The short version of research chemical fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-05-21. Anything still debated is marked as such rather than presented as settled.
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.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, which separates the target peptide from truncated or oxidised impurities. Mass spectrometry, most often coupled to liquid chromatography, confirms molecular mass and detects substitutions that chromatography alone may miss. Amino acid analysis and peptide mapping supply additional structural evidence, while nuclear magnetic resonance is reserved for full structural confirmation. Laboratories that examine samples sold online report wide variation in actual content, with some vials containing little or none of the labelled 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.
| Property | Value | Notes |
|---|---|---|
| Typical storage temperature | -20 °C or below | For the lyophilised powder, desiccated |
| Storage form | Sealed vial, protected from light | Amber glass or foil-wrapped containers |
| Reconstituted stability | Short, refrigerate | Degradation accelerates in solution |
| Typical analytical method | Reversed-phase HPLC with mass spectrometry | Purity assessment plus identity confirmation |
| Common synonyms | Melanotan II, MT-II | Also written melanotan-2 |
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.
Reversed-phase high-performance liquid chromatography is the routine method for purity assessment. Peptides absorb near 214 nm because of the peptide bond, and a gradient of acetonitrile in water separates the intact peptide from deletion sequences, oxidised products, and earlier-eluting fragments at neutral pH. Electrospray ionisation mass spectrometry provides an orthogonal check: the measured mass must agree with the theoretical value. Amino acid analysis and peptide mapping confirm structure but are used less often. Reference standards remain scarce because the peptide is not described in any pharmacopoeia.
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 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 research on the compound remains limited. Much of the human data comes from small, early-stage studies rather than large controlled trials, and several questions about effects and variability between individuals remain open. Investigators have examined receptor activity, pigment pathways, and related physiological responses in laboratory and animal models. Findings from those models do not automatically translate to human outcomes. Reviews frequently note the scarcity of rigorous clinical evidence and call for better-characterized study material.
Because the substance circulates mainly through informal markets, verification is a recurring theme in technical discussion. Independent analyses have found that labeled content and actual content can diverge, and that purity varies between samples. Analytical laboratories use reversed-phase chromatography to separate components and mass spectrometry to confirm identity. Isotope-labeled internal standards improve quantification in complex matrices. Such methods describe what a sample contains but say nothing about its sterility, lawful status, or suitability for any use. Open questions remain about how consistently testing is applied across the supply chain.
Regulatory treatment of this peptide varies by country. It holds no marketing authorization as a medicine in the United States, the European Union, or most other jurisdictions. Some countries classify products containing it as prescription-only or unlicensed medicines, which restricts lawful supply. Authorities have issued public notices warning that unregulated products may contain undeclared or incorrect ingredients. The molecule also appears on prohibited lists for competitive sport. These measures address supply oversight rather than any approved therapeutic role.
Melanotan II is a synthetic cyclic heptapeptide with the sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, corresponding to a molecular formula of C50H69N15O9 and a monoisotopic mass near 1024 daltons. It was designed as a structural analogue of alpha-melanocyte-stimulating hormone, a peptide hormone produced by cleavage of proopiomelanocortin. A lactam bridge between the aspartate and lysine side chains closes the ring, and the C-terminal amide removes a free carboxyl group. Both modifications increase resistance to enzymatic degradation compared with the linear parent hormone. Four substitutions distinguish it from afamelanotide, the linear analogue studied under the name melanotan I.
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.
=== Monotreme research === Flannery et al. (2026) review the fossil record and evolutionary history of monotremes. Chimento (2026) reports evidence of similarities of morphology of teeth and mandibles of monotremes, meridiolestidans and dryolestoids from Northern Hemisphere, and interprets the available data as consistent with origin of monotreme dental pattern from teeth of Gondwanan dryolestoids. Ziegler & Lockett (2026) report the discovery of a skull of Megalibgwilia owenii from the Foul Air Cave in the Buchan Caves Reserve, representing the first record of the species from Victoria (Australia).
