If you have been reading about melanogenesis and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-06-12. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
| 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 |
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.
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.
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.
Well-known disorders caused by thiamine deficiency include beriberi, Wernicke–Korsakoff syndrome, optic neuropathy, Leigh's disease, African seasonal ataxia (or Nigerian seasonal ataxia), and central pontine myelinolysis. Symptoms include malaise, weight loss, irritability and confusion. In Western countries, chronic alcoholism is a risk factor for deficiency. Also at risk are older adults, persons with HIV/AIDS or diabetes, and those who have had bariatric surgery. Varying degrees of thiamine insufficiency have been associated with the long-term use of diuretics.
== List of death row inmates granted clemency by the President == 1978: Mohamad Kunjo s/o Ramalan, a Singaporean convicted of murdering a lorry driver in 1975 and sentenced to hang in 1976. After losing his appeals against his sentence over the next two years, he filed for clemency, which was granted by President Benjamin Sheares in 1978. His death sentence was commuted to life imprisonment. 1980: Bobby Chung Hua Watt, a Singaporean convicted of murdering his brother-in-law's brother in 1975. He was found guilty of murder and condemned to hang. After losing his appeal against his death sentence, he was initially scheduled to be executed on 18 January 1980. However, on 15 January 1980, President Benjamin Sheares granted him clemency and his death sentence was commuted to life imprisonment. He was released from prison in 1993 for good behaviour after serving at least two-thirds of his life sentence. 1983: Siti Aminah binte Jaffar, a Singaporean convicted of drug trafficking in 1977 and sentenced to death in 1978 along with her lover, Anwar Ali Khan. The two of them appealed to President Devan Nair for clemency in 1983. Anwar's plea was rejected and he was executed, but Siti's was accepted and she had her death sentence changed to life imprisonment. She was released from prison in 1991. 1993: Sim Ah Cheoh, a Singaporean convicted of drug trafficking in 1985 and sentenced to death in 1988 along with her two accomplices.
=== Medications === Pentoxifylline is a useful add-on treatment to compression stockings and may also help by itself. It works by reducing platelet aggregation and thrombus formation. Gastrointestinal disturbances were reported as a potential adverse effect. Sulodexide, which reduces the formation of blood clots and reduces inflammation, may improve the healing of venous ulcers when taken in conjunction with proper local wound care. Further research is necessary to determine potential adverse effects, the effectiveness, and the dosing protocol for sulodexide treatment. An oral dose of aspirin is being investigated as a potential treatment option for people with venous ulcers. A 2016 Cochrane systematic review concluded that further research is necessary before this treatment option can be confirmed to be safe and effective. Oral zinc supplements have not been proven to be effective in aiding the healing of venous ulcers; however, more research is necessary to confirm these results. Treatments aimed at decreasing protease activity to promote healing in chronic wounds have been suggested; however, the benefit remains uncertain. There is also a lack of evidence on the effectiveness of testing for elevated proteases in venous ulcers and treating them with protease-modulating treatment. There is low certainty evidence that protease modulating matrix treatment is helpful in the healing of venous ulcers. Flavonoids may be useful for treating venous ulcers, but the evidence must be interpreted cautiously.
=== Filtration === Portable pump filters are commercially available with ceramic filters that filter 5,000 to 50,000 litres per cartridge, removing pathogens down to the 0.2–0.3 micrometer (μm) range. Some also utilize activated charcoal filtering. Most filters of this kind remove most bacteria and protozoa, such as Cryptosporidium and Giardia lamblia, but not viruses except for the very largest of 0.3 μm and larger diameters, so disinfection by chemicals or ultraviolet light is still required after filtration. It is worth noting that not all bacteria are removed by 0.2 μm pump filters; for example, strands of thread-like Leptospira spp. (which can cause leptospirosis) are thin enough to pass through a 0.2 μm filter. Effective chemical additives to address shortcomings in pump filters include chlorine, chlorine dioxide, iodine, and sodium hypochlorite (bleach). There have been polymer and ceramic filters on the market that incorporated iodine post-treatment in their filter elements to kill viruses and the smaller bacteria that cannot be filtered out, but most have disappeared due to the unpleasant taste imparted to the water, as well as possible adverse health effects when iodine is ingested over protracted periods. While the filtration elements may do an excellent job of removing most bacteria and fungi contaminants from drinking water when new, the elements themselves can become colonization sites. In recent years some filters have been enhanced by bonding silver metal nanoparticles to the ceramic element and/or to the activated charcoal to suppress growth of pathogens.
