This is a working overview of melanotan-2, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-06-16. Anything still debated is marked as such rather than presented as settled.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Lyophilised storage | −20 °C, dry, protected from light | Vials are sealed and allowed to reach room temperature before opening |
| Reconstituted storage | 2 to 8 °C, protected from light | Short-term holding; avoid repeated freeze-thaw cycles |
| Reconstitution solvent | Water for injection or bacteriostatic water | Added slowly along the vial wall to reduce foaming and shear |
| Purity measurement | RP-HPLC with area normalisation | Acetonitrile-water gradient monitored at roughly 214 nm |
| Identity confirmation | Electrospray ionisation mass spectrometry | Observed mass compared against the calculated peptide mass |
Melanotan-2 appears on the World Anti-Doping Agency prohibited list within the peptide hormone class, and several national regulators treat it as an unapproved prescription substance. Some countries restrict importation or sale for personal use. Because the compound is widely traded as a research chemical, the practical legal picture differs between jurisdictions and shifts over time. Human safety data covering long periods are limited, and whether repeated pigmentation changes carry any lasting risk to melanocytes remains an open question.
Freeze-dried melanotan-2 is normally kept as a desiccated powder at minus twenty degrees Celsius or lower, shielded from light and moisture. Peptides of this size degrade through hydrolysis, oxidation and deamidation, and each pathway accelerates as temperature and water activity rise. Repeated freeze-thaw cycles promote aggregation and loss of material, so aliquoting a stock solution before freezing is standard laboratory practice. Once dissolved, the solution is markedly less stable than the powder. In laboratory work, solutions are generally refrigerated and used within days rather than kept for months.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, which separates the target peptide from truncated or oxidised impurities. Mass spectrometry, most often coupled to liquid chromatography, confirms molecular mass and detects substitutions that chromatography alone may miss. Amino acid analysis and peptide mapping supply additional structural evidence, while nuclear magnetic resonance is reserved for full structural confirmation. Laboratories that examine samples sold online report wide variation in actual content, with some vials containing little or none of the labelled material.
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.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone, a naturally occurring peptide involved in pigmentation signalling. Its sequence incorporates modified residues that increase potency and extend biological activity relative to the native hormone. The compound binds receptors of the melanocortin family and is examined mainly in laboratory research. It does not occur naturally and exists only as a manufactured chemical entity produced by solid-phase synthesis.
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.
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.
The topology of a β-sheet describes the order of hydrogen-bonded β-strands along the backbone. For example, the flavodoxin fold has a five-stranded, parallel β-sheet with topology 21345; thus, the edge strands are β-strand 2 and β-strand 5 along the backbone. Spelled out explicitly, β-strand 2 is H-bonded to β-strand 1, which is H-bonded to β-strand 3, which is H-bonded to β-strand 4, which is H-bonded to β-strand 5, the other edge strand. In the same system, the Greek key motif described above has a 4123 topology. The secondary structure of a β-sheet can be described roughly by giving the number of strands, their topology, and whether their hydrogen bonds are parallel or antiparallel. β-sheets can be open, meaning that they have two edge strands (as in the flavodoxin fold or the immunoglobulin fold) or they can be closed β-barrels (such as the TIM barrel). β-Barrels are often described by their stagger or shear. Some open β-sheets are very curved and fold over on themselves (as in the SH3 domain) or form horseshoe shapes (as in the ribonuclease inhibitor). Open β-sheets can assemble face-to-face (such as the β-propeller domain or immunoglobulin fold) or edge-to-edge, forming one big β-sheet.
