alpha-MSH analogue 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 2026-01-22. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Research interest has centred on photoprotection and pigmentation, with a smaller body of work on appetite and sexual function. Published human data remain limited to small, frequently uncontrolled studies, and the compound has never received marketing approval from a national medicines regulator. Most laboratory work treats it as a pharmacological tool for probing melanocortin signalling in cell culture or animal models. Whether pigmentation changes observed in people translate into measurable protection against ultraviolet-induced DNA damage remains an open question.
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.
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controlled human data on melanotan-2 remain sparse, and much of what circulates online derives from small studies or unpublished reports.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.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | Melanotan II; MT-II; N-acetyl-norleucyl-cyclo[Asp-His-D-Phe-Arg-Trp-Lys] amide | Naming follows peptide convention; the numeral distinguishes it from melanotan-1 |
| Molecular formula | C50H69N15O9 | Includes the lactam bridge; no counter-ion assumed |
| Monoisotopic mass | 1023.53 Da | Free base; salts and counter-ions shift the observed value |
| Appearance | White to off-white lyophilised powder | Batch-to-batch colour variation is not itself proof of impurity |
| Typical analytical method | RP-HPLC purity determination with ESI-MS identity confirmation | Retention time alone does not establish sequence identity |
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.
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.
The compound emerged from research programs in the 1980s that examined analogues of alpha-melanocyte-stimulating hormone for pigmentation and photoprotection. Investigators modified the native sequence to extend activity duration and potency. A related analogue, afamelanotide, was developed within the same broad line of inquiry and eventually gained approval in certain jurisdictions for a rare light-sensitivity condition. Melanotan-2 itself did not progress through the same regulatory route and has no approved therapeutic indication.
Melanocortin receptors comprise five subtypes with distinct tissue distributions and functions. Melanotan-2 is described in the literature as a non-selective agonist that engages several of these subtypes, including MC1R, MC3R, MC4R, and MC5R. MC1R is the subtype most directly linked to melanin production in skin cells. Because the compound is not subtype-selective, its observed effects in experimental settings are generally attributed to activity across multiple receptor pathways rather than to a single target.
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.
==== Silver ==== A tarnished-silver or aluminium paint-like feces color characteristically results when biliary obstruction of any type (white stool) combines with gastrointestinal bleeding from any source (black stool). It can also suggest a carcinoma of the ampulla of Vater, which will result in gastrointestinal bleeding and biliary obstruction, resulting in silver stool.
Opioid rotation or opioid switching is the process of changing one opioid to another to improve pain control or reduce unwanted side effects. This technique was introduced in the 1990s to help manage severe chronic pain and improve the opioid response in cancer patients and non-cancer patients. In order to obtain adequate levels of pain relief, patients requiring chronic opioid therapy may require an increase in the original prescribed dose for a number of reasons, including increased pain or a worsening disease state. Over the course of long-term treatment, an increase in dosage cannot be continued indefinitely as unwanted side effects of treatment often become intolerable once a certain dose is reached, even though the pain may still not be properly managed. One strategy used to address this is to switch the patient between different opioid drugs over time, usually every few months. Opioid rotation requires strict monitoring in patients with ongoing levels of high opioid doses for extended periods of time, since long term opioid use can lead to a patient developing tolerance to the analgesic effects of the drug. Patients may also not respond to the first opioid prescribed to them at all, therefore needing to try another opioid to help manage their pain. A patient's specific response and sensitivity to opioids include many factors that include physiology, genetics and pharmacodynamic parameters, which together determine the amount of pain control and tolerance of a particular opioid.
stimulating action through direct receptor agonism and downstream effects depressing action through direct receptor agonism and downstream effects (ex.: inverse agonist) blocking/antagonizing action (as with silent antagonists), the drug binds the receptor but does not activate it stabilizing action, the drug seems to act neither as a stimulant or as a depressant (ex.: some drugs possess receptor activity that allows them to stabilize general receptor activation, like buprenorphine in opioid dependent individuals or aripiprazole in schizophrenia, all depending on the dose and the recipient) exchanging/replacing substances or accumulating them to form a reserve (ex.: glycogen storage) direct beneficial chemical reaction as in free radical scavenging direct harmful chemical reaction which might result in damage or destruction of the cells, through induced toxic or lethal damage (cytotoxicity or irritation)
Ionization of acids is less in an acidic solvent than in water. For example, hydrogen chloride is a weak acid when dissolved in acetic acid. This is because acetic acid is a much weaker base than water.
Root canal is also a colloquial term for a dental operation, endodontic therapy, wherein the pulp is cleaned out, the space disinfected and then filled. When rotary nickel titanium (NiTi) files are used in canals with flat-oval or tear-shaped cross sections, a circular bore is created due to the rotational action of the metal. Also, small cavities within the canal such as the buccal or lingual recesses may not be instrumented within the tooth, potentially leaving residual disease during disinfection. Tissue or biofilm remnants along such un-instrumented recesses may lead to failure due to both inadequate disinfection and the inability to properly obturate the root-canal space. Consequently, the biofilm should be removed with a disinfectant, commonly sodium hypochlorite, during root canal treatment.
