Everything below concerns lyophilised powder. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-10-18. Numbers and descriptions here follow the published literature rather than marketing material.
The compound was developed in the late 1980s and early 1990s by academic researchers investigating melanocortin signaling and pigmentation. Early work explored whether synthetic analogs could reproduce effects of the natural hormone under controlled conditions. The molecule never advanced through the full regulatory pathway required for approval as a medicine. From the mid-2000s onward it appeared in unregulated consumer markets, often distributed through informal channels. That gap between research origins and commercial availability shapes how the compound is discussed today.
Melanotan-2 is a synthetic peptide designed as an analog of alpha-melanocyte-stimulating hormone, a signaling molecule produced in the pituitary and skin. Its structure is a linear chain of seven amino acids that folds into a ring through an internal lactam bridge joining two side chains. The compound is sometimes written as MT-II or MEL-2 in informal and commercial contexts. It belongs to the melanocortin peptide family, a group of short signaling molecules that share a conserved core sequence recognized by melanocortin receptors.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic cyclic heptapeptide | Analog of alpha-MSH with an internal lactam bridge |
| Molecular weight | Approximately 1024 daltons | Free base value; salt forms differ |
| Appearance | White to off-white powder | Usually supplied as a lyophilized solid |
| Solubility | Freely soluble in water | Poorly soluble in nonpolar solvents |
| Typical storage | −20 °C, dry, protected from light | Repeated freeze-thaw cycles degrade peptides |
No regulatory authority has approved melanotan-2 for human use, and several countries classify it as a prescription-only or controlled substance, which restricts lawful supply. Material sold online is generally labelled as a research chemical and is not required to meet pharmaceutical standards of identity or purity. Published human data consist mainly of small uncontrolled studies, case reports and adverse-event notifications, so the evidence base is descriptive rather than confirmatory. Whether repeated melanocyte stimulation alters long-term naevus behaviour remains an open question that no completed trial has resolved.
Melanotan-2 is a synthetic cyclic heptapeptide designed as a structural analogue of alpha-melanocyte-stimulating hormone, the endogenous tridecapeptide that regulates pigment production. Two modifications distinguish it from the natural hormone: norleucine replaces methionine at the N-terminus, which limits oxidation, and a D-phenylalanine substitution raises receptor affinity. The ring is closed through an aspartate-lysine lactam bridge, giving the molecule a constrained conformation. The free base has a molecular mass near 1024 daltons, and commercial material is usually supplied as an acetate salt. It appears in the literature as a research peptide rather than an approved therapeutic agent.
Routine characterisation relies on reversed-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres, using a C18 column and a water-acetonitrile gradient containing trifluoroacetic acid. Electrospray ionisation mass spectrometry confirms the expected molecular mass and can reveal truncated or oxidised by-products that co-elute poorly. Sequence and stereochemistry require additional work, such as peptide mapping or amino acid analysis, because a chromatographic purity figure alone does not distinguish a diastereomer from the target peptide. Independent testing of research-grade material frequently shows measured content below the stated label, so a certificate of analysis is best read together with the method that produced it.
Melanotan-2 is handled in the laboratory as a lyophilised powder that dissolves readily in water, dimethyl sulfoxide and dimethylformamide, with limited solubility in ethanol. Stock solutions prepared in an organic solvent often precipitate when diluted into aqueous buffer, so gradual dilution with mixing is standard practice. The peptide carries a tryptophan residue and a histidine residue, both sensitive to oxidation and to alkaline conditions. Working solutions are therefore kept near neutral to slightly acidic pH, protected from light, and consumed within the same working session whenever that is practical.
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.
The knockout stage used a single-elimination format, starting with the newly introduced round of 32 on June 28 and culminating with the final on July 19, with a match for third place the day before. If the score was even after regulation time in a match, 30 minutes of extra time were added. If still tied after this, a penalty shootout determined the winner.
== Career == After his studies at Leipzig had ended, he began a year of work at the Moabit Hospital in Berlin as the resident pathologist. During this time, he began his research and studies on the issue of atherosclerosis. His first published works, dated during this period were in on the development of atherosclerosis in experimental animals when administered cholesterol. He also spent time working in the laboratory of Peter Rona at the Berlin Municipal Hospital. In 1926, Schoenheimer was invited by Ludwig Aschoff to join the faculty at the University of Freiburg. There he worked as an assistant professor. The investigation of pathological material was part of his work duties. During this time, he also researched atherosclerosis and the role of dietary cholesterol in its development. He became the active in 1927, and then the titular, head of his division in 1931. In 1930, until 1931, Schoenheimer was in the United States as the Douglas Smith Fellow at the University of Chicago. During this time Schoenheimer came into contact with the Josiah Macy Jr Foundation. Later in 1931, The Macy Foundation, with Ludwig Kast as its president, started supporting Schoenheimer in his atherosclerosis studies. Following his fellowship, he returned to the University of Freiburg, taking the position of head of the Pathological Chemistry department.
