Everything below concerns lyophilised powder. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-06-06. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Lyophilized peptide powder is generally stored frozen, protected from light and moisture. Tryptophan residues are susceptible to oxidation, and the lactam bridge can hydrolyze under strongly acidic or basic conditions. Solutions prepared for laboratory work degrade faster than dry powder, and repeated freeze-thaw cycles accelerate loss. Common practice is to aliquot solutions before freezing and to avoid alkaline buffers. Reported stability windows vary with concentration, buffer, and temperature, so exact shelf lives are method-specific rather than universal.
Regulatory status differs by country, and in many places supplying the compound for human consumption is unlawful. Vendors frequently label material as intended for research use only, a designation that shifts stated purpose but does not create a legal pathway for personal use. Certificates of analysis accompanying such products vary widely in detail and provenance. Third-party testing exists but is voluntary, and results are rarely linked to a specific lot in a publicly verifiable way.
Identity testing for a synthetic peptide relies on several complementary methods. Reversed-phase high-performance liquid chromatography separates the target from related impurities and reports purity as a percentage of total peak area. Mass spectrometry confirms molecular mass and can reveal deletions or truncations. Amino acid analysis and peptide mapping provide sequence-level confirmation, while counter-ion content and residual solvents are measured separately. A purity figure alone does not establish identity, so a complete dataset combines chromatographic and spectrometric evidence.
| 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.
Solid peptide kept dry at minus twenty degrees Celsius, shielded from light and moisture, is generally considered stable for extended periods. Solutions are divided into single-use aliquots and held at minus twenty or minus eighty degrees Celsius, because repeated freeze-thaw cycles promote aggregation and loss of material to container surfaces. Hydrolysis of the backbone and oxidation of tryptophan are the principal degradation routes in aqueous solution, and both accelerate at ambient temperature. Hygroscopic uptake after a vial is opened can also shift the actual mass weighed, which affects any concentration calculated from it.
Routine characterisation relies on reversed-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres, using a C18 column and a water-acetonitrile gradient containing trifluoroacetic acid. Electrospray ionisation mass spectrometry confirms the expected molecular mass and can reveal truncated or oxidised by-products that co-elute poorly. Sequence and stereochemistry require additional work, such as peptide mapping or amino acid analysis, because a chromatographic purity figure alone does not distinguish a diastereomer from the target peptide. Independent testing of research-grade material frequently shows measured content below the stated label, so a certificate of analysis is best read together with the method that produced it.
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.
On January 17, 2019, Pritzker signed a bill requiring state certification for gun dealers, which passed during the tenure of his predecessor, Bruce Rauner. It also requires gun dealers to ensure the physical security of their stores, to keep a detailed list of items on sale, and employees of such stores to undergo annual training. These requirements come on top of the mandatory federal license issued by the Bureau of Alcohol, Tobacco, Firearms and Explosives. Proponents say Senate Bill 337 prevents guns from falling "into the wrong hands" while opponents argue it creates additional bureaucracy, imposes a financial burden on gun business owners, and will neither enhance public safety nor reduce crime. The Illinois State Rifle Association argued that the bill violates the Second Amendment to the U.S. Constitution because it interferes with the right to bear arms, and filed a lawsuit alongside eight gun dealers. On May 18, 2022, Pritzker signed House Bill 4383, which banned the sale and possession of homemade firearms in Illinois. Illinois became the 11th state and first midwestern state to enact such a policy. On January 11, 2023, Pritzker signed a ban on assault weapons and high-capacity magazines. He said of the legislation, "With this legislation we are delivering on the promises Democrats have made and, together, we are making Illinois's gun laws a model for the nation." The new law took effect immediately, with approximately 2.5 million Illinois gun owners affected.
