Melanotan II 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 2025-10-22. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Receptor studies place melanotan-2 among non-selective melanocortin agonists, binding MC1R, MC3R, MC4R and MC5R rather than a single subtype. Activation of MC1R on cutaneous melanocytes raises tyrosinase activity and shifts pigment synthesis toward eumelanin, which is darker and more photostable than pheomelanin. Central receptors, particularly MC4R, are associated with appetite suppression and with reported effects on sexual function. Because subtype selectivity is low, the same molecule engages pigment, metabolic and vascular pathways at once, and this breadth is a common explanation offered for the range of adverse events described in user reports.
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 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.
The peptide acts as a non-selective agonist at melanocortin receptors, showing affinity for MC1R, MC3R, MC4R and MC5R. Activation of MC1R on melanocytes drives the conversion of tyrosine into melanin and shifts production toward the darker eumelanin form. MC4R signalling in the central nervous system is linked to appetite and energy balance, which helps explain why reduced food intake appeared in early human studies. Effects on MC4R and on vascular tone also account for the erectile responses recorded as unexpected findings in those same trials.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Free base; salt forms add to total mass |
| Molecular mass | About 1024 daltons | Calculated for the free base |
| Structural class | Cyclic heptapeptide | Contains D-phenylalanine and norleucine |
| Parent hormone | Alpha-melanocyte-stimulating hormone | Endogenous tridecapeptide of 13 residues |
| Receptor profile | Non-selective melanocortin agonist | Interacts with MC1R, MC3R, MC4R and MC5R |
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.
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.
Receptor binding at MC1R on melanocytes raises intracellular cyclic AMP and increases expression of tyrosinase and related enzymes. The downstream result is greater synthesis of eumelanin, the dark pigment, without ultraviolet exposure acting as the trigger. The compound is not selective, however, and also engages MC3R, MC4R and MC5R, which are expressed in the central nervous system and elsewhere. That lack of selectivity is the explanation usually offered for effects reported outside pigmentation, including appetite suppression and nausea. Selectivity remains a central theme in comparative studies of related peptides.
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.
Expansion of the bone marrow in the developing child leads to a distinctive facial shape often referred to as "Chipmunk facies". Other skeletal changes include osteoporosis, growth retardation, and malformation of the spine. People with thalassemia can get too much iron in their bodies, either from the disease itself as RBCs are destroyed, or as a consequence of frequent blood transfusions. Excess iron is not excreted, but forms toxic non-transferrin-bound iron. This can lead to organ damage, potentially affecting the heart, liver, endocrine system, bones and spleen. Symptoms include an irregular heartbeat, cardiomyopathy, cirrhosis of the liver, hypothyroidism, delayed puberty and fertility problems, brittle and deformed bones, and an enlarged spleen. The spleen is the organ which removes damaged red blood cells from circulation; in thalassemia patients it is abnormally active, causing it to enlarge and possibly become hyperactive, a condition called hypersplenism. The immune system can become compromised in a number of ways; anemia, iron overload, and hypersplenism may affect the immune response and increase the risk of severe infection.
On 3 September, Robert Fripp said that his differences with Adrian Belew had been resolved and that, while there were "no current plans for [him] to come out with the current formation," he could potentially be invited back to the band in the future. Belew subsequently confirmed this. On 14 October 2017, King Crimson released another contemporary live album, Live in Chicago, recorded on tour in June of the same year. As had been the case with its two predecessors, it included new material (in this case "Bellscape & Orchestral Werning", "The Errors" and "Interlude"); it also documented the return to the live set of material from Lizard (in the form of "Cirkus", which the band had begun adding to their sets in 2016, and the second half of the title suite), as well as new arrangements of some Belew-era songs. On 13 October 2017, it was announced that Rieflin would be unable to join the Three Over Five Formation on the 2017 Autumn tour in the U.S. He was temporarily replaced by Seattle-based Crafty Guitarist Chris Gibson. During 2018, King Crimson performed the extensive 33-date Uncertain Times tour through the UK and Europe between 13 June and 16 November. Although the band continued to avoid studio recording, April 2018 saw the full release of another live album, Live in Vienna, presenting the complete concert in Vienna on 1 December 2016.
Pests that can afflict tea plants include mosquito bugs, genus Helopeltis, which are true bugs and not to be confused with dipterous insects of family Culicidae ('mosquitos'). Mosquito bugs can damage leaves both by sucking plant materials, and by the laying of eggs (oviposition) within the plant. Spraying with synthetic insecticides may be deemed appropriate. Other pests are Lepidopteran leaf feeders and various tea diseases.
