This is a working overview of analytical characterisation, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-10-16 and is reviewed periodically as new material appears.
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.
Melanotan II binds several melanocortin receptor subtypes rather than a single target. MC1R on melanocytes drives melanin synthesis, while MC3R and MC4R participate in energy balance, appetite, and sexual response pathways. This lack of selectivity explains why reported effects extend beyond skin darkening. Substitutions at positions four and seven, including norleucine and D-phenylalanine, increase potency and resistance to peptidases. Understanding which receptor mediates which effect remains an active area of investigation.
Verification of a purchased sample requires documentation linking a batch to a certificate of analysis, and that document should be read for the methods used rather than the headline purity figure. A single chromatographic percentage does not establish identity. Independent laboratories can perform identity and content assays, but no such test establishes that a product is suitable for human use. Claims about efficacy rest largely on small, early studies rather than on replicated controlled trials, and that gap remains open.
Identity testing for a cyclic peptide of this size usually relies on reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The mass spectrum confirms molecular weight, while the chromatographic trace indicates the proportion of related impurities. Tandem mass spectrometry can provide sequence-level information when fragmentation data are compared against a reference standard. Nuclear magnetic resonance is sometimes used to confirm the lactam bridge, although it requires more material and greater operator expertise than routine chromatographic methods.
Lyophilised peptide powder is comparatively stable when kept dry, cold and protected from light. Once dissolved, the molecule is exposed to hydrolysis, oxidation and microbial growth, and degradation accelerates at higher temperatures and in alkaline solution. Repeated freeze-thaw cycles concentrate solutes and promote aggregation. Handling guidance for research peptides commonly clusters around freezer temperatures for powder and short refrigerated use for reconstituted solutions, with pH control and sterile technique applied throughout.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Analog of alpha-melanocyte-stimulating hormone |
| Primary receptor family | Melanocortin receptors MC1R through MC5R | Binding is not subtype-selective |
| Development period | 1980s | Synthesized during pigmentation and appetite research |
| Regulatory status | Not an approved medicine | No major regulator has authorized human use |
| Related compound | Afamelanotide | Linear analog studied for photoprotection |
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 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.
Lyophilised melanotan-2 is supplied as a solid, which is more stable than a solution. The material is hygroscopic, so weighing is done quickly, in low humidity, with the container kept sealed. Reconstitution usually uses water for injection or bacteriostatic water, added down the wall of the vial to limit foaming. A reconstituted solution is held at 2 to 8 °C and kept away from light. Repeated freezing and thawing of the same vial is avoided because ice crystal formation and concentration effects degrade the peptide.
Reversed-phase high-performance liquid chromatography is the routine method for purity assessment. Peptides absorb near 214 nm because of the peptide bond, and a gradient of acetonitrile in water separates the intact peptide from deletion sequences, oxidised products, and earlier-eluting fragments at neutral pH. Electrospray ionisation mass spectrometry provides an orthogonal check: the measured mass must agree with the theoretical value. Amino acid analysis and peptide mapping confirm structure but are used less often. Reference standards remain scarce because the peptide is not described in any pharmacopoeia.
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.
Two structural changes distinguish the synthetic peptide from the natural hormone. A norleucine residue replaces methionine at one position, and a D-configured phenylalanine replaces the natural L-form at another. Both substitutions slow enzymatic breakdown, which extends the molecule's persistence relative to the parent hormone. The lactam bridge further constrains the backbone into a stable conformation. These features are standard design strategies in peptide chemistry and are not unique to this compound; they appear across many research peptides built for improved stability.
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 has not received marketing authorisation from major regulatory agencies for any therapeutic indication. Several jurisdictions classify it as a prescription-only medicine or a controlled substance when supplied for human use. Because approved products do not exist, material sold online usually sits outside pharmaceutical supply chains and formal quality oversight. Regulators have issued public notices describing the compound as unapproved. Enforcement varies, and the legal position differs between countries, which complicates any single general statement about its status.
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.