Amirim, Israel. Founded in 1958 on vegetarian principles, the town features vegetarian guest houses and had a population of 865 in 2022. Cheremshanka, Altai Republic in Russia Community of the Ark, La Borie Noble, France. Founded in 1948 by Lanza del Vasto as a vegetarian, spiritual commune. Haridwar in Uttarakhand, India. In 2002 meat sales were banned in Haridwar. The ban was upheld by the Supreme Court in 2004. New Vrindaban in West Virginia, United States. Founded in 1968 by Kirtanananda Swami, New Virndaban is a vegetarian, intentional community. Palitana in Gujarat, India. In 2014, Palitana banned meat sales. Pushkar in Rajasthan, India. Pushkar is one of the world's oldest cities and a religious center. Because of its holy status and number of temples, Pushkar is a vegetarian city where the sale of meat, fish, eggs, and alcohol are all banned. Rishikesh in Uttarakhand, India. In 1956, Rishikesh banned the sale of meat, fish, and eggs. Tirumala in Andhra Pradesh, India The Farm in Tennessee, United States. Founded in 1971 by Stephen Gaskin and 300 spiritual seekers as a vegan, intentional community.
Sources: en.wikipedia.org
== Fare == Moe's offers various types of food on its menu, including burritos, tacos, quesadillas, nachos, salads, stacks, burrito bowls, and house-made seasonal salsas. Ingredients can be added or subtracted from the standard entree for customization. Every order comes with chips and salsa on the side.
The 2011 census stated that a majority of the population were Christians (71.93%); 51.48% of the total population were members of the Protestant Church in Germany, 18.34% were Catholics, 2.11% were members of other Christian denominations, 2.27% were members of other religions. 25.8% have no denomination. Even though there is a high level of official belonging to a Christian denomination, the people – especially in the cities – are highly secular in behaviour. As of 2020, the Protestant Church in Germany was the faith of 41.1% of the population. It is organised in the five Landeskirchen named Evangelical Lutheran State Church in Brunswick (comprising the former Free State of Brunswick), Evangelical Lutheran Church of Hanover (comprising the former Province of Hanover), Evangelical Lutheran Church in Oldenburg (comprising the former Free State of Oldenburg), Evangelical Lutheran Church of Schaumburg-Lippe (comprising the former Free State of Schaumburg-Lippe), and Evangelical Reformed Church (covering all the state). Together, these member churches of the Protestant Church in Germany gather a substantial part of the Protestant population in Germany. The Catholic Church was the faith of 16.3% of the population in 2020. It is organised in the three dioceses of Osnabrück (western part of the state), Münster (comprising the former Free State of Oldenburg) and Hildesheim (northern and eastern part of the state). The Catholic faith is mainly concentrated to the regions of Oldenburger Münsterland, the region of Osnabrück, the region of Hildesheim and in the Western Eichsfeld.
=== Pharmacokinetics === The elimination half-lives of clinically used orexin receptor antagonists are 12 hours for suvorexant, about 17 to 19 hours ("effective" half-life) or 55 hours (terminal elimination half-life) for lemborexant, and 6 to 10 hours for daridorexant. The elimination half-lives of investigational orexin receptor antagonists are 2 to 3 hours for seltorexant and about 1.5 to 3 hours for vornorexant. The pharmacokinetics of suvorexant are significantly affected by age, sex, and other factors, leading to increased blood concentrations in female, obese, and older patients. These factors do not significantly affect the pharmacokinetics of lemborexant or daridorexant. All three marketed orexin antagonists do not need to be dose adjusted in patients with reduced renal function, as the pharmacokinetic profiles of these medications are not significantly affected. In patients with moderate to severe hepatic impairment, dose adjustments of these medications may be necessary.
However those who drink 2–4 cups per day may be at a slightly increased risk. Caffeine increases intraocular pressure in those with glaucoma but does not appear to affect normal individuals. It may protect people from liver cirrhosis. There is no evidence that coffee stunts a child's growth. Caffeine may increase the effectiveness of some medications including ones used to treat headaches. Caffeine may lessen the severity of acute mountain sickness if taken a few hours prior to attaining a high altitude.
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.
The lyophilised solid is best kept cold, dry and dark, typically at minus twenty degrees Celsius. Moisture and repeated warming cycles are the main causes of degradation. Solutions prepared from the powder are less stable and are normally used quickly.