If you have been reading about cyclic heptapeptide 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 2026-01-09. 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.
Scientific discussion of Melanotan-2 spans pharmacology, dermatology, and public-health literature. Laboratory studies examine its receptor binding and cellular effects, while clinical reports describe outcomes observed after unregulated use. These two bodies of work differ in rigour and intent. Peer-reviewed trials of the compound as a medicine are limited, so much of the available information comes from case reports and surveillance data. Authors frequently note the gap between experimental findings and real-world use.
Reported observations after unregulated use include shifts in skin pigmentation and, in some accounts, unintended changes to moles and other lesions. Whether these outcomes are causally linked to the compound, and how often they occur, remain open questions because controlled data are scarce. The absence of standardised dosing and verified product purity complicates interpretation. Researchers have called for better surveillance and analytical characterisation of samples obtained outside regulated channels. Conclusions drawn from anecdotal evidence should be treated as provisional.
| 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 |
Published human data come mostly from small, short studies rather than large controlled trials. Reported outcomes include increased skin pigmentation and, in some reports, effects on appetite and libido, but sample sizes are small and follow-up is limited. Whether long-term use produces durable pigment changes or adverse effects is not established. Because products sold outside pharmacies are not standardized, the actual content of any given vial is often unknown. Independent testing of such material is uncommon.
Melanotan II is a synthetic cyclic heptapeptide analog derived from the core sequence of alpha-melanocyte-stimulating hormone. Researchers at the University of Arizona synthesized it during the 1980s while studying pigmentation and appetite signaling. The compound is not an approved medicine in any major jurisdiction and appears mainly in laboratory and research-chemical settings. Its structure incorporates a lactam bridge between side chains, which constrains the ring and slows enzymatic breakdown relative to the natural hormone.
Analytical confirmation of identity relies on mass spectrometry, most often coupled to liquid chromatography. Reversed-phase high-performance liquid chromatography separates the peptide from related impurities and provides a purity estimate based on peak area. Electrospray ionization mass spectrometry then confirms the expected molecular mass, while tandem mass spectrometry can map the fragment sequence. For research-grade material, these two techniques together form the standard minimum. Purity figures reported by vendors are frequently not traceable to an independent laboratory.
Independent verification is central to quality control because the compound is not produced under pharmaceutical manufacturing standards. Third-party laboratories can measure purity, identity, residual solvents, and microbial contamination, though the scope of testing varies between services. Reported analyses of vendor samples have shown batch-to-batch variation in peptide content and the presence of truncated or oxidized species. How much of this variation reflects synthesis conditions versus storage and shipping is not well characterized. No harmonized reference standard exists for the material as sold.
=== Research === Hepatitis B and its related disorders are important public health issues in China, which not only presents challenges for doctors and scientists but also increases the burden for the government. Last year, the Chinese Government funded research with around Ɲ3 billion (US$390 million), mainly against hepatitis B and related diseases over the next decade. Research will include: large retrospective and prospective studies of the population vaccinated against hepatitis B and the incidence of HCC; genetic variation in HBV and its subtypes, and mutations in HBV DNA in the response to interferon and nucleotide analogues; host-gene variation and the therapeutic response, including single-nuclear polymorphisms and gene copy-number variations; virus mutation and the mechanism of the immune response in fulminant liver failure, and the immunological factors which cause liver injury and the markers which predict reduction in liver function; assessment and prediction of liver fibrosis by non-invasive biomarkers, and interference with fibrosis from small chemical compounds or traditional Chinese medicines; prediction of the development, metastasis, and prognosis of HCC by molecular typing; and the identification of important signal transduction pathways in HCC and the development of new small chemical compounds to target HCC.
== History == Fentanyl was first synthesized in Belgium by Paul Janssen under the label of his relatively newly formed Janssen Pharmaceutica in 1959. It was developed by screening chemicals similar to pethidine (Demerol) for opioid activity. The widespread use of fentanyl triggered the production of fentanyl citrate (the salt formed by combining fentanyl and citric acid in a 1:1 stoichiometric ratio). Fentanyl citrate entered medical use as a general anesthetic in 1968, manufactured by McNeil Laboratories under the brand name Sublimaze. In the mid-1990s, Janssen Pharmaceutica developed and introduced into clinical trials the Duragesic patch, which is a formulation of an inert alcohol gel infused with select fentanyl doses, which are worn to provide constant administration of the opioid over 48 to 72 hours. After a set of successful clinical trials, Duragesic fentanyl patches were introduced into medical practice.
=== Laboratory tests === Laboratory tests including urea and creatinine levels, liver enzymes, glucose, thyroid function, full blood count, and clotting tests. The analysis of serum and urine for presence of monoclonal immunoglobulin is also done through immunofixation for detection of the monoclonal band. Presence of the monoclonal band would be consistent with light chain amyloidosis. For light chain amyloidosis, serum immunoglobulin free light chain assay can be used for diagnosis and following of the amyloidosis. In light-chain amyloidosis, a low paraprotein level can be present.
