This is a working overview of cyclic heptapeptide, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-08-05. Anything still debated is marked as such rather than presented as settled.
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.
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 | Melanocortin receptor agonist |
| Molecular formula | C50H69N15O9 | Neutral form, mass near 1024.2 g/mol |
| Primary targets | MC1R, MC3R, MC4R, MC5R | Binding is non-selective across subtypes |
| Related compounds | Alpha-MSH, melanotan I, afamelanotide | Structurally or functionally related peptides |
| Common abbreviations | MT-II, MT-2 | Naming in the literature is not uniform |
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.
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.
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.
Edwards Ltd is a British multinational vacuum pump and exhaust gas management systems manufacturer. Its headquarters are in Burgess Hill, UK, and has been part of the Atlas Copco Group since 2014. Edwards holds 1,700 patents, including for dry (oil-free) vacuum pumps, and produces equipment used for manufacturing semiconductors, scientific research, freeze drying and other industries. Its pumps remove contaminants at CERN's Large Hadron Collider. Manufacturing is predominantly handled by subsidiary businesses in the Czech Republic, South Korea, USA and China. Edwards' global research and development facilities remain in the UK. Major customers in 2012 included Samsung, Hynix, Agilent and LG.
== Towards Seismic Cloaking == Computations showed that seismic waves traveling toward a building, could be directed around the building, leaving the building unscathed, by using seismic metamaterials. The very long wavelengths of earthquake waves would be shortened as they interact with the metamaterials; the waves would pass around the building so as to arrive in phase as the earthquake wave proceeded, as if the building was not there. The mathematical models produce the regular pattern provided by metamaterial cloaking. This method was first understood with electromagnetic cloaking metamaterials—the electromagnetic energy is in effect directed around an object, or hole, and protecting buildings from seismic waves employs this same principle. Giant polymer-made split-ring resonators combined with other metamaterials are designed to couple at the seismic wavelength. Concentric layers of this material would be stacked, each layer separated by an elastic medium. The design that worked is ten layers of six different materials, which can be easily deployed in building foundations. As of 2009, the project is still in the design stage. In 2019, scientists identified flaws in models of seismic cloaks related to extrapolations from photonics, and proved that a perfect cloak, which bends out-of-plane waves completely away from a structure, is not feasible (though they can be dampened), but a cloak which protects against surface waves and dampens others is still possible.
== Pharmacokinetics == As R7 is a slightly larger molecule than tropoflavin, 72.5 mg R7 is molecularly equivalent to 50 mg tropoflavin. Relative to a roughly molecularly equivalent dose of tropoflavin, the area-under-curve levels of R7 were found to be 7.2-fold higher upon oral administration to mice, and R7 hence has a greatly improved oral bioavailability in mice of approximately 35%. Moreover, whereas tropoflavin itself is mostly metabolized in mice within 30 minutes, tropoflavin as a metabolite was still detectable in plasma at 8 hours after administration with R7, indicating that R7 sustainably releases tropoflavin into circulation. In accordance, the terminal half-life of R7 is about 195 minutes (3.25 hours) in mice. The Tmax of R7 is about 60 minutes in mice, and its Cmax for a 78 mg/kg dose was 262 ng/mL, whereas that for a 50 mg/kg dose of tropoflavin was 70 ng/mL.
Sources: en.wikipedia.org
The average age of participants was 66 years and more participants were male (77%) than female. To determine the drug's effectiveness, investigators examined the occurrence of cardiovascular death, hospitalization for heart failure, and urgent heart failure visits. Participants were randomly assigned to receive a once-daily dose of either 10 mg of dapagliflozin or a placebo (inactive treatment). After about 18 months, people who received dapagliflozin had fewer cardiovascular deaths, hospitalizations for heart failure, and urgent heart-failure visits than those receiving the placebo. In July 2020, the FDA granted AstraZeneca a Fast Track Designation in the US for the development of dapagliflozin to reduce the risk of hospitalization for heart failure or cardiovascular death in adults following a heart attack. In August 2020, detailed results from the Phase III DAPA-CKD trial reportedly showed that dapagliflozin on top of standard of care reduced the composite measure of worsening of renal function or risk of cardiovascular or renal death by 39% compared to placebo (p<0.0001) in patients with chronic kidney disease stages 2–4 and elevated urinary albumin excretion. The results were consistent in patients both with and without type 2 diabetes. In April 2021, the FDA expanded the indications for dapagliflozin to include reducing the risk of kidney function decline, kidney failure, cardiovascular death, and hospitalization for heart failure in adults with chronic kidney disease who are at risk of disease progression.
