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 2025-08-10. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Outside regulated medicine, melanotan II circulates through online vendors as a research chemical, often marketed for tanning. Products sold this way vary widely in purity, concentration, and labeling accuracy, and independent testing has documented discrepancies. Published reports describe both pigment effects and adverse reactions, including nausea, flushing, and darkening of existing moles. Long-term safety data are sparse, and no large controlled trial has established a risk profile. Questions about cumulative effects on melanocytes remain unresolved in the literature.
Melanotan II is a synthetic peptide analog modeled on alpha-melanocyte-stimulating hormone, a naturally occurring signaling peptide involved in pigmentation. Its structure is a cyclic heptapeptide containing two non-natural substitutions, norleucine at position four and D-phenylalanine at position seven. These modifications resist enzymatic breakdown and extend the molecule's activity relative to the native hormone. The compound binds melanocortin receptors and is studied mainly as a pharmacological tool rather than a therapeutic product. It has never received approval as a medicine in any major jurisdiction.
The compound was developed in the late 1980s and 1990s by academic researchers investigating photoprotection. The rationale held that stimulating melanin production might reduce ultraviolet damage to skin and lower skin cancer risk. Early work examined receptor binding, pigment response, and short-term tolerability in small studies. That program did not produce an approved drug, and formal development stalled after early-phase trials. Whether induced pigmentation confers meaningful photoprotection remains an open question.
| Property | Value | Notes |
|---|---|---|
| Solid-state storage | -20 degrees Celsius or lower | Desiccated and protected from light |
| Solution stability | Short and method-dependent | Confirm by stability testing |
| Purity assessment | Reversed-phase HPLC | Reported as area percent |
| Identity confirmation | LC-MS or comparable method | Mass match against expected value |
| Common synonyms | MT-II; melanotan II | Informal and catalogue names |
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.
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.
Identification in laboratories relies on reversed-phase liquid chromatography coupled with tandem mass spectrometry, with product-ion spectra compared against a certified reference standard. High-resolution mass spectrometry supplies accurate mass confirmation, and peptide mapping after enzymatic digestion separates melanotan II from closely related analogues. Quantitation of seized material is complicated by unknown counter-ions and residual trifluoroacetate left from purification. Immunoassays raised against alpha-melanocyte-stimulating hormone can cross-react, so chromatographic confirmation is normally required. Urinary detection windows are short, and reported limits of detection differ substantially between laboratories.
Melanotan II holds no marketing authorisation from the Food and Drug Administration, the European Medicines Agency, the UK Medicines and Healthcare products Regulatory Agency or Australia's Therapeutic Goods Administration. Products sold under that name are treated as unapproved new drugs, and their sale or import is prohibited in several jurisdictions. Other countries classify the peptide as a prescription-only medicine or place it among controlled substances, so the legal position changes with the destination market. No pharmacopoeial monograph supplies an official specification, because the material is not a licensed pharmaceutical. Consequently, products offered online are not manufactured to a shared public standard.
Although Prof. Rode's initial research activities were in field of inorganic chemistry, he soon extended his expertise into the rapidly developing field of theoretical and computational chemistry. Whereas in the beginning most studies focused on quantum chemical computations of a broad range of chemical systems, later application focused on the application of chemical simulation techniques such as Monte Carlo and molecular dynamics, mostly in the context of solution chemistry. A particular notable contribution of Prof. Rode's research is the development and application of hybrid quantum mechanical/molecular mechanical simulation techniques, focusing on a broad range of problems in solution chemistry. In 2004 an improved technique known as quantum mechanical charge field molecular dynamics explicitly aimed at the treatment of solvated systems has been developed in Prof. Rode's research group. During the last years the application of this technique enabled accurate simulations of ionic compounds and organic species as well as coordination complexes in aqueous solution. His most recent research is focussed on the lanthanoid ions in aqueous solution.
=== Non-dairy milk offerings === In 1997, Starbucks first offered non-dairy milk at its U.S. stores with the introduction of soy milk. In 2007, Starbucks stopped using milk originating from rBGH-treated cows. The company also adopted a new dairy standard for all espresso-based drinks, switching from whole to 2% reduced fat milk. In 2015, Starbucks began serving coconut milk. In 2016, it began serving almond milk. In January 2020, oat milk became available nationally. The company also offers non-dairy creamers at retail in partnership with Nestlé SA. CEO Kevin Johnson said in a 2020 interview that, milk substitutes would be a big part of reducing carbon emissions. That effort has prompted vegans, environmentalists, people with lactose intolerance and others to urge the company to eliminate the upcharge for drinks made with dairy-free milk. PETA encouraged sit-ins at Starbucks locations and purchased Starbucks stock to draw attention to what they believe is an unfair charge. A Starbucks Canada spokesperson told ET Canada that customizations such as added flavours, non-dairy beverages or an additional shot of espresso, would incur an additional charge. In December 2020, Starbucks announced it would offer Oatly oat milk in all US stores starting in spring 2021. With the launch of their holiday menu in November 2024, Starbucks ended the upcharge for non-dairy milk additions to drinks.
