The short version of cyclic heptapeptide fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-09-13 and is reviewed periodically as new material appears.
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.
Melanotan-2 is a synthetic cyclic heptapeptide designed as a structural analogue of alpha-melanocyte-stimulating hormone, the endogenous tridecapeptide that regulates pigment production. Two modifications distinguish it from the natural hormone: norleucine replaces methionine at the N-terminus, which limits oxidation, and a D-phenylalanine substitution raises receptor affinity. The ring is closed through an aspartate-lysine lactam bridge, giving the molecule a constrained conformation. The free base has a molecular mass near 1024 daltons, and commercial material is usually supplied as an acetate salt. It appears in the literature as a research peptide rather than an approved therapeutic agent.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Belongs to the melanocortin agonist family |
| Key substitutions | Nle4 and D-Phe7 | Improve resistance to enzymatic degradation |
| Molecular formula | C50H69N15O9 | Approximately 1024 g/mol |
| Regulatory status | Not approved as a medicine | Distributed as a research chemical |
| Common synonyms | Melanotan II, MT-II, MT-2 | Spelling varies across sources |
== Chemistry == Oxymorphone is commercially produced from thebaine, which is a minor constituent of the opium poppy (Papaver somniferum) but thebaine is found in greater abundance (3%) in the roots of the oriental poppy (Papaver orientale). German patents from the mid-1930s indicate that oxymorphone as well as hydromorphone, hydrocodone, oxycodone, and acetylmorphone can be prepared—without the need for hydrogen gas—from solutions of codeine, morphine, and dionine by refluxing an acidic aqueous solution, or the precursor drug dissolved in ethanol, in the presence of certain metals, namely palladium and platinum in fine powder or colloidal form or platinum black. Oxymorphone hydrochloride occurs as odourless white crystals or white to off-white powder. It darkens in colour with prolonged exposure to light. One gram of oxymorphone hydrochloride is soluble in 4 ml of water and it is sparingly soluble in alcohol and ether. It degrades upon contact with light. Oxymorphone can be acetylated like morphine, hydromorphone, and some other opioids. Mono-, di-, tri-, and tetra- esters of oxymorphone were developed in the 1930s but are not used in medicine at this time. Presumably other esters such as nicotinyl, benzoyl, formyl, or cinnamyl can be produced. The 2013 US DEA annual manufacturing quotas were 18 375 kilogrammes for conversion (a number of drugs can be made from oxymorphone, both painkillers and opioid antagonists like naloxone) and 6875 kg for direct manufacture of end-products.
Temozolomide, sold under the brand name Temodar among others, is an anticancer medication used to treat brain tumors such as glioblastoma and anaplastic astrocytoma. It is taken by mouth or via intravenous infusion. The most common side effects with temozolomide are nausea, vomiting, constipation, loss of appetite, alopecia (hair loss), headache, fatigue, convulsions (seizures), rash, neutropenia or lymphopenia (low white-blood-cell counts), and thrombocytopenia (low blood platelet counts). People receiving the solution for infusion may also have injection-site reactions, such as pain, irritation, itching, warmth, swelling and redness, as well as bruising. Temozolomide is an alkylating agent used to treat serious brain cancers; most commonly as second-line treatments for astrocytoma and as the first-line treatment for glioblastoma. Olaparib in combination with temozolomide demonstrated substantial clinical activity in relapsed small cell lung cancer. It is available as a generic medication.
== Metabolism == Telithromycin is metabolized mainly in the liver, the main elimination route being the bile, a small portion is also excreted into the urine. About one third is excreted unchanged in bile and urine, the biliary route being favoured. Telithromycin's half-life is approximately ten hours.
Sources: en.wikipedia.org
=== Rome === The traditional Roman diet consisted of grain, fruits, olive oil, meat and wine. Of all these, grain was extremely important to the Roman people. During Rome's height, it is estimated that the city itself needed 150,000 tons of grain and millions of liters of water and wine every year to survive. It was traditionally the responsibility of the Roman government to guarantee that there was enough food for distribution among the people. In times of shortages, bad harvests, or interference by pirates, the government made sure to fulfill its obligation to food distribution. Officials would sometimes buy food themselves and then sell it back to the people at little to no cost. When Rome eventually established its Empire, foreign lands would send taxes in grain to Rome, which helped decrease the chance of a food distribution crisis.
