Everything below concerns mass spectrometry. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-07-26. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Regulatory status varies by jurisdiction, and the substance is frequently described as unapproved for therapeutic use. Some authorities classify it alongside prescription-only medicines or controlled categories, while others address it through general consumer protection rules. Analytical surveys have reported mismatches between label claims and measured content in products sold online, although the scope of such testing is limited. Whether these discrepancies are widespread remains an open question. Discussion in the literature therefore tends to combine chemistry, supply-chain observation and policy analysis.
The material is commonly handled as a lyophilized powder in sealed vials. The solid dissolves readily in water and in polar organic solvents, producing a clear solution after reconstitution. Light, heat and repeated freeze-thaw cycles are the concerns most often raised in handling guidance, because peptide bonds and the constrained ring can degrade. Working solutions are generally prepared fresh, and material left in solution is treated as less stable than the dry form. These properties shape how laboratories store and aliquot reference material.
| 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 |
Receptor binding at MC1R on melanocytes raises intracellular cyclic AMP and increases expression of tyrosinase and related enzymes. The downstream result is greater synthesis of eumelanin, the dark pigment, without ultraviolet exposure acting as the trigger. The compound is not selective, however, and also engages MC3R, MC4R and MC5R, which are expressed in the central nervous system and elsewhere. That lack of selectivity is the explanation usually offered for effects reported outside pigmentation, including appetite suppression and nausea. Selectivity remains a central theme in comparative studies of related peptides.
Human data remain limited and mostly short-term. Reports describe small trials and observational accounts rather than large controlled studies, so questions about dose-response relationships and long-term effects on melanocytes stay open. Whether repeated exposure alters naevus behaviour is not settled in the published record. Researchers also note that self-administered use outside clinical settings makes actual exposure difficult to quantify. Statements about efficacy and safety should therefore be read as preliminary rather than established.
Melanotan II is a synthetic cyclic heptapeptide that acts as an agonist at melanocortin receptors. It was designed as a structural analogue of alpha-melanocyte-stimulating hormone, the endogenous peptide involved in pigment production. The analogue carries a lactam bridge that constrains the ring and slows enzymatic breakdown relative to the native hormone. In research literature it appears under several abbreviations, and naming conventions are not fully standardized. Published descriptions usually place it within the broader melanocortin agonist family.
Regulatory treatment varies by country. In the United States the peptide is not approved as a medicine, and products offered for human use may be treated as unapproved new drugs; some states also restrict sale. Australia, the United Kingdom, and European Union member states apply comparable restrictions to unapproved peptide products. Border agencies have seized shipments labelled as research chemicals. Classification may change over time, and the legal position for personal importation is not clearly settled in most published guidance.
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.
=== Cancer === Cilengitide, a cyclic pentapeptide (RGDfV), is an investigational drug intended to block the growth of new blood vessels in tumors by interfering with the activation of integrin αVβ3. This integrin is upregulated in tumor and activated endothelial cells. This and other anti-angiogenic therapies depend on cutting off the blood supply to the tumor micro-environment, leading to hypoxia and necrosis. Cilengitide has been evaluated for the treatment of glioblastoma, but, as is the case for other anti-angiogenic therapies, has not been shown to alter progression or improve survival either alone or in combination with standard treatments.
== Cannabinoids == Cannabinoids are the compounds found in cannabis, which is a euphoriant and hallucinogenic drug prepared from the dried leaves of the strong-smelling plant Cannabis sativa. It includes synthetic cannabinoids (spice, K2), and tetrahydrocannabinol (THC, Delta-8).
=== Brett Hazard: A Bully finds Religion === Meet Brett Hazard, a loud mouthed bully who picks on Zack because of his religion and even nominated him for Prom Queen. This episode did not air on American TV during the season's initial run on MTV but eventually aired on MTV2 on October 4, 2012. However, it has aired on the Fox8 channel of Foxtel and Austar in Australia. This episode is not available on the Bully Beatdown website or iTunes, and has not been leaked to the internet. A few clips of it can be seen at the end of the previous episode (Jordan: Bring Out The Boar). At the end of that episode, a preview for this episode was shown.