== Mechanical stress and activity indicators == Examining the effects that activities has upon the skeleton allows the archaeologist to examine who was doing what kinds of labor, and how activities were structured within society. Labor within the household may be divided according to gender and age, or be based on other social structures. Human remains can allow archaeologists to uncover these patterns. Living bones are subject to Wolff's law, which states that bones are physically affected and remodeled by physical activity or inactivity. Increases in mechanical stress tend to produce thicker and stronger bones. Disruptions in homeostasis caused by nutritional deficiency or disease or profound inactivity/disuse/disability can lead to bone loss. While the acquisition of bipedal locomotion and body mass appear to determine the size and shape of children's bones, activity during the adolescent growth period seems to exert a greater influence on the size and shape of adult bones than exercise later in life. Muscle or ligament attachment sites on bones (entheses) are also considered to be impacted by habitual biomechanical loading, leading to the occurrence of various entheseal changes. These changes are routinely used in the field to study activity-patterns.
In September 2017, the company announced it would acquire Rigontec, developer of a candidate to target the retinoic acid-inducible gene I pathway, for $554 million. In October 2017, the company granted the inaugural Merck-AGITG Clinical Research Fellowship in Gastro-Intestinal (GI) Cancer to David Lau, a professional in Melbourne, Australia. In June 2018, Merck acquired Viralytics, an Australian viral cancer drug company, for AUD$502 million. In 2018, Merck began the submission process for a Biologics License Application to the Food and Drug Administration under the Breakthrough Therapy Designation for an investigational vaccine, called V920, to fight the Zaire strain of the Ebola virus. In April 2019, the company acquired Immune Design for approximately $300 million, gaining access to its immunotherapy programs. It also acquired Antelliq Group for $2.4 billion, or $3.7 billion including debt. In May 2019, Merck announced it would acquire Peloton Therapeutics, developer of a HIF-2alpha inhibitor for Von Hippel–Lindau disease-associated renal cell carcinoma, for up to $2.2 billion. In June 2019, Merck announced it would acquire Tilos Therapeutics for up to $773 million. In November 2019, the company acquired Calporta, which focused on Parkinsons and Alzheimers treatments. In December 2019, Merck Animal Health acquired Vaki, an aquaculture company, from Pentair.
Biological thermodynamics of energy-requiring reactions Phosphorylation of Na+/K+-ATPase during the transport of sodium (Na+) and potassium (K+) ions across the cell membrane in osmoregulation to maintain homeostasis of the body's water content. Mediates enzyme inhibition Phosphorylation of the enzyme GSK-3 by AKT (Protein kinase B) as part of the insulin signaling pathway. Phosphorylation of src (pronounced "sarc") tyrosine kinase by C-terminal Src kinase (Csk) induces a conformational change in the enzyme, resulting in a fold in the structure, which masks its kinase domain, and is thus shut "off".
Highly refractory woods These woods are slow and difficult to dry if the final product is to be free from defects, particularly cracks and splits. Examples are heavy structural timbers with high density such as ironbark (Eucalyptus paniculata), blackbutt (E. pillularis), southern blue gum (E. globulus) and brush box (Lophostemon cofertus). They require considerable protection and care against rapid drying conditions for the best results. Moderately refractory woods These timbers show a moderate tendency to crack and split during seasoning. They can be seasoned free from defects with moderately rapid drying conditions (i.e. a maximum dry-bulb temperature of 85 °C can be used). Examples are Sydney blue gum (E. saligna) and other timbers of medium density, which are potentially suitable for furniture. Non-refractory woods These woods can be rapidly seasoned to be free from defects even by applying high temperatures (dry-bulb temperatures of more than 100 °C) in industrial kilns. If not dried rapidly, they may develop discolouration (blue stain) and mould on the surface. Examples are softwoods and low density timbers such as Pinus radiata.
Sources: en.wikipedia.org
== Chemistry == L-DOPA, also known as L-3,4-dihydroxyphenylalanine or L-3-hydroxytyrosine, is an aromatic amino acid derived from L-phenylalanine and L-tyrosine. It is a phenethylamine, monoamine, and catecholamine, and is a biological precursor of the neurotransmitters dopamine (3,4-dihydroxyphenethylamine), norepinephrine (3,4,β-trihydroxyphenethylamine), and epinephrine (3,4,β-trihydroxy-N-methylphenethylamine).
