This is a working overview of melanogenesis, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-06-15. Anything still debated is marked as such rather than presented as settled.
Melanotan II binds several melanocortin receptor subtypes rather than a single target. MC1R on melanocytes drives melanin synthesis, while MC3R and MC4R participate in energy balance, appetite, and sexual response pathways. This lack of selectivity explains why reported effects extend beyond skin darkening. Substitutions at positions four and seven, including norleucine and D-phenylalanine, increase potency and resistance to peptidases. Understanding which receptor mediates which effect remains an active area of investigation.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Analog of alpha-melanocyte-stimulating hormone |
| Primary receptor family | Melanocortin receptors MC1R through MC5R | Binding is not subtype-selective |
| Development period | 1980s | Synthesized during pigmentation and appetite research |
| Regulatory status | Not an approved medicine | No major regulator has authorized human use |
| Related compound | Afamelanotide | Linear analog studied for photoprotection |
The 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, 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.
=== Miscellaneous uses === Argon is used for thermal insulation in energy-efficient windows. Argon is also used in technical scuba diving to inflate a dry suit because it is inert and has low thermal conductivity. Argon is used as a propellant in the development of the Variable Specific Impulse Magnetoplasma Rocket (VASIMR). Compressed argon gas is allowed to expand, to cool the seeker heads of some versions of the AIM-9 Sidewinder missile and other missiles that use cooled thermal seeker heads. The gas is stored at high pressure. Argon-39, with a half-life of 269 years, has been used for a number of applications, primarily ice core and ground water dating. Also, potassium–argon dating and related argon-argon dating are used to date sedimentary, metamorphic, and igneous rocks. Argon has been used by athletes as a doping agent to simulate hypoxic conditions. In 2014, the World Anti-Doping Agency (WADA) added argon and xenon to the list of prohibited substances and methods, although at this time there is no reliable test for abuse.
== Clinical significance == A prolonged stimulation of these cells causes their hyperplasia. This is especially important in gastrinoma (the tumors in which there is an excessive secretion of gastrin), as this is one of the factors contributing to Zollinger–Ellison's syndrome. It was once believed that tumors of ECL origin form after a prolonged inhibition of gastric acid secretion, however there is no data to support this conclusion and proton pump inhibitors are not thought to contribute to gastric cancer.
== External links == The idea of antiangiogenesis was pioneered by Dr. Judah Folkman. See [1] and [2] Angiogenesis Inhibitors for Cancer – from The Angiogenesis Foundation, 23 June 2009 Angiogenesis Inhibitors for Eye Disease – from The Angiogenesis Foundation, 23 June 2009 Angiogenesis Inhibitors in the Treatment of Cancer – from the National Cancer Institute Angiogenesis+Inhibitors at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
=== Agonists === Non-selective Galanin Galanin 1-15 fragment Galanin-like peptide - agonist at GAL1 and GAL2 but not GAL3 Galmic Galnon NAX 5055 D-Gal(7-Ahp)-B2 GAL1 selective M617 GAL1/2 selective M1154 - has no GalR3 interaction GAL2 selective Galanin 2-11 amide - also called AR-M 1896, anticonvulsant in mice, CAS# 367518–31–8 M1145 - selective compared to both GalR1 and GalR3 M1153 - selective compared to both GalR1 and GalR3 CYM 2503 (positive allosteric modulator)
Benazepril (Lotensin) Cilazapril (Inhibace) Enalapril (Vasotec/Renitec/Berlipril/Enap/Enalapril Profarma) Imidapril (Tanatril) Lisinopril (Listril/Lopril/Novatec/Prinivil/Zestril, Lisidigal) Moexipril (Univasc) Perindopril (Coversyl/Aceon/Perindo) Quinapril (Accupril) Ramipril (Altace/Prilace/Ramace/Ramiwin/Triatec/Tritace/Ramitac) Trandolapril (Mavik/Odrik/Gopten)
Sources: en.wikipedia.org
Scarborough's drinking water is supplied by the R.C. Harris Filtration Plant at the foot of Victoria Park Avenue and the F. J. Horgan Filtration Plant. The F. J. Horgan Filtration Plant was built in 1979 and was formerly known as the 'Easterly Plant'. Upgrades completed in 2011 allow it to process up to 800 megalitres per day and it will also be the first plant to replace chlorine with ozone as its primary cleansing method. Wastewater for Scarborough is treated at the Highland Creek Treatment Plant. This plant was constructed in 1954 and started processing in 1956. It has undergone continual expansion to meet ongoing demand.