At high pressures, above approximately 10 GPa and temperatures of a few hundred kelvin or less, α-iron changes into another hexagonal close-packed (hcp) structure, which is also known as ε-iron. The higher-temperature γ-phase also changes into ε-iron, but does so at higher pressure. The physical properties of iron at very high pressures and temperatures have been studied extensively because of their relevance to theories about the cores of the Earth and other planets. The Earth's inner core is generally presumed to consist of an iron-nickel alloy with ε (or β) structure. Some controversial experimental evidence exists for a stable β phase at pressures above 50 GPa and temperatures of at least 1500 K. It is supposed to have an orthorhombic or a double hcp structure. (Confusingly, the term "β-iron" is sometimes also used to refer to α-iron above its Curie point, when it changes from being ferromagnetic to paramagnetic, even though its crystal structure has not changed.)
Muscle fatigue is when muscles that were initially generating a normal amount of force, then experience a declining ability to generate force. It can be a result of vigorous exercise, but abnormal fatigue may be caused by barriers to or interference with the different stages of muscle contraction. There are two main causes of muscle fatigue: the limitations of a nerve's ability to generate a sustained signal (neural fatigue); and the reduced ability of the muscle fiber to contract (metabolic fatigue). Muscle fatigue is not the same as muscle weakness, though weakness is an initial symptom. Despite a normal amount of force being generated at the start of activity, once muscle fatigue has set in and progressively worsens, if the individual persists in the exercise they will eventually lose their hand grip, or become unable to lift or push with their arms or legs, or become unable to maintain an isometric position (such as plank). Other symptoms may accompany such as myalgia (muscle pain), shortness of breath, fasciculations (muscle twitching), myokymia (muscle trembling), and muscle cramps during exercise; muscle soreness may occur afterwards. An inappropriate rapid heart rate response to exercise may be seen, such as in the metabolic myopathy of McArdle disease (GSD-V), where the heart tries to compensate for the deficit of ATP in the skeletal muscle cells (metabolic fatigue) by increasing heart rate to maximize delivery of oxygen and blood borne fuels to the muscles for oxidative phosphorylation.
However, the functional importance of CSP proteins in olfaction/chemosensing remains to be proved. Since then, this protein gene family has been proved to act outside the chemosensory system [32]. They were called pherokines to designate proteins in abundance in the fly hemolymph in response to microbial or viral infection [33]. It was even proposed to rename these proteins to cuticular sensory proteins to keep the name but to emphasize on their expression level not only in sensory organs, but also in the immune barriers between the insect and the environment [49-50]. An email forum was organized to find most suitable new name considering the growing evidence that CSPs do not play a central and unique role in chemosensing, if any [32]. The term “CSP” has grown and is taken to mean belonging to a group of soluble proteins with a particular four-cysteine pattern and a high level of structural similarity [4, 14, 23-36, 32-37, 50]. The term “CSP” is rather unsuitable especially to designate the whole protein gene family because it means literally “Chemosensory Proteins” [3]. This term should not be used to unite under a common name all genes and proteins that are related in an evolutionary context from bacteria to honeybees. The knowledge to name the CSPs properly comes now with this thorough analysis of sea crustaceans, arthropod, bacteria and insect genome and Expressed Sequence Tag (EST) databases in the continuity of molecular data that demonstrate that CSPs are not exclusively tuned to olfactory/taste chemosensory organs [4, 14, 23-36, 32-37, 50].
In late June 2019, Pritzker signed the bipartisan capital bill named Rebuild Illinois, worth $45 billion to be spent in six years and estimated to create 540,000 jobs. It was the first capital-spending bill in Illinois in 10 years. The plan includes $33.2 billion for transportation projects, including $25 billion for road upgrades, with local governments deciding which roads they want to prioritize; $3.5 billion for public and private schools and universities; $1 billion for environmental protection; $420 million for expanding broadband Internet service to rural Illinois; $465 million for health care and human services facilities; and $1.8 billion for libraries, museums, and minority-owned businesses. Financing for this plan will come from multiple sources. The gas tax was set to match inflation since the last gas-tax increase in 1990, increasing from 19 cents per gallon to 38 cents; the special fuel tax on diesel, liquefied natural gas, and propane increased to 7.5 cents per gallon. Fuel taxes will be indexed to inflation. Vehicle registration fees increased by $50. The state's bonding authority will increase from $22.6 billion to $60.8 billion. Newly authorized casinos are expected to create thousands of jobs and deliver hundreds of millions of dollars in tax revenue for construction projects. Cook County municipalities may raise their own gas taxes by up to three cents per gallon, though Chicago mayor Lori Lightfoot said she opposed raising the gas tax in her city and increasing Chicago Transit Authority fares.
