If you have been reading about research chemical 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 2026-04-28. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
Identity and purity are assessed with chromatographic and mass spectrometric techniques. Reversed-phase high-performance liquid chromatography separates the target peptide from related impurities and degradation products, and the resulting retention time is compared against a reference standard. Mass spectrometry, often coupled to liquid chromatography, confirms molecular mass. Amino acid analysis or peptide mapping can provide additional sequence-level confirmation when required. Results are only as reliable as the reference materials used alongside them.
| 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 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 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.
=== Brain-powered remote control for paralyzed people === The brain–computer interface system of Professor Jonathan Wolpaw aims to facilitate the communication of patients with locked-in syndrome. It enables patients to move a cursor on a computer screen, dictate a text or control a robotic arm.
=== Sendai virus minigenome === The Sendai virus minigenome is a shortened version of its viral genome, in which some portions of the coding sequences of the virus have been removed. The removed genes can be replaced with a foreign transgene of interest. The minigenome can be multiplied in cells expressing a minimal set of complementary viral proteins or infected with a homologous wild-type helper virus. Sendai virus minigenomes are used to produce recombinant proteins of interest, and in a vector system to reprogram cells into pluripotent stem cells (iPSCs). A Sendai virus minigenome lacking fusion protein but expressing emerald green fluorescent protein (EmGFP) as a reporter was found to be an efficient gene delivery vector in several human pancreatic cancer cells.
=== Head Office Locations === Medpace Holdings, Inc. is headquartered in Cincinnati, Ohio, United States. The company’s main campus, known as the Medpace Campus, is located in the Madisonville neighborhood of Cincinnati and includes multiple office buildings, laboratories, and clinical facilities. In addition to its headquarters, Medpace operates regional offices and clinical sites across North America, Europe, Asia Pacific, and Latin America to support global clinical trial operations.
{\displaystyle u_{\mathrm {r} }(n_{\mathrm {A} })^{2}\propto {\frac {(R_{\mathrm {A} }-R_{\mathrm {B} })^{2}}{(R_{\mathrm {A} }-R_{\mathrm {AB} })^{2}(R_{\mathrm {AB} }-R_{\mathrm {B} })^{2}}}u(R_{\mathrm {AB} })^{2}}
The exact definition of "vegetable" may vary simply because of the many parts of a plant consumed as food worldwide—roots, stems, leaves, flowers, fruits, and seeds. The broadest definition is the word's use adjectivally to mean "matter of plant origin". More specifically, a vegetable may be defined as "any plant, part of which is used for food", a secondary meaning then being "the edible part of such a plant". A more precise definition is "any plant part consumed for food that is not a fruit or seed, but including mature fruits that are eaten as part of a main meal". Falling outside these definitions are edible fungi (such as edible mushrooms) and edible seaweed which, although not parts of plants, are often treated as vegetables.
Sources: en.wikipedia.org
=== Vertebrates === Several animal species, including fish, amphibians, and reptiles have been shown to tolerate freezing. At least four species of frogs (Pseudacris crucifer, Hyla versicolor, Pseudacris triseriata, Lithobates sylvaticus) and several species of turtles (Terrapene carolina, hatchling Chrysemys picta), lizards, and snakes are freeze tolerant and have developed adaptations for surviving freezing. While some frogs hibernate underground or in water, body temperatures still drop to −5 to −7 °C, causing them to freeze. The wood frog (Lithobates sylvaticus) can withstand repeated freezing, during which about 65% of its extracellular fluid is converted to ice. Rats have been reanimated from near-0 (but not frozen) temperatures.
Сорокин) "Rugby" (Регби) in English translation of Great Soviet Encyclopedia (Progress Publishers, Moscow, 1978) Starmer-Smith, Nigel (ed) Rugby - A Way of Life, An Illustrated History of Rugby (Lennard Books, 1986 ISBN 0-7126-2662-X) Thau, Chris Soviet Rugby in Starmer-Smith, Nigel & Robertson, Ian (eds) The Whitbread Rugby World '89 (Lennard Books, 1988 ISBN 1-85291-038-0) Thau, Chris Soviet Students in Starmer-Smith, Nigel & Robertson, Ian (eds) The Whitbread Rugby World '90 (Lennard Books, 1989 ISBN ) The Ultimate Encyclopaedia of Rugby, (Carlton Books, 1997 ISBN 1-85868-076-X) Dancing On Our Bones: New Zealand, South Africa, Rugby and Racism by Trevor Richards (Bridget Williams Books, 1999). The author was one of a small group of people who founded Halt All Racist Tours (HART) in Auckland in 1969 and worked for the organisation for many years, serving as chair (1969–1980) and international secretary (1980–1985).
