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.
Updated 2025-08-18. Numbers and descriptions here follow the published literature rather than marketing material.
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.
| 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.
Human data remain limited and mostly short-term. Reports describe small trials and observational accounts rather than large controlled studies, so questions about dose-response relationships and long-term effects on melanocytes stay open. Whether repeated exposure alters naevus behaviour is not settled in the published record. Researchers also note that self-administered use outside clinical settings makes actual exposure difficult to quantify. Statements about efficacy and safety should therefore be read as preliminary rather than established.
Melanotan II is a synthetic cyclic heptapeptide that acts as an agonist at melanocortin receptors. It was designed as a structural analogue of alpha-melanocyte-stimulating hormone, the endogenous peptide involved in pigment production. The analogue carries a lactam bridge that constrains the ring and slows enzymatic breakdown relative to the native hormone. In research literature it appears under several abbreviations, and naming conventions are not fully standardized. Published descriptions usually place it within the broader melanocortin agonist family.
=== Singapore === Due to the risk of liver toxicity, the Health Sciences Authority of Singapore banned the sale of kava and its extracts in July 2002. The commercial sale, supply and import of "Piper methysticum (kava-kava), the active constituents of; kava pyrones (kavalactones); their quaternary compounds; their salts" remains banned in Singapore under the Poisons Act.
== Toxicity and overdose == The toxicity of nutmeg constituents such as myristicin has been studied and described in animals and in humans. There is at least one known case of death in humans, an eight-year-old boy who ate two whole nutmegs, became comatose, and then died within 24 hours, published in 1908. Other fatal cases have also since been reported. Cats are more sensitive to the toxic effects of nutmeg or isolated myristicin and after a delay of a few days die due to severe hepatotoxicity when given these substances in sufficient amounts. Hepatoxicity has also been observed in guinea pigs and rabbits given very high doses of nutmeg.
This multi-page article lists pharmaceutical drugs alphabetically by name. Many drugs have more than one name and, therefore, the same drug may be listed more than once. Brand names and generic names are differentiated by capitalizing brand names. See also the list of the top 100 bestselling branded drugs, ranked by sales. Abbreviations are used in the list as follows:
=== Puberty === Puberty is the onset of the ability to reproduce, and takes place over two to three years, producing a number of changes. The structures of the vulva become proportionately larger and may become more pronounced. Pubarche, the first appearance of pubic hair develops, firstly on the labia majora, and later spreads to the mons pubis, and sometimes to the inner thighs and perineum. Pubic hair is much coarser than other body hair, and is considered a secondary sex characteristic. Pubarche can occur independently of puberty. Premature pubarche may sometimes indicate a later metabolic-endocrine disorder seen at adolescence. The disorder sometimes known as a polyendocrine disorder is marked by elevated levels of androgen, insulin, and lipids, and may originate in the fetus. Instead of being seen as a normal variant it is proposed that premature pubarche may be seen as a marker for these later endocrine disorders. Apocrine sweat glands secrete sweat into the pubic hair follicles. This is broken down by bacteria on the skin and produces an odor, which some consider to act as an attractant sex pheromone. The labia minora may grow more prominent and undergo changes in color. At puberty, the first monthly period known as menarche marks the onset of menstruation. In prepubertal girls, the skin of the vulva is thin and delicate, and its neutral pH makes it prone to irritation. The production of the female sex hormone estradiol (an estrogen) at puberty, causes the perineal skin to thicken by keratinising, and this reduces the risk of infection.
The college's prospectus, published in 1884, offered three diplomas: Christian Scientist (C.S.) for Christian Scientists' Association members; Christian Metaphysician (C.M.) for Eddy's 12-lesson course and three years' practice; and Doctor of Christian Science (D.C.S.) for C.M.s whose "life and character conform to Divine science." In 1886, the Bachelor of Christian Science (C.S.B.) diploma was offered. Students could study metaphysics, science of the scriptures, mental healing and obstetrics, using two textbooks, Science and Health and the Bible. Between 1881 and October 1889, when Eddy closed the college, 4,000 students took the course at $300 per person or married couple, making her a rich woman. Mark Twain wrote sarcastically that she had turned a sawdust mine (possibly Quimby's) into a Klondike.