Over the next thirty years many calibration curves were published using a variety of methods and statistical approaches. These were superseded by the IntCal series of curves, beginning with IntCal98, published in 1998, and updated in 2004, 2009, 2013, and 2020. The improvements to these curves are based on new data gathered from tree rings, varves, coral, plant macrofossils, speleothems, and foraminifera. There are separate curves for the northern hemisphere (IntCal20) and southern hemisphere (SHCal20), as they differ systematically because of the hemisphere effect. The continuous sequence of tree-ring dates for the northern hemisphere goes back to 13,910 BP as of 2020, and this provides close to annual dating for IntCal20 much of the period, reduced where there are calibration plateaus, and increased when short term 14C spikes due to Miyake events provide additional correlation. Radiocarbon dating earlier than the continuous tree ring sequence relies on correlation with more approximate records. SHCal20 is based on independent data where possible and derived from the northern curve by adding the average offset for the southern hemisphere where no direct data was available. There is also a separate marine calibration curve, MARINE20. For a set of samples forming a sequence with a known separation in time, these samples form a subset of the calibration curve. The sequence can be compared to the calibration curve and the best match to the sequence established. This "wiggle-matching" technique can lead to more precise dating than is possible with individual radiocarbon dates.
Greater lactose tolerance has come about in two ways. Some populations have developed genetic changes to allow the digestion of lactose: lactase persistence. Other populations developed cooking methods like milk fermentation. Lactase persistence in humans evolved relatively recently (in the last 10,000 years) among some populations. Around 8,000 years ago in modern-day Turkey, humans became reliant on newly-domesticated animals that could be milked; such as cows, sheep, and goats. This resulted in higher frequency of lactase persistence. Lactase persistence became high in regions such as Europe, Scandinavia, the Middle East and Northwestern India. However, most people worldwide remain lactase non-persistent. Populations that raised animals not used for milk tend to have 90–100 percent of a lactose intolerant rate. For this reason, lactase persistence is of some interest to the fields of anthropology, human genetics, and archaeology, which typically use the genetically derived persistence/non-persistence terminology. The rise of dairy and producing dairy related products from cow milk alone, varies across different regions of the world, aside from genetic predisposition. The process of turning milk into cheese dates back earlier than 5200 BC. DNA analysis in February 2012 revealed that Ötzi was lactose intolerant, supporting the theory that lactose intolerance was still common at that time, despite the increasing spread of agriculture and dairying.
On 15 June 2022, Michael Duff was appointed head coach of Barnsley on a three-year contract. In May 2022, it was revealed that Pacific Media Group did not actually own all the shares they claimed to own, and were simply a nominee for a group of 4 investors who owned 20% of the club. Following this revelation, Neerav Parekh purchased the shares of 2 of the investors, while Matt Edmonds purchased the shares of the 4th investor. Following the purchases and further equity raises, the new ownership of the club is now understood to be split between Neerav Parekh (61.14%), the Cryne family (21.30%), Julie Anne Quay and Matt Edmonds (11%), Chien Lee (4.60%), and Conway's company Pacific Media Group (1.96%). With this reconstituted shareholding and a loss of majority control, Paul Conway, Chien Lee, Grace Hung and Dickson Lee were voted off the board of Barnsley Football Club, and were replaced by Jean Cryne and Julie Anne Quay in May 2022. In July 2023, the EFL charged Barnsley with 5 breaches of the EFL Regulations related to the ownership of the club under Conway and Lee's tenure, whilst also charging Conway and Lee individually with causing these breaches in regulations.
Studies have found a significant correlation between cellular hCTR1 levels and cisplatin accumulation and sensitivity to the drug. Raising extracellular copper can reduce cisplatin uptake and toxicity, likely by downregulating hCTR1 at the membrane. Conversely, copper chelation or deficiency might increase hCTR1 levels and potentially enhance cisplatin import.
Sources: en.wikipedia.org
French authorities say that 4 people, including a 2-year-old boy, died trying to cross the Channel to the UK. According to the Home Office, 973 people crossed the English Channel on this date in 17 boats, the highest daily number for 2024, making the total number so far for the year 26,612 people in 503 boats. 6 October Sue Gray resigns as Downing Street Chief of Staff following revelations that her salary was £3,000 higher than that of the prime minister. In her resignation statement, Gray says she "risked becoming a distraction". Morgan McSweeney is appointed to replace her. Johnnie Walker announces his retirement from broadcasting after 58 years because of ill health. 7 October 1,000 jobs are to be lost at fast food restaurant TGI Fridays despite a rescue package after the company went into administration. From this date onwards, all UK payment service providers are required to reimburse victims of authorised push payment fraud. This new regulation supersedes a voluntary code introduced in May 2019, of which only 10 payment service providers were members. The price of a first class stamp increases by 30p to £1.65. 8 October In his annual update of security threats posed to the UK, Ken McCallum, the head of MI5, says that Russia's intelligence agency has been on a mission to generate "sustained mayhem on British and European streets".