== Efficacy == There is currently no standardized form of dry needling. There is a general scarcity of extensive research in the field. Many studies published about dry needling are not randomized, contain small sample sizes, and have high dropout rates. A review recommended the usage of dry needling, compared to sham or placebo, for decreasing pain immediately after treatment and at 4 weeks in patients with upper quarter myofascial pain syndrome. However, the authors caution that "the limited number of studies performed to date, combined with methodological flaws in many of the studies, prompts caution in interpreting the results of the meta-analysis performed". Similarly, a second review of dry needling found insufficient high-quality evidence for the use of direct dry needling for short and long-term pain and disability reduction in patients with musculoskeletal pain syndromes. The same review reported that robust evidence validating the clinical diagnostic criteria for trigger point identification or diagnosis is lacking and that high-quality studies demonstrate that manual examination for the identification and localization of a trigger point is neither valid nor reliable between examiners.
=== Herbal medicine === In traditional Chinese medicine, Lonicera japonica is called rěn dōng téng (忍冬藤); literally "winter enduring vine") or jīn yín huā (Chinese: 金銀花; literally "gold-silver flower", in reference to the presence of flowers of different age on the same plant as each flower changes from white (silver) to yellow (gold)). Alternative Chinese names include er hua (二花) and shuang hua (雙花), meaning double-[color] flowers.
Sources: en.wikipedia.org
== History == During 2008 and 2009, all non-U.S. foreign forces withdrew from Iraq. Withdrawal of all non-U.S. forces was complete by 31 July 2009. As of 1 January 2009, the Iraqi government became fully responsible, through its security ministries, for maintaining and providing security and rule of law for its populace. Furthermore, as of 28 June 2009, no foreign forces were stationed within any of Iraq's major cities. The United States decided after negotiations to cease combat operations, that is, patrolling, serving arrest warrants, route clearance, etc., within Iraq by 1 September 2010, and to transition to an advisory, training and assistance role. The changing mission entailed major troop reductions. Numbers dropped from 115,000 on 15 December 2009, to 50,000 by 1 September 2010, and to zero by 31 December 2011.
==== Common welfare concerns ==== Welfare in aquaculture can be impacted by a number of issues such as stocking densities, behavioural interactions, disease and parasitism. A major problem in determining the cause of impaired welfare is that these issues are often all interrelated and influence each other at different times. Optimal stocking density is often defined by the carrying capacity of the stocked environment and the amount of individual space needed by the fish, which is very species specific. Although behavioural interactions such as shoaling may mean that high stocking densities are beneficial to some species, in many cultured species high stocking densities may be of concern. Crowding can constrain normal swimming behaviour, as well as increase aggressive and competitive behaviours such as cannibalism, feed competition, territoriality and dominance/subordination hierarchies. This potentially increases the risk of tissue damage due to abrasion from fish-to-fish contact or fish-to-cage contact. Fish can suffer reductions in food intake and food conversion efficiency. In addition, high stocking densities can result in water flow being insufficient, creating inadequate oxygen supply and waste product removal. Dissolved oxygen is essential for fish respiration and concentrations below critical levels can induce stress and even lead to asphyxiation. Ammonia, a nitrogen excretion product, is highly toxic to fish at accumulated levels, particularly when oxygen concentrations are low.
The recent epidemic increase of obesity prevalence has thus contributed to changes in the prevalence and in the characteristics of pediatric OSA, the severity of OSA is proportional to the degree of obesity. Obesity leads to narrowing of the upper airway structure due to fatty infiltration and fat deposits in the anterior neck region and cervical structures. Alongside with the additional weight loading on the respiratory system, it increases the risk of pharyngeal collapsibility while reducing the intrathoracic volume and diaphragm excursion. Moreover, excessive daytime sleepiness resulting from sleep fragmentation can decrease physical activity and thus lead to weight gain (by sedentary habits or increased food intake to overcome somnolence). The obesity-related obstruction of upper airway structure has led some authors to distinguish between two types of OSA in children: type I is associated with marked lymphadenoid hypertrophy without obesity and type II is first associated with obesity and with milder upper airway lymphadenoid hyperplasia. The two types of OSA in children can result in different morbidities and consequences. Studies have shown that weight loss in obese adolescents can reduce sleep apnea and thus the symptoms of OSA.
The penile raphe is the visible ridge between the lateral halves of the penis, found on the ventral or underside of the penis, running from the meatus and continuing as the perineal raphe across the scrotum and the perineum (area between scrotum and anus). The human penis differs from those of most primates, as it has no baculum and relies entirely on erectile tissue. A distal ligament buttresses the glans penis and plays an integral role to the penile fibroskeleton, and the structure is called "os analog", a term coined by Geng Long Hsu in the Encyclopedia of Reproduction. It is a remnant of the baculum that has likely evolved due to change in mating practice. The human penis cannot be withdrawn into the groin, and it is larger than average in the animal kingdom in proportion to body mass. The human penis is reciprocating from a cotton soft to a bony rigidity resulting from penile arterial flow varied between 2–3 to 60–80 mL/Min implies the most ideal milieu to apply Pascal's law in the entire human body; the overall structure is unique.
