If you have been reading about alpha-MSH analogue 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 2025-09-03. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
Regulatory treatment varies between countries. Several national medicines agencies have classified the peptide as unapproved, and customs authorities in some jurisdictions seize shipments on that basis. A few jurisdictions channel supply through prescription-only frameworks that do not list the substance by name. Because the material circulates mainly through online vendors, composition and purity are rarely verified before sale. Surveys of unapproved peptide products have reported labels that did not match measured content in a substantial fraction of samples.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic cyclic heptapeptide | Analog of alpha-MSH with an internal lactam bridge |
| Molecular weight | Approximately 1024 daltons | Free base value; salt forms differ |
| Appearance | White to off-white powder | Usually supplied as a lyophilized solid |
| Solubility | Freely soluble in water | Poorly soluble in nonpolar solvents |
| Typical storage | −20 °C, dry, protected from light | Repeated freeze-thaw cycles degrade peptides |
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.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone, a naturally occurring peptide involved in pigmentation signalling. Its sequence incorporates modified residues that increase potency and extend biological activity relative to the native hormone. The compound binds receptors of the melanocortin family and is examined mainly in laboratory research. It does not occur naturally and exists only as a manufactured chemical entity produced by solid-phase synthesis.
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.
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.
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.
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.
== Adverse effects == The main adverse drug reaction associated with calcitriol therapy is hypercalcaemia – early symptoms include: nausea, vomiting, constipation, anorexia, apathy, headache, thirst, pruritus, sweating, and/or polyuria. Compared to other vitamin D compounds in clinical use (cholecalciferol, ergocalciferol), calcitriol has a higher risk of inducing hypercalcemia. However, such episodes may be shorter and easier to treat due to its relatively short half-life. High calcitriol levels may also be seen in human disease states in patients not on supplementation. In someone with hypercalcaemia and high calcitriol levels, low intact parathyroid hormone levels are usually present. The major conditions with hypercalcaemia due to elevated calcitriol levels are lymphoma, tuberculosis and sarcoidosis where excess production occurs due to ectopic 25(OH)D-1-hydroxylase (CYP27B1) expressed in macrophages. Other conditions producing similar findings including:
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== History == During the 1980s, Jean-Pierre Raufman worked as a postdoctoral researcher at the National Institutes of Health for John Pisano, a biochemist who specialized in collecting venom from various animals and looking for novel substances that could affect human physiology. In the course of this work, Raufman focused on the Gila monster, because he was curious about its practice of eating once or twice per year. He reported that Gila monster venom had biologically active molecules that provoked inflammation of the pancreas in test animals. In 1992, after learning of Raufman's findings, John Eng of the Veterans Administration Medical Center in New York City used radioimmunoassay to isolate a novel substance from Gila monster venom. The new substance, which Eng called exendin-4, was similar to GLP-1 in that it reduced blood glucose in diabetic mice, but exendin-4 had a much longer half-life than GLP-1, whose extremely short half-life had defeated earlier attempts to turn it into a drug. Eng filed a patent application for exendin-4 in 1993. He then spent three years searching for a pharmaceutical industry partner interested in commercializing exendin-4. In 1996, Amylin Pharmaceuticals licensed Eng's patent and created a synthetic version of exendin-4 called exenatide. In 2002, Eli Lilly and Company partnered with Amylin to develop exenatide and secure approval to market the drug. Exenatide's 2005 approval by the U.S.
=== Opioid use disorder === Long-acting injectable naltrexone, sold under the brand name Vivitrol, is an opioid antagonist, blocking the effects of heroin and other opioids, and decreases heroin use compared to placebo in the context of opioid use disorder (OUD). Unlike methadone and buprenorphine, it is not a controlled medication. It may reduce opioid cravings after several weeks and lower the risk of opioid overdose—at least while naltrexone remains active—but concerns about overdose risk for those who stop treatment continue. Injection naltrexone is administered once monthly and has demonstrated greater consistency in patient adherence and efficacy, as measured by opiate-negative urine samples, in comparison to placebo for OUD. A drawback of injectable naltrexone is that it requires patients with OUD and ongoing physical dependence to be fully detoxified before initiation to prevent severe opioid withdrawal. In contrast, initiation of buprenorphine only requires delaying the first dose until the patient begins to manifest at least mild withdrawal symptoms. Among patients able to successfully initiate injectable naltrexone, long-term remission rates were similar to those seen in clinical buprenorphine/naloxone administration. The consequence of relapse when weighing the best course of treatment for opiate use disorder remains a concern. Methadone and buprenorphine administration maintain greater drug tolerance while naltrexone allows tolerance to fade, leading to higher instances of an overdose in people who relapse and thus higher mortality.
Sources: en.wikipedia.org
Using fundamental principles established by IUPAC, the delta (Δ) system for lipid notation was developed by researchers within the mid-20th century, to address the need for distinction between fatty acids with the same acyl chain length but different double bond positions. Thus, the Δ system defines the position of double bonds by virtue of the carboxyl (–COOH) carbon using the general formula: C:DΔy where C is the total number of carbons, D is the number of double bonds, and Δy indicates the position of each double bond, counting from the –COOH end of the fatty acid. Unlike the omega nomenclature system, each double bond of the fatty acid must be described in the delta system.
