If you have been reading about alpha-MSH analog 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 2025-12-24. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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 |
|---|---|---|
| Lyophilised storage | −20 °C, dry, protected from light | Vials are sealed and allowed to reach room temperature before opening |
| Reconstituted storage | 2 to 8 °C, protected from light | Short-term holding; avoid repeated freeze-thaw cycles |
| Reconstitution solvent | Water for injection or bacteriostatic water | Added slowly along the vial wall to reduce foaming and shear |
| Purity measurement | RP-HPLC with area normalisation | Acetonitrile-water gradient monitored at roughly 214 nm |
| Identity confirmation | Electrospray ionisation mass spectrometry | Observed mass compared against the calculated peptide mass |
Regulatory status differs by country, and in many places supplying the compound for human consumption is unlawful. Vendors frequently label material as intended for research use only, a designation that shifts stated purpose but does not create a legal pathway for personal use. Certificates of analysis accompanying such products vary widely in detail and provenance. Third-party testing exists but is voluntary, and results are rarely linked to a specific lot in a publicly verifiable way.
Identity testing for a synthetic peptide relies on several complementary methods. Reversed-phase high-performance liquid chromatography separates the target from related impurities and reports purity as a percentage of total peak area. Mass spectrometry confirms molecular mass and can reveal deletions or truncations. Amino acid analysis and peptide mapping provide sequence-level confirmation, while counter-ion content and residual solvents are measured separately. A purity figure alone does not establish identity, so a complete dataset combines chromatographic and spectrometric evidence.
Lyophilized peptide powder is generally stored frozen, protected from light and moisture. Tryptophan residues are susceptible to oxidation, and the lactam bridge can hydrolyze under strongly acidic or basic conditions. Solutions prepared for laboratory work degrade faster than dry powder, and repeated freeze-thaw cycles accelerate loss. Common practice is to aliquot solutions before freezing and to avoid alkaline buffers. Reported stability windows vary with concentration, buffer, and temperature, so exact shelf lives are method-specific rather than universal.
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 II is a synthetic cyclic heptapeptide analog derived from the core sequence of alpha-melanocyte-stimulating hormone. Researchers at the University of Arizona synthesized it during the 1980s while studying pigmentation and appetite signaling. The compound is not an approved medicine in any major jurisdiction and appears mainly in laboratory and research-chemical settings. Its structure incorporates a lactam bridge between side chains, which constrains the ring and slows enzymatic breakdown relative to the natural hormone.
Melanotan-2 is handled in the laboratory as a lyophilised powder that dissolves readily in water, dimethyl sulfoxide and dimethylformamide, with limited solubility in ethanol. Stock solutions prepared in an organic solvent often precipitate when diluted into aqueous buffer, so gradual dilution with mixing is standard practice. The peptide carries a tryptophan residue and a histidine residue, both sensitive to oxidation and to alkaline conditions. Working solutions are therefore kept near neutral to slightly acidic pH, protected from light, and consumed within the same working session whenever that is practical.
Solid peptide kept dry at minus twenty degrees Celsius, shielded from light and moisture, is generally considered stable for extended periods. Solutions are divided into single-use aliquots and held at minus twenty or minus eighty degrees Celsius, because repeated freeze-thaw cycles promote aggregation and loss of material to container surfaces. Hydrolysis of the backbone and oxidation of tryptophan are the principal degradation routes in aqueous solution, and both accelerate at ambient temperature. Hygroscopic uptake after a vial is opened can also shift the actual mass weighed, which affects any concentration calculated from it.
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.
No regulatory authority has approved melanotan-2 for human use, and several countries classify it as a prescription-only or controlled substance, which restricts lawful supply. Material sold online is generally labelled as a research chemical and is not required to meet pharmaceutical standards of identity or purity. Published human data consist mainly of small uncontrolled studies, case reports and adverse-event notifications, so the evidence base is descriptive rather than confirmatory. Whether repeated melanocyte stimulation alters long-term naevus behaviour remains an open question that no completed trial has resolved.
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.