== Contraindications == Oxprenolol is a potent beta blocker and should not be administered to asthmatics under any circumstances due to their low beta levels as a result of depletion due to other asthma medication, and because it can cause irreversible, often fatal, airway failure and inflammation.
Severe side effects are rare and occur mostly in those with poor immune function. Its use in people with HIV/AIDS should be done with care. It is not recommended during pregnancy; however, the few times it has been given during pregnancy no problems resulted. The vaccine is available either by itself or along with the MMR vaccine, in a version known as the MMRV vaccine. It is made from weakened virus. A live attenuated varicella vaccine, the Oka strain, was developed by Michiaki Takahashi and his colleagues in Japan in the early 1970s. American vaccinologist Maurice Hilleman's team developed a chickenpox vaccine in the United States in 1981, based on the "Oka strain" of the varicella virus. The chickenpox vaccine first became commercially available in 1984. It was first licensed for use in the US by Merck, under the brand name Varivax, in 1995. It is on the World Health Organization's List of Essential Medicines.
Sources: en.wikipedia.org
In 1958, the UN established a Good Offices Committee which continued to invite South Africa to bring South West Africa under trusteeship. The Good Offices Committee proposed a partition of the mandate, allowing South Africa to annex the southern portion while either granting independence to the north, including the densely populated Ovamboland region, or administering it as an international trust territory. The proposal met with overwhelming opposition in the General Assembly; fifty-six nations voted against it. Any further partition of South West Africa was rejected out of hand.
=== World Health Organization === Vaccines developed for multinational distribution via the United Nations Children's Fund (UNICEF) require pre-qualification by the WHO to ensure international standards of quality, safety, immunogenicity, and efficacy for adoption by numerous countries. The process requires manufacturing consistency at WHO-contracted laboratories following Good Manufacturing Practice (GMP). When UN agencies are involved in vaccine licensure, individual nations collaborate by 1) issuing marketing authorization and a national license for the vaccine, its manufacturers, and distribution partners; and 2) conducting postmarketing surveillance, including records for adverse events after the vaccination program. The WHO works with national agencies to monitor inspections of manufacturing facilities and distributors for compliance with GMP and regulatory oversight. Some countries choose to buy vaccines licensed by reputable national organizations, such as EMA, FDA, or national agencies in other affluent countries, but such purchases typically are more expensive and may not have distribution resources suitable to local conditions in developing countries.
The fundamental process in photoionization is the absorption of a high-energy photon by the molecule and subsequent ejection of an electron. In direct APPI, this process occurs for the analyte molecule, forming the molecular radical cation M•+. The analyte radical cation can be detected as M•+ or it can react with surrounding molecules and be detected as another ion. The most common reaction is the abstraction of a hydrogen atom from the abundant solvent to form the stable [M+H]+ cation, which is usually the observed ion. In dopant-APPI (or photoionization-induced APCI), a quantity of photoionizable molecules (e.g., toluene or acetone) is introduced into the sample stream to create a source of charge carriers. Use of a photoionizable solvent can also achieve the same effect. The dopant or solvent ions can then react with neutral analyte molecules via proton transfer or charge exchange reactions. The above table simplifies the dopant process. In fact, there may be extensive ion-molecule chemistry between dopant and solvent before the analyte becomes ionized. APPI can also produce negative ions by creating a high abundance of thermal electrons from dopant or solvent ionization or by photons striking metal surfaces in the ionization source. The cascade of reactions that can lead to M− or dissociative negative ions [M-X]− often involve O2 as an electron charge carrier. Examples of negative ionization mechanisms include: Direct or dopant-assisted negative ion APPI
Lücking and colleagues (2021) emphasize distinguishing real species from minor variants with differing allele frequencies or subtle sequence divergence. These issues reflect the balance between scientific progress and maintaining a practical, stable nomenclature for ecological and conservation work. The LPR framework is one attempt to impose a higher bar: requiring evidence of reproductive isolation or ecological differentiation, not just genetic distinctness, to call something a new species. Additionally, nomenclatural stability is an ongoing issue. When molecular studies reorder relationships, it often necessitates changes in genus or family assignments. The 2016 global lichen classification (and its 2017 update) made hundreds of such changes to align names with phylogeny. They noted that fully half of all lichen genera had to be moved to a different family or order compared to the previous decade's understanding. These scientifically justified changes can be disruptive for end-users like ecologists or land managers who suddenly have to learn new names for familiar organisms. The challenge for systematists is to communicate these changes clearly and perhaps even temper the pace of renaming by holding off until results are strongly corroborated. Some stability measures (like proposing nomenclatural conservation of widely used names even if they are technically nested in another group) can mitigate the impact on the broader community.
