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 2025-11-23. Where a claim depends on a specific study, the study is described rather than over-claimed.
Activity is attributed to agonism at melanocortin receptors, particularly MC1R and MC4R. Activation of MC1R on melanocytes increases melanin synthesis, which underlies the reported tanning effect. MC4R engagement in the central nervous system is linked to appetite suppression and to effects on sexual arousal reported in early clinical studies. Those studies were small and were not designed to establish efficacy or long-term safety. Receptor selectivity among the melanocortin subtypes is not absolute, which complicates attribution of any effect to a single pathway.
Regulatory treatment varies between countries. Several national medicines agencies have classified the peptide as unapproved, and customs authorities in some jurisdictions seize shipments on that basis. A few jurisdictions channel supply through prescription-only frameworks that do not list the substance by name. Because the material circulates mainly through online vendors, composition and purity are rarely verified before sale. Surveys of unapproved peptide products have reported labels that did not match measured content in a substantial fraction of samples.
Melanotan-2 is a synthetic cyclic heptapeptide designed as a structural analogue of alpha-melanocyte-stimulating hormone, the endogenous tridecapeptide that regulates pigment production. Two modifications distinguish it from the natural hormone: norleucine replaces methionine at the N-terminus, which limits oxidation, and a D-phenylalanine substitution raises receptor affinity. The ring is closed through an aspartate-lysine lactam bridge, giving the molecule a constrained conformation. The free base has a molecular mass near 1024 daltons, and commercial material is usually supplied as an acetate salt. It appears in the literature as a research peptide rather than an approved therapeutic agent.
Receptor studies place melanotan-2 among non-selective melanocortin agonists, binding MC1R, MC3R, MC4R and MC5R rather than a single subtype. Activation of MC1R on cutaneous melanocytes raises tyrosinase activity and shifts pigment synthesis toward eumelanin, which is darker and more photostable than pheomelanin. Central receptors, particularly MC4R, are associated with appetite suppression and with reported effects on sexual function. Because subtype selectivity is low, the same molecule engages pigment, metabolic and vascular pathways at once, and this breadth is a common explanation offered for the range of adverse events described in user reports.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Analogue of alpha-melanocyte-stimulating hormone |
| Common synonyms | MT-II; melanotan 2 | No internationally accepted non-proprietary name |
| Typical presentation | Lyophilised powder in a sealed vial | Often supplied alongside a separate diluent |
| Regulatory status | Unapproved therapeutic substance | Customs seizure reported in several jurisdictions |
| Reported route in use | Subcutaneous injection | Self-administered outside clinical settings |
Melanotan II is a synthetic cyclic heptapeptide that acts as an agonist at melanocortin receptors. It was designed as a structural analogue of alpha-melanocyte-stimulating hormone, the endogenous peptide involved in pigment production. The analogue carries a lactam bridge that constrains the ring and slows enzymatic breakdown relative to the native hormone. In research literature it appears under several abbreviations, and naming conventions are not fully standardized. Published descriptions usually place it within the broader melanocortin agonist family.
Receptor binding at MC1R on melanocytes raises intracellular cyclic AMP and increases expression of tyrosinase and related enzymes. The downstream result is greater synthesis of eumelanin, the dark pigment, without ultraviolet exposure acting as the trigger. The compound is not selective, however, and also engages MC3R, MC4R and MC5R, which are expressed in the central nervous system and elsewhere. That lack of selectivity is the explanation usually offered for effects reported outside pigmentation, including appetite suppression and nausea. Selectivity remains a central theme in comparative studies of related peptides.
Human data remain limited and mostly short-term. Reports describe small trials and observational accounts rather than large controlled studies, so questions about dose-response relationships and long-term effects on melanocytes stay open. Whether repeated exposure alters naevus behaviour is not settled in the published record. Researchers also note that self-administered use outside clinical settings makes actual exposure difficult to quantify. Statements about efficacy and safety should therefore be read as preliminary rather than established.
The compound was developed in the late 1980s and 1990s by academic researchers investigating photoprotection. The rationale held that stimulating melanin production might reduce ultraviolet damage to skin and lower skin cancer risk. Early work examined receptor binding, pigment response, and short-term tolerability in small studies. That program did not produce an approved drug, and formal development stalled after early-phase trials. Whether induced pigmentation confers meaningful photoprotection remains an open question.
Outside regulated medicine, melanotan II circulates through online vendors as a research chemical, often marketed for tanning. Products sold this way vary widely in purity, concentration, and labeling accuracy, and independent testing has documented discrepancies. Published reports describe both pigment effects and adverse reactions, including nausea, flushing, and darkening of existing moles. Long-term safety data are sparse, and no large controlled trial has established a risk profile. Questions about cumulative effects on melanocytes remain unresolved in the literature.