This variation is often found in Purwokerto. The word mendoan originates in the Banyumas regional dialect, and means 'flash-fried'. The tempeh is first dipped in spiced flour before quickly frying in very hot oil, resulting in a product that is cooked on the outside, but raw or only partially so on the inside. It has a limp, soft texture compared to the more common, crisp, fully fried tempeh.
== History == The first scholars to propose that there are three primary colors for painters were Scarmiglioni (1601), Savot (1609), de Boodt (1609) and Aguilonius (1613). From these, the most influential was the work of Franciscus Aguilonius (1567–1617), although he did not arrange the colors in a wheel. Jacob Christoph Le Blon was the first to apply the RYB color model to printing, specifically mezzotint printing, and he used separate plates for each color: yellow, red and blue plus black to add shades and contrast. In 'Coloritto', Le Blon asserted that “the art of mixing colours…(in) painting can represent all visible objects with three colours: yellow, red and blue; for all colours can be composed of these three, which I call Primitive”. Le Blon added that red and yellow make orange; red and blue, make purple; and blue and yellow make green (Le Blon, 1725, p6). In the 18th century, Moses Harris advocated that a multitude of colors can be created from three "primitive" colors – red, yellow, and blue. Mérimée referred to "three simple colours (yellow, red, and blue)" that can produce a large gamut of colors and details. "United in pairs, these three primitive colours give birth to three other colours as distinct and brilliant as their originals; thus, yellow mixed with red, gives orange; red and blue, violet; and green is obtained by mixing blue and yellow" (Mérimée, 1839, p245).
Sources: en.wikipedia.org
The four substrates of this enzyme are naphthalene, reduced nicotinamide adenine dinucleotide (NADH), oxygen and a proton. Its products are (1R, 2S)-cis 1,2 dihydroxy-1,2-dihydronaphthalene and oxidised NAD+. This enzyme is an oxidoreductase that uses molecular oxygen as oxidant and incorporates both its atoms into the starting material. The systematic name of this enzyme class is naphthalene,NADH:oxygen oxidoreductase (1,2-hydroxylating). Other names in common use include naphthalene dioxygenase, and naphthalene oxygenase. The enzyme is an iron–sulfur protein that contains ferredoxin and participates in metabolic pathways that degrade polycyclic aromatic hydrocarbons and ethylbenzene.
In addition to regulating the experiments that were conducted, the guidelines also forbade the performance of other experiments. One such experiment was the cloning of recombinant DNAs derived from highly pathogenic organisms. In addition, neither the cloning of DNA containing toxin genes nor large-scale experiments using recombinant DNAs that were able to make products that were potentially harmful to humans, animals, or plants were allowed under the guidelines. These experiments were banned because the potential biohazards could not be contained by the then-current safety precautions.
Deoxyribozymes, also called DNAzymes or catalytic DNA, were first discovered in 1994. They are mostly single stranded DNA sequences isolated from a large pool of random DNA sequences through a combinatorial approach called in vitro selection or systematic evolution of ligands by exponential enrichment (SELEX). DNAzymes catalyze variety of chemical reactions including RNA-DNA cleavage, RNA-DNA ligation, amino acids phosphorylation-dephosphorylation, carbon-carbon bond formation, etc. DNAzymes can enhance catalytic rate of chemical reactions up to 100,000,000,000-fold over the uncatalyzed reaction. The most extensively studied class of DNAzymes is RNA-cleaving types which have been used to detect different metal ions and designing therapeutic agents. Several metal-specific DNAzymes have been reported including the GR-5 DNAzyme (lead-specific), the CA1-3 DNAzymes (copper-specific), the 39E DNAzyme (uranyl-specific) and the NaA43 DNAzyme (sodium-specific). The NaA43 DNAzyme, which is reported to be more than 10,000-fold selective for sodium over other metal ions, was used to make a real-time sodium sensor in cells.
=== Potency of laudanum === Opium tincture is one of the most potent oral formulations of morphine available by prescription. Accidental or deliberate overdose is easily possible with opium tincture given the highly concentrated nature of the solution. Overdose and death may occur with a single oral dose of between 100 and 150 mg of morphine in a healthy adult who has no tolerance to opiates. This represents the equivalent of between two and three teaspoons (10–15 mL) of opium tincture. Overdose of laudanum was an occurrence in the mid-19th century. Prudent medical judgment necessitates toward dispensing very small quantities of opium tincture in small dropper bottles or in pre-filled syringes to reduce the risk of intentional or accidental overdose.
Sources: en.wikipedia.org
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.
Activation of MC1R increases pigment synthesis independently of ultraviolet exposure, which is the mechanism usually cited for darkening without sun exposure. Ultraviolet light still influences skin response through separate biological pathways.
Because the peptide binds several melanocortin receptor subtypes, its effects are not confined to pigmentation. This complicates interpretation of both intended and unintended outcomes reported in studies.
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.