If you have been reading about Melanotan II 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.
Updated 2026-03-25. Numbers and descriptions here follow the published literature rather than marketing material.
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 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.
Freeze-dried melanotan-2 is normally kept as a desiccated powder at minus twenty degrees Celsius or lower, shielded from light and moisture. Peptides of this size degrade through hydrolysis, oxidation and deamidation, and each pathway accelerates as temperature and water activity rise. Repeated freeze-thaw cycles promote aggregation and loss of material, so aliquoting a stock solution before freezing is standard laboratory practice. Once dissolved, the solution is markedly less stable than the powder. In laboratory work, solutions are generally refrigerated and used within days rather than kept for months.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, which separates the target peptide from truncated or oxidised impurities. Mass spectrometry, most often coupled to liquid chromatography, confirms molecular mass and detects substitutions that chromatography alone may miss. Amino acid analysis and peptide mapping supply additional structural evidence, while nuclear magnetic resonance is reserved for full structural confirmation. Laboratories that examine samples sold online report wide variation in actual content, with some vials containing little or none of the labelled material.
| 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-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.
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.
Lyophilised melanotan-2 is comparatively robust when kept dry, cold and dark, and a desiccated powder stored at minus twenty degrees Celsius or below is generally expected to retain its chemical integrity for extended periods. In solution the peptide is far less stable, with degradation proceeding through oxidation of tryptophan and histidine residues, hydrolysis adjacent to the lactam bridge, and aggregation at higher concentrations. Repeated freeze-thaw cycling accelerates loss of the parent peak. Working aliquots are therefore prepared once, held cold, and used without letting the stock return to ambient temperature.
Quality assessment of research-grade peptide rests mainly on reversed-phase high-performance liquid chromatography for purity and on mass spectrometry for identity confirmation. A single main peak above a stated threshold, commonly ninety-eight percent by peak area, is the usual release criterion applied by suppliers. Independent analyses commissioned by laboratories and consumer organisations have repeatedly reported discrepancies between label claims and measured content, including truncated sequences, residual trifluoroacetate, and lower-than-declared peptide mass. Those findings do not establish that every supplier is unreliable, but they indicate that purity figures printed on a vial are claims requiring verification rather than settled facts.
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.
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.
Identity and purity are assessed mainly by reversed-phase high-performance liquid chromatography with ultraviolet detection, often paired with mass spectrometry. Retention time supports identity, while the mass spectrum confirms the molecular weight of the intact peptide. Purity is frequently reported as a percentage of total peak area, a figure that depends on the wavelength, column and gradient used. Impurity profiling may also look for truncated sequences, oxidised forms and residual counterions. Amino acid analysis and peptide mapping provide orthogonal confirmation when required.
A member state of the United Nations since 1955, Portugal is a member of almost all major international organisations, and is among the countries that founded NATO in 1949, the OECD in 1961, EFTA in 1960, and the Community of Portuguese Language Countries (CPLP) in 1996, an international organisation of countries with Portuguese as an official language. Portugal has a stable foreign policy that is the result of its history, geography, and specific foreign policy choices. It is structured around six principal regional and policy priorities: Europe, NATO and relations with the United Kingdom and with the United States, the Portuguese-speaking world, the importance of and support for Portuguese communities abroad, the internationalisation of the national economy, and the strengthening of multilateralism. Portugal regards the success of European integration as paramount and is prepared, where a consensus exists among European Union member states, to endorse policies that go against with the country's national interests; it also supports general disarmament, the dismantling of political-military blocs, and the creation of a collective security system aimed at establishing an international order grounded in peace and justice among peoples. Portugal has two territorial disputes, both of which are with Spain: the Spanish town of Olivenza which has been claimed by Portugal since the 19th century, and the surrounding waters of the Portuguese Savage Islands which have been claimed by Spain since the 15th century.
In infants and adults, the excess β chains form unstable tetramers called hemoglobin H or HbH comprising 4 beta chains. In the fetus, the excess γ chains combine hemoglobin Bart's comprising 4 gamma chains Both HbH and Hb Bart's have a strong affinity for oxygen but do not release it, causing oxygen starvation in the tissues. They can also precipitate within the RBC damaging its membrane and shortening the life of the cell. The severity of the α-thalassemias is correlated with the number of affected α-globin alleles: the greater, the more severe will be the manifestations of the disease.
downregulation Also repression or suppression. Any process, natural or artificial, which decreases the level of gene expression of a certain gene. A gene which is observed to be expressed at relatively low levels (such as by detecting lower levels of its mRNA transcripts) in one sample compared to another sample is said to be downregulated. Contrast upregulation.
