Researchers who contributed to the initial scientific investigation of this direction include Robert Schleip, Jan Wilke, Michael Kjaer and Adamantios Arampatzis.
=== In stimulation === It is possible for some men to achieve orgasm solely through stimulation of the prostate gland, such as via prostate massage or anal intercourse. This has led to the area of the rectal wall adjacent to the prostate to be popularly referred to as the "male G-spot".
=== Nutrition === The high levels of muscle growth and repair achieved by bodybuilders require a specialized diet. Generally speaking, bodybuilders require more calories than the average person of the same weight to provide the protein and energy requirements needed to support their training and increase muscle mass. In preparation of a contest, a sub-maintenance level of food energy is combined with cardiovascular exercise to lose body fat. Proteins, carbohydrates and fats are the three major macronutrients that the human body needs to build muscle. The ratios of calories from carbohydrates, proteins, and fats vary depending on the goals of the bodybuilder.
==== E-I balance as crucial for visual cortex function ==== By computational modeling, Sur’s group proposed that a key feature of visual cortex networks - local and long-range connections between excitatory neurons critically balanced by inhibition - is essential for explaining feature-selective responses. They demonstrated that inhibition and excitation are exquisitely tuned across cortical sites, as demonstrated by imaging and intracellular recordings.
Sources: en.wikipedia.org
Mikania micrantha is a widespread weed in the tropics. It grows very quickly (as fast as 80 to 90 millimetres (3.1 to 3.5 in) in 24 hours for a young plant) and covers other plants, shrubs and even trees. Mikania is a problem in Nepal, covering more than 20% of the Chitwan National Park. Various control measures against Mikania have been tried in many countries. It is moderately susceptible to the herbicides 2,4-D and 2,4,5-T and paraquat. Cuscuta, a parasitic plant, has been used in Assam and Sri Lanka to suppress the spread of Mikania from waste land to tea plantations. Other control measures include the rust fungus Puccinia spegazzinii and the thrips species Liothrips mikaniae. An example of its success can be seen in Hong Kong where first recorded in 1884, it has now spread throughout the region and invades its country parks. Economic gains due to Mikania are meager compared to the loss due to its infestation in various ecosystems. It is used as a fodder in many countries. Sheep preferentially grazed Mikania in Malaysia and other cattle also relish it. In Kerala, India, the weed is utilized as a fodder in some parts of the state, especially during summer when the availability of grass is scarce. However, Mikania is known to cause hepatotoxicity and liver damage in dairy cattle. The antibacterial effect of Mikania and its efficacy in wound healing has been reported. In Assam (NE India), Kabi tribes use the leaf juice of Mikania as an antidote for insect bite and scorpion sting. The leaves are also used for treating stomachache.
=== Structure-based methods === NeoaPred is a structure-based approach that predicts immunogenicity from structural information. It primarily focuses on cancer neoantigens since it requires mutant–wild-type pairs for immunogenicity prediction.
=== Interwar years (1919-1941) === Following the Ottoman Empire's post-World War I dismemberment and the foundation of the successor Turkish Republic in 1923, Mustafa Kemal Atatürk banned all Sufi orders and installed the Directorate of Religious Affairs as sole governing entity over religion. Bektashi lodges in Turkey were subsequently closed in 1925, with the order's leadership relocating to Albania and establishing its headquarters in Tirana. Salih Nijazi was the last Dedebaba in Turkey and the first in Albania, formerly appointed to his role in the latter country on 30 March 1930. The order became involved in Albanian politics, and some of its members, including Ismail Qemali, were major leaders of the Albanian National Awakening (Rilindja). After the lodges in Turkey were shut down, the order's headquarters moved to Albania. On 20 March 1930, Salih Nijazi was elected as the Dedebaba of the Bektashi community in Albania. Before Nijazi, the Dedebaba was Haxhi Fejzullah in Turkey. Njazi established the Bektashi World Headquarters in Tirana. Its construction was finished in 1941 during the Italian occupation of Albania. Nijazi promoted Bektashi Islam by introducing major ceremonies at popular tekkes. After he was murdered in 1941, Ali Riza succeeded him as the Dedebaba.
Sherman leaves with Richmond and a tennis ball covered in the youth formula and heads to a presentation at Phleer Pharmaceuticals that Buddy is giving about the youth formula. Meanwhile, a worried Denise discovers what has happened and that Sherman's brain damage is progressing. With Cletus' help, Denise goes after him. Sherman takes advantage of the canine DNA crossed with Buddy's and throws the tennis ball to distract him. Buddy catches the ball in his mouth, and the youth formula transforms him back into a toddler, then further into a glowing mass of sentient genetic material. Sherman chases the genetic material, intent on drinking it to correct his condition. However, the material evaporates on the edge of a fountain before he can get to it. Cletus and Denise arrive too late to save him, and Denise breaks into tears, which hit the genetic material and fall into the fountain. As they go to leave, Sherman looks into the fountain, remarking that it is "pretty". Seeing the water is glowing, Denise realizes the genetic material has reconstituted thanks to her tears and that if Sherman drinks the fountain water before it dissipates, he will be restored to normal. Sherman drinks the water and is able to restore his genetic makeup to its proper order, restoring his intelligence. With Buddy Love defeated, Sherman and Denise finally get married. During the wedding reception, Sherman's older brother, Ernie Klump Sr., sings a song in honor of the couple, while Richmond continues to be hexed by the now normal-sized hamster.
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.
Laboratory confirmation typically combines retention time matching on a chromatographic system with mass measurement. A reference standard of known identity is needed for a meaningful comparison. Sequence-level techniques can add further confirmation.