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.
Updated 2025-08-12. Numbers and descriptions here follow the published literature rather than marketing material.
Early published reports described melanotan-2 as a tanning agent without sun protection, which means darkening is not the same as protection against ultraviolet radiation. Later studies explored the peptide in erectile dysfunction, hemorrhagic shock, and some skin conditions. No regulator in the United States or Europe has approved it for clinical use. Many products labelled melanotan-2 are sold without approval and their identity and purity are unverified. Its long-term safety in humans remains an open question.
Melanotan-2, also written Melanotan II, is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone. Its sequence is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, and the lactam bridge between the aspartate and lysine side chains constrains the peptide into a ring. This structural change increases receptor affinity and metabolic stability relative to the native hormone. The compound was created in the 1980s as a research tool for studying pigmentation biology.
Melanocytes are the pigment-producing cells of the skin, and they carry melanocortin-1 receptors on their surface. When the receptor is activated, cyclic adenosine monophosphate rises inside the cell and raises the activity of enzymes such as tyrosinase, which increases melanin output. Melanotan-2 binds melanocortin-1 receptors in vitro and in animal models, and this binding is generally described as the basis for the tanning effect. Other receptors account for different effects: melanocortin-4 receptors contribute to appetite and erectile signalling, while melanocortin-3 and melanocortin-5 receptors contribute to energy balance and exocrine function.
Reversed-phase high-performance liquid chromatography is the routine method for purity assessment. Peptides absorb near 214 nm because of the peptide bond, and a gradient of acetonitrile in water separates the intact peptide from deletion sequences, oxidised products, and earlier-eluting fragments at neutral pH. Electrospray ionisation mass spectrometry provides an orthogonal check: the measured mass must agree with the theoretical value. Amino acid analysis and peptide mapping confirm structure but are used less often. Reference standards remain scarce because the peptide is not described in any pharmacopoeia.
Regulatory treatment varies by country. In the United States the peptide is not approved as a medicine, and products offered for human use may be treated as unapproved new drugs; some states also restrict sale. Australia, the United Kingdom, and European Union member states apply comparable restrictions to unapproved peptide products. Border agencies have seized shipments labelled as research chemicals. Classification may change over time, and the legal position for personal importation is not clearly settled in most published guidance.
Lyophilised melanotan-2 is supplied as a solid, which is more stable than a solution. The material is hygroscopic, so weighing is done quickly, in low humidity, with the container kept sealed. Reconstitution usually uses water for injection or bacteriostatic water, added down the wall of the vial to limit foaming. A reconstituted solution is held at 2 to 8 °C and kept away from light. Repeated freezing and thawing of the same vial is avoided because ice crystal formation and concentration effects degrade the peptide.
| Property | Value | Notes |
|---|---|---|
| Compound class | Synthetic cyclic heptapeptide | Alpha-MSH analogue containing a D-phenylalanine residue |
| Molecular formula | C50H69N15O9 | Average molecular mass approximately 1024.2 g/mol |
| Appearance | White to off-white lyophilised powder | Normally supplied as a freeze-dried solid in a sealed vial |
| Solubility | Freely soluble in water and polar solvents | Dissolves readily in aqueous buffers and in alcohol-water mixtures |
| Receptor targets | MC1R, MC3R, MC4R, MC5R | Acts as a non-selective melanocortin receptor agonist |
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.
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.
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.
Regulatory status varies by jurisdiction, and the substance is frequently described as unapproved for therapeutic use. Some authorities classify it alongside prescription-only medicines or controlled categories, while others address it through general consumer protection rules. Analytical surveys have reported mismatches between label claims and measured content in products sold online, although the scope of such testing is limited. Whether these discrepancies are widespread remains an open question. Discussion in the literature therefore tends to combine chemistry, supply-chain observation and policy analysis.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone, the naturally occurring peptide involved in pigmentation signalling. Its sequence is conventionally written as Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, with a lactam bridge joining the aspartate side chain to the lysine side chain. The empirical formula is C50H69N15O9 and the monoisotopic mass lies near 1023.5 daltons. N-terminal acetylation and the D-configured phenylalanine both increase resistance to enzymatic breakdown compared with the parent hormone.
