If you have been reading about cyclic heptapeptide 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.
Last reviewed on 2026-02-26. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| 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 jurisdiction and has changed over time. In several countries the peptide is handled as an unapproved prescription medicine, and import or sale for human use is restricted, while elsewhere it falls under poisons or controlled-substance schedules. Enforcement activity against online vendors has been reported in Australia, New Zealand, the United Kingdom and the United States. Scholarly writing discusses melanotan-2 chiefly as an experimental tool and as a case study in unregulated peptide supply, and its precise legal position in any given country should be checked against current national schedules.
Lyophilised melanotan-2 is comparatively robust when kept dry, cold and dark, and a desiccated powder stored at minus twenty degrees Celsius or below is generally expected to retain its chemical integrity for extended periods. In solution the peptide is far less stable, with degradation proceeding through oxidation of tryptophan and histidine residues, hydrolysis adjacent to the lactam bridge, and aggregation at higher concentrations. Repeated freeze-thaw cycling accelerates loss of the parent peak. Working aliquots are therefore prepared once, held cold, and used without letting the stock return to ambient temperature.
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.
Identity and purity are assessed mainly by reversed-phase high-performance liquid chromatography with ultraviolet detection, often paired with mass spectrometry. Retention time supports identity, while the mass spectrum confirms the molecular weight of the intact peptide. Purity is frequently reported as a percentage of total peak area, a figure that depends on the wavelength, column and gradient used. Impurity profiling may also look for truncated sequences, oxidised forms and residual counterions. Amino acid analysis and peptide mapping provide orthogonal confirmation when required.
Regulatory status varies by jurisdiction, and the substance is frequently described as unapproved for therapeutic use. Some authorities classify it alongside prescription-only medicines or controlled categories, while others address it through general consumer protection rules. Analytical surveys have reported mismatches between label claims and measured content in products sold online, although the scope of such testing is limited. Whether these discrepancies are widespread remains an open question. Discussion in the literature therefore tends to combine chemistry, supply-chain observation and policy analysis.
The material is commonly handled as a lyophilized powder in sealed vials. The solid dissolves readily in water and in polar organic solvents, producing a clear solution after reconstitution. Light, heat and repeated freeze-thaw cycles are the concerns most often raised in handling guidance, because peptide bonds and the constrained ring can degrade. Working solutions are generally prepared fresh, and material left in solution is treated as less stable than the dry form. These properties shape how laboratories store and aliquot reference material.
==== Distribution ==== The apparent volume of distribution of gepirone is approximately 94.5 L. The plasma protein binding of gepirone in vitro is 72% and is independent of concentration. The plasma protein binding of 3'-OH-gepirone is 59% and of 1-PP is 42%.
Due to Swedish law, stores in Sweden cannot sell cider with less than 15 percentage juice by volume under the name Cider. "Cider" with none or less than 15% juice is instead usually sold as "Apple/Pear beverage of cider character" (Swedish: "Äpple-/Pärondryck med Ciderkaraktär"). Brands of cider in Sweden include Rekorderlig, Kivik, Herrljunga and Kopparberg. As of 2024, there are around 30 producers of cider in Sweden. Cider beverages have a long history in Sweden since medieval times. Due to the strong impact from the Swedish temperance movement, nearly all beverages sold as cider during the 20th century were sweetened and flavoured non-alcoholic beverages similar to soft drinks. It was not until the 1990s that Systembolaget began to sell alcoholic cider. The notably sweet "Swedish cider" with flavours of apple and pear, or elderberry and wild berries, is consumed in many countries, including the United Kingdom as an alternative to traditional British cider.
At Arsenal, Wenger has enjoyed a great deal of support and backing from the club board of directors, who demonstrated exceptional faith in the manager and his long-term vision. His arrival at the club prompted a change in their football style – once derided as "boring, boring Arsenal" for a lack of creativity, pundit Alan Hansen described the 2004 team as "quite simply the most fluid, devastating team the British Isles has seen". Brian Clough once quipped: "Arsenal caress a football the way I dreamed of caressing Marilyn Monroe". Wenger himself reflected that his greatest legacy at Arsenal would be the style he implemented. Supporters regularly display banners such as "Arsène knows" and "In Arsène we trust" during home matches, though there became a growing number of protests against his management.