For the first time, clubs were allowed to trade future selections from the next year's draft as well as the current draft. Geelong became the first AFL club to trade a future draft pick on 14 October 2015 when they traded their 2016 first round pick to Carlton for Lachie Henderson.
== Society and culture == It is manufactured by GlaxoSmithKline (GSK), Mylan Pharmaceuticals, Cipla, Dr. Reddy's Laboratories and Sun Pharmaceutical. The discovery of the drug's utility in restless legs syndrome has been used as an example of successful drug repurposing.
=== 1961 === January 3: President Eisenhower severs diplomatic relations with Cuba. January 13: Patrice Lumumba, elected President of the Republic of the Congo (Léopoldville) is assassinated with the support of the CIA in the context of the Congo Crisis January 20: John F. Kennedy becomes President of the United States. January 31: Ham is launched into space as a part of Project Mercury, a mission to successfully place a human into orbit and return them safely. February 4: Angolan nationalists, including communists, begin an insurgency against Portuguese rule. This marked the beginning of the Portuguese Colonial War. February 12: Venera 1 is successfully launched by the Soviet Union with the intention of conducting a flyby mission to Venus. April 12: Yuri Gagarin becomes the first human in space and first to orbit the Earth when the Soviet Union successfully launches Vostok 1. April 17–19: Bay of Pigs Invasion: A CIA-backed invasion of Cuba by counter-revolutionaries ends in failure. April 21: Sierra Leone becomes independent from the UK under Commonwealth status. May 5: Alan Shepard becomes the first American to go into space when Freedom 7 is launched successfully. May 19: Venera 1 successfully reaches Venus being the first spacecraft to do so, but is unable to transmit any data. May 25: John F. Kennedy announces the US intention to put a man on the Moon – kickstarting Project Mercury, America's first human spaceflight program. June 4: Kennedy meets with Khrushchev in Vienna.
Sources: en.wikipedia.org
Frequently, neighborhood associations relied on restrictive covenants to mandate legal barriers to black homeownership in middle-class neighborhoods to avoid the radical disinvestment that would stem from a racially integrated neighborhood. During the legality of restrictive covenants, these deed restrictions were explicitly racist and took the form of; "people of color can't purchase this home", or only for the "Caucasian race". By leveraging the legally discriminatory capacity of restrictive covenants, neighborhood associations prioritized the stability of homeownership through the preservation of neighborhood investment and relatively high single-family home values. The homogenization of the economic and social fabric of middle-class neighborhoods reflected the white-afflicted segregation of Black Detroiters that confined these residents to Detroit's oldest and worst housing stock. However, in the midst of a mid-twentieth century movement for civil rights reform, certain hallmark legal cases of discrimination in housing such as Shelley vs Kraemer deemed restrictive covenants unconstitutional. Upon this Supreme Court ruling, neighborhood associations were forced to change their restrictive zoning regulations as black Detroiters began moving out of the dilapidated Detroit ghetto and sought residency in middle-class neighborhoods. Therefore, the repealing of restrictive covenants resulted in neighborhood associations relying on extralegal subversions of restrictive covenants to alternatively stunt black residential integration.
=== Precursor of nitric oxide === L-Arginine is the sole precursor of nitric oxide in humans and many other animals (NO), one of the smallest messenger substances in the human body. Through the action of NO synthases (nitric oxide synthases), L-arginine is converted into the endothelium-derived relaxing factor (EDRF), which has been identified as NO. Physiologically, EDRF induces vasodilation by diffusing NO into the vascular smooth muscle layer. There, it activates soluble guanylate cyclase, leading to relaxation of the smooth muscle and a reduction in vascular tone. Studies show that arginine can significantly reduce elevated blood pressure through this vasodilatory effect.
== Properties == The alcohol dehydrogenases comprise a group of several isozymes that catalyse the oxidation of primary and secondary alcohols to aldehydes and ketones, respectively, and also can catalyse the reverse reaction. In mammals this is a redox (reduction/oxidation) reaction involving the coenzyme nicotinamide adenine dinucleotide (NAD+).