Pharmacologically, melanotan-2 behaves as a non-selective agonist across the melanocortin receptor family. Binding at MC1R on dermal melanocytes promotes eumelanin synthesis, which underlies the tanning response described in early human work. Activity at the centrally expressed MC4R receptor is associated with reported effects on appetite and erectile function. Because the peptide does not discriminate strongly among receptor subtypes, attributing any single observed effect to one receptor pathway is generally not possible without selective antagonists or receptor knockout models.
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.
Regulatory treatment varies by jurisdiction and has changed over time. In several countries the peptide is handled as an unapproved prescription medicine, and import or sale for human use is restricted, while elsewhere it falls under poisons or controlled-substance schedules. Enforcement activity against online vendors has been reported in Australia, New Zealand, the United Kingdom and the United States. Scholarly writing discusses melanotan-2 chiefly as an experimental tool and as a case study in unregulated peptide supply, and its precise legal position in any given country should be checked against current national schedules.
In July 2018, Michael Collins, deputy assistant director of the CIA's East Asia mission center, told the Aspen Security Forum in Colorado that he believed China under General Secretary of the Chinese Communist Party Xi Jinping, while unwilling to go to war, was waging a "quiet kind of cold war" against the United States, seeking to replace the US as the leading global power. He further elaborated: "What they're waging against us is fundamentally a cold war — a cold war not like we saw during [the] Cold War (between the U.S. and the Soviet Union) but a cold war by definition". In October 2018, Hong Kong's Lingnan University professor Zhang Baohui told The New York Times that a speech by United States Vice-president Mike Pence at the Hudson Institute "will look like the declaration of a new Cold War". In January 2019, Robert D. Kaplan of the Center for a New American Security wrote that "it is nothing less than a new cold war: The constant, interminable Chinese computer hacks of American warships' maintenance records, Pentagon personnel records, and so forth constitute war by other means. This situation will last decades and will only get worse". In February 2019, Joshua Shifrinson, an associate professor from Boston University, said concerns over a new cold war was "overblown", saying US–China relations were different from that of US–Soviet Union relations during the original Cold War, and that ideology would play a less prominent role in their bilateral relationship.
=== Colombia === The Military Forces of Colombia issues the Campaign Ration (Spanish: Ración de Campaña), a dark olive green plastic bag weighing between 1092 and 1205 grams and providing 3,097 to 3,515 kcal (12,960 to 14,710 kJ). Inside are the retort pouch main courses and supplements needed by a soldier for one day. The individual meals, which cater to South American tastes, consist of a breakfast, a lunch, and a main meal (Tamal, envueltos, lentils with chorizo, arvejas con carne, garbanzo beans a la madrileña, arroz atollado, ajiaco con pollo, and sudado con papas y carne). The ration also includes bread products, beverage mixes, candy and accessories. All items except the beverage mixes require no further preparation and can be eaten either hot or cold. The beverage powders must be mixed with hot or cold water before consumption. Each ration also contains raw sugar, a can of condensed milk, sandwich cookies, sweetened and thickened cream spread, hard candy or caramels, peanuts or trail mix or 25 g of roasted almonds, instant coffee, salt, paper towels, a plastic spoon, 2 water purification tablets, and a multivitamin tablet.
=== Cancer === A meta-analysis concluded that supplementation with β-carotene does not appear to decrease the risk of cancer overall, nor specific cancers including: pancreatic, colorectal, prostate, breast, melanoma, or skin cancer generally. High levels of β-carotene may increase the risk of lung cancer in current and former smokers. Results are not clear for thyroid cancer.
Insulin ( ; from Latin insula 'island') is a peptide hormone produced by beta cells of the pancreatic islets encoded in humans by the insulin (INS) gene. It is the main anabolic hormone of the body. It regulates the metabolism of carbohydrates, fats, and protein by promoting the absorption of glucose from the blood into cells of the liver, fat, and skeletal muscles. In these tissues the absorbed glucose is converted into either glycogen, via glycogenesis, or fats (triglycerides), via lipogenesis; in the liver, glucose is converted into both. Glucose production and secretion by the liver are strongly inhibited by high concentrations of insulin in the blood. Circulating insulin also affects the synthesis of proteins in a wide variety of tissues. It is thus an anabolic hormone, promoting the conversion of small molecules in the blood into large molecules in the cells. Low insulin in the blood has the opposite effect, promoting widespread catabolism, especially of reserve body fat. Beta cells are sensitive to blood sugar levels so that they secrete insulin into the blood in response to high level of glucose, and inhibit secretion of insulin when glucose levels are low. Insulin production is also regulated by glucose: high glucose promotes insulin production while low glucose levels lead to lower production. Insulin enhances glucose uptake and metabolism in the cells, thereby reducing blood sugar.