Blood tests can be done to determine if a patient has high levels of antibodies that are indicative of the disease, such as antinuclear antibody (ANA) and rheumatoid factor (because Sjögren's is considered to occur frequently “secondary” to rheumatoid arthritis), which are associated with autoimmune diseases. Typical Sjögren’s disease ANA patterns are SSA/Ro and SSB/La, of which anti-SSB/La is far more specific; anti-SSA/Ro is associated with numerous other autoimmune conditions, but is often present in Sjögren’s disease. However, anti-SSA and anti-SSB tests are frequently not positive in Sjögren’s.
Sources: en.wikipedia.org
Pterygoplichthyini is a tribe of catfishes (order Siluriformes) of the family Loricariidae. It includes two genera, Pterygoplichthys and the currently undescribed genus referred to as the Hemiancistrus annectens group, This group was earlier misspelled as Pterygoplichthini. Pterygoplichthyines are known from nearly the entire range of loricariids except for the Guyanas and coastal streams in southeastern Brazil. although later work by the same authority, and his co-authors, placed this group among the genus Hypostomus. Pterygoplichthyini is sister to the tribe Ancistrini, which shares the derived presence of an evertible patch of plates on the cheek. Pterygoplichthys and the H. annectens group differ most obviously in the number of dorsal fin rays (7 in the H. annectens group and 9+ in Pterygoplichthys). The two genera are supported as sisters by only one derived characteristic: a modified stomach that is attached to the abdominal wall by a net of connective tissue. This modified stomach allows these fish to breathe air. The stomach is vascularized. A white net of connective tissue surrounds the organ, leaving a circular area in the middle of the stomach free; this connective tissue firmly holds the stomach to the body wall and is better developed in adults. It may also function as a hydrostatic organ, allowing the fish to remain buoyant midwater.
19 January – The European Court of Human Rights announces that Ireland launched legal action against the United Kingdom on 17 January over the Northern Ireland Troubles (Legacy and Reconciliation) Act 2023. The UK government gives its backing to the Pet Abduction Bill, a private member's bill that makes it illegal to steal cats and dogs in England and Northern Ireland. 20 January – A speech to the Fabian Society conference by Shadow Foreign Secretary David Lammy is interrupted by pro-Palestinian protestors. 21 January – Scotland's First Minister, Humza Yousaf, tells the BBC's Sunday with Laura Kuenssberg he is willing to work with Sir Keir Starmer if he becomes prime minister after the next general election. 22 January – The House of Lords votes 214–171 in favour of an amendment to the Safety of Rwanda (Asylum and Immigration) Bill that calls for the delay of ratification of the bill until Rwanda improves its asylum procedures. The UK government rejects calls from Welsh MPs to add the Six Nations Championship to the list of guaranteed free-to-air sporting events on British television. 23 January – Following more air strikes against Houthi targets, Sunak tells Parliament the UK would not hesitate to launch further strikes if the rebel group continue to attack shipping targets in the Red Sea, but does not seek confrontation with them.
Anti-obesity medication or weight loss medications are pharmacological agents that reduce excess body fat and cause weight loss. These medications alter one of the fundamental processes of weight regulation, by: reducing appetite and consequently energy intake, increasing energy expenditure, redirecting nutrients from adipose to lean tissue, or interfering with the absorption of calories. Weight loss drugs have been developed since the early twentieth century, and many have been banned or withdrawn from the market due to adverse effects, including deaths; other drugs proved ineffective. Although many earlier drugs were stimulants such as amphetamines, in the early 2020s, GLP-1 receptor agonists became popular for weight loss. As of 2023, the medications liraglutide, naltrexone/bupropion, orlistat, semaglutide, tirzepatide and phentermine/topiramate are approved by the US Food and Drug Administration (FDA) for weight management in combination with reduced-calorie diet and increased physical activity. Medications to treat obesity may be considered in those with a body mass index above 30, or above 27 with obesity related complications (such as hypertension, hyperlipidemia, cardiovascular disease, or obstructive sleep apnea). As of 2022, no medication has been shown to be as effective at long-term weight reduction as bariatric surgery.