== Terminology == Jammu and Kashmir is named after the two regions it encompasses: the Jammu region and the Kashmir Valley. India collectively refers to the parts of Kashmir under Pakistani administration as "Pakistan-occupied Kashmir" (POK), and considers the region corresponding to Azad Kashmir as part of Jammu and Kashmir. Pakistan collectively refers to the Indian-administered territories of Kashmir as "Indian-occupied Kashmir" (IOK) or "Indian-held Kashmir" (IHK). Neutral sources use "Indian-administered Kashmir"/"Pakistan-administered Kashmir" and "Indian-controlled Kashmir"/"Pakistan-controlled Kashmir" to demarcate the areas.
The second concern would be that some of the heavy metals that could be released can have some level of toxicity to not only organisms inhabiting that area but also organisms passing through the mining site area. The concerns surrounding increased sediment release are mainly related to the other two mining waste processes, side cast sediment and seafloor sediment disturbance. The main environmental concern would be the smothering of organisms below as a result of redistributing large amounts of sediment to other areas on the seafloor, which could potentially threaten the population of organisms inhabiting the area. Redistribution of large quantities of sediment can also affect the feeding and gas exchange processes between organisms, posing a serious threat to the population. Finally, these processes can also increase the sedimentation rate on the seafloor, resulting in a predicted minimum of 500 m per every 1–10 km. A large amount of work is currently being engaged in by both of the above-mentioned companies to ensure that the potential environmental impacts of seafloor mining are well understood and control measures are implemented before exploitation commences. However, this process has been arguably hindered by the disproportionate distribution of research effort among vent ecosystems; the best studied and understood hydrothermal vent ecosystems are not representative of those targeted for mining. Attempts have been made in the past to exploit minerals from the seafloor.
Public transportation in and around Raleigh is provided by GoRaleigh (formerly Capital Area Transit), which operates 33 fixed bus routes, including the R-Line. Although there are 33 routes, some routes are designed to cover multiple other routes at times when they are not served. Depending on the time of the day, and the day of the week, the number of routes operating is between 5 and 29. Raleigh is also served by GoTriangle (formerly Triangle Transit Authority). GoTriangle offers scheduled, fixed-route regional and commuter bus service between Raleigh and the region's other principal cities of Durham, Cary and Chapel Hill, as well as to and from the Raleigh-Durham International Airport, Research Triangle Park and several of the region's larger suburban communities. Triangle Transit also coordinates an extensive vanpool and rideshare program that serves the region's larger employers and commute destinations. North Carolina State University also maintains its own transit system, the Wolfline, that provides zero-fare bus service to the general public along multiple routes serving the university's campuses in southwest Raleigh. Government agencies throughout the Raleigh-Durham metropolitan area have struggled with determining the best means of providing fixed-rail transit service for the region. From 1995 the cornerstone of Triangle Transit's long-term plan was a 28-mile rail corridor from northeast Raleigh, through downtown Raleigh, Cary, and Research Triangle Park, to Durham using DMU technology.