In March 2003, 2–325 of the 2nd BCT was attached to the 75th Ranger Regiment as part of a special operations task force to conduct a parachute assault to seize Saddam International Airport, part of Operation Iraqi Freedom. On 21 March 2003, Company D, 2-325 crossed the Saudi Arabia–Iraq border as part of Task Force Hunter to escort HIMARS artillery systems to destroy Iraqi artillery batteries in the western Iraqi desert. Upon cancellation of the parachute assault to seize the airport, the battalion returned to its parent 2nd Brigade at Talil Airfield near An Nasariyah, Iraq. The 2nd Brigade then conducted operations in Samawah, Fallujah, and Baghdad. The brigade returned to the United States by the end of February 2004. The early days of the 82nd Airborne's participation in the deployment were chronicled by embedded journalist Karl Zinsmeister in his 2003 book Boots on the Ground: A Month with the 82nd Airborne in the Battle for Iraq. In April 2003, according to Human Rights Watch, soldiers from a subordinate unit, the 1st battalion of the 325th Infantry, allegedly fired indiscriminately into a crowd of Iraqi civilians protesting their presence in the city of Fallujah, killing and wounding many civilians. The battalion suffered no casualties. The 3rd Brigade deployed to Iraq in the summer, redeploying to the US in spring 2004. The 1st Brigade deployed in January 2004. The last units of the division left by the end of April 2004. The 2nd Brigade deployed on 7 December 2004 to support the free elections and returned on Easter Sunday in 2005.
=== Chinese communities under colonial rule === Chinese communities living in colonial port cities were influenced by the diverse cultures they encountered, which also led to evolving understandings of medical practices where Chinese forms of medicine were combined with Western medical knowledge. For example, the Tung Wah Hospital was established in Hong Kong in 1869 based on the widespread rejection of Western medicine for pre-existing medical practices, although Western medicine would still be practiced in the hospital alongside Chinese medicinal practices. The Tung Wah Hospital was likely connected to another Chinese medical institution, the Kwong Wai Shiu Hospital of Singapore, which had previous community links to Tung Wah, was established for similar reasons, and also provided both Western and Chinese medical care. By 1935, English-language newspapers in Colonial Singapore already used the term "Traditional Chinese Medicine" to label Chinese ethnic medical practices. In the Chinese Communist Party-controlled areas prior to the founding of the People's Republic of China, there was a lack of access to Western-style medical resources. To improve health care, the Chinese Communist Party (CCP) promoted the integration of traditional Chinese medicine with Western medical science. In the Yan'an Soviet, mass campaigns sought to "scientize Chinese medicine" and "make Western medicine Chinese."
The Russell 1000 is a stock market index tracking the stock performance of 1,000 companies listed on stock exchanges in the United States that are considered to have large or medium market capitalizations. The Russell 1000 is a subset of the Russell 3000. It is maintained by FTSE Russell and its components are determined via strict rules-based methodology, with an annual rebalancing in late June, the only time new entrants are added to the index. The index is a public-float-weighted/capitalization-weighted index. The index includes approximately 93% of the total market capitalization of U.S. public companies, with an aggregate market capitalization of more than $70.70 trillion as of September 25, 2026. As of June 16, 2026, the median market capitalization of the components of the index is $17.5 billion and components range in market capitalization from $5.7 billion to $4.8 trillion. Products linked to the Russell 1000 include index funds (exchange-traded funds/ETFs and mutual funds) as well as derivatives (options and futures contracts), which are available for trading in many countries with the goal of replicating the performance of the index. Also available are modified index funds; they replicate the performance of the index with modifications such as the use of covered call strategies, equal weighting, performance buffers, leverage, inclusion of only growth or value stocks, or exclusion of certain sectors, all with the goal of changing the risk/return and yield.
Sources: en.wikipedia.org
=== Gynecomastia === Flutamide, as a monotherapy, causes gynecomastia in 30 to 79% of men, and also produces breast tenderness. However, more than 90% of cases of gynecomastia with NSAAs including flutamide are mild to moderate. Tamoxifen, a selective estrogen receptor modulator (SERM) with predominantly antiestrogenic actions, can counteract flutamide-induced gynecomastia and breast pain in men.
