Everything below concerns alpha-MSH analogue. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-10-26. Numbers and descriptions here follow the published literature rather than marketing material.
The peptide was developed during the 1980s by researchers investigating melanocortin signalling and skin pigmentation pathways. Early work focused on analogues of alpha-melanocyte-stimulating hormone that would resist enzymatic breakdown more effectively than the parent molecule. Melanotan-2 emerged from that programme as a shortened, cyclised variant. Reports describing its synthesis and receptor activity later appeared in the scientific literature. Commercial availability grew through unregulated channels rather than through pharmaceutical approval.
Structurally, Melanotan-2 retains the core recognition motif of alpha-melanocyte-stimulating hormone while adding a lactam bridge that links two side chains and constrains the molecule into a ring. This modification lowers susceptibility to enzymatic degradation. The compound acts as an agonist at melanocortin receptors, particularly subtypes associated with melanin production. Because the same receptor family influences several physiological processes, researchers note that its activity is not confined to pigmentation alone. Receptor selectivity continues to be examined in published studies.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone, a naturally occurring peptide involved in pigmentation signalling. Its sequence incorporates modified residues that increase potency and extend biological activity relative to the native hormone. The compound binds receptors of the melanocortin family and is examined mainly in laboratory research. It does not occur naturally and exists only as a manufactured chemical entity produced by solid-phase synthesis.
Melanocortin receptors comprise five subtypes with distinct tissue distributions and functions. Melanotan-2 is described in the literature as a non-selective agonist that engages several of these subtypes, including MC1R, MC3R, MC4R, and MC5R. MC1R is the subtype most directly linked to melanin production in skin cells. Because the compound is not subtype-selective, its observed effects in experimental settings are generally attributed to activity across multiple receptor pathways rather than to a single target.
Melanotan-2 is a synthetic linear peptide built from seven amino acids arranged in a short chain. Its sequence is commonly written as Ac-Nle-Asp-His-D-Phe-Arg-Trp-Lys-NH2, which includes a modified N-terminus and an amidated C-terminus. The molecule belongs to the melanocortin family and acts as a receptor agonist. Structural features such as the D-phenylalanine residue and the Nle substitution are associated with increased stability against enzymatic degradation relative to the natural parent peptide.
The compound emerged from research programs in the 1980s that examined analogues of alpha-melanocyte-stimulating hormone for pigmentation and photoprotection. Investigators modified the native sequence to extend activity duration and potency. A related analogue, afamelanotide, was developed within the same broad line of inquiry and eventually gained approval in certain jurisdictions for a rare light-sensitivity condition. Melanotan-2 itself did not progress through the same regulatory route and has no approved therapeutic indication.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Synthetic cyclic heptapeptide |
| Molecular mass | Approximately 1024 g/mol | Depends on counter-ion content |
| Appearance | White to off-white powder | Commonly supplied as a lyophilised solid |
| Solubility | Freely soluble in water | Also dissolves in common aqueous buffers |
| Typical storage | -20 degrees Celsius, desiccated | Protect from light and repeated freeze-thaw |
Activity is attributed to agonism at melanocortin receptors, particularly MC1R and MC4R. Activation of MC1R on melanocytes increases melanin synthesis, which underlies the reported tanning effect. MC4R engagement in the central nervous system is linked to appetite suppression and to effects on sexual arousal reported in early clinical studies. Those studies were small and were not designed to establish efficacy or long-term safety. Receptor selectivity among the melanocortin subtypes is not absolute, which complicates attribution of any effect to a single pathway.
Regulatory treatment varies between countries. Several national medicines agencies have classified the peptide as unapproved, and customs authorities in some jurisdictions seize shipments on that basis. A few jurisdictions channel supply through prescription-only frameworks that do not list the substance by name. Because the material circulates mainly through online vendors, composition and purity are rarely verified before sale. Surveys of unapproved peptide products have reported labels that did not match measured content in a substantial fraction of samples.
Melanotan II is a synthetic cyclic heptapeptide with the sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, corresponding to a molecular formula of C50H69N15O9 and a monoisotopic mass near 1024 daltons. It was designed as a structural analogue of alpha-melanocyte-stimulating hormone, a peptide hormone produced by cleavage of proopiomelanocortin. A lactam bridge between the aspartate and lysine side chains closes the ring, and the C-terminal amide removes a free carboxyl group. Both modifications increase resistance to enzymatic degradation compared with the linear parent hormone. Four substitutions distinguish it from afamelanotide, the linear analogue studied under the name melanotan I.
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.
Two structural changes distinguish the synthetic peptide from the natural hormone. A norleucine residue replaces methionine at one position, and a D-configured phenylalanine replaces the natural L-form at another. Both substitutions slow enzymatic breakdown, which extends the molecule's persistence relative to the parent hormone. The lactam bridge further constrains the backbone into a stable conformation. These features are standard design strategies in peptide chemistry and are not unique to this compound; they appear across many research peptides built for improved stability.
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.
== Applications of SSMS == Spark source mass spectrometry has been used for trace analysis and multielement analysis applications for highly conducting, semiconducting, and nonconducting materials. Some examples of SSMS applications are the trace element analysis of high-purity materials, multielement analysis of elements in technical alloys, geochemical and cosmochemical samples, biological samples, industrial stream samples, and radioactive material.