Sources: en.wikipedia.org
The short features a cover of "Pure Imagination" from Willy Wonka & the Chocolate Factory, sung by Fiona Apple. It was named one of the worst advertisements of 2013 by The Wall Street Journal. In 2011, Chipotle created the "Farm Team", which is a rewards program available only by invitation from restaurant managers. The Farm Team members have access to a special Chipotle website, where members can earn rewards, i.e. free food and T-shirts. The site offers members to, "learn where Chipotle's food comes from, take quizzes and polls, play games and watch videos about the company". In April 2014, the Farm Team program was shut down. Chipotle sponsors Team Garmin-Barracuda (formerly Team Garmin-Chipotle, Team Garmin-Slipstream, Team Garmin-Transitions and Team Garmin-Cervélo) of the International Cycling Union, and is an official team partner of the Boston Celtics, and the Boston Bruins. In June 2009, Chipotle sponsored free screenings of Food, Inc., a film that criticizes the corporate food industry. Founder Steve Ells stated that he hoped the film would make customers appreciate Chipotle's Food With Integrity policy. From May until September 2009, Chipotle ran a contest on mychipotle.com, a microsite which had a competition for the best user-created audio and video presentations about different combinations of ingredients. In July 2010, Chipotle began a campaign to support healthier lunch alternatives for students, in which money will be donated to The Lunch Box program based on how many spam Emails consumers forward to a company Email address.
== Diagnosis == A diagnosis of IRP may be suspected when there are symptoms of obstructed defecation. However, there are many other possible factors which may contribute to obstructed defecation. The medical history is taken, including any history of surgery involving the anal canal or rectum. Obstetric history (information about previous childbirths) is also potentially important. History of sexual abuse is also identified. The psychiatric or psychologic status of patients is usually assessed, because sometimes functional complaints are psychosomatic in nature. Mentally instability is also a relative contraindication for surgery.
=== One-two-hybrid === Simultaneous use of the one- and two-hybrid methods (that is, simultaneous protein–protein and protein–DNA interaction) is known as a one-two-hybrid approach and expected to increase the stringency of the screen.
Arthur 'Blaine' Bowman (born 1946 in Ogden, Utah, USA) is a leading proponent of ion chromatography, who has served variously as chairman, president, chief executive officer, and director of Dionex Corporation, a manufacturer of analytical instruments. Bowman received the 2015 Pittcon Heritage Award in recognition of his contributions to the field of ion chromatography. Arthur 'Blaine' Bowman was born in 1946 in Ogden, Utah, US. Around age 10, his family moved to Southern California, where he grew up. Bowman attended Brigham Young University in Provo, Utah in the physics program. As an undergraduate, he worked in the summer as an engineer at McDonnell Douglas, testing modules for the Apollo rocket. Bowman received his B.S. in physics in 1970. Next, Bowman worked as a product engineer at Motorola's Semiconductor Products Division in Phoenix, Arizona, where he became interested in business. He attended Stanford University's school of business from 1971 to 1973, receiving his M.B.A. in 1973. He then joined McKinsey & Company as a management consultant.
The non-selective sigma receptor agonists DTG and (+)-3-PPP partially substitute for ibogaine, whereas the σ1 receptor-selective agonists (+)-SKF-10,047 and (+)-pentazocine failed to substitute for ibogaine. These findings suggest a role of σ2 receptor signaling in the effects of ibogaine. Induction of gamma oscillations with a profile that resembles that of REM sleep may be involved in the hallucinogenic and oneirogenic effects of ibogaine. Noribogaine, but not ibogaine, produces psychoplastogenic effects in vitro in preclinical research. This can be blocked by the serotonin 5-HT2A receptor antagonist ketanserin, by the mTOR inhibitor rapamycin, and by a TrkB antagonist.
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.