alpha-MSH analogue is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2026-04-28. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Published pharmacokinetic information is limited and comes mainly from small studies rather than registrational trials. Plasma half-life is usually described as short, on the order of tens of minutes, followed by rapid tissue distribution and clearance of the intact peptide. Metabolites and low concentrations of parent compound have been reported in urine, a detail relevant to anti-doping and forensic testing. Whether repeated exposure changes receptor sensitivity or clearance over time remains an open question. Values differ noticeably between analytical assays, so published numbers should be read as approximate rather than definitive.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Cyclic heptapeptide, C-terminally amidated |
| Approximate molecular mass | 1024 Da | Monoisotopic mass of the free peptide |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility class | Soluble in water and polar solvents | Also dissolves in neutral aqueous buffer |
| Common synonyms | Melanotan II, MT-II, MT-2 | Described as a melanocortin agonist in early literature |
Melanocytes are the pigment-producing cells of the skin, and they carry melanocortin-1 receptors on their surface. When the receptor is activated, cyclic adenosine monophosphate rises inside the cell and raises the activity of enzymes such as tyrosinase, which increases melanin output. Melanotan-2 binds melanocortin-1 receptors in vitro and in animal models, and this binding is generally described as the basis for the tanning effect. Other receptors account for different effects: melanocortin-4 receptors contribute to appetite and erectile signalling, while melanocortin-3 and melanocortin-5 receptors contribute to energy balance and exocrine function.
Early published reports described melanotan-2 as a tanning agent without sun protection, which means darkening is not the same as protection against ultraviolet radiation. Later studies explored the peptide in erectile dysfunction, hemorrhagic shock, and some skin conditions. No regulator in the United States or Europe has approved it for clinical use. Many products labelled melanotan-2 are sold without approval and their identity and purity are unverified. Its long-term safety in humans remains an open question.
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.
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.
Beryllium (4Be) has 11 known isotopes and 3 known isomers, but only one of these isotopes (9Be) is stable and a primordial nuclide. As such, beryllium is considered a monoisotopic element. It is also a mononuclidic element, because its other isotopes have such short half-lives that none are primordial and their abundance is very low. Beryllium is unique as being the only monoisotopic element with an even number of protons (even atomic number) and also has an odd number of neutrons; the 25 other monoisotopic elements all have odd numbers of protons (odd atomic number), and even of neutrons, so the total mass number is still odd. Of the 10 radioisotopes of beryllium, the most stable are 10Be with a half-life of 1.387 million years and 7Be with a half-life of 53.22 days. All other radioisotopes have half-lives shorter than 15 seconds. The 1:1 neutron–proton ratio seen in stable isotopes of many light elements (up to oxygen, and in elements with even atomic number up to calcium) is prevented in beryllium by the extreme instability of 8Be toward splitting into two 4He nuclei, which may be seen either alpha decay or a type of fission; in any case the half-life is only 8.2×10−17 s, short enough to normally be considered unbound. This, as with the relative instability of all lithium, beryllium, and boron isotopes, is favored due to the extremely tight binding of the helium-4 nucleus. Beryllium is prevented from having a stable isotope with 4 protons and 6 neutrons by the very lopsided neutron–proton ratio for such a light element.
== Engineering and computer science == Renewable energy target Renewable energy technology Resolution enhancement technology, image processing technology used to manipulate dot characteristics ret, return from subroutine instruction in the x86 assembly language Registered engineering technologist, former certification in Alberta, Canada Rehabilitation engineering technologist, a role in rehabilitation engineering Ret, a measurement of the resistance to evaporative heat loss
Dayhoff was born an only child in Philadelphia, but moved to New York City when she was ten. Her academic promise was evident from the outset – she was valedictorian (class of 1942) at Bayside High School, Bayside, New York, and from there received a scholarship to Washington Square College of New York University, graduating magna cum laude in mathematics in 1945 and getting elected to Phi Beta Kappa.
Following his defeat, Dingane burned his royal household and fled north. Mpande, the half-brother who had been spared from Dingane's purges, defected with 17,000 followers, and, together with Pretorius and the Voortrekkers, went to war with Dingane. Dingane was assassinated near the modern Swaziland border. Mpande then took over rulership of the Zulu nation. Following the campaign against Dingane, in 1839 the Voortrekkers, under Pretorius, formed the Boer republic of Natalia, south of the Tugela, and west of the British settlement of Port Natal (now Durban). Mpande and Pretorius maintained peaceful relations. However, in 1842, war broke out between the British and the Boers, resulting in the British annexation of Natalia. Mpande shifted his allegiance to the British, and remained on good terms with them. In 1843, Mpande ordered a purge of perceived dissidents within his kingdom. This resulted in numerous deaths, and the fleeing of thousands of refugees into neighbouring areas (including the British-controlled Natal). Many of these refugees fled with cattle. Mpande began raiding the surrounding areas, culminating in the invasion of Swaziland in 1852. However, the British pressured him into withdrawing, which he did shortly.
Type I: Properdin levels are unable to be detected Type II: Properdin levels are from 1-10% in comparison to normal levels; function is intact Type III: Properdin levels are normal but the function is absent Evaluations for properdin deficiency may take place in patients with frequenct Neisserial infections with a functioning classical complement pathway (CH50). The AH50 assay is based on the lysis of unsensitized rabbit erythrocytes, however, normal results have been reported in patients with Type I properdin deficiency. Family history of X-linked inheritance should be considered. Further testing includes: Factor D Function by Hemolytic Assay, Properdin Level by ELISA, and gene sequencing to detect mutations for confirmation. Patients with Factor D deficiency or properdin deficiency are advised to receive meningococcal vaccinations and frequent evaluations for meningococcal antibodies. For those with recurring infections, prophylactic antibiotics are administered.
