afamelanotide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-07-13 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-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.
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.
=== Names === Relugolix is the generic name of the drug and its INNTooltip International Nonproprietary Name, USANTooltip United States Adopted Name, and JANTooltip Japanese Accepted Name. It is also known by its former developmental code names RVT-601 and TAK-385. Relugolix is sold under the brand name Orgovyx for the treatment of prostate cancer and under the brand name Relumina for the treatment of uterine fibroids. Relugolix compounded with estradiol hemihydrate and norethindrone is sold under the brand name Myfembree for the treatment of uterine fibroids.
=== Byzantine mosaics === Raymond created 55 plates grouped together under the title Essai de reconstitution de mosaïques byzantines (Attempt to reproduce Byzantine mosaics). He portrayed the most famous mosaics of Greek, Italian and Turkish churches. He used photographs that he divided into segments and then scale reproduced down to the finest detail; a technique that would much later be known as “micro-mosaics”.
The New Union Treaty (Russian: Новый союзный договор, romanized: Novyy soyuznyy dogovor) was a 1990 draft treaty that would have replaced the 1922 Treaty on the Creation of the Union of Soviet Socialist Republics (USSR) to salvage and reform the USSR. The preparation of this treaty was known as the Novo-Ogaryovo process, named after Novo-Ogaryovo, a governmental estate where the work on the document was carried out and where Soviet President and CPSU General Secretary Mikhail Gorbachev talked with leaders of Union republics. A ceremony of the Russian SFSR signing the treaty was scheduled for 20 August 1991, but was prevented by the August Coup. In its aftermath, the Soviet Union ultimately dissolved by December of the same year, and the Commonwealth of Independent States was set up in its place.
== References == Huynh, Ngan Ngoc; Chin-Dusting, Jaye (2006). "Amino Acids, Arginase and Nitric Oxide in Vascular Health". Clinical and Experimental Pharmacology and Physiology. 33 (1–2): 1–8. doi:10.1111/j.1440-1681.2006.04316.x. PMID 16445692. S2CID 45083834. Schmitz, M; Hagemeister, H; Erbersdobler, HF (1991). "Homoarginine labeling is suitable for determination of protein absorption in miniature pigs". The Journal of Nutrition. 121 (10): 1575–80. doi:10.1093/jn/121.10.1575. PMID 1722509. Lin, C. W.; Fishman, W. H. (1972). "L-Homoarginine: an organ-specific, uncompetitive inhibitor of human liver and bone alkaline phosphohydrolases" (PDF). Journal of Biological Chemistry. 247: 3082–3087. doi:10.1016/S0021-9258(19)45215-0. Ryan, W. L.; Wells, I. C. (1964). "Homocitrulline and Homoarginine Synthesis from Lysine". Science. 144 (3622): 1122–7. Bibcode:1964Sci...144.1122R. doi:10.1126/science.144.3622.1122. PMID 14148430. S2CID 2732208. Drechsler, C.; Meinitzer, A.; Pilz, S.; Krane, V.; Tomaschitz, A.; Ritz, E.; Marz, W.; Wanner, C. (2011). "Homoarginine, heart failure, and sudden cardiac death in haemodialysis patients". European Journal of Heart Failure. 13 (8): 852–9. doi:10.1093/eurjhf/hfr056. PMC 3143829. PMID 21791541.
=== Radioisotope thermoelectric generators (RTGs) === The radioactive decay of 90Sr generates a significant amount of heat, 0.920 W/g in the form of pure strontium metal or 0.445 W/g as strontium titanate and is cheaper than the alternative 238Pu. It is used as a heat source in many Russian/Soviet radioisotope thermoelectric generators, usually in the form of strontium titanate. It was also used in the US "Sentinel" series of RTGs. Startup company Zeno Power is developing RTGs that use strontium-90 from the DOD, and is aiming to ship product by 2026.
Sources: en.wikipedia.org
Gender incongruence is marked and sustained Patient meets diagnostic criteria for gender incongruence prior to gender-affirming hormone treatment in regions where a diagnosis is necessary to access health care Patient has capacity to consent to hormone therapy treatment Other possible causes of apparent gender incongruence have been identified and excluded Mental health and physical conditions that could negatively impact the outcome of treatment have been assessed Understands the effect of gender-affirming hormone treatment on reproduction and they have explored reproductive options The WPATH standards of care distinguish between gender-affirming hormone therapy, and hormone replacement therapy, with the latter referring to the replacement of endogenous hormones after a gonadectomy to prevent cardiovascular and musculoskeletal issues.
==== Dissolution and reestablishment ==== On August 9, 2017, President Rodrigo Duterte signed Executive Order No. 38, revoking the Executive Order No. 183 signed by (former) President Benigno Aquino III on May 29 of 2015, due to the reason of the lack of funds to fully establish the NIR according to Benjamin Diokno, the Secretary of Budget and Management. Its dissolution upset the NIR regional officials and provoked strong negative reactions from the Negrenses. On June 13, 2024, Negros island together with neighboring Siquijor were grouped together under the reestablished Negros Island Region with the signing of Republic Act No. 12000 by President Bongbong Marcos.
The bowfin has a rounded, heterocercal tail that resembles a homocercal tail. This type of tail gives the body a streamlined shape, which allows the bowfin to improve its swimming ability by reducing drag. These types of tails are common in fish with gas bladders, because the bladder supplies the fish with natural buoyancy.