24395Am + 188O → 261103Lr* → 256103Lr + 5 10n Further experiments in 1969 at Dubna, and in 1970 at Berkeley, demonstrated an actinide chemistry for the new element; so by 1970 it was known that element 103 is the last actinide. In 1970, the Dubna group reported the synthesis of 255Lr with half-life 20 s and alpha decay energy 8.38 MeV. However, it was not until 1971, when the nuclear physics team at University of California at Berkeley successfully did a whole series of experiments aimed at measuring the nuclear decay properties of the lawrencium isotopes with mass numbers 255 to 260, that all previous results from Berkeley and Dubna were confirmed, apart from the Berkeley's group initial erroneous assignment of their first produced isotope to 257Lr instead of the probably correct 258Lr. All final doubts were dispelled in 1976 and 1977 when the energies of X-rays emitted from 258Lr were measured.
Sources: en.wikipedia.org
== External links == 3D model of Primaporta-type head of Augustus via photogrammetric survey of a plaster cast of the Ny Carlsberg Glyptotek's marble Page on the statue, in German, with coloured reconstruction and close-up of breastplate Archived 2009-11-19 at the Wayback Machine Description on VIAMUS Catalogue record on VIAMUS 360 degree computer reconstruction Media related to Augustus of Prima Porta at Wikimedia Commons
Several small-scale studies involving 15 or fewer test subjects conducted in the 1950s and 1960s reported that adrenochrome triggered psychotic reactions such as thought disorder and derealization. In 1954, researchers Abram Hoffer and Humphry Osmond claimed that adrenochrome is a neurotoxic, psychotomimetic substance and may play a role in schizophrenia and other mental illnesses. In what Hoffer called the "adrenochrome hypothesis", he and Osmond in 1967 speculated that megadoses of vitamin C and niacin could cure schizophrenia by reducing brain adrenochrome. The treatment of schizophrenia with such potent anti-oxidants is controversial. In 1973, the American Psychiatric Association reported methodological flaws in Hoffer's work on niacin as a schizophrenia treatment and referred to follow-up studies that did not confirm any benefits of the treatment. Multiple additional studies in the United States, Canada, and Australia similarly failed to find benefits of megavitamin therapy to treat schizophrenia. The adrenochrome theory of schizophrenia waned, despite some evidence that it may be psychotomimetic, as adrenochrome was not detectable in people with schizophrenia. In the early 2000s, interest was renewed by the discovery that adrenochrome may be produced normally as an intermediate in the formation of neuromelanin. This finding may be significant because adrenochrome is detoxified at least partially by glutathione-S-transferase. Some studies have found genetic defects in the gene for this enzyme. Adrenochrome is also believed to have cardiotoxic properties.
Casein ( KAY-seen; from Latin caseus, 'cheese') is a family of related phosphoproteins (αS1, aS2, β, κ) that are commonly found in mammalian milk, comprising about 80% of the proteins in cow's milk and between 20% and 60% of the proteins in human milk. Sheep and cow milk have a higher casein content than other types of milk with human milk having a particularly low casein content. Casein does not appear to be essential in mammals. For example, the β-casein gene can be deleted in mice. The resulting mice are healthy and fertile, but the growth of their pups is reduced. Similarly, mice lacking the κ-casein gene are healthy, but they did not suckle their pups and failed to lactate, hence the gene is required for reproductive success.
Sources: en.wikipedia.org
No regulator in a major market has approved it for human use. It appears in research settings and in products marketed outside pharmacy channels. Legal status for personal possession varies by country.
Afamelanotide is a linear analog that has received approval in some jurisdictions for a specific photoprotection indication. Melanotan II is cyclic and less selective across melanocortin receptors. The two are related but are not interchangeable in regulatory or clinical terms.
A compound that activates several receptor subtypes may produce effects beyond pigmentation. Selectivity influences which tissues respond and shapes the side-effect profile described in reports. Designing subtype-selective analogs is a stated goal of melanocortin research.
Mass spectrometry combined with liquid chromatography provides both molecular weight confirmation and a measure of related impurities. Tandem mass spectrometry adds sequence information. A purity percentage reported without a mass measurement does not confirm what the material is.