Sources: en.wikipedia.org
Americium-243, an alpha emitter, has a half-life of 7350 years, the longest of all americium isotopes. It is formed in the nuclear fuel cycle mainly by neutron capture on plutonium-242 followed by beta decay. Production increases exponentially with increasing burnup as a total of 5 neutron captures on 238U are required. If MOX-fuel is used, particularly MOX-fuel high in 241Pu and 242Pu, more americium overall and more 243Am will be produced. It decays by either emitting an alpha particle (decay energy 5.439 MeV) to become 239Np, which then quickly goes to 239Pu, or, very rarely, spontaneous fission. The fission rate is about 60% that of americium-241 or about 0.7/g/s. As for the other americium isotopes, and more generally for all alpha emitters, 243Am is carcinogenic in case of internal contamination after being inhaled or ingested. 243Am also presents a risk of external irradiation associated with the gamma ray emitted by its short-lived decay product 239Np. The external irradiation risk for the other two americium isotopes (241Am and 242mAm) is less than 10% of that for americium-243.
==== Reaction with compounds containing active methylene groups ==== In the presence of alkoxides, reactions of ethylene oxide with compounds containing active methylene group leads to the formation of butyrolactones:
Maisie Mosco (7 December 1924 – 31 October 2011) wrote 16 novels between 1979 and 1998. These include the 'Almonds and Raisins' series (Almonds & Raisins, Scattered Seed, Children's Children, Out of the Ashes, and New Beginnings), about a Jewish family who around 1900 fled anti-Jewish pogroms in the Russian Empire and emigrated to north Manchester in England. These books contained elements of her own family history and were dramatized for BBC Radio 4. Michael Moritz (b. 1954) billionaire venture capitalist, philanthropist, author, journalist; works for Sequoia Capital, wrote history of Apple Inc., The Little Kingdom, and Going for Broke: Lee Iacocca's Battle to Save Chrysler; was writer at Time magazine and member of board of directors of Google; founded Technologic Partners; named as the No. 1 venture capitalist on the Forbes Midas List; appointed Knight Commander of the Order of the British Empire (KBE). Claus Moser, Baron Moser, (24 November 1922 – 4 September 2015) was a British statistician, scholar and author who made major contributions in both academia and the Civil Service.
== History == The market-leading RAST methodology was invented and marketed in 1974 by Pharmacia Diagnostics AB, Uppsala, Sweden, and the acronym RAST is actually a brand name. In 1989, Pharmacia Diagnostics AB replaced it with a superior test named the ImmunoCAP Specific IgE blood test, which literature may also describe as: CAP RAST, CAP FEIA (fluorenzymeimmunoassay), and Pharmacia CAP. A review of applicable quality assessment programs shows that this new test has replaced the original RAST in approximately 80% of the world's commercial clinical laboratories, where specific IgE testing is performed. The newest version, the ImmunoCAP Specific IgE 0–100, is the only specific IgE assay to receive FDA approval to quantitatively report to its detection limit of 0.1kU/L. This clearance is based on the CLSI/NCCLS-17A Limits of Detection and Limits of Quantitation, October 2004 guideline.The guidelines for diagnosis and management of food allergy issues by the National Institute of Health state that: In 2010 the United States National Institute of Allergy and Infectious Diseases recommended that the RAST measurements of specific immunoglobulin E for the diagnosis of allergy be abandoned in favor of testing with more sensitive fluorescence enzyme-labeled assays.
The major difference between quantification methods is some use labels on the peptides such as tandem mass tags (TMT) or dimethyl labels which are used to identify which cell a certain protein came from (proteins coming from each cell have a different label) while others do not use labels but rather quantify cells individually. The mass spectroscopy data is then analyzed by running data through databases that count the peptides identified to quantify protein levels. These methods are very similar to those used to quantify the proteome of bulk cells, with modifications to accommodate the very small sample volume.
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.
The dry powder is more stable during transport and storage than a solution. It also allows a known amount of material to be reconstituted at a chosen concentration.