=== Mutation === IDH1 mutations are heterozygous, typically involving an amino acid substitution in the active site of the enzyme in codon 132. These mutations are somatic, meaning they primarily occur in cells that can become cancerous, such as those in brain and bone tumors. The mutation results in a loss of normal enzymatic function and the abnormal production of 2-hydroxyglutarate (2-HG). It has been considered to take place due to a change in the binding site of the enzyme. 2-HG has been found to inhibit enzymatic function of many alpha-ketoglutarate dependent dioxygenases, including histone and DNA demethylases, causing widespread changes in histone and DNA methylation and potentially promoting tumorigenesis.
It was inspired by the documentary Bond Girls Are Forever, which she produced with Planetgrande, featuring d'Abo and other Bond girls, including Ursula Andress, Honor Blackman, Jill St. John, Maud Adams, Lois Chiles, Judi Dench, Rosamund Pike, Eva Green, Halle Berry, and Carey Lowell. The documentary appeared on the American AMC network in 2002, timed to coincide with the theatrical release of Die Another Day. It was later included as a gift with the purchase of Die Another Day on DVD by some retailers. In 2006, a new version of the documentary, updated to include interviews with cast from Casino Royale (2006) was again aired on the AMC network and later released as a bonus feature on the March 2007 Blu-ray disc and DVD release of Casino Royale. In 2004 she wrote and, with Cabin Creek Films, co-produced the documentary film Bearing Witness, about five female war reporters featuring Marie Colvin and Janine di Giovanni, which Barbara Kopple and Marijana Wotton directed for A&E. The feature documentary premiered at the Tribeca Film Festival. In 2007, she had surgery for a brain hemorrhage; after recovering, she was inspired to meet other people who had similar experiences. She then worked on and produced a 2011 documentary on the topic titled Rupture: A Matter of Life and Death. In 2009, she had a supporting role in the British period fantasy-thriller Dorian Gray. She appeared in the 2014 Indian film Tigers directed by Danis Tanovic, and made her return to the horror genre in 2025 with the British film The Baby in the Basket. D'Abo is signed to Models 1.
Sonic Corporation, founded as Sonic Drive-In and more commonly known as Sonic (stylized in all caps), is an American drive-in fast-food chain owned by Inspire Brands, the parent company of Arby's, Jimmy John's, Buffalo Wild Wings, Baskin-Robbins, and Dunkin'. Sonic, founded by Troy N. Smith Sr., opened its first location in 1953, under the name Top Hat Drive-In. Originally a walk-up root beer stand outside a log-cabin steakhouse selling soda, hamburgers, and hot dogs, Sonic expanded to over 3,400 locations in the United States. Sonic is known for its use of carhops on roller skates, and hosts an annual competition in most locations to determine the top skating carhop in the company. The company's core products include the "Chili Cheese Coney", "Sonic Cheeseburger Combo", "Sonic Blasts", "Master Shakes", and "Wacky Pack Kids Meals".
Women have served on US Navy surface ships since 1993, and as of 2011–2012, began serving on submarines for the first time. Until presently, the Navy allowed only three exceptions to women being on board military submarines: female civilian technicians for a few days at most, women midshipmen on an overnight during summer training for Navy ROTC and Naval Academy, and family members for one-day dependent cruises. In 2009, senior officials, including then-Secretary of the Navy Ray Mabus, Joint Chief of Staff Admiral Michael Mullen, and Chief of Naval Operations Admiral Gary Roughead, began the process of finding a way to implement women on submarines. The US Navy rescinded its "no women on subs" policy in 2010. Both the US and British navies operate nuclear-powered submarines that deploy for periods of six months or longer. Other navies that permit women to serve on submarines operate conventionally powered submarines, which deploy for much shorter periods—usually only for a few months. Prior to the change by the US, no nation using nuclear submarines permitted women to serve on board. In 2011, the first class of female submarine officers graduated from Naval Submarine School's Submarine Officer Basic Course (SOBC) at the Naval Submarine Base New London. Additionally, more senior ranking and experienced female supply officers from the surface warfare specialty attended SOBC as well, proceeding to fleet Ballistic Missile (SSBN) and Guided Missile (SSGN) submarines along with the new female submarine line officers beginning in late 2011.
