A practical reference on prescription control: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-03-27 and is reviewed periodically as new material appears.
Receptor-binding studies classify melanotan II as a non-selective melanocortin agonist. It interacts with MC1R, MC3R, MC4R and MC5R, with reported affinities in the low nanomolar range and no strong subtype preference. Activation of MC1R on dermal melanocytes shifts pigment synthesis toward eumelanin, the dark polymer deposited in melanosomes and transferred to keratinocytes. Because the same peptide engages MC4R in the hypothalamus, it also appears in animal work on food intake and erectile response, which is why it is discussed in both pigment and metabolic research. Which receptor populations dominate after systemic exposure in humans is not fully established.
Published pharmacokinetic information is limited and comes mainly from small studies rather than registrational trials. Plasma half-life is usually described as short, on the order of tens of minutes, followed by rapid tissue distribution and clearance of the intact peptide. Metabolites and low concentrations of parent compound have been reported in urine, a detail relevant to anti-doping and forensic testing. Whether repeated exposure changes receptor sensitivity or clearance over time remains an open question. Values differ noticeably between analytical assays, so published numbers should be read as approximate rather than definitive.
Melanotan II is a synthetic cyclic heptapeptide with the sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, corresponding to a molecular formula of C50H69N15O9 and a monoisotopic mass near 1024 daltons. It was designed as a structural analogue of alpha-melanocyte-stimulating hormone, a peptide hormone produced by cleavage of proopiomelanocortin. A lactam bridge between the aspartate and lysine side chains closes the ring, and the C-terminal amide removes a free carboxyl group. Both modifications increase resistance to enzymatic degradation compared with the linear parent hormone. Four substitutions distinguish it from afamelanotide, the linear analogue studied under the name melanotan I.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Cyclic heptapeptide, C-terminally amidated |
| Approximate molecular mass | 1024 Da | Monoisotopic mass of the free peptide |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility class | Soluble in water and polar solvents | Also dissolves in neutral aqueous buffer |
| Common synonyms | Melanotan II, MT-II, MT-2 | Described as a melanocortin agonist in early literature |
The peptide was developed during the 1980s by researchers investigating melanocortin signalling and skin pigmentation pathways. Early work focused on analogues of alpha-melanocyte-stimulating hormone that would resist enzymatic breakdown more effectively than the parent molecule. Melanotan-2 emerged from that programme as a shortened, cyclised variant. Reports describing its synthesis and receptor activity later appeared in the scientific literature. Commercial availability grew through unregulated channels rather than through pharmaceutical approval.
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.
Because the substance circulates mainly through informal markets, verification is a recurring theme in technical discussion. Independent analyses have found that labeled content and actual content can diverge, and that purity varies between samples. Analytical laboratories use reversed-phase chromatography to separate components and mass spectrometry to confirm identity. Isotope-labeled internal standards improve quantification in complex matrices. Such methods describe what a sample contains but say nothing about its sterility, lawful status, or suitability for any use. Open questions remain about how consistently testing is applied across the supply chain.
Regulatory treatment of this peptide varies by country. It holds no marketing authorization as a medicine in the United States, the European Union, or most other jurisdictions. Some countries classify products containing it as prescription-only or unlicensed medicines, which restricts lawful supply. Authorities have issued public notices warning that unregulated products may contain undeclared or incorrect ingredients. The molecule also appears on prohibited lists for competitive sport. These measures address supply oversight rather than any approved therapeutic role.
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.
Identity and purity are assessed with chromatographic and mass spectrometric techniques. Reversed-phase high-performance liquid chromatography separates the target peptide from related impurities and degradation products, and the resulting retention time is compared against a reference standard. Mass spectrometry, often coupled to liquid chromatography, confirms molecular mass. Amino acid analysis or peptide mapping can provide additional sequence-level confirmation when required. Results are only as reliable as the reference materials used alongside them.
Regulatory treatment varies by country. In the United States, melanotan-2 is not approved for any indication, and products marketed for human use fall outside the approved drug framework. Some other jurisdictions have placed it under prescription controls or listed it as a prohibited or restricted substance. Online listings frequently describe the material as a research chemical, a category that does not carry the same manufacturing and labelling requirements as approved medicines.
Solid peptide material is generally stable when kept cold and dry. Common practice is storage at -20 degrees Celsius or lower, with desiccant and protection from light. Repeated freeze-thaw cycles and exposure to moisture are associated with degradation, aggregation, or loss of material. Once dissolved, stability depends on solvent, concentration, and temperature, and solutions are usually treated as short-lived unless stability data support longer periods. Handling notes typically emphasise minimising time at ambient temperature.