=== Felim Bichan === Felim Bichan (Andrew Buchan) is a Scottish hedge fund manager and initially Pierpoint's biggest client with a decades-long client relationship with Eric. A firm, principled man who ascended from humble beginnings, Felim initially cuts ties with Eric and Pierpoint after Eric drunkenly makes offensive comments in front of Felim's wife. On Eric's orders, Harper attempts to coax Felim back to the firm, but Felim gently warns Harper not to fall prey to Eric's malign influence. In series 2, Felim returns as Pierpoint's client so long as Harper act the intermediary between him and Eric. Harper, however, blows off a client meeting with Eric and Felim to meet with notorious independent investor Jesse Bloom, who she is courting as a client. Felim is initially the anchor on a $3.3 billion block trade for shares of healthcare startup Rican, with Eric promising him pre-buy stock options. Felim, however, pulls out of the trade after Harper misses the client meeting, as it reaffirms his distrust of Eric, and Harper sells the shares to Bloom at the last minute instead. Felim, Jesse, Harper and Eric attend a duck shoot in Wales for Rican investors, which Pierpoint initially organized to celebrate Felim's planned purchase of Rican stock. Felim and Jesse remain at odds since Felim rejects his modest beginnings while Jesse embraces his, and Felim chastises Harper for gravitating towards bullies. Jesse later injures Felim's face with shrapnel while trying to shoot a rare pheasant.
Avanti West Coast operates an hourly service between Manchester Piccadilly and London Euston, via Crewe Northern Trains operates regular local services to Manchester Piccadilly, Stockport, Manchester Airport, Alderley Edge and Crewe Transport for Wales operates an hourly service to Cardiff Central, via Crewe, Shrewsbury and Hereford; alternate services continue on to Carmarthen, Fishguard Harbour, Milford Haven or Pembroke Dock.
Sources: en.wikipedia.org
Prolactin tests measure the amount of prolactin within the blood. This test can also be used to assess the function of the pituitary gland. Dysregulation of the pituitary gland, such as due to hypopituitarism, can cause low levels of prolactin. Normal levels of prolactin are typically lower for males in comparison to females, at 20ng/mL, compared to 25ng/mL. This level rises in women during pregnancy or breastfeeding to be between 80 and 400ng/mL. Prolactin cells are classified as acidophils, staining pink/reddish due to acidic dyes such as eosin used with hematoxylin.
Bacolod is the most populous city on the island and the center of the Bacolod Metropolitan Area (which also contains the cities of Talisay and Silay), as well as the 19th most populous city of the whole Philippines, while Dumaguete is the most densely populated city in the whole region. Negros Occidental contains 13 cities (12 component and one highly urbanized) and 19 municipalities, which are further subdivided into 601 barangays. It has the most number of chartered cities amongst all the provinces of the Philippines. Although Bacolod serves as the capital, it is governed independently from its corresponding province as a highly urbanized city. Negros Oriental comprises six cities and 19 municipalities, subdivided further into 557 barangays.
=== Peroxisomes receptor agonists === An important regulator in bile acid homeostasis is the alpha and delta isoforms of the peroxisome proliferator-activated receptor (PPARα, PPARδ). The function of PPARα is that it promotes bile acid excretion and lowers inflammation by acting on nuclear transcription factors. A well known agonist are fibrates and in the clinical trials, there was a significant biochemical response in most patients. A combination therapy with bezafibrate showed remarkable biochemical improvement, with 67% of patients normalizing their alkaline phosphatase levels. Another study of 48 patients with PBC found a combination of bezafibrate and UDCA showed a decrease of alkaline phosphatase in all patients. Further, the study found those treated had a marked relief in pruritus. However, fibrates are associated with a number of adverse effects including arthritis, leg edema, polydipsia, and myalgias. Elevations of creatinine and creatine phosphokinase were also found over a long term use.
Lilac Park, founded in 1958, contains a permanent sculpture display and a large rosarium. Moscow has long been popular with tourists. Some well-known attractions include one of the city's UNESCO World Heritage Sites—the Moscow Kremlin and Red Square, which were built between the 14th and 17th centuries. The Church of the Ascension at Kolomenskoye, which dates from 1532, is another UNESCO World Heritage Site and a popular attraction. Near the New Tretyakov Gallery, there is a sculpture garden, Museon—often called "the graveyard of fallen monuments"—that displays statues from the former Soviet Union that were removed from their places after the USSR's dissolution. Other Moscow attractions include the Moscow Zoo, a zoological garden in two sections (the valleys of two streams) linked by a bridge, containing nearly 1,000 species and more than 6,500 specimens. Each year, the zoo attracts more than 1.2 million visitors. Many of Moscow's parks and landscaped gardens are protected natural environments.
== Further reading == Glutathione synthetase deficiency at NLM Genetics Home Reference Beutler, E; Gelbart, T; Pegelow, C (1986). "Erythrocyte glutathione synthetase deficiency leads not only to glutathione but also to glutathione-S-transferase deficiency". Journal of Clinical Investigation. 77 (1): 38–41. doi:10.1172/JCI112298. PMC 423305. PMID 3944259.
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.