== Adverse effects == The most common adverse drug reactions (ADRs) are dose-related and arise from the effect of loop diuretics on diuresis and electrolyte balance. Common ADRs include: hyponatremia, hypokalemia, hypomagnesemia, dehydration, hyperuricemia, gout, dizziness, postural hypotension, syncope. The loss of magnesium as a result of loop diuretics has also been suggested as a possible cause of pseudogout (chondrocalcinosis). Infrequent ADRs include: dyslipidemia, increased serum creatinine concentration, hypocalcemia, rash. Metabolic alkalosis may also be seen with loop diuretic use. Ototoxicity (damage to the inner ear) is a serious, but rare ADR associated with use of loop diuretics. This may be limited to tinnitus and vertigo, but may result in deafness in serious cases. Loop diuretics may also precipitate kidney failure in patients concurrently taking an NSAID and an ACE inhibitor—the so-called "triple whammy" effect. Because furosemide, torsemide and bumetanide are technically sulfa drugs, there is a theoretical risk that patients sensitive to sulfonamides may be sensitive to these loop diuretics. This risk is stated on drug packaging inserts. However, the actual risk of crossreactivity is largely unknown and there are some sources that dispute the existence of such cross reactivity. In one study it was found that only 10% of patients with allergy to antibiotic sulfonamides were also allergic to diuretic sulfonamides, but it is unclear if this represents true cross reactivity or the nature of being prone to allergy.
Sources: en.wikipedia.org
Cancers are usually named using -carcinoma, -sarcoma or -blastoma as a suffix, with the Latin or Greek word for the organ or tissue of origin as the root. For example, the most common cancer of the liver parenchyma ("hepato-" = liver), arising from malignant epithelial cells ("carcinoma"), would be called a hepatocarcinoma, while a malignancy arising from primitive liver precursor cells is called a hepatoblastoma. Similarly, a cancer arising from malignant fat cells would be termed a liposarcoma. For some common cancers, the English organ name is used. For example, the most common type of breast cancer is called ductal carcinoma of the breast. Benign tumors (which are not cancers) are usually named using -oma as a suffix with the organ name as the root. For example, a benign tumor of smooth muscle cells is called a leiomyoma (the common name of this frequently occurring benign tumor in the uterus is fibroid). Confusingly, some types of cancer use the -noma suffix, examples including melanoma and seminoma. Some types of cancer are named for the size and shape of the cells under a microscope, such as giant cell carcinoma, spindle cell carcinoma, and small-cell carcinoma.
Sedative drugs and sleeping pills, including lorazepam, have been associated with an increased risk of death. Sedation is the side effect people taking lorazepam most frequently report. In a group of around 3,500 people treated for anxiety, the most common side effects complained of from lorazepam were sedation (15.9%), dizziness (6.9%), weakness (4.2%), and unsteadiness (3.4%). Side effects such as sedation and unsteadiness increased with age. Cognitive impairment, behavioral disinhibition and respiratory depression as well as hypotension may also occur.
== Lewis acid strength in non-aqueous solutions == Lewis acids have been classified in the ECW model and it has been shown that there is no one order of acid strengths. The relative acceptor strength of Lewis acids toward a series of bases, versus other Lewis acids, can be illustrated by C-B plots. It has been shown that to define the order of Lewis acid strength at least two properties must be considered. For Pearson's qualitative HSAB theory the two properties are hardness and strength while for Drago's quantitative ECW model the two properties are electrostatic and covalent.
When IMS is used with mass spectrometry, ion mobility spectrometry-mass spectrometry offers many advantages, including better signal to noise, isomer separation, and charge state identification. IMS has commonly been attached to several mass spec analyzers, including quadropole, time-of-flight, and Fourier transform cyclotron resonance.
Albany has a home rule charter and a council–manager government. A full-time unelected city manager administers the day-to-day operations of the city for the council. The city manager since 2018 is Peter Troedsson. The mayor is elected at large every two years. The six council members represent the three geographic wards of the city and have overlapping four-year terms. The city charter was first adopted in 1891, and the most recent version of the city charter became effective on January 1, 1957, modified since then by ordinances adopted by the council. The mayor, as of 2025, is Alex Johnson II, and the council members are Steph Newton and Michael Thomson from Ward I, Carolyn McLeod and Chris Van Drimmelen from Ward II, and Ramycia McGhee and Marilyn Smith from Ward III. Albany City Hall is located on Broadalbin Street in the downtown section of the city and was built in 1995. In 2018, City Hall houses:
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.
Major regulatory agencies have not approved it for any indication. Some countries permit it only under prescription frameworks, while others classify it as a controlled substance.