Sources: en.wikipedia.org
In September 1986, the band parted ways with manager Alan McGee, and came close to splitting up later in the year, with Jim Reid suffering from "exhaustion". John Moore had become an established member, but moved to rhythm guitar, with former Redskins member Martin Hewes joining the band briefly (although he strongly denies ever joining) and former Dead Can Dance percussionist James Pinker taking over on drums. Blanco y Negro manager Geoff Travis took over management duties, and the band returned in December with two gigs at the National Ballroom in Kilburn, London where they premiered new songs including "April Skies" and "Hit". Early in 1987, they entered the studio to record their second album. The first fruits of these sessions were released on the "April Skies" single in April, which saw the band have their first top ten hit. The Beach Boys influence was evident on the B-side, which included "Kill Surf City", a reworking of Brian Wilson's "Surf City". The various formats released also included a cover of Bo Diddley's "Who Do You Love?", a tribute to him with "Bo Diddley is Jesus", and a live version of Can's "Mushroom". "Happy When It Rains" was the second pre-album single, strongly influenced by Smokey Robinson's "My Girl", but it failed to match the success of "April Skies", only reaching number twenty-five. The band set out on another UK tour, this time with sets stretching to 45 minutes, although to a mixed reaction from the music press. They toured without a drummer, instead using a drum machine.
Official website – Government of Belize. Archived 10 January 2021 at the Wayback Machine. Official webpage of Queen Elizabeth II (as former Queen of Belize) Wikimedia Atlas of Belize Profile at U.S. Department of State Archived 25 November 2017 at the Wayback Machine Belize National Emergency Management Organization – Official governmental site Belize Wildlife Conservation Network – Belize Wildlife Conservation Network (archived 4 February 2013) CATHALAC – Water Center for the Humid Tropics of Latin America and the Caribbean (archived 5 February 2012) LANIC Belize page Archived 17 December 2024 at the Wayback Machine Belize. The World Factbook. Central Intelligence Agency. Belize at UCB Libraries GovPubs (archived 11 May 2013) Belize from the BBC News Key Development Forecasts for Belize from International Futures Hydromet.gov.bz – Official website of the Belize National Meteorological Service Bileez Kriol Wiki – A wiki in Belizean Creole about Belize
Genetic associations include mutations in pulmonary surfactant proteins A1, A2, C (SFTPA1, SFTPA2B) and mucin (MUC5B). A remarkable aspect of the MUC5B variant is its high frequency of detection, as it is found in approximately 20% of individuals with Northern and Western European ancestry and in 19% of the Framingham Heart Study population. Mutations in human telomerase genes are also associated with familial pulmonary fibrosis and in some patients with sporadic IPF (e.g. the TERT, TERC genes). Recently an X-linked mutation in a third telomerase-associated gene, dyskerin (DKC1), has been described in a family with IPF.
Sources: en.wikipedia.org
=== Non-biologic surface interaction === Non-biologic surface coatings will occur via two mechanisms, the first being direct hydrophobic interaction of the lipid tail with a hydrophobic surface resulting in a monolayer of FSL at the surface. The second surface coating will be through the formation of bilayers, which probably either encapsulate fibres or being via the hydrophilic F group. This is the expected mechanism by which FSLs bind to fibrous membranes such as paper and glass fibres. A recent study has found that when FSL Kode constructs are optimised, could in a few seconds glycosylate almost any non-biological surface including metals, glass, plastics, rubbers, and other polymers.
=== Mechanism of action === Plecanatide works as a laxative by drawing water in to the gastrointestinal tract thereby softening stool and encouraging its natural passage. Similar to its endogenous counterpart, plecanatide activates guanylate cyclase-C on endothelial cells within the gastrointestinal tract. The activation of guanylate cyclase-C catalyses the production of the second messenger guanosine 3’,5’-cyclic monophosphate (cGMP) which leads to the protein kinase A (PKA) and protein kinase G II (PKGII)-mediated phosphorylation of the cystic fibrosis transmembrane conductance regulator (CFTR) protein. CFTR is an anion channel and upon activation it will secrete negatively charged ions, particularly chloride (Cl−) and bicarbonate (HCO3−) in to the GI tract lumen. This disruption to the electrochemical gradient is in part rectified by the passive secretion of positively charged sodium ions in to the lumen and water follows by osmosis. Plecanatide is also known to have an anti-nociceptive effect in animal models, however the exact mechanism of action is not yet fully elucidated. It has been suggested that this may be in part to the anti-inflammatory action of guanylate cyclase-C by its inhibition of pro-inflammatory cytokines, or through the inhibition of associated sensory neurons.
Growth hormone secretagogue receptor(GHS-R), also known as ghrelin receptor, is a G protein-coupled receptor that binds growth hormone secretagogues (GHSs), such as ghrelin, the "hunger hormone". The role of GHS-R is thought to be in regulating energy homeostasis and body weight. In the brain, they are most highly expressed in the hypothalamus, specifically the ventromedial nucleus and arcuate nucleus. GSH-Rs are also expressed in other areas of the brain, including the ventral tegmental area, hippocampus, and substantia nigra. Outside the central nervous system, too, GHS-Rs are also found in the liver, in skeletal muscle, and even in the heart.
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.
The lyophilised solid is best kept cold, dry and dark, typically at minus twenty degrees Celsius. Moisture and repeated warming cycles are the main causes of degradation. Solutions prepared from the powder are less stable and are normally used quickly.