== Use in sport == Lipotropin is on the Prohibited List of substances by the World Anti Doping Agency. Lipotropin has also, under its alternate name AOD-9604 (Anti-Obesity Drug-9604), been connected with controversies in Australian Rules Football. Allegations have arisen around the use of the drug and its administration to players of the Essendon Football Club in the Essendon Football Club supplements saga, including weekly administration to players in the 2012 season. The matters are currently under investigation due to the relationship between Lipotropin and growth hormones, as noted by club medical staff.
== Characterization == Solution precipitation as a core synthesis technique produces homogenous-sized nanoparticles, which can be advantageous in controlling specific physical properties such as surface tension and packing density of the atoms in a crystalline lattice structure. The most common methods of characterizing nanoparticle size distribution and morphology of the core in aquasomes include scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In a study by Kommimeni et al. in 2012, researchers employed TEM to verify that the ceramic particles were spherical and also in the acceptable nano-range for aquasomes. The carbohydrate coating size can also be characterized using SEM and TEM, but Fourier-transform infrared spectroscopy (FTIR) is commonly utilized to check for the presence of the coat. In a study by Kommimeni et al. in 2020, FTIR was used to confirm the presence of the coating by analyzing the IR spectra bands that correspond to the functional groups of either the core or the sugar coat. The bioactive drug loaded onto the aquasome can be characterized in a variety of ways depending on the molecular classification of the drug. In Kossovsky et al. in 1996, which studied the effect of insulin as the bioactive drug of interest, immunogold labeling was employed. Through this technique, the different binding efficiencies of carbohydrate coatings for insulin were able to be observed.
Any condition that results in the production of abnormal hemoglobin is included under the broad category of hemoglobinopathies. Worldwide, it is estimated that 7% of the population may carry a hemoglobinopathy with clinical significance. The most well known condition in this group is sickle cell disease. Newborn screening for a large number of hemoglobinopathies is done by detecting abnormal patterns using isoelectric focusing, which can detect many different types of abnormal hemoglobins. In the United States, newborn screening for sickle cell disease was recommended for all infants in 1987, however it was not implemented in all 50 states until 2006. Early identification of individuals with sickle cell disease and other hemoglobinopathies allows treatment to be initiated in a timely fashion. Penicillin has been used in children with sickle cell disease, and blood transfusions are used for patients identified with severe thalassemia.
The enzyme characterised from yeast converts nicotinamide adenine dinucleotide to nicotinamide adenine dinucleotide phosphate by transferring a phosphate group from the cofactor, adenosine triphosphate (ATP), which is converted to adenosine diphosphate (ADP). The enzyme is encoded by the gene NADK2. This enzyme is a transferases, specifically one transferring phosphorus-containing groups (phosphotransferases) with an alcohol group as acceptor. The systematic name of this enzyme class is ATP:NADH 2'-phosphotransferase. Other names in common use include reduced nicotinamide adenine dinucleotide kinase (phosphorylating), DPNH kinase, reduced diphosphopyridine nucleotide kinase, and NADH kinase. This enzyme has at least one activator, acetate.
Sources: en.wikipedia.org
==== In midlife ==== The midlife crisis may mark the first reliable drop in happiness during an average human's life. Evidence suggests most people generally become happier with age, with the exception of the years 40 – 50, which is the typical age at which a crisis might occur. Researchers specify that people in both their 20s and 70s are happier than during midlife, although the extent of happiness changes at different rates. For example, feelings of stress and anger tend to decline after age 20, worrying drops after age 50, and enjoyment very slowly declines in adulthood but finally starts to rise after age 50. Well-being in late life is more likely to be related to other contextual factors including proximity to death. However, most of this terminal decline in well-being could be attributed to other changes in age-normative functional declines including physical health and function. Also, there is growing debate that assumptions that a single population estimate of age-related changes in well-being truly reflects the lived experiences of older adults has been questioned. The use of growth mixture modelling frameworks has allowed researchers to identify homogenous groups of individuals who are more similar to each other than the population based on their level and change in well-being and has shown that most report stable well-being in their late life and in the decade prior to death.