The main advantages with respect to solvent gradient batch chromatography are high yields also for difficult separations, less solvent consumption, higher productivity, usage of countercurrent solid movement, which increases the separation efficiency. The process is continuous. Once a steady state is reached, it delivers continuously purified product in constant quality and quantity. Automatic cleaning in place is integrated. A pure empirical design of the operating conditions from a single solvent gradient batch chromatogram is possible.
12 September Your Flight in Their Hands, about aviation safety in Europe; over a million passenger flights occurred in the UK each year in the early 1990s, but no crash due to ATC error has taken place; flights were expected to double in 20 years; the technology being deployed in UK airspace, with Gordon Doggett, head of the London Area Control Centre (LATCC); Keith Mack, the Director-General from 1988 to 1993 of Eurocontrol; a British Airways Boeing 737 BA466 takes a route over Ortac to Madrid; Karl-Heinz Neumeister, the Secretary-General of the Association of European Airlines; the aviation writer Rigas Doganis. Directed by Richard Vaughan, produced by Chris Haws, made by InCA Productions 19 September Fear of Falling, about rock climbing and caving equipment; the single-rope technique (SRT), demonstrated by Nigel Atkins of Pennine National Caving, with a dynamic climbing rope, maillon rapide, snap-gate carabiner, ascender and descender; Ben Lyon of Tebay; a climbing harness, designed by Don Whillans, and the belay loop at Troll Safety Equipment (later Bacou-Dalloz, bought by Sperian of France) in Saddleworth; Simon Nadin; the Foundry indoor climbing centre, opened by Jerry Moffatt in 1991; Undercover Rock at St Werburgh's Church, Bristol; sport climbing; Ben Moon in Derbyshire. Directed by Steve Stevenson, produced by Mike Wallington, made by Parvenu Productions 3 October Family Fortunes, about how children's mental development or health is affected or hindered by growing up in a one-parent-family.
=== Selected articles === Ajayaghosh, Ayyappanpillai, Subi J. George (2001). “First phenylenevinylene based organogels: self-assembled nanostructures via cooperative hydrogen bonding and π-stacking”. J. Am. Chem. Soc. 2001, 123, 21, 5148-5149. https://doi.org/10.1021/ja005933+. Ajayaghosh, Ayyappanpillai, Priya Carol, and Sivaramapanicker Sreejith (2005) “A Ratiometric Fluorescence Probe for Selective Visual Sensing of Zn2+”. J. Am. Chem. Soc. 2005, 127, 43, 14962-14963. https://doi.org/10.1021/ja054149s. Ajayaghosh, Ayyappanpillai, Vakayil K. Praveen, Chakkooth Vijayakumar, Subi J. George (2007). “Molecular Wire Encapsulated into π Organogels: Efficient Supramolecular Light-Harvesting Antennae with Color-Tunable Emission”. Angew. Chem. Int. Ed. 2007, 46, 6260-6265. https://doi.org/10.1002/anie.200701925. Ajayaghosh, Ayyappanpillai, Vakayil K. Praveen (2008). “π-Organogels of Self-Assembled p-Phenylenevinylenes: Soft Materials with Distinct Size, Shape, and Functions”. Acc. Chem. Res. 2007, 40, 8, 644-656. https://doi.org/10.1021/ar7000364 Vijayakumar, Chakkooth; Praveen, Vakayil K.; Kartha, Kalathil K.; Ajayaghosh, Ayyappanpillai (2011). "Excitation energy migration in oligo(p-phenylenevinylene) based organogels: structure-property relationship and FRET efficiency". Physical Chemistry Chemical Physics. 13 (11): 4942–4949. Bibcode:2011PCCP...13.4942V. doi:10.1039/C0CP02110E. PMID 21321716. S2CID 19328938. Kartha, Kalathil K.; Babu, Sukumaran S.; Srinivasan, Sampath; Ajayaghosh, Ayyappanpillai (2012).
=== Gut === Eluxadoline is a peripherally restricted KOR agonist as well as MOR agonist and DOR antagonist that has been approved for the treatment of diarrhea-predominant irritable bowel syndrome. Asimadoline and fedotozine are selective and similarly peripherally restricted KOR agonists that were also investigated for the treatment of irritable bowel syndrome and reportedly demonstrated at least some efficacy for this indication but were ultimately never marketed.