16 June – Buckingham Palace announces that Charles III has given Queen Camilla Scotland's highest honour, the Order of the Thistle. 17 June Scottish Labour's deputy leader, Jackie Baillie, becomes the first sitting MSP to receive a damehood in the 2023 Birthday Honours, while others recognised in the Honours include footballer John Greig. First Minister Humza Yousaf urges Prime Minister Rishi Sunak to ask the Indian government to release Scottish Sikh blogger Jagtar Singh Johal, who has been in prison in India since 2017. 20 June Circular Economy Minister Lorna Slater confirms that Circularity Scotland, a firm due to manage a controversial recycling scheme in Scotland, has gone into administration. Nicola Sturgeon returns to Parliament for the first time since her arrest in connection with the ongoing investigation into SNP finances. A recall petition opens in the Rutherglen and Hamilton West constituency to determine whether Margaret Ferrier will face a by-election; 10% of eligible voters must sign it to trigger the by-election. 22 June – MSPs vote 66–44 to approve the Bail and Release from Custody (Scotland) Bill, designed to reduce Scotland's prison population. 24 June – Addressing a convention in Dundee, Scotland's First Minister, Humza Yousaf, says the SNP will use the next general election as a referendum to negotiate independence with the UK government if the party wins a majority in Scotland. 25 June – The Caledonian Sleeper is formally taken back into public ownership as the Scottish Government takes over responsibility for running the overnight train service.
P-ATPases (sometime known as E1-E2 ATPases) are found in bacteria and also in eukaryotic plasma membranes and organelles. Its name is due to short time attachment of inorganic phosphate at the aspartate residues at the time of activation. Function of P-ATPase is to transport a variety of different compounds, like ions and phospholipids, across a membrane using ATP hydrolysis for energy. There are many different classes of P-ATPases, which transports a specific type of ion. P-ATPases may be composed of one or two polypeptides, and can usually take two main conformations, E1 and E2.
Another method of possible remediation for CEC is through the use of membrane bioreactors (MBRs) that act through mechanisms of sorption and biodegradation. Membrane bioreactors have shown results on being able to filter out certain solutes and chemicals from wastewater through methods of microfiltration, but due to the extremely small size of CEC, MBRs must rely on other mechanisms in order to ensure the removal of CEC. One mechanism that MBRs use to remove CEC from wastewater is sorption. Sorption of the CEC to sludge deposits in the MBR's system can allow the deposits to sit and be bombarded with water, causing the eventual biodegradation of CEC in the membrane. Sorption of a particular CEC can be even more efficient in the system if the CEC is hydrophobic, causing it to move from the wastewater to the sludge deposits more quickly.
Sources: en.wikipedia.org
=== The JGRB and the Representative Body for Guards === From 1927 to 1962, Garda members were represented for limited purposes by a Joint Garda Representative Body (JGRB); this body was criticised as dominated by senior officers and unable to secure needed changes in conditions of work. After a major and unauthorised meeting of hundreds of rank-and-file Gardaí at the Macushla Ballroom in Dublin, a chain of events led to the establishment by the then Minister for Justice, Charles Haughey, of three new representative bodies, divided by rank, including the Representative Body for Guards (RBG). The new organisation was permitted to appoint a Garda, on secondment, as its full-time general secretary, the first such appointment, in June 1962, being of Jack Marrinan. It was also permitted to form an executive committee of three, and to apply to the Garda Commissioner for permission to request a subscription from members. The three bodies could, and were required to if requested by the Garda Commissioner, form a temporary joint representative body.
In the 1880s, while studying Beggiatoa (a bacterium living in a sulfur rich environment), Sergei Winogradsky found that it oxidized hydrogen sulfide (H2S) as an energy source, forming intracellular sulfur droplets. Winogradsky referred to this form of metabolism as inorgoxidation (oxidation of inorganic compounds). Another contributor, who continued to study it was Selman Waksman. Primitive bacteria that live around deep ocean volcanic vents oxidize hydrogen sulfide for their nutrition, as discovered by Robert Ballard. Sulfur oxidizers can use as energy sources reduced sulfur compounds, including hydrogen sulfide, elemental sulfur, sulfite, thiosulfate, and various polythionates (e.g., tetrathionate). They depend on enzymes such as sulfur oxygenase and sulfite oxidase to oxidize sulfur to sulfate. Some lithotrophs can even use the energy contained in sulfur compounds to produce sugars, a process known as chemosynthesis. Some bacteria and archaea use hydrogen sulfide in place of water as the electron donor in chemosynthesis, a process similar to photosynthesis that produces sugars and uses oxygen as the electron acceptor. Sulfur-based chemosynthesis may be simplifiedly compared with photosynthesis:
In molecular biology, Proteinase K (EC 3.4.21.64, protease K, endopeptidase K, Tritirachium alkaline proteinase, Tritirachium album serine proteinase, Tritirachium album proteinase K) is a broad-spectrum serine protease. The enzyme was discovered in 1974 in extracts of the fungus Parengyodontium album (formerly Engyodontium album or Tritirachium album). Proteinase K is able to digest hair (keratin), hence, the name "Proteinase K". The predominant site of cleavage is the peptide bond adjacent to the carboxyl group of aliphatic and aromatic amino acids with blocked alpha amino groups. It is commonly used for its broad specificity. This enzyme belongs to Peptidase family S8 (subtilisin). The molecular weight of Proteinase K is 28,900 daltons (28.9 kDa).