=== Extraction === After cooking, the alkaline liquid (known as nejayote from Nahuatl nexayotl - nextli 'ash' y ayotl 'liquid'), containing dissolved hull, starch, and other corn matter, is decanted and discarded (or sometimes used for making amate bark paper). The kernels are washed thoroughly of remaining nejayote, which has an unpleasant flavor. The pericarp is then removed, leaving the endosperm of the grain with or without the germ, depending on the process. This hulling is performed by hand, in traditional or very small-scale preparation, or mechanically, in larger scale or industrial production. The prepared grain is called hominy, mote, or nixtamal. Nixtamal has many uses, contemporary and historic. Whole nixtamal may be used fresh or dried for later use. Whole nixtamal is used in the preparation of pozole, menudo, and other foods. Ground fresh nixtamal is made into masa (nixtamal dough) and used to make tortillas, tamales, and pupusas. Dried and ground, it is called masa harina or instant masa flour, and is reconstituted and used like masa. The term hominy may refer to whole, coarsely ground, or finely ground nixtamal, or to a cooked porridge (also called grits) prepared from any of these. Samp is similar to grits, but a product of a different process.
By using QDs, only the necessary colors for ideal images are contained in the screen. The first commercial application of quantum dots was the Sony XBR X900A series of flat panel televisions released in 2013. In June 2006, QD Vision announced technical success in making a proof-of-concept quantum dot display and show a bright emission in the visible and near infrared region of the spectrum. A QD-LED integrated at a scanning microscopy tip was used to demonstrate fluorescence near-field scanning optical microscopy (NSOM) imaging.
Sources: en.wikipedia.org
On 23 August 1990 — just over a month before German reunification on 3 October — East Germany reconstituted the five original Länder. Legally, it was these Länder that then acceded to the Federal Republic of Germany. In reality, the restored Länder did not fully reconstitute themselves until after reunification. On 14 October 1990, elections to the Landtage (state parliaments) were held in the five new states, initiating the formation of state governments. Since changes to the boundaries of municipal districts were not reversed, and also due to considerations of expediency, the territorial make-up of the restored Länder differed somewhat from the borders before 1952. Saxony and Saxony-Anhalt initially retained the rural and urban districts as administrative entities (Regierungsbezirke). Saxony-Anhalt later abolished them in 2003, while Saxony transformed them into directorates in 2008.
There is no disease-modifying treatments proven to cure Alzheimer's disease, and because of this, AD research has focused on interventions to prevent the onset and progression. There is no evidence that supports any particular measure in preventing AD, and studies of measures to prevent the onset or progression have produced inconsistent results. Epidemiological studies have proposed relationships between an individual's likelihood of developing AD and modifiable factors, such as medications, lifestyle, and diet. There are some challenges in determining whether interventions for AD act as a primary prevention method, preventing the disease itself, or a secondary prevention method, identifying the early stages of the disease. These challenges include duration of intervention, different stages of disease at which intervention begins, and lack of standardization of inclusion criteria regarding biomarkers specific for AD. Further research is needed to determine factors that can help prevent AD.
== Identification == Burkholderia pseudomallei is not fastidious and grows on a large variety of culture media (blood agar, MacConkey agar, EMB, etc.). Ashdown's medium (or Burkholderia cepacia medium) may be used for selective isolation. Cultures typically become positive in 24 to 48 hours (this rapid growth rate differentiates the organism from B. mallei, which typically takes a minimum of 72 hours to grow). Colonies are wrinkled, have a metallic appearance, and possess an earthy odor. On Gram staining, the organism is a Gram-negative rod with a characteristic "safety pin" appearance (bipolar staining). On sensitivity testing, the organism appears highly resistant (it is innately resistant to many antibiotics including colistin and gentamicin) and that again differentiates it from B. mallei, which is in contrast, exquisitely sensitive to many antibiotics. For environmental specimens only, differentiation from the nonpathogenic B. thailandensis using an arabinose test is necessary (B. thailandensis is never isolated from clinical specimens). The laboratory identification of B. pseudomallei has been described in the literature. The classic textbook description of B. pseudomallei in clinical samples is of an intracellular, bipolar-staining, Gram-negative rod, but this is of little value in identifying the organism from clinical samples. Some suggest the Wayson stain is useful for this purpose, but this has been shown not to be the case. Laboratory identification of B. pseudomallei can be difficult, especially in Western countries where it is rarely seen.
Angus Monfries (born 19 January 1987) is a former professional Australian rules footballer who played for the Essendon Football Club and Port Adelaide Football Club in the Australian Football League (AFL). Monfries played as a forward pocket or half forward.