Tigecycline can treat complicated skin and structure infections caused by: Escherichia coli, vancomycin-susceptible Enterococcus faecalis, methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus agalactiae, Streptococcus anginosus grp., Streptococcus pyogenes, Enterobacter cloacae, Klebsiella pneumoniae, and Bacteroides fragilis. Tigecycline is indicated for the treatment of complicated intra-abdominal infections caused by: Citrobacter freundii, Enterobacter cloacae, Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, vancomycin-susceptible Enterococcus faecalis, methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus anginosus grp., Bacteroides fragilis, Bacteroides thetaiotaomicron, Bacteroides uniformis, Bacteroides vulgatus, Clostridium perfringens, and Peptostreptococcus micros. Tigecycline may be used for treatment of community-acquired bacterial pneumonia caused by: penicillin-susceptible Streptococcus pneumoniae, Haemophilus influenzae that does not produce Beta-lactamase and Legionella pneumophila. Tigecycline is given intravenously and has activity against a variety of Gram-positive and Gram-negative bacterial pathogens, many of which are resistant to existing antibiotics. Tigecycline successfully completed phase III trials in which it was at least equal to intravenous vancomycin and aztreonam to treat complicated skin and skin structure infections, and to intravenous imipenem and cilastatian to treat complicated intra-abdominal infections.
Sources: en.wikipedia.org
== Release and promotion == BioShock's first public showing was at E3 2006. After a fan petition calling for a special edition of the game reached 5,000 signatures, 2K Games announced a limited edition of the game, featuring a Big Daddy figurine, making-of materials, and the game's soundtrack. Before the special edition was released, the proposed soundtrack CD was replaced with The Rapture EP. BioShock was released on August 21, 2007, in North America, and August 24 in Europe and Australia for Windows and Xbox 360 platforms. The demo released the week before release was so popular the demand crashed Xbox Live's servers. The Windows release shipped with SecuROM copy protection that required activation from 2K Games' servers over the Internet; the unavailability of these servers was reported as the reason for the cancellation of the game's midnight release in Australia. Complaints from players caused 2K Games to raise the simultaneous installation limit for the game from two to five copies; the activation limit was removed after the release of the game, though other copy protection methods remained. Levine admitted that their initial approach to the activation process was malformed, harming their reputation during the launch period. The initial release of the game also cropped the top and bottom of the field of view in order to fit widescreen monitors, resulting in less vertical view instead of more horizontal view compared to 4:3 monitors.
== Habitat == Brown recluse spiders build asymmetrical (irregular) webs that frequently include a shelter consisting of disorderly threads. They frequently build their webs in woodpiles and sheds, closets, garages, plenum spaces, cellars, and other places that are dry and generally undisturbed. When dwelling in human residences they seem to favor cardboard, possibly because it mimics the rotting tree bark which they inhabit naturally. Human-recluse contact often occurs when such isolated spaces are disturbed and the spider feels threatened. Unlike most web weavers, they leave these lairs at night to hunt. Males move around more when hunting than the females, which tend to remain nearer to their webs.
In solar water disinfection (often shortened as "sodis"), microbes are destroyed by temperature and UVA radiation provided by the sun. Water is placed in a transparent plastic PET bottle or plastic bag, oxygenated by shaking partially filled capped bottles prior to filling the bottles all the way, and left in the sun for 6–24 hours atop a reflective surface.
=== Claude D. Pepper Older Americans Independence Center === The San Antonio Claude D. Pepper Older Americans Independence Center (OAIC) is one of only fifteen National Institute on Aging (NIA)-funded Pepper Centers in the United States. Established in 2015, the Center serves as the translational arm of the Barshop Institute's aging research enterprise, with the overarching goal of improving the health, physical function, and independence of older adults. In partnership with the South Texas Veterans Health Care System Geriatric Research, Education and Clinical Center (GRECC), the Center brings together basic scientists, clinician investigators, epidemiologists, and population scientists to translate discoveries in the biology of aging into interventions that preserve functional independence and improve quality of life. The San Antonio Pepper Center is nationally recognized as the first Claude D. Pepper Center organized around the principles of geroscience—the concept that aging itself is the primary biological risk factor underlying most chronic diseases and functional decline. Rather than studying age-related diseases in isolation, investigators focus on the fundamental mechanisms of aging that contribute to conditions such as frailty, sarcopenia, mobility impairment, cardiovascular disease, type 2 diabetes, Alzheimer's disease and related dementias, and other chronic disorders affecting older adults.
Sources: en.wikipedia.org
==== Japan ==== In Japanese cuisine, they are called harusame (春雨), literally "spring rain". Unlike Chinese glass noodles, they are usually made from potato starch. They are commonly used to make salads, or as an ingredient in hot pot dishes. They are also often used to make Japanese adaptations of Chinese and Korean dishes. Shirataki noodles are translucent, traditional Japanese noodles made from the konjac yam and sometimes tofu.