Not all of the population supported participating in the war. A poll by the magazine Tiempo revealed that 40.7% supported Mexico's further involvement in World War II, while 59.8% opposed it. To change public opinion, the government began a propaganda campaign to justify its decision. It used Rodolfo Chacón, a survivor of the German attack on Potrero del Llano as the focal point of the propaganda. Regarding military service, there was also division among Mexicans, provoking violent protests that led the government to exempt draftees from overseas service, which helped quell civil unrest. However, Mexican citizens living in other countries were drafted into their respective armies, resulting in high casualty rates. The press and the popular opinion, on one side was the sympathy with the aliadophiles and on the other the germanophile current. For the former, the gazettes and newspapers in general were full of praise "with the full assurance of conquering the laurels of triumph". And in cities throughout the Republic, "darkening exercises" were carried out, in which the civilian population had to participate by turning off all sources of light, as a strategy to hinder possible bombing of the cities. On the other hand, in the newspaper La Nación, organ of diffusion of the National Action Party, Efraín González Luna stated:
== Drug pricing issue and exit in the Swiss market == In July 2025, Roche withdrew Lunsumio from the Swiss market following failed price negotiations with the Swiss Federal Office of Public Health (BAG). The drug had been available since February 2023 through a special "Early Access" program that allowed reimbursement before complete clinical data was available. Under this arrangement, Roche initially covered treatment costs until efficacy was demonstrated, after which the remaining therapy could exceed 100,000 Swiss francs. When Swissmedic extended the temporary authorization in February 2025 due to still-missing complete clinical data from Phase III studies, Roche rejected the previously negotiated pricing model and demanded higher prices. The BAG refused to modify the agreement, citing concerns that exceptions would set a precedent for other pharmaceutical companies and demanding additional efficacy evidence despite the drug showing positive effects in Phase II studies. According to Swissmedic pricing data, a single 60-mg dose (two vials) of Lunsumio costs over 7,000 Swiss francs. The withdrawal was announced to oncologists on July 1, 2025, affecting approximately 24 patients annually who suffer from follicular lymphoma—a slowly progressing cancer of the lymph nodes with about 500 new cases per year in Switzerland. Roche also refused to provide individual case reimbursements—a standard Swiss mechanism for exceptional medical situations.
Sources: en.wikipedia.org
Gemini 4 (officially Gemini IV) was the second crewed spaceflight in NASA's Project Gemini, occurring in June 1965. It was the tenth crewed American spaceflight (including two X-15 flights at altitudes exceeding 100 kilometers (62 mi; 54 nmi)). Astronauts James McDivitt and Ed White orbited the Earth 66 times in four days, making it the first US flight to approach the five-day flight of the Soviet Vostok 5. The highlight of the mission was the first space walk by an American, during which White floated free outside the spacecraft, tethered to it, for approximately 23 minutes. The flight also included the first attempt to make a space rendezvous as McDivitt attempted to maneuver his craft close to the Titan II upper stage which launched it into orbit, but this was not successful. The flight was the first American flight to perform many scientific experiments in space, including use of a sextant to investigate the use of celestial navigation for lunar flight in the Apollo program.
=== Regulation of the insulin receptor signal === PI3K (phosphoinositide 3-kinase) is one of the important components in the regulation of the insulin signaling pathway. It maintains the insulin sensitivity in the liver. PI-3K is composed of a regulatory subunit (P85) and a catalytic subunit (P110). P85 regulates the activation of PI3K enzyme. In the PI-3K heterodimer (P85-P110), P85 is responsible for the PI3K activity, by binding to the binding site on the insulin receptor substrates (IRS). It was noted that an increase of P85 a (isoform of P85) results in a competition between the later and the P85-P110 complex to the IRS binding site, reducing the PI3K activity and leading to insulin resistance. Insulin resistance refers also to type 2 diabetes. It was also noted that increased serine phosphorylation of IRS is involved in the insulin resistance by reducing their ability to attract PI3K. The serine phosphorylation can also lead to degradation of IRS-1.
At the beginning of Hong Kong's opening up, Western medicine was not yet popular, and Western medicine doctors were mostly foreigners; local residents mostly relied on Chinese medicine practitioners. In 1841, the British government of Hong Kong issued an announcement pledging to govern Hong Kong residents in accordance with all the original rituals, customs and private legal property rights. As traditional Chinese medicine had always been used in China, the use of traditional Chinese medicine was not regulated. The establishment in 1870 of the Tung Wah Hospital was the first use of Chinese medicine for the treatment in Chinese hospitals providing free medical services. As the promotion of Western medicine by the British government started from 1940, Western medicine started being popular among Hong Kong population. In 1959, Hong Kong had researched the use of traditional Chinese medicine to replace Western medicine.
Sources: en.wikipedia.org
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.
No regulatory agency has approved it for any indication. It is encountered as a research chemical sold outside pharmaceutical supply chains. Products marketed this way are not subject to the manufacturing and labeling requirements that apply to approved drugs.
Reports describe increased skin pigmentation as well as side effects such as nausea, flushing, and changes to existing moles. Much of the evidence comes from small studies and case reports rather than large trials. The long-term safety profile is therefore uncertain.
No regulatory agency has authorised melanotan-2 as a medicine for any indication. It circulates mainly as a research chemical or through unregulated channels. As a result, identity, purity and content are not independently guaranteed.