Flutamide, sold under the brand name Eulexin among others, is a nonsteroidal antiandrogen (NSAA) which is used primarily to treat prostate cancer. It is also used in the treatment of androgen-dependent conditions like acne, excessive hair growth, and high androgen levels in women. It is taken by mouth, usually three times per day. Side effects in men include breast tenderness and enlargement, feminization, sexual dysfunction, and hot flashes. Conversely, the medication has fewer side effects and is better-tolerated in women with the most common side effect being dry skin. Diarrhea and elevated liver enzymes can occur in both sexes. Rarely, flutamide can cause liver damage, lung disease, sensitivity to light, elevated methemoglobin, elevated sulfhemoglobin, and deficient neutrophils. Numerous cases of liver failure and death have been reported, which has limited the use of flutamide. Flutamide acts as a selective antagonist of the androgen receptor (AR), competing with androgens like testosterone and dihydrotestosterone (DHT) for binding to ARs in tissues like the prostate gland. By doing so, it prevents their effects and stops them from stimulating prostate cancer cells to grow. Flutamide is a prodrug to a more active form. Flutamide and its active form stay in the body for a relatively short time, which makes it necessary to take flutamide multiple times per day. Flutamide was first described in 1967 and was first introduced for medical use in 1983. It became available in the United States in 1989.
Sources: en.wikipedia.org
The cause of capsular contracture is unknown, but the common incidence factors include bacterial contamination, device-shell rupture, filler leakage, and hematoma. The surgical implantation procedures that have reduced the incidence of capsular contracture include submuscular emplacement, the use of breast implants with a textured surface (polyurethane-coated); limited pre-operative handling of the implants, limited contact with the chest skin of the implant pocket before the emplacement of the breast implant, and irrigation of the recipient site with triple-antibiotic solutions. The correction of capsular contracture might require an open capsulotomy (surgical release) of the collagen-fiber capsule, or the removal, and possible replacement, of the breast implant. Furthermore, in treating capsular contracture, the closed capsulotomy (disruption via external manipulation) once was a common maneuver for treating hard capsules, but now is a discouraged technique, because it can rupture the breast implant. Non-surgical treatments for collagen-fiber capsules include massage, external ultrasonic therapy, leukotriene pathway inhibitors such as zafirlukast (Accolate) or montelukast (Singulair), and pulsed electromagnetic field therapy (PEMFT).
=== Bison === Greeted by songs and prayers in the fall of 2014, 38 bison were transferred to the tribe from Badlands National Park. The herd, which has grown to about 215 bison, roams a 500-acre pasture (200 ha) in Bull Hollow.
When Anna asserts her reputation of being a pessimist about love, Ariadne tells her that she will win her back. Grace emerges from the shadows and she and Lucie talk about resurrecting Jesse. Magnus Bane finds Matthew feeling desolate, as he notices the younger boy looking towards James and Cordelia dancing merrily. It is then that he reveals his attraction towards Cordelia and hints about the false marriage. Magnus is intrigued and decides that he needed to stay in London for a little while longer. Cordelia reflects on how drastically her life had changed since her arrival in London. James talks to her and tells her that he wishes she could be happy. He also states that the events of the whispering room had been a pretense. Cordelia is saddened but resolves to spend this one year with James happily. Meanwhile, in Chiswick manor, Tatiana, who is now being banished to the Adamant Citadel, visits her son's coffin. She finds Belial waiting for her, and he says that he will rise much earlier than the Nephilim assumed. He also states that since Tatiana was now in the Adamant Citadel, they will strike at the heart of the Shadowhunters - their Adamas. Saying this he vanishes again, leaving Tatiana satisfied.
=== Soviet Union === One result of the Tehran Conference in November 1943 was an invitation for an Anglo-American scientific mission to visit the Soviet Union. The British team consisted of Florey and Sanders; the American of Albert Baird Hastings and Michael Boris Shimkin. After a month's travel via North Africa and Iran, they reached Moscow on 23 January 1944, where they met Soviet microbiologist Zinaida Yermolyeva. Florey gave her samples of penicillin, and she gave him a sample of the antibiotic Gramicidin S. He arrived back at Oxford on 29 March 1944.
Leukolike vectors are a type of nanoparticles made of nanoporous silicon encapsulated by extracted native leukocyte membranes. These particles were among the first artificial white blood cells to be studied as a proof of concept of using cellular membranes to prolong circulation of nanoparticles throughout the blood. Studies have shown that leukolike vectors have a specific advantage in chemotherapy drug delivery to cancer. This is because leukolike vectors specifically have the potential to bind to tumor endothelium.
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 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.