Tropoelastin is a protein, of size 72kDa, that comes together via cross-links to form elastin in the extracellular matrix of the cell. The cross-link formation process is mediated by lysyl oxidase. One of the major reasons that elastin can withstand high levels of stress in the body without experiencing any physical deformation is that the underlying tropoelastin contains domains that are highly hydrophobic. These hydrophobic domains, consisting overwhelmingly of alanine, proline, glycine, and valine, tend towards instability and disorderliness, ensuring that the elastin does not lock into any specific confirmation. Thus, ELPs consisting of the Val-Pro-Gly-X-Gly monomeric units, which bear resemblance to the repetitive tropoelastin hydrophobic domains, are highly disordered below their Tt. Even above their Tt in their aggregated state, ELPs are only partially ordered. This is due to the fact that the proline and glycine amino acids are present in high amounts in the ELP. Glycine, due to the lack of a bulky side chain, enables the biopolymer to be flexible and proline prevents the formation of stable hydrogen bonds in the ELP backbone. Certain segments of the ELP may be able to form instantaneous type II β turns, but these turns are not long-lasting and do not resemble true β sheets, when the NMR chemical shifts are compared.
A schematic diagram of instrumentation which can be used for electron ionization is shown to the right. The ion source block is made out of metal. As the electron source, the cathode, which can be a thin filament of tungsten or rhenium wire, is inserted through a slit to the source block. Then it is heated up to an incandescent temperature to emit electrons. A potential of 70 V is applied between the cathode and source block to accelerate them to 70 eV kinetic energy to produce positive ions. The potential of the anode (electron trap) is slightly positive and it is placed on the outside of the ionization chamber, directly opposite to the cathode. The unused electrons are collected by this electron trap. The sample is introduced through the sample hole. To increase the ionization process, a weak magnetic field is applied parallel to the direction of the electrons' travel. Because of this, electrons travel in a narrow helical path, which increases their path length. The positive ions that are generated are accelerated by the repeller electrode into the accelerating region through the slit in the source block. By applying a potential to the ion source and maintaining the exit slit at ground potential, ions enter the mass analyzer with a fixed kinetic energy. To avoid the condensation of the sample, the source block is heated to approximately 300 °C.
Sources: en.wikipedia.org
Certain serpins spontaneously undergo the S to R transition without having been cleaved by a protease, to form a conformation termed the latent state. Latent serpins are unable to interact with proteases and so are no longer protease inhibitors. The conformational change to latency is not exactly the same as the S to R transition of a cleaved serpin. Since the RCL is still intact, the first strand of the C-sheet has to peel off to allow full RCL insertion. Regulation of the latency transition can act as a control mechanism in some serpins, such as PAI-1. Although PAI-1 is produced in the inhibitory S conformation, it "auto-inactivates" by changing to the latent state unless it is bound to the cofactor vitronectin. Similarly, antithrombin can also spontaneously convert to the latent state, as an additional modulation mechanism to its allosteric activation by heparin. Finally, the N-terminus of tengpin, a serpin from Thermoanaerobacter tengcongensis, is required to lock the molecule in the native inhibitory state. Disruption of interactions made by the N-terminal region results in spontaneous conformational change of this serpin to the latent conformation.
Distinguished as a biochemist. Was the first to show the possibility of using counter-current liquid-liquid extraction in the separation of N-acetylamino acids. In collaboration with A.J.P. Martin this led to the development of partition chromatography, which they have applied with conspicuous success in problems related to the composition and structure of proteins, particularly wool keratin. Synge's recent work on the composition and structure of gramicidins is outstanding and illustrates vividly the great advances in technique for which he and Martin are responsible. In 1963 he was elected a Fellow of the Royal Society of Edinburgh. His proposers were Magnus Pyke, Andrew Phillipson, Sir David Cuthbertson and John Andrew Crichton. He was for several years the treasurer of the Chemical Information Group of the Royal Society of Chemistry, and was an honorary Professor in Biological Sciences at the University of East Anglia from 1968 to 1984. He was awarded an honorary Doctor of Science (ScD) from the University of East Anglia in 1977, and an honorary doctorate from the Faculty of Mathematics and Science at Uppsala University, Sweden in 1980.
Plastination is a technique or process used in anatomy to preserve bodies or body parts, first developed by Gunther von Hagens in 1977. The water and fat are replaced by certain plastics, yielding specimens that can be touched, do not smell or decay, and even retain most properties of the original sample.
In terms of management, many professionals have limited knowledge of associated metabolic conditions, recommended screening, and psychological impacts. Diagnosis is often delayed, and those with PMOS are usually dissatisfied with care.
Sources: en.wikipedia.org
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.
There is no single harmonised standard governing these products, and manufacturing conditions differ. Impurities may include truncated sequences, oxidation products, residual solvents, and counter-ions. Independent testing is often the only way to characterise a given lot.
Reported studies have looked at pigmentation, photoprotection, and metabolic or appetite-related endpoints in small experimental settings. Much of the evidence base is early-stage and limited in size. Questions about long-term effects and clinical relevance remain open.
It is a synthetic cyclic peptide designed as an analog of alpha-melanocyte-stimulating hormone. It acts on melanocortin receptors and is best known from research into pigmentation. It is not an approved pharmaceutical product.