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.
Last reviewed on 2026-02-13. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Human data remain limited and mostly short-term. Reports describe small trials and observational accounts rather than large controlled studies, so questions about dose-response relationships and long-term effects on melanocytes stay open. Whether repeated exposure alters naevus behaviour is not settled in the published record. Researchers also note that self-administered use outside clinical settings makes actual exposure difficult to quantify. Statements about efficacy and safety should therefore be read as preliminary rather than established.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Free base; salt forms differ |
| Molecular weight | Approximately 1024 g/mol | Calculated for the free base |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility | Soluble in water and polar solvents | Poorly soluble in non-polar solvents |
| Typical storage | -20 degrees Celsius, dry, protected from light | Refers to the solid form |
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.
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.
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.
Melanotan-2 is frequently confused with afamelanotide, a linear analogue authorised in the European Union for erythropoietic protoporphyria. The two compounds differ in chain length, ring structure and receptor selectivity, so findings for one cannot be transferred directly to the other. Published controlled human data on melanotan-2 remain sparse, and much of what circulates online derives from small studies or unpublished reports. Questions about effect size, dose-response behaviour and long-term safety therefore remain unresolved.
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.
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.
Veins vary in size from the smallest post-capillary venules, and more muscular venules, to small veins, medium veins, and large veins. The thickness of the walls of the veins varies as to their location – in the legs the vein walls are much thicker than those in the arms. In the circulatory system, blood first enters the venous system from capillary beds where arterial blood changes to venous blood. Large arteries such as the thoracic aorta, subclavian, femoral and popliteal arteries lie close to a single vein that drains the same region. Other arteries are often accompanied by a pair of veins held in a connective tissue sheath. The accompanying veins are known as venae comitantes, or satellite veins, and they run on either side of the artery. When an associated nerve is also enclosed, the sheath is known as a neurovascular bundle. This close proximity of the artery to the veins helps in venous return due to the pulsations in the artery. It also allows for the promotion of heat transfer from the larger arteries to the veins in a counterflow exchange that helps to preserve normal body heat.
=== Cardiac biomarkers === There are many different biomarkers used to determine the presence of cardiac muscle damage. Troponins, measured through a blood test, are considered to be the best, and are preferred because they have greater sensitivity and specificity for measuring injury to the heart muscle than other tests. A rise in troponin occurs within 2–3 hours of injury to the heart muscle, and peaks within 1–2 days. The level of the troponin, as well as a change over time, are useful in measuring and diagnosing or excluding myocardial infarctions, and the diagnostic accuracy of troponin testing is improving over time. One high-sensitivity cardiac troponin can rule out a heart attack as long as the ECG is normal. Other tests, such as CK-MB or myoglobin, are discouraged. CK-MB is not as specific as troponins for acute myocardial injury, and may be elevated with past cardiac surgery, inflammation or electrical cardioversion; it rises within 4–8 hours and returns to normal within 2–3 days. Copeptin may be useful to rule out MI rapidly when used along with troponin.
On January 15, 2020, it was announced that the Doobie Brothers were one of the six groups that would be inducted into the 2020 Rock and Roll Hall of Fame. The induction included living members Tom Johnston, Patrick Simmons, Michael McDonald, John McFee, Tiran Porter, John Hartman and Jeff Baxter, while Keith Knudsen and Michael Hossack would be inducted posthumously. The induction ceremony was originally scheduled to take place on May 2, 2020, in Cleveland, but was postponed to November 7 due to the COVID-19 pandemic. The November 7 induction ceremony was held virtually on HBO Max, with Johnston, McDonald, and Simmons pre-recording their induction speeches on behalf of the other band members who were inducted alongside them. In February 2020, the Doobie Brothers had a scheduled residency at the Venetian in Las Vegas. The band was only three shows into their eight-day residency when they were forced to cancel the remaining five dates after it was mentioned that there was an illness in the band. It was later discovered that Johnston had an early version of COVID-19, the virus that would end up becoming designated as a pandemic just one month later. On May 26, 2020, the Doobie Brothers officially announced that they had rescheduled their 50th Anniversary tour to 2021 as a result of the COVID-19 pandemic and confirmed that the line up of this tour would include McDonald for the first time in 25 years. During their time in isolation throughout 2020, the Doobie Brothers released at-home performances of "Black Water", "Listen to the Music", and "Takin' it to the Streets".
intensive farming methods requires 214 liters (47 imp gal; 57 U.S. gal) of water; using hydroponics, 70 liters (15 imp gal; 18 U.S. gal); and only 20 liters (4.4 imp gal; 5.3 U.S. gal) using aeroponics. Hydroponic cultures lead to highest biomass and protein production compared to other growth substrates, of plants cultivated in the same environmental conditions and supplied with equal amounts of nutrients. Hydroponics is not only used on earth, but has also proven itself in plant production experiments in Earth orbit.
