melanocortin receptor comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2025-11-03. Where a claim depends on a specific study, the study is described rather than over-claimed.
Melanotan II is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone, a naturally occurring peptide involved in pigmentation signalling. Its structure substitutes a lactam bridge between side chains to increase stability relative to the native hormone. The compound is also known by the shorthand MT-II and by several non-proprietary synonyms used in research catalogues. It is not an approved therapeutic product in any major jurisdiction; material sold under this name is typically offered as a laboratory reagent rather than as a medicine.
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.
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.
The compound was developed in the late 1980s and 1990s by academic researchers investigating photoprotection. The rationale held that stimulating melanin production might reduce ultraviolet damage to skin and lower skin cancer risk. Early work examined receptor binding, pigment response, and short-term tolerability in small studies. That program did not produce an approved drug, and formal development stalled after early-phase trials. Whether induced pigmentation confers meaningful photoprotection remains an open question.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Analogue of alpha-melanocyte-stimulating hormone |
| Common synonyms | MT-II; melanotan 2 | No internationally accepted non-proprietary name |
| Typical presentation | Lyophilised powder in a sealed vial | Often supplied alongside a separate diluent |
| Regulatory status | Unapproved therapeutic substance | Customs seizure reported in several jurisdictions |
| Reported route in use | Subcutaneous injection | Self-administered outside clinical settings |
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.
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.
=== Singles series and Full Cold Moon (2012–present) === In September 2012, Eisold announced Cold Cave would be touring the US later in the year, he would be recording a new album, and that the new live lineup included: Hunter Burgan (AFI), London May (Samhain), Jessie Nelson, and Cody Votolato (The Blood Brothers). This lineup was exclusive to this two-and-a-half-week tour and Eisold said performing with a full band was something that failed to materialize during Cherish the Light Years tours. While continuing to work on a follow-up to Cherish the Light Years and not under contract with a label, Eisold began independently releasing a series of stand-alone singles. Eisold wrote and recorded these new songs by himself similar to how songs on Cremations and Love Comes Close were crafted. He said they were created "by myself, at a desk in my apartment. It was freeing and exciting in a way because I didn't owe anyone an album. I got to just make them to make them. The songs were minimal, honest, electronic and without help." The first single in the series was "A Little Death to Laugh." The single was released in October 2012 through Heartworm and a music video for the song was released in March 2013. In 2013, Eisold released "Oceans with No End" (through Jacob Bannon's Deathwish Inc.), "God Made the World" and "Black Boots", for which Slava Tsukerman, known for his 1982 film Liquid Sky, directed a music video. In October 2013, Cold Cave released a digital-only, fifth stand-alone single titled "Nausea, The Earth and Me."
By the 17th century, water pump designs had improved to the point that they produced measurable vacuums, but this was not immediately understood. What was known was that suction pumps could not pull water beyond a certain height: 18 Florentine yards according to a measurement taken around 1635, or about 34 feet (10 m). This limit was a concern in irrigation projects, mine drainage, and decorative water fountains planned by the Duke of Tuscany, so the duke commissioned Galileo Galilei to investigate the problem. Galileo suggested, incorrectly, in his Two New Sciences (1638) that the column of a water pump will break of its own weight when the water has been lifted to 34 feet. Other scientists took up the challenge, including Gasparo Berti, who replicated it by building the first water barometer in Rome in 1639. Berti's barometer produced a vacuum above the water column, but he could not explain it. A breakthrough was made by Galileo's student Evangelista Torricelli in 1643. Building upon Galileo's notes, he built the first mercury barometer and wrote a convincing argument that the space at the top was a vacuum. The height of the column was then limited to the maximum weight that atmospheric pressure could support; this is the limiting height of a suction pump. In 1650, Otto von Guericke invented the first vacuum pump. Four years later, he conducted his famous Magdeburg hemispheres experiment, showing that teams of horses could not separate two hemispheres from which the air had been evacuated.
It shares many similar causes, with the most common being chronic alcohol use, with other causes including recurrent acute episodes and cystic fibrosis. Abdominal pain, characteristically relieved by sitting forward or drinking alcohol, is the most common symptom. When the digestive function of the pancreas is severely affected, this may lead to problems with fat digestion and the development of steatorrhoea; when the endocrine function is affected, this may lead to diabetes. Chronic pancreatitis is investigated in a similar way to acute pancreatitis. In addition to management of pain and nausea, and management of any identified causes (which may include alcohol cessation), because of the digestive role of the pancreas, enzyme replacement may be needed to prevent malabsorption.
Sources: en.wikipedia.org
The carbonyl groups of reducing sugars react with the amino groups of amino acids in the Maillard reaction, a complex series of reactions that occurs when cooking food. Maillard reaction products (MRPs) are diverse; some are beneficial to human health, while others are toxic. However, the overall effect of the Maillard reaction is to decrease the nutritional value of food. One example of a toxic product of the Maillard reaction is acrylamide, a neurotoxin and possible carcinogen that is formed from free asparagine and reducing sugars when cooking starchy foods at high temperatures (above 120 °C). However, evidence from epidemiological studies suggest that dietary acrylamide is unlikely to raise the risk of people developing cancer.