== Internal standard yield == Yields can also be calculated by measuring the amount of product formed (typically in the crude, unpurified reaction mixture) relative to a known amount of an added internal standard, using techniques like Gas chromatography (GC), High-performance liquid chromatography, or Nuclear magnetic resonance spectroscopy (NMR spectroscopy) or magnetic resonance spectroscopy (MRS). A yield determined using this approach is known as an internal standard yield. Yields are typically obtained in this manner to accurately determine the quantity of product produced by a reaction, irrespective of potential isolation problems. Additionally, they can be useful when isolation of the product is challenging or tedious, or when the rapid determination of an approximate yield is desired. Unless otherwise indicated, yields reported in the synthetic organic and inorganic chemistry literature refer to isolated yields, which better reflect the amount of pure product one is likely to obtain under the reported conditions, upon repeating the experimental procedure.
30 August – Nicky Gavron, 82, British politician, deputy mayor of London (2000–2003, 2004–2008). 3 September – Flora Fraser, 21st Lady Saltoun, 93, Scottish peer, member of the House of Lords (1979–2014). 18 September – Malcolm Mitchell-Thomson, 3rd Baron Selsdon, 86, British peer, banker and businessman, member of the House of Lords (1963–2021). 1 October – Michael Ancram, 13th Marquess of Lothian, 79, British politician and peer, three-times MP, member of the House of Lords (since 2010). 2 October – Herman Ouseley, Baron Ouseley, 79, Guyanese-born British civil rights activist and politician, member of the House of Lords (2001–2019). 4 October – Alexander Leitch, Baron Leitch, 76, British businessman and life peer, member of the House of Lords (since 2004). 7 October – Hugh Cholmondeley, 5th Baron Delamere, 90, British peer, member of the House of Lords (1979–1999). 12 October – Alex Salmond, 69, Scottish politician, first minister (2007–2014). 20 October – Paul White, Baron Hanningfield, 84, British politician and life peer, member of the House of Lords (since 1998). 4 November – Robin Renwick, Baron Renwick of Clifton, 86, British diplomat and life peer, ambassador to the United States (1991–1995). 6 November – Anna Lo, 74, Northern Irish politician, MLA (2007–2016). Sir John Nott, 92, British politician, MP (1966–1983) and defence secretary (1981–1983). 20 November – John Prescott, Baron Prescott, 86, British politician, deputy prime minister (1997–2007), first secretary of state (2001–2007), and MP (1970–2010).
The fictional timeline of the MCU includes the feature films, television series, television specials, short films, and the I Am Groot shorts from Marvel Studios and Marvel Television's Netflix series. While the early films of Phase One and Phase Two of the franchise followed each other in the timeline similar to their release order, Phase Three saw many of the films overlapping with each other in the timeline, while also introducing the first prequel property, Captain Marvel. The Phase Three film Avengers: Endgame featured characters traveling into the past and introduced a five-year time jump, with many subsequent releases in Phase Four and Phase Five set after Endgame's events in the timeline. The television series Loki and What If...? were the first properties to occur outside of the main timeline and explore alternative timelines and universes. There have been numerous attempts by Marvel Studios and others to codify the events of the MCU, which have been subject to perceived continuity errors, resulting in Marvel Studios releasing an official timeline book in 2023 for their first four phases that were designated as part of their "Sacred Timeline". This book did not feature projects produced by other companies, such as Marvel Television's series, which were all loosely connected to the films; however, it was noted that all of these outside projects were part of the larger Marvel canon. In early 2024, Marvel Studios formally integrated Marvel Television's group of Netflix series into its Disney+ timeline.
While APHL primarily focuses on public health laboratories in the United States, their global health program makes an effort to help other countries strengthen their own laboratory practices.APHL works with more than 30 countries to: Share effective testing procedures Develop laboratory policies Improve the quality of data Train laboratory leaders Utilize information management systems Create strategies to monitor and detect Establish emergency response programs Design training programs APHL also works with public health laboratories around the world to share information on global health crises and promotes cross-border collaboration.