Sources: en.wikipedia.org
== Prognosis == Symptoms usually get worse over the course of two weeks, then stabilize, and finally begin to improve. Motor problems, including chorea, settle within an average of 2–3 months. Recurrence is seen in 16–40% of cases. It is sometimes but not always associated with a rise in ASO titre or other evidence of new streptococcal infection. Recurrence is more likely with poor compliance with penicillin prophylaxis. It is more likely if there is failure to remit within 6 months of onset. Recurrence is associated in women with pregnancy (chorea gravidorum) and with female hormone treatment, although the onset of chorea can be delayed by months or more. Intramuscular penicillin given every 2–3 weeks is superior to a 4 weekly regime for preventing relapse, but a risk assessment may conclude that twice daily oral penicillin is sufficiently effective, less painful for the child, and less demanding on the family. Higher recurrence rates are seen with the longest follow up. Relapse can be seen 10 years or more after the initial episode, so might be underestimated by series with shorter follow up. Recurrence is usually only chorea, even if the original case was associated with rheumatic fever. There are two total reports of heart disease worsening after recurrence of chorea. The Thailand study also had 2 cases where carditis, which had improved after initial diagnosis, came back again. Some suggest that recurrent chorea is a different disease altogether. 10% reported long-term tremor in one study (10 years follow up).
== AFL career == Monfries was drafted by the Bombers with selection 14 in the 2004 AFL draft. He played football for Walkerville Junior Football Club before moving to Melbourne. He made his debut in Round 1, 2005 against Melbourne, which saw him become the 200th player to have played under coach Kevin Sheedy. Monfries maintained his position in the senior side until round 4, but was dropped for the Anzac Day clash in round 5, against Collingwood and did not play at senior level again until round 12. In round 13 against St Kilda, he kicked two goals and, alongside other young Bombers, played a role in a fifteen-point win. He then went on to play every game for the remainder of the season. In 2006, his second season, Monfries played 21 games, missing only one game due to a minor calf strain. In 2007, Monfries played 20 out of 22 games, omitted on form for two weeks at midseason. He was, however, named as an emergency for both matches and quickly returned to the team due to pressures caused by injuries and suspensions to other key players. In 2009, Monfries became a key player within the Essendon Football Club. He defined his role further as a key position forward and finished second in the club's goalkicking after Matthew Lloyd. On 5 October 2012, Angus told Essendon that he will be leaving and be signing a new four-year deal with Port Adelaide. On 8 October 2012, Essendon announced that Monfries would be traded to Port Adelaide for pick 48. He made his debut for Port Adelaide in round 1, 2013, against Melbourne.
Swiss chemist Albert Hofmann first synthesized LSD in 1938 and discovered its potent psychedelic effects in 1943 after accidental ingestion. It became widely studied in the 1950s and 1960s. The drug was initially explored for psychiatric use due to its structural similarity to serotonin and safety profile. It was used experimentally in psychiatry for treating alcoholism and schizophrenia. By the mid-1960s, LSD became central to the youth counterculture in places like San Francisco and London, influencing art, music, and social movements through events like Acid Tests and figures such as Timothy Leary, Owsley Stanley and Michael Hollingshead. Its psychedelic effects inspired distinct visual art styles and musical innovations, and caused a lasting cultural impact. However, its association with the counterculture movement of the 1960s led to its classification as a Schedule I drug in the United States in 1970. It was also listed as a Schedule I controlled substance by the United Nations in 1971 and remains without approved medical uses. Despite its legal restrictions, LSD remains influential in scientific and cultural contexts. Research on LSD declined due to cultural controversies by the 1960s, but has resurged since 2009. In 2024, the United States Food and Drug Administration designated LSD (code name MM120 or DT120) as a breakthrough therapy for generalized anxiety disorder. As of 2017, about 10% of people in the United States had used LSD at some point, with 0.7% having used it in the past year.
Sources: en.wikipedia.org
No regulator in a major market has approved it for human use. It appears in research settings and in products marketed outside pharmacy channels. Legal status for personal possession varies by country.
Afamelanotide is a linear analog that has received approval in some jurisdictions for a specific photoprotection indication. Melanotan II is cyclic and less selective across melanocortin receptors. The two are related but are not interchangeable in regulatory or clinical terms.
A compound that activates several receptor subtypes may produce effects beyond pigmentation. Selectivity influences which tissues respond and shapes the side-effect profile described in reports. Designing subtype-selective analogs is a stated goal of melanocortin research.
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.