That nationalist betrayal of socialism was denounced by a small group of socialist leaders who opposed the Great War, including Rosa Luxemburg, Karl Liebknecht and Lenin, who said that the European socialists had failed the working classes for preferring patriotic war to proletarian internationalism. To debunk patriotism and national chauvinism, Lenin explained in the essay Imperialism, the Highest Stage of Capitalism (1917) that capitalist economic expansion leads to colonial imperialism which is then regulated with nationalist wars such as the Great War among the empires of Europe. To relieve strategic pressures from the Western Front (4 August 1914 – 11 November 1918), Imperial Germany impelled the withdrawal of Imperial Russia from the war's Eastern Front (17 August 1914 – 3 March 1918) by sending Lenin and his Bolshevik cohort in a diplomatically sealed train, anticipating them partaking in revolutionary activity.
Rita Levi-Montalcini and Stanley Cohen discovered NGF in the 1950s while faculty members at Washington University in St. Louis, for which they were awarded a Nobel Prize in Physiology or Medicine in 1986. The critical preliminary discovery was done by Levi-Montalcini and Hertha Meyer at the Carlos Chagas Filho Biophysics Institute of the Federal University of Rio de Janeiro in 1952. Their publication in 1954 became the definitive proof for the existence of the protein. Levi-Montalcini later remarked:The tumor had given a first hint of its existence in St. Louis but it was in Rio de Janeiro that it revealed itself, and it did so in a theatrical and grand way, as if spurred by the bright atmosphere of that explosive and exhuberant manifestation of life that is the Carnival in Rio.However, its discovery, along with the discovery of other neurotrophins, was not widely recognized until 1986, when it won the Nobel Prize in Physiology or Medicine. Studies in 1971 determined the primary structure of NGF. This eventually led to the discovery of the NGF gene. NGF is abundant in seminal plasma. Recent studies have found that it induces ovulation in some mammals. Nerve Growth Factors (NGF) were initially discovered due to their actions during development, but NGF are now known to be involved in the function throughout the life of the animal.
Sources: en.wikipedia.org
Common side effects include drowsiness, dry mouth, loss of appetite, sweating, insomnia, and sexual dysfunction. Serious side effects may include suicide in those under the age of 25, serotonin syndrome, and mania. While the rate of side effects appears similar compared to other SSRIs and SNRIs, antidepressant discontinuation syndromes may occur more often. Use in pregnancy is not recommended, while use during breastfeeding is relatively safe. The Federal Aviation Administration (FAA), the U.S. agency responsible for regulating civil aviation, considers paroxetine to be an antidepressant medication that is ineligible for an FAA Authorization of Special Issuance (SI) or Special Consideration (SC) of a medical certificate. Paroxetine shares many of the common adverse effects of SSRIs, including (with the corresponding rates seen in people treated with placebo in parentheses):
=== Comparison to other formulations === Lisdexamphetamine dimesylate is one marketed formulation delivering dextroamphetamine. The following table compares the drug to other amphetamine pharmaceuticals.
=== Biochemical and biomedical roles === Sulfur dioxide or its conjugate base bisulfite is produced biologically as an intermediate in both sulfate-reducing organisms and in sulfur-oxidizing bacteria, as well. The role of sulfur dioxide in mammalian biology is not yet well understood. Sulfur dioxide blocks nerve signals from the pulmonary stretch receptors and abolishes the Hering–Breuer inflation reflex. It is considered that endogenous sulfur dioxide plays a significant physiological role in regulating cardiac and blood vessel function, and aberrant or deficient sulfur dioxide metabolism can contribute to several different cardiovascular diseases, such as arterial hypertension, atherosclerosis, pulmonary arterial hypertension, and stenocardia. It was shown that in children with pulmonary arterial hypertension due to congenital heart diseases the level of homocysteine is higher and the level of endogenous sulfur dioxide is lower than in normal control children. Moreover, these biochemical parameters strongly correlated to the severity of pulmonary arterial hypertension. Authors considered homocysteine to be one of useful biochemical markers of disease severity and sulfur dioxide metabolism to be one of potential therapeutic targets in those patients. Endogenous sulfur dioxide also has been shown to lower the proliferation rate of endothelial smooth muscle cells in blood vessels, via lowering the MAPK activity and activating adenylyl cyclase and protein kinase A.
=== Variations === Type 1 juncturae is mostly seen between the index and the middle fingers (second inter metacarpal space). Type 2 juncturae is observed mainly between the middle and the ring fingers (third inter-metacarpal space). Type 3 juncturae tendinum is mostly found between the ring and the little finger (fourth inter-metacarpal space). Normally, the extensor indicis proprius do not receive any juncture tendinum, but it is rarely seen and the mobility of the index finger is compromised. The absence of the tendon of the extensor digitorum communis to the little finger is associated with the thicker type 3r juncturae tendinum in the fourth intermetacarpal space. Hirai et al. reported type 1 junturae tendinum between the extensor digiti minimi and the extensor digitorum communis to the ring finger in 6% of the specimens.
Sources: en.wikipedia.org
No. No major regulatory agency has granted a marketing authorisation for melanotan II as a medicine. Products sold under this name are generally presented as laboratory reagents and are not subject to the batch-release testing applied to approved drugs.
It was developed in the 1980s by researchers investigating analogues of alpha-melanocyte-stimulating hormone for pigmentation and related endpoints. Early work included small human studies during the 1990s. Development did not progress to licensing, and the compound remained a research and grey-market item.
Peptides are prone to truncation, oxidation and aggregation during synthesis and handling. Without independent testing, a buyer cannot confirm the identity or the content of a vial. Analytical surveys of unapproved peptide products have repeatedly found discrepancies between label claims and measured composition.
It is a synthetic cyclic peptide designed as an analog of alpha-melanocyte-stimulating hormone. It acts on melanocortin receptors and is best known from research into pigmentation. It is not an approved pharmaceutical product.