=== Genetic === Worldwide, RA affects approximately 1% of the adult population and occurs in one in 1,000 children. Studies show that RA primarily affects individuals between the ages of 40–60 years and is seen more commonly in females. A family history of RA increases the risk around three to five times; as of 2016, it was estimated that genetics may account for 40–65% of cases of seropositive RA, but only around 20% for seronegative RA. RA is strongly associated with genes of the inherited tissue type major histocompatibility complex (MHC) antigen. HLA-DR4 is the major genetic factor implicated – the relative importance varies across ethnic groups. Genome-wide association studies examining single-nucleotide polymorphisms have found around one hundred alleles associated with RA risk. Risk alleles within the HLA (particularly HLA-DRB1) genes harbor more risk than other loci. The HLA encodes proteins that control recognition of self- versus non-self molecules. Other risk loci include genes affecting co-stimulatory immune pathways—for example CD28 and CD40, cytokine signaling, lymphocyte receptor activation threshold (e.g., PTPN22), and innate immune activation—appear to have less influence than HLA mutations. Despite the strong genetic components of the disease, identical twin studies have shown only 12–15% concordance for twins raised in separate households. This suggests that rheumatoid arthritis most likely results from a combination of genetic and environmental factors in the majority of cases.
==== Neutrophil extracellular traps ==== In 2004, Brinkmann and colleagues described a striking observation that activation of neutrophils causes the release of web-like structures of DNA; this represents a third mechanism for killing bacteria. These neutrophil extracellular traps (NETs) comprise a web of fibers composed of chromatin and serine proteases that trap and kill extracellular microbes; thus, by forming NETs (NETosis), neutrophils can bind, disarm, and kill microbes independent of phagocytic uptake. These functions are achieved through the release of highly concentrated antimicrobial components including proteins from granules and powerful histone proteins from the nucleus. In addition to their possible antimicrobial properties, NETs may serve as a physical barrier that prevents further spread of pathogens. Trapping of bacteria may be a particularly important role for NETs in sepsis, where NETs are formed within blood vessels. Finally, NET formation has been demonstrated to augment macrophage bactericidal activity during infection. Recently, NETs have been shown to play a role in inflammatory diseases, as NETs could be detected in preeclampsia, a pregnancy-related inflammatory disorder in which neutrophils are known to be activated. Neutrophil NET formation may also impact cardiovascular disease, as NETs may influence thrombus formation in coronary arteries. NETs are now known to exhibit pro-thrombotic effects both in vitro and in vivo. More recently, in 2020 NETs were implicated in the formation of blood clots in cases of severe COVID-19.
==== Vertebrates ==== In the early development of vertebrate embryos, growth and formation of muscle happens in successive waves or phases of myogenesis. The myosin heavy chain isotype is a major determinant of the specific fiber type. In zebrafish embryos, the first muscle fibers to form are the slow twitch fibers. These cells will undergo migration from their original location to form a monolayer of slow twitch muscle fibers. These muscle fibers undergo further differentiation as the embryo matures.
=== Laboratory synthesis === Heavy neutron irradiation of plutonium results in four major isotopes of einsteinium: 253Es (α-emitter; half-life 20.47 days, spontaneous fission half-life 7×105 years); 254mEs (β-emitter, half-life 39.3 hours), 254Es (α-emitter, half-life 276 days) and 255Es (β-emitter, half-life 39.8 days). An alternative route involves bombardment of uranium-238 with high-intensity nitrogen or oxygen ion beams. 247Es (half-life 4.55 min) was produced by irradiating 241Am with carbon or 238U with nitrogen ions. The latter reaction was first realized in 1967 in Dubna, Russia, and the involved scientists were awarded the Lenin Komsomol Prize. 248Es was produced by irradiating 249Cf with deuterium ions. It mainly β-decays to 248Cf with a half-life of 25±5 minutes, but also releases 6.87-MeV α-particles; the ratio of β's to α-particles is about 400.
Sources: en.wikipedia.org
No. It is a synthetic analogue carrying four amino acid changes, a lactam ring and an amidated C-terminus. The natural hormone is a linear thirteen-amino-acid peptide processed from proopiomelanocortin.
Afamelanotide is the linear analogue [Nle4-D-Phe7]-alpha-MSH, sometimes called melanotan I, while melanotan II is cyclic and carries three further substitutions. The two are distinct molecules and are not interchangeable in analytical testing.
Binding to the four melanocortin receptor subtypes is well documented in vitro. The relative contribution of each subtype to whole-body effects in humans is far less certain.
Low temperature slows hydrolysis and oxidation, the two main routes by which the peptide backbone and side chains are modified. A lyophilised powder stored at −20 °C is more stable than one kept at room temperature, and once the material is dissolved the degradation rate rises, making refrigeration more important.