Sources: en.wikipedia.org
== History == Benorterone was developed in the late 1950s, was first reported to possess antiandrogenic activity in 1964, and was investigated in clinical trials in the mid-to-late 1960s. It was the first known antiandrogen to be studied in humans. The drug was found to be effective in the treatment of acne, seborrhea, and hirsutism in women. In addition, unlike progestogenic antiandrogens such as cyproterone acetate, it seldom produced side effects in women and did not affect menstruation. However, in males, benorterone was not effective for acne, and produced high rates of gynecomastia (in 12 out of 13 or 92% of young men treated with 75 to 300 mg/day benorterone). Shortly following the observance of this side effect, it was withdrawn from clinical studies. Subsequently, cyproterone acetate, which has a greatly reduced risk of gynecomastia by virtue of its concomitant progestogenic and antigonadotropic actions (which results in suppression of estrogen levels), was developed instead and was introduced for medical use in 1973. In addition, spironolactone, a steroidal antimineralocorticoid that was introduced for medical use in 1959, was discovered to possess potent antiandrogenic activity in 1969, and became widely used clinically as an antiandrogen after its first use in an androgen-dependent condition in 1978.
=== Oil === One estimate for yield of oil from kernels is 250 L/ha (22 imperial gallons per acre). The oil can be used as a food supplement, as a base for cosmetics, and for hair and the skin. Seeds of Moringa can also be used in production of biofuel.
In August 2023, Pritzker vetoed legislation to lift a moratorium on nuclear power plant construction in Illinois, citing concerns over nuclear waste. But later that year, he signed into law bipartisan legislation that suspends the moratorium with relation to the deployment of new nuclear capacity through small modular reactors, defined at a maximum capacity of 300 megawatts, and establishes a regulatory structure of the construction of SMRs. In January 2026, Pritzker signed the Clean and Reliable Grid Affordability Act (CRGA), an energy reform package that lifts the moratorium on nuclear power plant construction, creates incentives for battery storage systems, and introduces "virtual power plants" aimed at harvesting wind and solar energy from homes and businesses to boost the reliability of Illinois's grids. He also signed an executive order directing state agencies to develop a plan, in coordination with local governments, research institutions, developers, and labor organizations, to deploy at least two gigawatts of new nuclear energy capacity, with construction to begin by 2033. On September 15, 2021, Pritzker signed into law the Climate and Equitable Jobs Act, which directed the Illinois Environmental Protection Agency to establish rebate and grant programs for electric vehicles and charging stations and oversee the phase-out of coal-fired power plants by 2035 and natural gas plants by 2045. It also doubled the state's annual funding for the transition to clean energy sources like solar and wind, with the aim to source 50% of its energy from renewables by 2040.
== Possible purpose of photorespiration == Lowering photorespiration may not result in increased growth rates for plants. Photorespiration may be necessary for the assimilation of nitrate from soil. Thus, a lowering in photorespiration by genetic engineering or because of increasing atmospheric carbon dioxide may not benefit plants as has been proposed. Several physiological processes may be responsible for linking photorespiration and nitrogen assimilation. Photorespiration increases availability of NADH, which is required for the conversion of nitrate to nitrite. Certain nitrite transporters also transport bicarbonate, and elevated CO2 has been shown to suppress nitrite transport into chloroplasts. However, in an agricultural setting, replacing the native photorespiration pathway with an engineered synthetic pathway to metabolize glycolate in the chloroplast resulted in a 40 percent increase in crop growth. Although photorespiration is much lower in C4 species, it is still an essential pathway – mutants without functioning 2-phosphoglycolate metabolism cannot grow in normal conditions. One mutant was shown to rapidly accumulate glycolate. Although the functions of photorespiration remain controversial, it is widely accepted that this pathway influences a wide range of processes from bioenergetics, photosystem II function, and carbon metabolism to nitrogen assimilation and respiration.
Sources: en.wikipedia.org
No. No major regulatory agency has granted a marketing authorisation for melanotan II as a medicine. Products sold under this name are generally presented as laboratory reagents and are not subject to the batch-release testing applied to approved drugs.
It was developed in the 1980s by researchers investigating analogues of alpha-melanocyte-stimulating hormone for pigmentation and related endpoints. Early work included small human studies during the 1990s. Development did not progress to licensing, and the compound remained a research and grey-market item.
Peptides are prone to truncation, oxidation and aggregation during synthesis and handling. Without independent testing, a buyer cannot confirm the identity or the content of a vial. Analytical surveys of unapproved peptide products have repeatedly found discrepancies between label claims and measured composition.
No regulatory agency has authorised melanotan-2 as a medicine for any indication. It circulates mainly as a research chemical or through unregulated channels. As a result, identity, purity and content are not independently guaranteed.