=== Setting and characters === Whereas Half-Life was set in a single location, the Black Mesa research facility, Valve wanted "a much more epic and global feel" for the sequel. One concept had the player teleporting between planets, which was discarded as it would make continuity between levels difficult. At the suggestion of the art director, Viktor Antonov, who was Bulgarian, the team settled on a city in an Eastern European location. In this early concept, players would start at the boarding of the Borealis, an icebreaker bound for the city. Nova Prospekt was conceived as a small rail depot built on an old prison in the wasteland and grew from a stopping-off point to the destination itself. After observing how players had connected to minor characters in Half-Life, the team developed the characterization, with more detailed character models and realistic animation. The animator Ken Birdwell studied the work of the psychologist Paul Ekman, who had researched how facial muscles express emotion. The writer Marc Laidlaw created family relationships between the characters, saying that it was a "basic dramatic unit everyone understands" but rarely used in games. The voice cast included Louis Gossett Jr., Robert Guillaume and Robert Culp.
Parafollicular cells, also called C cells, are neuroendocrine cells in the thyroid. They are called C cells because the primary function of these cells is to secrete calcitonin. They are located adjacent to the thyroid follicles and reside in the connective tissue. These cells are large and have a pale stain compared with the follicular cells. In birds and teleost fishes these cells occupy a structure outside the thyroid gland named the ultimopharyngeal body.
=== Laurent's half-shade polarimeter === When plane-polarised light passes through some crystals, the velocity of left-polarized light is different from that of the right-polarized light, thus the crystals are said to have two refractive indices, i.e. double refracting. Construction: The polarimeter consists of a monochromatic source S which is placed at focal point of a convex lens L. Just after the convex lens there is a Nicol Prism P which acts as a polariser. H is a half shade device which divides the field of polarized light emerging out of the Nicol P into two halves, generally of unequal brightness. T is a glass tube in which an optically active solution is filled. The light, after passing through T, is allowed to fall on the analyzing Nicol A which can be rotated about the axis of the tube. The rotation of the analyzer can be measured with the help of a scale C. Working principle: To understand the need of a half-shade device, let us suppose that it is not present. The position of the analyzer is adjusted so that the field of view is dark when the tube is empty. The position of the analyzer is noted on the circular scale. Now the tube is filled with the optically active solution and it is set in its proper position. The optically active solution rotates the plane of polarization of the light emerging out of the polarizer P by some angle, so the light is transmitted by analyzer A and the field of view of the telescope becomes bright. Now the analyzer is rotated by a finite angle so that the field of view of the telescope again becomes dark.
=== China === There are no regulations on beak trimming in the People's Republic of China. Some companies have decided to voluntarily phase out debeaking, such as Ningxia Xiaoming Farming and Animal Husbandry Co. Ltd.
Sources: en.wikipedia.org
Irreversible inhibitors first form a reversible non-covalent complex with the enzyme (EI or ESI). Subsequently, a chemical reaction occurs between the enzyme and inhibitor to produce the covalently modified "dead-end complex" EI* (an irreversible covalent complex). The rate at which EI* is formed is called the inactivation rate or kinact. Since formation of EI may compete with ES, binding of irreversible inhibitors can be prevented by competition either with substrate or with a second, reversible inhibitor. This protection effect is good evidence of a specific reaction of the irreversible inhibitor with the active site. The binding and inactivation steps of this reaction are investigated by incubating the enzyme with inhibitor and assaying the amount of activity remaining over time. The activity will be decreased in a time-dependent manner, usually following exponential decay. Fitting these data to a rate equation gives the rate of inactivation at this concentration of inhibitor. This is done at several different concentrations of inhibitor. If a reversible EI complex is involved the inactivation rate will be saturable and fitting this curve will give kinact and Ki. Another method that is widely used in these analyses is mass spectrometry. Here, accurate measurement of the mass of the unmodified native enzyme and the inactivated enzyme gives the increase in mass caused by reaction with the inhibitor and shows the stoichiometry of the reaction. This is usually done using a MALDI-TOF mass spectrometer.
=== Support for 18th Amendment === Bhutto Zardari has repeatedly criticized the historical One Unit Scheme, and warned against any attempt to bring in a presidential system, explaining that it will not be in the interest of democracy. During a press conference on 27 April 2019, he stated that the "presidential system is neither in the interest of the country nor the federation and all democratic forces will resist any such move."
According to the Sustainable Development Goals Index 2021, 10.35% of the population of Jammu and Kashmir live below the national poverty line, the third-highest among union territories in the country.
=== Maternal === Fetal AFP levels can be monitored in the urine of pregnant women. Since AFP is quickly cleared from the mother's serum via her kidneys, maternal urine AFP correlates with fetal serum levels, although the maternal urine level is much lower than the fetal serum level. AFP levels rise until about week 32. Maternal serum alpha-fetoprotein (MSAFP) screening is performed at 16 to 18 weeks of gestation. If MSAFP levels indicate an anomaly, amniocentesis may be offered to the patient.
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide and an analogue of alpha-melanocyte-stimulating hormone. The molecule is produced by chemical synthesis rather than extracted from a biological source.
It is shorter than the native hormone and carries a cyclic constraint that improves stability. These changes raise receptor potency and slow breakdown relative to the naturally occurring peptide.
Published accounts date its development to the 1980s, when researchers were generating analogues of melanocyte-stimulating hormone. That work aimed to produce more stable compounds for studying pigmentation biology.
No. Melanotan-2 is manufactured synthetically. The naturally occurring peptide in the same family is alpha-melanocyte-stimulating hormone, which the body produces as part of normal endocrine and neural signalling.