Sources: en.wikipedia.org
== Variations == Grilled: The noodles and sauce are put in a grilling basket. Fry: Popular primarily in Mishan. The noodles are fried and then brushed with sauce. Teppanyaki: This is the most common way to cook the dish using Teppanyaki cold noodles with onion, eggs and sausage.
=== 3D graphene === In 2013, a three-dimensional honeycomb of hexagonally arranged carbon was termed 3D graphene, and self-supporting 3D graphene was also produced. 3D structures of graphene can be fabricated by using either CVD or solution-based methods. A 2016 review by Khurram and Xu et al. provided a summary of then-state-of-the-art techniques for fabrication of the 3D structure of graphene and other related two-dimensional materials. In 2013, researchers at Stony Brook University reported a novel radical-initiated crosslinking method to fabricate porous 3D free-standing architectures of graphene and carbon nanotubes using nanomaterials as building blocks without any polymer matrix as support. These 3D graphenes (all-carbon) scaffolds/foams have applications in several fields such as energy storage, filtration, thermal management, and biomedical devices and implants. Box-shaped graphene (BSG) nanostructure appearing after mechanical cleavage of pyrolytic graphite was reported in 2016. The discovered nanostructure is a multilayer system of parallel hollow nanochannels located along the surface and having quadrangular cross-section. The thickness of the channel walls is approximately equal to 1 nm.
Myoepithelioma of the head and neck – A (usually) benign tumor of the head/neck consisting of solely myoepithelial cells. Epithelial-myoepithelial carcinoma (of the salivary glands) – A low-grade malignant tumor composed of both neoplastic epithelial and neoplastic myoepithelial cells (a biphasic tumor). Epithelial-myoepithelial carcinoma of the lung – A malignant tumor composed of both epithelial and myoepithelial tissues whose pathology resemble salivary cells. Adenomyoepithelioma of the breast – A (usually) benign tumor of the breast composed of Myoepithelial and Adeno (glandular) cells. Myoepithelioma of the breast – A usually benign or exceedingly rare malignant tumor which mimics IDC but with cells resembling adenoid cysts. If malignant, this is also known as a Myoepithelial carcinoma.
NAD-dependent deacetylase sirtuin 2 is an enzyme that in humans is encoded by the SIRT2 gene. SIRT2 is an NAD+ (nicotinamide adenine dinucleotide)-dependent deacetylase. Studies of this protein have often been divergent, highlighting the dependence of pleiotropic effects of SIRT2 on cellular context. The natural polyphenol resveratrol is known to exert opposite actions on neural cells according to their normal or cancerous status. Similar to other sirtuin family members, SIRT2 displays a ubiquitous distribution. SIRT2 is expressed in a wide range of tissues and organs and has been detected particularly in metabolically relevant tissues, including the brain, muscle, liver, testes, pancreas, kidney, and adipose tissue of mice. Of note, SIRT2 expression is much higher in the brain than all other organs studied, particularly in the cortex, striatum, hippocampus, and spinal cord.
In response to the February 1945 Yalta Conference directives, a Polish Provisional Government of National Unity was formed in June 1945 under Soviet auspices; it was soon recognized by the United States and many other countries. The Soviet domination was apparent from the beginning, as prominent leaders of the Polish Underground State were brought to trial in Moscow (the "Trial of the Sixteen" of June 1945). In the immediate post-war years, the emerging communist rule was challenged by opposition groups, including militarily by the so-called "cursed soldiers", of whom thousands perished in armed confrontations or were pursued by the Ministry of Public Security and executed. Such guerillas often pinned their hopes on expectations of an imminent outbreak of World War III and defeat of the Soviet Union. The Polish right-wing insurgency faded after the amnesty of February 1947. The Polish people's referendum of June 1946 was arranged by the communist Polish Workers' Party to legitimize its dominance in Polish politics and claim widespread support for the party's policies. Although the Yalta agreement called for free elections, the Polish legislative election of January 1947 was controlled by the communists. Some democratic and pro-Western elements, led by Stanisław Mikołajczyk, former prime minister-in-exile, participated in the Provisional Government and the 1947 elections, but were ultimately eliminated through electoral fraud, intimidation and violence.