Sources: en.wikipedia.org
In 1917–18, two groups of scientists, Lise Meitner in collaboration with Otto Hahn of Germany and Frederick Soddy and John Cranston of Great Britain, independently discovered another isotope, 231Pa, having a much longer half-life of 32,760 years. Meitner changed the name "brevium" to protactinium as the new element was part of the decay chain of uranium-235 as the parent of actinium (from the Greek: πρῶτος prôtos, meaning "first, before"). The IUPAC confirmed this naming in 1949. The discovery of protactinium completed one of the last gaps in early versions of the periodic table, and brought fame to the involved scientists. Aristid von Grosse produced 2 milligrams of Pa2O5 in 1927, and in 1934 first isolated elemental protactinium from 0.1 milligrams of Pa2O5. He used two different procedures: in the first, protactinium oxide was irradiated by 35 keV electrons in vacuum. In the other, called the van Arkel–de Boer process, the oxide was chemically converted to a halide (chloride, bromide or iodide) and then reduced in a vacuum with an electrically heated metallic filament:
Each lactoferrin molecule can reversibly bind two ions of iron, zinc, copper or other metals. The binding sites are localized in each of the two protein globules. There, each ion is bonded with six ligands: four from the polypeptide chain (two tyrosine residues, one histidine residue and one aspartic acid residue) and two from carbonate or bicarbonate ions. Lactoferrin forms a reddish complex with iron; its affinity for iron is 300 times higher than that of transferrin. The affinity increases in weakly acidic medium. This facilitates the transfer of iron from transferrin to lactoferrin during inflammations, when the pH of tissues decreases due to accumulation of lactic and other acids. The saturated iron concentration in lactoferrin in human milk is estimated as 10 to 30% (100% corresponds to all lactoferrin molecules containing 2 iron atoms). It is demonstrated that lactoferrin is involved not only in the transport of iron, zinc and copper, but also in the regulation of their intake. Presence of loose ions of zinc and copper does not affect the iron binding ability of lactoferrin, and might even increase it.
Phosphomimetics are amino acid substitutions that mimic a phosphorylated protein, thereby activating (or deactivating) the protein. Within cells, proteins are commonly modified at serine, tyrosine and threonine amino acids by adding a phosphate group. Phosphorylation is a common mode of activating or deactivating a protein as a form of regulation. However some non-phosphorylated amino acids appear chemically similar to phosphorylated amino acids. Therefore, by replacing an amino acid, the protein may maintain a higher level of activity. For example, aspartic acid can be considered chemically similar to phospho-serine, due to it also carrying a negative charge. Therefore, when an aspartic acid replaces a serine, it is a phosphomimetic of phospho-serine and can imitate the protein always in its phosphorylated form. However, differences between the phosphomimetic compound and the phosphorylated residue, notably differences in Ramachandran distributions, charge states and size, can alter the protein sufficiently to result in significant differences in behavior. Phosphonate-based compounds have been used as phosphotyrosine analogues, as they are less enzyme labile and are physiologically more stable.
This is an example of the Nernst equation. The potential is known as a reduction potential. Standard electrode potentials are available in a table of values. Using these values, the actual electrode potential for a redox couple can be calculated as a function of the ratio of concentrations. The equilibrium potential for a general redox half-reaction (See #Equilibrium constant above for an explanation of the symbols)
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.
Dry powder is usually held frozen, shielded from light, and kept away from moisture. Desiccant packaging limits hydrolysis during storage. Solutions are typically aliquoted and frozen once, because repeated thawing shortens useful life.