Sources: en.wikipedia.org
=== 1989 Kramatorsk, Ukraine === The 1989 Kramatorsk incident happened in 1989 when a small capsule 8 by 4 millimetres (0.3 by 0.2 inches) in size of caesium-137 was found inside the concrete wall of an apartment building in Kramatorsk, Ukrainian SSR. It is believed that the capsule, originally a part of a measurement device, was lost in the late 1970s and ended up mixed with gravel used to construct the building in 1980. Over 9 years, two families had lived in the apartment. By the time the capsule was discovered, 6 residents of the building had died, 4 from leukemia and 17 more receiving varying doses of radiation.
== Manufacturing == Commercial preparations of lente insulin are standardized to 30% semilente (amorphous precipitates of insulin), and 70% ultralente (crystallized insulin). In early versions, the semilente insulin was extracted from pigs, and the ultralente insulin was extracted from cows.
The education system is divided into three parts: basic education, secondary cycle, and tertiary education. "Basic education" lasts 11 years (ages 4‒15). It is divided into kindergarten (two years), primary school (two modules of three years) and junior high (three years). Junior high school ends with the Basic Education Certificate Examination. Once certified, the pupil can proceed to the secondary cycle. Hence, the pupil has the choice between general education (offered by the senior high school) and vocational education (offered by the technical senior high school or the technical and vocational institutes). Senior high school lasts three years and leads to the West African Senior School Certificate Examination, which is a prerequisite for enrollment in a university bachelor's degree programme. Polytechnics are open to vocational students. A bachelor's degree requires four years of study. It can be followed by a one- or two-year master's degree programme, which can be followed by a PhD programme of at least three years. A polytechnic programme lasts two or three years. Ghana possesses colleges of education. Some of the universities are the University of Ghana, Kwame Nkrumah University of Science and Technology, and University of Cape Coast. There are more than 95% of children in school. The literacy rate of youth ages 15 to 24 years old was 81% in 2010, with males at 82%, and females at 80%. The education system annually attracts foreign students, particularly in the university sector.
== Notable ascents == 1953 2nd ascent Yosemite Point Buttress. (With Royal Robbins) 1953 2nd ascent North Face Sentinel Rock. (With Royal Robbins and Don Wilson) 1953 Palisades Traverse Thunderbolt Peak to Mount Sill via North Palisade. (With Gary Hemming) 1954 5th ascent Lost Arrow Spire. (With Wayne Merry) 1955 3rd ascent Lost Arrow Chimney. (With Charles Wilts and Don Wilson) 1956 1st ascent Spider Rock, Canyon de Chelly National Monument, AZ, USA, March 30. (With Mark Powell and Don Wilson) 1956 1st ascent East Buttress of Middle Cathedral Rock, Yosemite National Park, CA, USA, June 16. (With Mark Powell and Don Wilson) 1956 5th ascent Castle Rock Spire. (With Charles Wilts) 1956 1st ascent Cleopatra's Needle, Valley of the Thundering Water, NM, USA, September 6. (With Mark Powell and Don Wilson) 1957 1st ascent The Step, Tahquitz Idyllwild, CA, USA, May 18. (With Royal Robbins) 1957 1st ascent Totem Pole, Monument Valley, AZ, USA. June 13. (With Bill Feuerer, Mark Powell, and Don Wilson) 1957 1st ascent Northwest Face of Half Dome, Yosemite, CA, USA, June 23–27. First grade VI climb in America. (With Mike Sherrick and Royal Robbins)
Sources: en.wikipedia.org
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.
Liquid chromatography coupled to mass spectrometry is the most common approach because it combines a retention time with a mass measurement. A chromatographic peak alone cannot establish which peptide is present, so mass determination or amino acid analysis is used as an orthogonal confirmation alongside the separation.
This depends on buffer, pH, and concentration, and published stability data for this peptide are limited. In practice laboratories work through a refrigerated solution within a few weeks and discard samples that show cloudiness or visible particles. Freezing and thawing repeatedly is generally discouraged.
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.