There have been several structures solved for this class of enzymes, given PDB accession codes, and published in peer-reviewed journals. At least 4 such structures have been solved using pig enzymes: PDB: 1OHV, PDB: 1OHW, PDB: 1OHY, PDB: 1SF2, and at least 4 such structures have been solved in Escherichia coli: PDB: 1SFF, PDB: 1SZK, PDB: 1SZS, PDB: 1SZU. There are actually some differences between the enzyme structure for these organisms. E. coli enzymes of GABA-T lack an iron-sulfur cluster that is found in the pig model. Amino acid residues found in the active site of 4-aminobutyrate transaminase include Lys-329, which are found on each of the two subunits of the enzyme. This site will also bind with a pyridoxal 5'- phosphate co-enzyme. Aminooxyacetic acid Gabaculine Phenelzine Phenylethylidenehydrazine (PEH) Rosmarinic acid Valproic acid Vigabatrin 4-Aminobutyrate+Transaminase at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Pearl PL, Parviz M, Hodgeman R, Gibson KM, Reimschisel T (2015). "GABA-transaminase deficiency". MedLink Neurology.
Sources: en.wikipedia.org
234U occurs in natural uranium as an indirect decay product of uranium-238, but makes up only 55 parts per million of the uranium because its half-life of 245,500 years is only about 1/18,000 that of 238U. The path of production of 234U is this: 238U alpha decays to thorium-234. Next, with a short half-life, 234Th beta decays to protactinium-234. Finally, 234Pa beta decays to 234U. 234U alpha decays to thorium-230, except for a small percentage of nuclei that undergo spontaneous fission. Extraction of small amounts of 234U from natural uranium could be done using isotope separation, similar to normal uranium-enrichment. However, there is no real demand in chemistry, physics, or engineering for isolating 234U. Very small pure samples of 234U can be extracted via the chemical ion-exchange process, from samples of plutonium-238 that have aged somewhat to allow some alpha decay to 234U. Enriched uranium contains more 234U than natural uranium as a byproduct of the uranium enrichment process aimed at obtaining uranium-235, which concentrates lighter isotopes even more strongly than it does 235U. The increased percentage of 234U in enriched natural uranium is acceptable in current nuclear reactors, but (re-enriched) reprocessed uranium might contain even higher fractions of 234U, which is undesirable. This is because 234U is not fissile, though it is fertile. It tends to absorb slow neutrons in a nuclear reactor, becoming fissile 235U.
=== Legal status === Empagliflozin/metformin was approved for use in the European Union in May 2015. Empagliflozin/metformin was approved for use in the United States in August 2015. The extended release version was approved for use in the United States in December 2016. Empagliflozin/metformin was approved for use in Australia in May 2020.
=== Fraudulent products during the COVID-19 outbreak === During the COVID-19 pandemic in the United States, the FDA and Federal Trade Commission (FTC) warned consumers about marketing scams of fraudulent supplement products, including homeopathic remedies, cannabidiol products, teas, essential oils, tinctures and colloidal silver, among others. By August 2020, the FDA and FTC had issued warning letters to dozens of companies advertising scam products, which were purported "to be drugs, medical devices or vaccines. Products that claim to cure, mitigate, treat, diagnose or prevent disease, but are not proven safe and effective for those purposes, defraud consumers of money and can place consumers at risk for serious harm"
=== Plants === Potassium is crucial for diverse plant species. It has a vital role in maintaining cell sap and internal root pressure required for plant growth. Potassium increases plant metabolism and uptake of carbon dioxide.
Blunt-ended PCR product normally lacks a 5'-phosphate, therefore it needs to be phosphorylated by treatment with T4 polynucleotide kinase. Blunt-end ligation is also reversibly inhibited by high concentration of ATP. PCR usually generates blunt-ended PCR products, but note that PCR using Taq polymerase can add an extra adenine (A) to the 3' end of the PCR product. This property may be exploited in TA cloning where the ends of the PCR product can anneal to the T end of a vector. TA ligation is therefore a form of sticky end ligation. Blunt-ended vectors may be turned into vector for TA ligation with dideoxythymidine triphosphate (ddTTP) using terminal transferase.
Sources: en.wikipedia.org
It is a synthetic seven-amino-acid peptide modeled on alpha-melanocyte-stimulating hormone. It carries two non-natural substitutions and a cyclic bridge that increase its stability relative to the natural hormone. It circulates as a research chemical and is not an approved medicine.
Melanotan-1, also called afamelanotide, is a shorter linear analog with a different amino acid sequence and no lactam ring. It has been evaluated in formal clinical programs, while melanotan-2 has not. The two are distinct molecules and are not interchangeable.
No. Bremelanotide is a related but distinct cyclic peptide that reached approved status for one specific clinical indication. Melanotan-2 is a separate molecule with its own sequence and properties. Shared ancestry in the melanocortin family does not make them the same substance.
Only a small number of early-stage human studies have been reported, and most were limited in size and duration. No large late-stage program has established a general efficacy or safety profile. The evidence base is therefore thin compared with approved medicines.