Sambunigrin, also a glycoside of mandelonitrile, is found in several species of the genus elderberry (Sambucus), including black elderberry and Canadian elderberry, as well as in Ximenia americana. Vicianin, another mandelonitrile glycoside, occurs in ferns of the genus Davellia (family Davalliaceae). Dhurrin is a cyanogenic glycoside of 4-hydroxymandelonitrile found in sorghum millet and other species of the genus sorghum millet, including Sorghum halepense. Linamarin (with the aglycone acetone cyanohydrin) and lotaustralin (with the aglycone butanone cyanohydrin) occur in the genera Linum (for example in common flax) and lotus flowers, as well as in the common bean. Both compounds are also present in cassava. The mistletoe species Loranthus micranthus (genus Loranthus) contains linamarin gallate, a derivative in which linamarin is additionally esterified with gallic acid. The rubber tree also contains linamarin; studies indicate that in this case the compound likely serves as an important storage substance in addition to its defensive function. The seeds contain particularly high concentrations, and during seedling development the compound is metabolized without releasing hydrocyanic acid, suggesting utilization in other biosynthetic pathways.
Through additional reactions the nitrogen is incorporated into glutamine and glutamate and eventually used in the synthesis of other amino acids and nitrogenous compounds. After harvest, the majority (around 80%) of available nitrogenous compounds found in the grapes are concentrated in the skins and seeds. These compounds get released into the must during the process of crushing and during maceration/skin contact. Even after pressing up to 80% of initial nitrogen content within each grape berry will be left behind in the pomace.
Reagan was supported by the UK, but opposed by other European allies, who argued it contravened international law. In Operation El Dorado Canyon, orchestrated on 15 April 1986, US military planes launched air-strikes, bombing military installations, killing around 100 Libyans, including civilians. One target had been Gaddafi's home. Himself unharmed, two of Gaddafi's sons were injured, and he claimed his adopted daughter Hanna was killed, although her existence has since been questioned. Gaddafi retreated to the desert to meditate. There were sporadic clashes between Gaddafists and army officers who wanted to overthrow the government. Although the US was condemned internationally, Reagan received a popularity boost at home. Publicly lambasting US imperialism, Gaddafi's reputation as an anti-imperialist was strengthened domestically and across the Arab world, and, in June 1986, he ordered the names of the months to be changed in Libya.
=== Other tissues === The thermal effects of microwaves can cause testicular degeneration and lower sperm count. Pulmonary burn can be present when lungs are exposed; chest radiography is used for diagnosing. Exposure of abdomen may lead to bowel obstruction due to stenosis of the affected bowel; flat and upright abdominal radiography is used to check for this condition.
Volume or capacity of data is often compared to works of literature or large collections of writing. Popular units include the Bible, the Encyclopædia Britannica, phone books, the complete works of Shakespeare, and the Library of Congress. When the Compact Disc began to be used as a data storage device as the CD-ROM, journalists often described the disc capacity (650 megabytes) by using the number of Christian Bibles that can be stored. The King James Version of the Bible in uncompressed plain 8-bit text contains about 4.5 million characters, so a CD-ROM can store about 150 Bibles. The print version of the Encyclopædia Britannica is another common data volume metric. It contains approximately 300 million characters, so two copies would fit onto a CD-ROM and still have 50 megabytes (or about 11 bibles) left over. The term Library of Congress is often used. It refers to the US Library of Congress. Information researchers have estimated that the entire print collections of the Library of Congress represent roughly 10 terabytes of uncompressed textual data.
Sources: en.wikipedia.org
The most common gastrointestinal complications of anorexia nervosa are delayed stomach emptying and constipation, but also include elevated liver function tests, diarrhea, acute pancreatitis, gastroesophageal reflux disease (GERD), difficulty swallowing, and, rarely, superior mesenteric artery syndrome. Acid exposure from GERD and self-induced vomiting can cause dental problems, such as tooth enamel erosion and gum disease. Delayed stomach emptying, or gastroparesis, often develops following food restriction and weight loss; the most common symptom is bloating with gas and abdominal distension, and often occurs after eating. Other symptoms of gastroparesis include early satiety, fullness, nausea, and vomiting. The symptoms may inhibit efforts at eating and recovery, but can be managed by limiting high-fiber foods, using liquid nutritional supplements, or using metoclopramide to increase emptying of food from the stomach. Gastroparesis generally resolves when weight is regained.