Sources: en.wikipedia.org
It is preferable not to invoke such powerful immuno-suppressive therapy in most cases of CH in which spontaneous regression of lesions or episodic disease activation is more likely to occur. Microscopic features of SH and CH The lesions of SH in most tissues consist of perivascular infiltrates of large histiocytes and variable populations of lymphocytes, neutrophils and eosinophils. The histiocytes frequently invade vessel walls and this may lead to vascular compromise and infarction of surrounding tissues. The widespread distribution of lesions of SH is only fully appreciated at necropsy. Histiocytic lesions have been observed in skin, lung, liver, bone marrow, spleen, peripheral and visceral lymph nodes, kidneys, testes, orbital tissues, nasal mucosa and others. In skin, the lesions of SH and CH are virtually identical — they consist of perivascular histiocytic infiltrates containing lymphocytes and other inflammatory cells in variable proportions (neutrophils, plasma cells, and occasionally eosinophils). The lesions usually involve the deep dermis and subcutis. Involvement of the superficial dermis is inconsistent and epidermotropism of the histiocytes is not observed. In CH the lesions are limited to the skin and draining lymph nodes.
=== Tropical diseases === Ivermectin is also of interest in the prevention of malaria, as it is toxic to both the malaria plasmodium itself and the mosquitos that carry it. The performance of ivermectin's mosquitocidal efficacy was also favourably tested in An. gambiae mosquitoes although it was less effective killing older mosquitoes that are more likely to be transmitting the malaria parasite. A direct effect on malaria parasites could not be shown in an experimental infection of volunteers with Plasmodium falciparum. Use of ivermectin at higher doses necessary to control malaria is probably safe, though large clinical trials have not yet been done to definitively establish the efficacy or safety of ivermectin for prophylaxis or treatment of malaria. Mass drug administration of a population with ivermectin to treat and prevent nematode infestation is effective for eliminating malaria-bearing mosquitos and thereby potentially reducing infection with residual malaria parasites. Whilst effective in killing malaria-bearing mosquitos, a 2021 Cochrane review found that, to date, the evidence shows no significant impact on reducing incidence of malaria transmission from the community administration of ivermectin. One alternative to ivermectin is moxidectin, which has been approved by the Food and Drug Administration for use in people with river blindness.
Chain Home, or CH for short, was the codename for the ring of coastal early warning radar stations built by the Royal Air Force (RAF) before and during the Second World War to detect and track aircraft. Initially known as RDF, and given the official name Air Ministry Experimental Station Type 1 (AMES Type 1) in 1940, the radar units were also known as Chain Home for most of their life. Chain Home was the first early warning radar network in the world and the first military radar system to reach operational status. Its effect on the war made it one of the most powerful systems of what became known as the "Wizard War". In late 1934, the Tizard Committee asked radio expert Robert Watson-Watt to comment on the repeated claims of radio death rays and reports suggesting Germany had built some sort of radio weapon. His assistant, Arnold Wilkins, demonstrated that a death ray was impossible but suggested radio could be used for long-range detection. In February 1935, a successful demonstration was arranged by placing a receiver near a BBC short wave transmitter and flying an aircraft around the area. Using commercial short wave radio hardware, Watt's team built a prototype pulsed transmitter and, by June 1935, it detected an aircraft that happened to be flying past. Basic development was completed by the end of the year, with detection ranges on the order of 100 mi (160 km). In 1936, attention was focused on a production version, and early 1937 saw the addition of height finding.
Responsibility for educational supervision in Germany is primarily organised within the individual states. Optional kindergarten education is provided for all children between three and six years old, after which school attendance is compulsory for at least nine years depending on the state. Primary education usually lasts for four to six years. Secondary schooling is divided into tracks based on whether students pursue academic or vocational education. A system of apprenticeship called Duale Ausbildung leads to a skilled qualification which is almost comparable to an academic degree. It allows students in vocational training to learn in a company as well as in a state-run trade school. This model is well regarded and reproduced all around the world. Most of the German universities are public institutions, and students traditionally study without fee payment. The general requirement for attending university is the Abitur. According to an OECD report from 2014, Germany is the world's third leading destination for international study. The established universities in Germany include some of the oldest in the world, with Heidelberg University (established in 1386), Leipzig University (established in 1409) and the University of Rostock (established in 1419) being the oldest in the country. The Humboldt University of Berlin, founded in 1810 by the liberal educational reformer Wilhelm von Humboldt, became the academic model for many Western universities.
=== Resistance === Despite flucloxacillin being insensitive to beta-lactamases, some organisms have developed resistance to it and other narrow-spectrum β-lactam antibiotics including methicillin. Such organisms include methicillin-resistant Staphylococcus aureus, which has developed resistance to flucloxacillin and other penicillins by having an altered penicillin-binding protein.
Sources: en.wikipedia.org
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.
Both are synthetic analogues derived from the same parent hormone. Reference descriptions usually characterise afamelanotide as more selective for the MC1R subtype, whereas melanotan-2 is reported to interact with a wider range of melanocortin receptors.
Early studies explored melanocortin signalling and pigmentation, which later led to informal use of the label tanning peptide. That label is not a regulatory category and does not imply approved status for any purpose.
It is a synthetic cyclic heptapeptide and a non-selective melanocortin receptor agonist. Structurally it is modelled on alpha-melanocyte-stimulating hormone, a peptide that occurs naturally in the body.