Sources: en.wikipedia.org
Other signature items at Roy Rogers are the Gold Rush chicken sandwich (a fried chicken breast with bacon, a slice of Monterey Jack cheese, and a honey-based BBQ sauce) and the Double-R Bar Burger (a cheeseburger with ham). The side items featured at Roy Rogers are french fries, baked potatoes, mashed potatoes with gravy, and baked beans. Seasonal items that select Roy Rogers locations occasionally offer include the beer-battered cod sandwich and platter.
=== Pain Management === Intracerebroventricular injection has also been used for pain management. Several studies of refractory head and facial pain, peripheral nerve injury, and other persistent pain conditions have been completed. In one study, six patients with either refractory trigeminal neuralgia or cluster headaches were treated with an ICV opiate infusion pump. Visual analog scores (VAS) were obtained before and after injection to measure effectiveness. When compared, VAS scores improved from an average of 7.8 to 2.8 after the procedure. Most complications that occurred from this procedure consisted of nausea and drowsiness. These symptoms went away after the pump was adjusted. ICV pumps are typically kept in and replaced every four to five years, making the procedure ideal for patients with chronic pain. The CTK 01512-2 peptide toxin can act as a voltage-gated calcium channel (VGCC) blocker. In previous studies, it was shown to have a prolonged effect on preventing and reducing the processing of harmful stimuli by the central nervous system and peripheral nervous system. To strengthen this finding, the CTK 01512-2 toxin was tested on two models of persistent pain. These models include chronic post-ischemia pain (CPIP) and paclitaxel-induced peripheral neuropathy. Additionally, the peptide was injected using three routes of administration: intravenous, intrathecal, and intracerebroventricular. This approach is beneficial for patients who do not respond to traditional pain management approaches.
=== Evaluation === The thyroid is examined by observation of the gland and surrounding neck for swelling or enlargement. It is then felt, usually from behind, and a person is often asked to swallow to better feel the gland against the fingers of the examiner. The gland moves up and down with swallowing because of its attachments to the thyroid and cricoid cartilages. In a healthy person the gland is not visible yet is palpable as a soft mass. Examination of the thyroid gland includes the search for abnormal masses and the assessment of overall thyroid size. The character of the thyroid, swellings, nodules, and their consistency may all be able to be felt. If a goitre is present, an examiner may also feel down the neck consider tapping the upper part of the chest to check for extension. Further tests may include raising the arms (Pemberton's sign), listening to the gland with a stethoscope for bruits, testing of reflexes, and palpation of the lymph nodes in the head and neck. An examination of the thyroid will also include observation of the person as a whole, to look for systemic signs such as weight gain or loss, hair loss, and signs in other locations – such as protrusion of the eyes or swelling of the calves in Graves' disease.
WOSM's emblem and trademark is a purple circular logo with a white fleur-de-lis in the centre with a purple five-point star in each outer lobe, surrounded by a circle of white rope tied with a reef or square knot at the base.
Sources: en.wikipedia.org
No. It is a laboratory-made peptide, while the natural hormone is alpha-melanocyte-stimulating hormone, a longer peptide produced by the pituitary gland and by skin cells. Melanotan-2 mimics only a short active region of that hormone and contains non-natural residues such as D-phenylalanine.
No approved regulatory indication exists in major markets. An approval exists for a different peptide, afamelanotide, which is used for a rare photosensitivity disorder called erythropoietic protoporphyria. Melanotan-2 itself remains a research compound with no cleared clinical role.
Melanocortin-1 receptors on melanocytes are the receptor most closely linked to pigment production. The peptide is not selective, however, and also activates melanocortin-3, melanocortin-4, and melanocortin-5 receptors. That lack of selectivity is the usual explanation offered for both its range of observed effects and its off-target effects.
Low temperature slows hydrolysis and oxidation, the two main routes by which the peptide backbone and side chains are modified. A lyophilised powder stored at −20 °C is more stable than one kept at room temperature, and once the material is dissolved the degradation rate rises, making refrigeration more important.