==== Eliminated in primary ==== Jarvis Johnson, former state representative from the 139th district (2016–2025), candidate for this district in 2010, candidate for Texas's 15th Senate district in the 2024 special and regular elections, and candidate for the 18th district in 2024 Robert Slater, business owner and candidate for the 18th district in 2024 and 2025
== Neuron-intrinsic changes == Immediately following injury, neurons undergo a large number of transcriptional and proteomic changes which switch the cell from a mature, synaptically active neuron to a synaptically silent, growth state. This process is dependent on new transcription, as blocking the ability of cells to transcribe new mRNA severely impairs regeneration. A number of signaling pathways have been shown to be turned on by axon injury and help to enable long distance regeneration including BMP, TGFβ, and MAPKs. Similarly, a growing number of transcription factors also boost the regenerative capacity of peripheral neurons including ASCL1, ATF3, CREB1, HIF1α, JUN, KLF6, KLF7, MYC, SMAD1, SMAD2, SMAD3, SOX11, SRF, STAT3, TP53, and XBP1. Several of these can also boost the regenerative capacity of CNS neurons, making them potential therapeutic targets for treating spinal cord injury and stroke.
Major challenges to the use of cecropins as cancer therapeutics are delivery of the peptides to tumor cells. Repeated administration of peptides is necessary to maintain systemic levels of cecropins at sufficient concentrations for anti-cancer activity. This need for repeated administration complicates potential treatment plans. One proposed alternative suggests use of gene therapy to introduce cecropin genes into cancer cells. A study in which cecropin genes were expressed in a human bladder carcinoma cell line showed that tumor cells bearing cecropin genes have reduced tumorigenicity, up to complete loss of tumorigenicity in some cell clones. More recent studies have identified new cecropins, which may be prove useful in development of cancer therapeutics. For example, genome and transcriptome analyses of the spruce budworm Choristoneura fumiferana resulted in identification of novel cecropins which differ from previously characterized cecropins in that they are negatively charged, rather than positively charged. A BH3-like motif (amino acid sequence G-[KQR]-[HKQNR]-[IV]-[KQR]) is present in both anionic and cationic cecropins, and analysis suggests that this motif may interact with Bcl-2, a protein implicated in apoptosis. Further study of cecropin structure and anticancer properties may inform design of novel cancer therapeutics.
Food plays various roles in social and cultural life. In Chinese folk religion, ancestor veneration is conducted by offering food to ancestors and Chinese festivals involve the consumption and preparation of specific foods which have symbolic meanings attached to them. Specific religions in China have their own cuisines such as the Taoist diet, Buddhist cuisine and Chinese Islamic Cuisine. The Kaifeng Jews in Henan province once had their own Chinese Jewish cuisine but the community has largely died out in the modern era and not much is known about the specifics of their cuisine but they did influence foods eaten in their region and some of their dishes remain. Chinese dishes with purported Kaifeng Jewish roots include Kaifeng xiao long bao, Mayuxing bucket-shaped chicken, Chrysanthemum hot pot, and Four Treasures. Food also plays a role in daily life. The formality of the meal setting can signify what kind of relationship people have with one another, and the type of food can indicate ones' social status and their country of origin. In a formal setting, up to sixteen of any combination of hot and cold dishes would be served to respect the guests. On the other hand, in a casual setting, people would eat inexpensive meals such as at food stalls or homemade food. The typical disparity in food in the Chinese society between the wealthy and everyone below that group lies in the rarity and cost of the food or ingredient, such as shark fins and bear paws.
Sources: en.wikipedia.org
Low temperature slows hydrolysis and oxidation, the two main routes by which the peptide backbone and side chains are modified. A lyophilised powder stored at −20 °C is more stable than one kept at room temperature, and once the material is dissolved the degradation rate rises, making refrigeration more important.
Liquid chromatography coupled to mass spectrometry is the most common approach because it combines a retention time with a mass measurement. A chromatographic peak alone cannot establish which peptide is present, so mass determination or amino acid analysis is used as an orthogonal confirmation alongside the separation.
This depends on buffer, pH, and concentration, and published stability data for this peptide are limited. In practice laboratories work through a refrigerated solution within a few weeks and discard samples that show cloudiness or visible particles. Freezing and thawing repeatedly is generally discouraged.
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.