Sources: en.wikipedia.org
The Mojave rattlesnake is widely regarded as producing one of the most toxic snake venoms in the New World, based on LD50 studies in laboratory mice. Their potent venom is the result of a presynaptic neurotoxin composed of two distinct peptide subunits. The basic subunit (a phospholipase A2) is mildly toxic and apparently rather common in North American rattlesnake venoms. The less common acidic subunit is not toxic by itself, but in combination with the basic subunit, produces the potent neurotoxin called "Mojave toxin". Nearly identical neurotoxins have been discovered in five North American rattlesnake species besides the Mojave rattlesnake. However, not all populations express both subunits. The venom of many Mojave rattlesnakes from south-central Arizona lacks the acidic subunit and has been designated "venom B", while Mojave rattlesnakes tested from all other areas express both subunits and have been designated "venom A" populations.
ketogenic diet (KD) – usually less than 50 grams of carbohydrates per day (assuming total intake of 2,000 calories). very low-calorie ketogenic diet (VLCKD) – same as KD, but limits total calories to a maximum of 800 calories per day. ketogenic low-carbohydrate high-fat diet (K-LCHF) – same as KD, with the additional restriction of 60 to 80% of calories coming from fat. modified Atkins diet (MAD) – fewer carbohydrates than K-LCHF (less than 10 grams per day), and encourages high-fat foods without specifying a specific required amount. A very low calorie ketogenic diet that is high in fat but low in protein is an effective means for weight loss in those who are overweight or obese, yielding an average weight loss of 10 kg over four weeks, with maintenance of the weight loss for up to two years. However, concerns about serum sodium levels led researchers to propose the diet only be used in "selected" people, and under strict medical supervision. In 2021 the American Heart Association issued a scientific statement on dietary guidance to improve cardiovascular health which noted that "there is insufficient evidence to support any existing popular or fad diets such as the ketogenic diet and intermittent fasting to promote heart health".
The thorough pre-operative medical and surgical histories, and the physical examination of the patient's periorbital area (eyebrow-to-cheek-to-nose), determine if the patient can safely undergo a blepharoplasty procedure to feasibly resolve (correct or modify, or both) the functional and aesthetic indications presented by the patient. Sequentially, lower eyelid blepharoplasty can successfully address the anatomic matters of excess eyelid skin, slackness of the eye-muscles and of the orbital septum (palpebral ligament), excess orbital fat, malposition of the lower eyelid, and prominence of the nasojugal groove, where the orbit (eye socket) meets the slope of the nose. Concerning the upper eyelid, a blepharoplasty procedure can resolve the loss of peripheral vision, caused by the slackness of the upper-eyelid skin draping over the eyelashes; the outer and the upper portions of the field of vision of the patient are affected and cause him or her difficulty in performing mundane activities such as driving an automobile and reading a book.
Organic geochemists also have an interest in studying the diagenesis of biogenic substances in petroleum and how they are transformed in sediment and fossils. While 90% of this organic material is insoluble in common organic solvents – called kerogen – 10% is in a form that is soluble and can be extracted, from where biogenic compounds can then be isolated. Saturated linear fatty acids and pigments have the most stable chemical structures and are therefore suited to withstanding degradation from the diagenesis process and being detected in their original forms. However, macromolecules have also been found in protected geological regions. Typical sedimentation conditions involve enzymatic, microbial and physicochemical processes as well as increased temperature and pressure, which lead to transformations of biogenic substances. For example, pigments that arise from dehydrogenation of chlorophyll or hemin can be found in many sediments as nickel or vanadyl complexes. A large proportion of the isoprenoids in sediments are also derived from chlorophyll. Similarly, linear saturated fatty acids discovered in the Messel oil shale of the Messel Pit in Germany arise from organic material of vascular plants. Additionally, alkanes and isoprenoids are found in soluble extracts of Precambrian rock, indicating the probable existence of biological material more than three billion years ago. However, there is the potential that these organic compounds are abiogenic in nature, especially in Precambrian sediments.
Sources: en.wikipedia.org
In collaboration with Professor Jack Henion at Cornell University and Dr. Peter Dawson at the National Research Council of Canada, the first application of liquid chromatography-mass spectrometry-mass spectrometry (LC-MS-MS) was demonstrated on the TAGA 6000 in 1982. This proof of concept led to the development of the heated nebulizer LC interface for APCI, using pneumatic nebulization to allow the full LC flow to enter the ion source. In 1983, LC-MS-MS using ion evaporation, a spray method similar to electrospray but compatible with higher flow rates of up to 1 mL/min, was demonstrated on the TAGA 6000 but was not commercialized. The API III LC-MS-MS system introduced in 1989 provided both ion spray (developed by Bruins, Covey and Henion at Cornell University) and heated nebulizer LC inlets on a triple quadrupole platform based on the TAGA 6000 architecture. It was the second commercial LC-MS in the market, and the first that provided electrospray ionization. The atmospheric pressure spray methods of electrospray, ion spray and APCI which helped to drive the burgeoning LC-MS market are now available on a wide variety of MS platforms and from a variety of vendors. In 1998, the cryopump API III platform began to be replaced with turbo-molecular-pumped single and triple quadrupole mass spectrometer products that evolved from the API 2000 (benchtop) and API 3000 to the current API 7500 series.