In biochemistry the substrate is known as a receptor. A receptor is a protein molecule, embedded in either the plasma membrane or the cytoplasm of a cell, to which one or more specific kinds of signalling molecules may bind. A ligand may be a peptide or another small molecule, such as a neurotransmitter, a hormone, a pharmaceutical drug, or a toxin. The specificity of a receptor is determined by its spatial geometry and the way it binds to the ligand through non-covalent interactions, such as hydrogen bonding or Van der Waals forces. If a receptor can be isolated a synthetic drug can be developed either to stimulate the receptor, an agonist or to block it, an antagonist. The stomach ulcer drug cimetidine was developed as an H2 antagonist by chemically engineering the molecule for maximum specificity to an isolated tissue containing the receptor. The further use of quantitative structure-activity relationships (QSAR) led to the development of other agents such as ranitidine. "Selectivity" when referring to a drug is relative. For example, in a higher dose, a specific drug molecule may also bind to other receptors than those said to be "selective".
Skittles are multicolored fruit-flavored lentil-shaped sweets produced and marketed by the Wrigley Company, a division of Mars Inc. Skittles consist of hard sugar shells imprinted with the letter 'S' in lowercase, similar to M&M's which have the letter 'M'. The interior consists mainly of sugar, corn syrup, and hydrogenated palm kernel oil along with fruit juice, citric acid, and natural and artificial flavors. Skittles are sold in a variety of flavor collections, such as Tropical, Wild Berry, Smoothie, and Sour.
Shānghán Zábìng Lùn (傷寒雜病論), or The Treatise on Cold Damage and Miscellaneous Diseases, is the first Chinese monograph on diseases by Zhang Zhongjing. The original work is lost, but most of its contents are preserved in two extant works called Shānghán Lùn (傷寒論; "The Treatise on Cold Damage") and Jīnguì Yàolüè (金匱要略; "Essential Prescriptions from the Golden Chamber"). The first work primarily addresses externally triggered conditions while the latter work describes internally generated conditions. Zhang's specialized chapter on xiāo kě is found in Shānghán Lùn and Jīnguì Yàolüè. Nine subsections and nine formulae (herbal remedies) on wasting-thirst were recorded. The text proposed a theory of "three wasting-thirsts": upper- (associated with the lungs), middle- (associated with the stomach), and lower- (associated with the kidneys), all three of which shared excessive urine and thirst as symptoms. This theory was later expanded through the works of Liu Wansu (1120–1200 AD) and Wang Kentang (1549–1613 AD). According to Liu, "lower wasting-thirst" attributed to "kidney-yin deficiency" was associated with sweet urine (glycosuria). This may indicate differentiation akin to modern-day differentiation of diabetes mellitus and diabetes insipidus.
== Anti-thyroid drugs == Iodine uptake against a concentration gradient is mediated by a sodium–iodine symporter and is linked to a sodium-potassium ATPase. Perchlorate and thiocyanate are drugs that can compete with iodine at this point. Compounds such as goitrin, carbimazole, methimazole, propylthiouracil can reduce thyroid hormone production by interfering with iodine oxidation.
Sources: en.wikipedia.org
. Even for a simple homogeneous sphere of radius a whose refractive index, n, is very nearly the same as the refractive index "n0" of the suspending fluid, i.e. Rayleigh–Gans approximation, the scattering function in the scattering plane is the relatively complex quantity
=== Nuclear magnetic resonance spectroscopy === Metal carbonyls are often characterized by 13C NMR spectroscopy. To improve the sensitivity of this technique, complexes are often enriched with 13CO. Typical chemical shift range for terminally bound ligands is 150 to 220 ppm. Bridging ligands resonate between 230 and 280 ppm. The 13C signals shift toward higher fields with an increasing atomic number of the central metal. NMR spectroscopy can be used for experimental determination of the fluxionality. The activation energy of ligand exchange processes can be determined by the temperature dependence of the line broadening.
== Tetanus Toxoid Immunization Schedule for Women == When given to women of childbearing age, vaccines that contain tetanus toxoid (TT or Td) not only protect women against tetanus, but also prevent neonatal tetanus in their newborn infants.
== Uses == The fruits are mainly consumed and have a juicy, edible center of many seeds. The parts of the fruit eaten are the pulpy, juicy seeds. Passion fruits are commonly squeezed to make juice, or used for pastries and other baked products, and as an ice cream flavor. When passion fruit seeds are added to snack bars, the dietary fiber content rose from 4.17% to 5.66% while the fat content rose from 15.02% to 19.63%.
== Technology == OpenELIS is web-based, with a Java/Spring backend and a React front end, and is deployed using Docker-based containerised infrastructure. It provides interoperability through the HL7 FHIR R4 standard, for which the project publishes a FHIR implementation guide, alongside ASTM and HL7 v2 interfaces for laboratory analyzers and LOINC and SNOMED terminology, and is aligned with the OpenHIE architecture for exchange with electronic medical records and health information exchanges. It is released under the Mozilla Public License 2.0. OpenELIS is recognised as a Digital Square "global good for health" and is listed as a digital public good by the Digital Public Goods Alliance.
Sources: en.wikipedia.org
It is a synthetic seven-amino-acid peptide modeled on alpha-melanocyte-stimulating hormone. It carries two non-natural substitutions and a cyclic bridge that increase its stability relative to the natural hormone. It circulates as a research chemical and is not an approved medicine.
Melanotan-1, also called afamelanotide, is a shorter linear analog with a different amino acid sequence and no lactam ring. It has been evaluated in formal clinical programs, while melanotan-2 has not. The two are distinct molecules and are not interchangeable.
No. Bremelanotide is a related but distinct cyclic peptide that reached approved status for one specific clinical indication. Melanotan-2 is a separate molecule with its own sequence and properties. Shared ancestry in the melanocortin family does not make them the same substance.
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.