== Structure and action == Brilacidin, a non-peptide chemical mimic, is an aryl amide foldamer designed to replicate the amphiphilic properties of antimicrobial peptides while solving the problems encountered by peptide-based antimicrobials. Brilacidin, a broad-spectrum antibiotic, has potent Gram positive activity and Gram negative coverage, and is highly effective in treating the 'superbug' methicillin-resistant Staphylococcus aureus (MRSA). Brilacidin has low cytotoxicity against mammalian cells while selectively targeting bacteria, directly and rapidly disrupting their membranes, resulting in the bacteria's death. Due to this unique mechanism of action (mimicking the host's natural immune response, proven to be successful in fighting off infections over millions of years of evolution), bacterial antibiotic resistance is less likely to develop.
Sources: en.wikipedia.org
== Toxicity of related species == Illicium verum is not toxic. However, other related species are toxic. Japanese star anise (Illicium anisatum), a similar tree, is highly toxic and inedible; in Japan, it has instead been burned as incense. Cases of illness, including "serious neurological effects, such as seizures", reported after using star anise tea may be a result of deliberate economically motivated adulteration with this species. Japanese star anise contains the neurotoxin anisatin, which also causes severe inflammation of the kidneys (nephritis), urinary tract, and digestive organs when ingested. Swamp star anise Illicium parviflorum, a similar tree found in the southern United States, is highly toxic and should not be used for folk remedies or as a cooking ingredient.
Valve announced Steam, its digital distribution service, at the 2002 Game Developers Conference. It was launched in September 2003 and was first used to deliver patches and other updates to Valve's online games. On August 1, 2012, Valve announced revisions to the Steam Subscriber Agreement (SSA) to prohibit class action lawsuits by users against the service provider. By July 2014, there were over 3,400 games available on Steam, with over 150 million registered accounts by January 2018. Alongside these changes to the SSA, the company also declared publicly the incorporation of Valve S.a.r.l., a subsidiary based in Luxembourg. Valve set up a physical office in Kirchberg, Luxembourg. According to Valve's project manager Mike Dunkle, the location was chosen for eCommerce capabilities and infrastructure, talent acquisition, tax advantages and central geographic location – most major partners are accessible, 50% within driving distance. Valve S.a.r.l. was used to sell games to UK users to avoid paying the full 20% value-added tax (VAT). The tax loophole was expected to close on January 1, 2015. In December 2015, the French consumer group UFC Que Choisir initiated a lawsuit against Valve for several of its Steam policies that conflict or run afoul of French law. One of the reasons was for using the tax loophole. Valve S.a.r.l. ceased business on January 1, 2017, with the main company taking over EU sales again. In August 2017, Valve announced that Steam had reached over 67 million monthly and 33 million daily active users on the platform.
== Function == Many roles for DSIP have been suggested following research carried out using peptide analogues with a greater molecular stability and through measuring DSIP-like immunological (DSIP-LI) response by injecting DSIP antiserum and antibodies.
Returning American strike pilots generally assessed these carriers as more crippled than they actually were, mistaking for devastating direct hits what Japanese post-war records revealed to have actually been huge geysers caused by near misses. The battleship Haruna was also hit by two bombs, including one directly on a main battery turret. Damage was contained, and she was able to keep station because her captain promptly called to flood the turret's magazine to avoid the possibility of an explosion. Twenty American aircraft in the strike were destroyed by Japanese fighters and anti-aircraft fire that made up for a relative lack of accuracy with high volume of fire. After the protracted strike, it became clear that most of the aircraft returning to their carriers were running dangerously low on fuel, and to worsen matters, night had fallen. At 20:45, the first returning U.S. aircraft reached TF 58. Knowing his aviators would have difficulty finding their carriers, Admiral Joseph J. Clark of Hornet decided to illuminate his carrier, shining searchlights directly up into the night, despite the risk of attack from Japanese submarines and night-flying aircraft. Mitscher backed up the decision, and soon every ship in Task Force 58 was lit up, in spite of the risks involved. Picket destroyers fired starshells to help the aircraft find the task groups. Planes were given clearance to land on any available flight deck (not just their home carriers, as usual), and many did land on other carriers. Despite this, 80 of the returning aircraft were lost.
=== Stocking === Research from the late 1800s to the 1980s suggests a trend of intentional stockings of nonindigenous fish into ponds, lakes, and rivers in the United States. At that time, little was known about environmental impacts or long-term effects of new species establishment and spread as a result of "fish rescue and transfer" efforts, or the importance of nongame fish to the ecological balance of aquatic ecosystems. Introductions of bowfin to areas they were considered a nonindigenous species included various lakes, rivers, and drainages in Connecticut, Delaware, Georgia, Illinois, Iowa, Kansas, Kentucky, Maryland, Massachusetts, Minnesota, Missouri, New Jersey, New York, North Carolina, Ohio, Oklahoma, Pennsylvania, Virginia, West Virginia, and Wisconsin. Many of the introductions were intentional stockings, positively determining distribution resulting from flood transfers, or other inadvertent migrations is not possible. Bowfin are typically piscivorous, but as an introduced species, they are capable of being voracious predators that pose a threat to native fish and their prey.
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.