Among these mixed communities, the largest Christian populations in Druze towns are found in Maghar, followed by Isfiya and Peki'in. Conversely, the largest Druze communities in predominantly Christian towns are located in Rameh, followed by Kafr Yasif. Before Israel's occupation, Christians accounted for 12% of the population of the Golan Heights, and they tended to have a high representation in science and in the white collar professions. But a few Christians remain of a much larger community that left the area. In 2010 more than 8,000 Christians lived in Druze-majority towns and cities in Israel, including Daliyat al-Karmel, Ein Qiniyye, Hurfeish, Isfiya, Kisra-Sumei, Majdal Shams, Maghar and Peki'in. Additionally, in 2016, more than 2,700 Druze lived in Rameh and Kafr Yasif, which are Christian-majority towns located in the Galilee region, and more than 12,000 Christians and 9,800 Druze lived Abu Snan and Shefa-Amr, which have a Muslim majority. Before 1948, some Druze towns such as Beitegen, Julis, Sajur and Yarka were inhabited by small Christian communities.
In August 2020, scientists described one way cells—in particular cells of a slime mold and mouse pancreatic cancer-derived cells—are able to navigate efficiently through a body and identify the best routes through complex mazes: generating gradients after breaking down diffused chemoattractants which enable them to sense upcoming maze junctions before reaching them, including around corners.
On September 22, on the first-ever Raw to be broadcast from Madison Square Garden, McMahon told Austin he wasn't physically cleared to compete, and after several weeks of build-up, Austin delivered his Stone Cold Stunner to McMahon, causing the fans in attendance to go ballistic. Austin was then arrested as part of the storyline, and was sidelined until Survivor Series. However, in the interim, he made several appearances, one being at Badd Blood where he was involved in the finish of a match between Owen and Faarooq for the vacant Intercontinental Championship. Austin hit Faarooq with the Intercontinental Championship belt while the referee's back was turned, causing Hart to win the match and the title. Austin's motive was to keep Owen as champion, as demonstrated when he interfered in Hart's matches on Raw. Austin regained the Intercontinental Championship from Hart at Survivor Series. With Owen Hart out of the way, Austin set his sights on The Rock, who stole Austin's championship belt after Austin suffered a beating by his Nation of Domination stablemates. In the weeks to come, The Rock began declaring himself to be "the best damn Intercontinental Champion ever." The Rock kept possession of the championship belt until D-Generation X: In Your House, when Austin defeated him to retain the championship and regain the belt. As Austin had used his pickup truck to aid his victory, McMahon ordered him to defend the championship against The Rock the next night on Raw.
Pottery – many indigenous American cultures and peoples independently invented and then refined pottery in the Americas into fine works of art, as well for utilitarian usage. The Moche and Maya were some of the best potters from the ancient Americas, and their work still inspires awe amongst us for the level of artistry, creativity, and sophistication, which such highly prized works of arts involved. The Navajo are also very skilled developers of pottery and their works in the present time are highly detailed and much prized. Many other indigenous American cultures also developed their own pottery styles during the pre-Columbian time periods and continued to refine their artwork into the modern era. Pumpkins – indigenous Americans were the first to domesticate and grow pumpkins. Puna ibis - the Puna ibis was domesticated by the Uru people. Puquios Pyramids – advanced civilizations in Mexico, such as the Toltecs, Olmecs, Zapotecs, Aztecs, Mayans, Mixtecs, developed their own myriad styles of pyramids, usually step pyramid, which served for ceremonial/religious and administrative functions. In Mesoamerica, the largest pyramid in the world—The Great Pyramid of Cholula—began to be constructed by the inhabitants of Cholula in the 3rd century BCE. In the Andean regions, the Moches, and some ancient Peruvians also constructed gigantic pyramids as well without any influence from Old World civilizations.
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone, containing seven amino acids with a lactam ring and a D-configured phenylalanine residue. It is supplied as a lyophilised powder for laboratory research.
The natural hormone is a linear tridecapeptide that is rapidly degraded in circulation. Melanotan-2 is shortened, cyclised, N-terminally acetylated, and carries a D-amino acid substitution, all of which slow enzymatic breakdown.
No national medicines regulator has approved melanotan-2 for therapeutic or cosmetic use. In several jurisdictions it is treated as an unapproved prescription medicine, and its legal classification differs from country to country.
It is a synthetic cyclic heptapeptide modelled on alpha-melanocyte-stimulating hormone. A lactam bridge links two side chains, forming a ring that stabilises the molecule against proteolysis. It belongs to the broader melanocortin peptide family.