Brower has been credited with popularizing the term "ecological chemistry" which appeared in the title of a paper he published in Science in 1968 and again the following year in an article he wrote for Scientific American, where the term also appeared on the front cover under an image of a giant bluejay towering over two monarch butterflies. The specialized Journal of Chemical Ecology was established in 1975, and the Journal Chemoecology was founded in 1990. In 1984, the International Society of Chemical Ecology was established and in 1996, the Max Planck Institute of Chemical Ecology was founded in Jena, Germany.
Hormones in cattle had been studied in North America for 50 years prior to the ban, accompanied by long-term use in over 20 countries. Canada and the United States asserted that these practices provided empirical evidence of long-term safety. The EU had already established other measures that restricted the import of North American beef. The primary North American product affected by the new ban was edible offal. A series of "hormone scandals" emerged in Italy in the late 1970s and early 1980s. The first, in 1977, was the discovery of premature puberty in northern Italian schoolchildren. Investigators cast suspicion on school lunches that used illegal hormone-treated meat. No concrete evidence was found–no samples of the suspect meals were available for analysis. In 1980 diethylstilbestrol (DES), another illegal synthetic hormone, was discovered in veal-based baby foods. Little or no scientific evidence supported these restrictions. However, consumer groups successfully influenced the European Parliament to enact regulations in the 1980s, and influenced public perceptions. In the US at the time, consumer organizations evinced little interest prior to the 1980s, and regulations were driven by a coalition of export-oriented industry and farming interests, opposed only by organic farming groups. Until 1980, the use of growth hormones was completely prohibited in Italy, Denmark, the Netherlands, and Greece. Germany, the EU's largest beef producer at the time, prohibited only exogenous growth hormones.
=== Theatres === Bromley has a number of theatres in the borough, in the town centre there are three, a professional, the Churchill Theatre, an amateur, the Bromley Little Theatre (close to Bromley North railway station) and an outdoor amphitheatre located in "Church House Gardens" behind the Churchill Theatre. The Churchill Theatre was opened on 19 July 1977 by the Prince of Wales, and seats 781. It is run on a contract currently held by HQ Theatres Ltd acting as both a receiving and producing house, with productions often transferring to the West End or touring nationally. Recent tours have included: An Inspector Calls (2024) and Fawlty Towers (2025).
== Function == The encoded protein, commonly abbreviated IRR, is an orphan receptor and one of three receptor tyrosine kinases in the insulin receptor family, alongside the insulin receptor and insulin-like growth factor 1 receptor. No endogenous peptide or protein ligand is known for IRR. In experimental systems, extracellular pH above approximately 7.9 activates the receptor and triggers autophosphorylation. The Human Protein Atlas classifies INSRR RNA expression as cell type enhanced in renal collecting-duct intercalated cells. In rodents, IRR has been localized to non-A intercalated cells; a rat study reported basolateral localization in type B intercalated cells of the cortical collecting duct. In mice, inactivation of Insrr impairs urinary bicarbonate excretion following alkali loading, supporting a role for the receptor in renal acid–base homeostasis. A 2023 cryo-electron microscopy study of the human IRR ectodomain, combined with mutagenesis and cell-based assays, supported a model in which alkaline pH produces electrostatic repulsion involving pH-sensitive motifs at an interprotomer interface, disrupting the autoinhibited state and promoting a scissor-like rotation into a T-shaped active conformation.
Sources: en.wikipedia.org
The lyophilised solid is best kept cold, dry and dark, typically at minus twenty degrees Celsius. Moisture and repeated warming cycles are the main causes of degradation. Solutions prepared from the powder are less stable and are normally used quickly.
Reversed-phase liquid chromatography assesses purity, while mass spectrometry confirms molecular mass and detects sequence errors. Amino acid analysis and peptide mapping add structural detail. These techniques are complementary rather than interchangeable.
It is listed as a prohibited peptide hormone by the World Anti-Doping Agency. No medicines regulator has approved it for human use. Import and sale rules vary by country.
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.