Sources: en.wikipedia.org
FOP is an autosomal dominant disorder. Thus, a child of an affected heterozygous parent and an unaffected parent has a 50% probability of being affected. Two affected individuals can produce unaffected children. Two unaffected individuals can produce an affected offspring as a result of the mutation of the gene. The homozygous dominant form is more severe than the heterozygous form. The protein that causes ossification is normally deactivated by an inhibitory protein after a fetus's bones are formed in the womb, but in patients with FOP, the protein keeps working. Aberrant bone formation in patients with FOP occurs when injured connective tissue or muscle cells at the sites of injury or growth incorrectly express an enzyme for bone repair during apoptosis (self-regulated cell death), resulting in lymphocytes containing excess bone morphogenetic protein 4 (BMP4) provided during the immune system response. The bone that results occurs independently of the normal skeleton, forming its own discrete skeletal elements. These elements, however, can fuse with normal skeletal bone. The diaphragm, tongue, and extra-ocular muscles are spared in this process, as well as cardiac and smooth muscle. Since the incorrect enzyme remains unresolved within the immune response, the body continues providing the incorrect BMP4-containing lymphocytes. BMP4 is a product that contributes to the development of the skeleton in the normal embryo. The ACVR1 gene encodes a bone morphogenic protein (BMP) receptor; this gene is mutated in FOP.
== External links == Creatine+Kinase,+BB+Form at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Human CKB genome location and CKB gene details page in the UCSC Genome Browser. This article incorporates text from the United States National Library of Medicine, which is in the public domain.
== See also == Politics of Serbia and Montenegro Prime Minister of Serbia and Montenegro List of heads of state of Yugoslavia President of Montenegro List of presidents of Montenegro President of Serbia List of presidents of Serbia
Sources: en.wikipedia.org
==== MeSH D12.776.964.775.750 – retroviridae proteins, oncogenic ==== MeSH D12.776.964.775.750.320 – fusion proteins, gag-onc MeSH D12.776.964.775.750.320.700 – oncogene protein p65(gag-jun) MeSH D12.776.964.775.750.470 – gene products, rex MeSH D12.776.964.775.750.480 – gene products, tax MeSH D12.776.964.775.750.650 – oncogene protein gp140(v-fms) MeSH D12.776.964.775.750.710 – oncogene protein p21(ras) MeSH D12.776.964.775.750.750 – oncogene protein p55(v-myc) MeSH D12.776.964.775.750.760 – oncogene protein pp60(v-src) MeSH D12.776.964.775.750.817 – oncogene protein v-maf MeSH D12.776.964.775.750.875 – oncogene proteins v-abl MeSH D12.776.964.775.750.882 – oncogene proteins v-erba MeSH D12.776.964.775.750.883 – oncogene proteins v-erbb MeSH D12.776.964.775.750.887 – oncogene proteins v-fos MeSH D12.776.964.775.750.900 – oncogene proteins v-mos MeSH D12.776.964.775.750.903 – oncogene proteins v-myb MeSH D12.776.964.775.750.920 – oncogene proteins v-raf MeSH D12.776.964.775.750.925 – oncogene proteins v-rel MeSH D12.776.964.775.750.935 – oncogene proteins v-sis
==== US death penalty ==== In August 2018, Nebraska became the first American state to use fentanyl to execute a prisoner. Carey Dean Moore, then one of the longest-serving death row inmates in the United States, was executed at the Nebraska State Penitentiary. Moore received a lethal injection, administered as an intravenous series of four drugs that included fentanyl citrate, to inhibit breathing and render the subject unconscious. The other drugs included diazepam as a tranquilizer, cisatracurium besylate as a muscle relaxant, and potassium chloride to stop the heart. The use of fentanyl in execution caused concern among death penalty experts because it was part of a previously untested drug cocktail. The execution was also protested by anti-death penalty advocates at the prison during the execution and later at the Nebraska State Capitol.
O-GlcNAc has been implicated in influenza A virus (IAV)-induced cytokine storm. Specifically, O-GlcNAcylation of S430 on interferon regulatory factor-5 (IRF5) has been shown to promote its interaction with TNF receptor-associated factor 6 (TRAF6) in cellular and mouse models. TRAF6 mediates K63-linked ubiquitination of IRF5 which is necessary for IRF5 activity and subsequent cytokine production. Analysis of clinical samples showed that blood glucose levels were elevated in IAV-infected patients compared to healthy individuals. In IAV-infected patients, blood glucose levels positively correlated with IL-6 and IL-8 levels. O-GlcNAcylation of IRF5 was also relatively higher in peripheral blood mononuclear cells of IAV-infected patients.
Sources: en.wikipedia.org
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.
Melanotan-1, also called afamelanotide, is a linear analogue with greater selectivity for MC1R and has received approval in some jurisdictions for a specific photosensitivity disorder. Melanotan-2 is cyclic, less selective, and reaches central receptors more readily. The two are often confused in online discussion despite different pharmacology and regulatory status.
Alpha-MSH is an endogenous tridecapeptide derived from pro-opiomelanocortin. Melanotan-2 reproduces its core receptor-binding sequence inside a shortened, stabilised ring. The result is a molecule with a longer effective half-life and higher potency than the parent hormone.
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.