Sources: en.wikipedia.org
– the particles are not coated or surface modified. In July 2025, the Scientific Committee on Consumer Safety (SCCS) adopted its fourth opinion (Submission IV), concluding that nano‑hydroxyapatite is safe at concentrations up to 29.5% in toothpaste and up to 10% in mouthwash, under defined particle morphology constraints.
=== Sulfur insertion into unreactive C-H bonds === Sulfurtransferases are a small subset of radical SAM enzymes. Two well-known examples are BioB and LipA which are independently responsible for biotin synthesis and lipoic acid metabolism, respectively.
== Early life and education == Melo was born on 24 July 1958. He was born and raised in Piracanjuba, in the interior of the state of Goiás. He moved to Porto Alegre in February 1978. He is married to Valéria Leopoldino, with whom he has two children: Pablo Melo and João Arthur. He graduated with a law degree from Unisinos.
Hydrolyzed vegetable protein (HVP) products are foodstuffs obtained by the hydrolysis of protein, and have a meaty, savory taste similar to broth (bouillon). Regarding the production process, a distinction can be made between acid-hydrolyzed vegetable protein (aHVP), enzymatically produced HVP, and other seasonings, e.g., fermented soy sauce. Hydrolyzed vegetable protein products are particularly used to round off the taste of soups, sauces, meat products, snacks, and other dishes, as well as for the production of ready-to-cook soups and bouillons.
Sources: en.wikipedia.org
=== Hospitals === The Assistance Publique–Hôpitaux de Paris (AP-HP) preserves numerous archives, some dating back to the Middle Ages. The oldest hospitalization registers—approximately one million pages—have been digitized and made available online. “Population registers” document admissions, discharges, births, and deaths. Each hospital maintains two types of annual records: alphabetical indexes to locate individuals and chronological registers specifying civil status, reasons for admission, and, in some cases, causes of death.
=== Approximation of the reactant === During enzyme catalytic reaction, the substrate and active site are brought together in a close proximity. This approach has various purposes. Firstly, when substrates bind within the active site the effective concentration of it significantly increases than in solution. This means the number of substrate molecules involved in the reaction is also increased. This process also reduces the desolvation energy required for the reaction to occur. In solution substrate molecules are surrounded by solvent molecules and energy is required for enzyme molecules to replace them and contact with the substrate. Since bulk molecules can be excluded from the active site this energy output can be minimised. Next, the active site is designed to reorient the substrate to reduce the activation energy for the reaction to occur. The alignment of the substrate, after binding, is locked in a high energy state and can proceed to the next step. In addition, this binding is favoured by entropy as the energy cost associated with solution reaction is largely eliminated since solvent cannot enter active site. In the end, the active site may manipulate the Molecular orbital of the substrate into a suitable orientation to reduce activation energy. The electrostatic states of substrate and active site must be complementary to each other. A polarized negatively charged amino acid side chain will repel uncharged substrate. But if the transition state involves the formation of an ion centre then the side chain will now produce a favourable interaction.
==== Administration ==== Drugs should only be administered using protective medical devices such as needle lists and closed systems and techniques such as priming of IV tubing by pharmacy personnel inside a ventilated cabinet. Workers should always wear personal protective equipment such as double gloves, goggles, and protective gowns when opening the outer bag and assembling the delivery system to deliver the drug to the patient, and when disposing of all material used in the administration of the drugs. Hospital workers should never remove tubing from an IV bag that contains an antineoplastic drug, and when disconnecting the tubing in the system, they should make sure the tubing has been thoroughly flushed. After removing the IV bag, the workers should place it together with other disposable items directly in the yellow chemotherapy waste container with the lid closed. Protective equipment should be removed and put into a disposable chemotherapy waste container. After this has been done, one should double bag the chemotherapy waste before or after removing one's inner gloves. Moreover, one must always wash one's hands with soap and water before leaving the drug administration site.
== Principles == Ion milling operates on the principles of sputtering and erosion. Sputtering occurs as the high-energy ions bombard the sample surface. Ions collide with the atoms and molecules on the surface and knock off surface atoms. As the high-energy ions are directed onto the material's surface, a collision cascade occurs. Ions bombard the surface of the specimen, and energy is transferred from the ions onto the surface atoms. If the transferred energy surpasses the binding energy of the target atoms, they are dislodged from the surface. Material that juts out has less surface binding energy and is more likely to be ejected through sputtering. As the ion milling process continues, the sample surface is slowly eroded away, resulting in a thin, flat, and damage-free surface. Specific results can be achieved by changing the angle of incidence of ions, the ion energy, and the type of ions used.
Nedaplatin, sold in Japan as Aqupla (see External Links), is a platinum-based chemotherapy agent. It is toxic to DNA, causing damage to DNA, limiting DNA repair and ultimately limiting DNA synthesis, limiting the propagation of cancer cells.
Sources: en.wikipedia.org
No. It is a synthetic analogue carrying four amino acid changes, a lactam ring and an amidated C-terminus. The natural hormone is a linear thirteen-amino-acid peptide processed from proopiomelanocortin.
Afamelanotide is the linear analogue [Nle4-D-Phe7]-alpha-MSH, sometimes called melanotan I, while melanotan II is cyclic and carries three further substitutions. The two are distinct molecules and are not interchangeable in analytical testing.
Binding to the four melanocortin receptor subtypes is well documented in vitro. The relative contribution of each subtype to whole-body effects in humans is far less certain.
No regulatory agency has authorised melanotan-2 as a medicine for any indication. It circulates mainly as a research chemical or through unregulated channels. As a result, identity, purity and content are not independently guaranteed.