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 2026-01-26. Where a claim depends on a specific study, the study is described rather than over-claimed.
Melanotan-2 is frequently confused with afamelanotide, a linear analogue authorised in the European Union for erythropoietic protoporphyria. The two compounds differ in chain length, ring structure and receptor selectivity, so findings for one cannot be transferred directly to the other. Published controlled human data on melanotan-2 remain sparse, and much of what circulates online derives from small studies or unpublished reports. Questions about effect size, dose-response behaviour and long-term safety therefore remain unresolved.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone. Its sequence incorporates a lactam bridge that constrains the peptide into a ring, which increases resistance to enzymatic breakdown relative to the natural hormone. Researchers at the University of Arizona synthesised the compound in the late 1980s and early 1990s while studying pigmentation pathways. It has never received marketing approval from any national medicines regulator. In the scientific literature it is usually described as a laboratory research reagent rather than a therapeutic product.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Alpha-MSH analogue with a lactam ring |
| Molecular formula | C50H69N15O9 | Commonly cited value for the neutral peptide |
| Molecular weight | 1024.18 g/mol | Calculated for the free molecule |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility | Soluble in water, DMSO and ethanol | Dissolution in pure water is often slow |
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.
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.
Early published reports described melanotan-2 as a tanning agent without sun protection, which means darkening is not the same as protection against ultraviolet radiation. Later studies explored the peptide in erectile dysfunction, hemorrhagic shock, and some skin conditions. No regulator in the United States or Europe has approved it for clinical use. Many products labelled melanotan-2 are sold without approval and their identity and purity are unverified. Its long-term safety in humans remains an open question.
Melanotan-2, also written Melanotan II, is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone. Its sequence is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, and the lactam bridge between the aspartate and lysine side chains constrains the peptide into a ring. This structural change increases receptor affinity and metabolic stability relative to the native hormone. The compound was created in the 1980s as a research tool for studying pigmentation biology.
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.
=== Possible uses === While gliotoxin exposure at high concentrations shows cytotoxic effects via a multitude of different pathways, low-dose gliotoxin has been shown to have beneficial biological functions. Low-dose gliotoxin can exert antioxidant activities in the presence of the thioredoxin redox system that can counter the release of ROS in cells as a result of the electron transport chain (ETC) during cellular respiration. Moderate doses of gliotoxin have also been found to exhibit an anti-inflammatory effect in vivo due to the suppression of NF-κB activity by gliotoxin. Doses of gliotoxin less than 40 nM can also activate latent HIV-1 gene expression, serving as a diagnostic of HIV infection. Gliotoxin can activate HIV-1 expression by targeting (LARP7), which results in the release of active P-TEFb and the positive regulation of transcription of HIV proteins. Treatment of 20 nM gliotoxin reversed HIV-1 latency without interfering in the activation of CD4+ or CD8+ T-cells that are involved in the elimination of HIV-infected cells. While research on this possible gliotoxin use is in early stages, this provides a possible future direction for HIV diagnosis and treatment.
=== External proton gradient model === Biochemist Nick Lane has proposed the following hypothesis. Deep-sea hydrothermal vents, emitting hot acidic or alkaline water, would have created external proton gradients. These provided energy that primordial organisms could have exploited. To keep the flows separate, such an organism could have wedged itself in the rock of the hydrothermal vent, exposed to the hydrothermal flow on one side and the more alkaline water on the other. As long as the organism's membrane (or passive ion channels within it) is permeable to protons, the mechanism can function without ion pumps. Such a proto-organism could then have evolved further mechanisms such as ion pumps and ATP synthase.
Booker Brooks (George Clooney) – The original foreman at Wellman. Booker wasn't always taken seriously by the workers, but compared to their future boss, Roseanne and the others appreciate him more. He dated Jackie for a while, and they tried to keep it a secret. He set the quotas at Wellman at 5,500, much lower than the 8,000 set by their next boss Keith Faber (Fred Thompson). Vonda Green (Charlayne Woodard, credited as Charlaine Woodard)- Spirited and perky friend of Jackie and Roseanne, also has a great singing voice. Sylvia Foster (Anne Faulkner)- Older Wellman employee working there since the late 1950s, she occasionally hangs out with Jackie, Roseanne, and the rest of the gang at the Lobo. Has a husband named Joe who is hard of hearing. Juanita Herrara (Evelina Fernandez)- Hispanic co-worker who after leaving Wellman with the rest of the gang opens a successful small business in Lanford with her husband Emilio and their teenage son. Meg Wellman (Debra Mooney) – Owner of the Wellman factory, who believes she and Roseanne are good friends. Unaware she's getting their names wrong, she comically refers to Roseanne as "Roxanne Conway" and Jackie as Janet. Accidentally hits Roseanne's car with her car in one episode.
== Selected recent publications == Biggar, K.K., and Storey, K.B. Functional impact of non-coding RNA regulation in extreme stress adaptation. J. Mol. Cell. Biol. In Press. doi.org/10.1093/jmcb/mjx053 Biggar, K.K., Wang Z. and Li, S. SnapShot: Lysine methylation beyond histones. Mol. Cell 68(5):1016–1016.e1. Invited submission Singal, S.S., Nygard, K.*, Biggar, K.K.*, Shehab, M.A., S.S.C. Li, Jansson, T. and Gupta, M.B. Interaction between IGFBP-1, protein kinase CSNK-2 and mTOR in HepG2 cells as demonstrated by dual immunofluorescence and in situ PLA. Am. J. Pathol. In press, doi.org/10.1016/j.ajpath.2017.09.009 Biggar, K.K., Dawson, N.J. and Storey, K.B. Native protein denaturation using urea. Biotechniques 62(1): xiii (epub) Shehab, M.A., Biggar, K.K., Singal, S.S., Nygard, K., Li, S.S.C., Jansson, T. and Gupta, M.B. Exposure of decidualized HESC to low oxygen tension and leucine deprivation results in increased IGFBP-1 phosphorylation and reduced IGF-I bioactivity. Mol. Cell. Endo. 452:1-14 Wu, Z., Connolly, J. and Biggar, K.K. Beyond histones: The expanding roles of lysine methylation. FEBS J. 284(17): 2732-2744 Biggar, K.K. and Storey, K.B. Exploration of low temperature microRNA function in an anoxia tolerant vertebrate ectotherm, the red eared slider turtle (Trachemys scripta elegans). J. Thermal Biol. In Press Wu, C.W., Biggar, K.K., Luu, B.E., Szereszewski, K.E. and Storey, K.B. Analysis of microRNA expression during the torpor-arousal cycle of a mammalian hibernator, the 13-lined ground squirrel. Physiol. Genomics DOI: 10.1152/physiolgenomics.00005.2016
Sources: en.wikipedia.org
== Standard, ensign and coat of arms == After the personal union with the United Kingdom ended in 1837 with the accession of Queen Victoria, Hanover kept the British royal arms and standard, only introducing a new Crown, after the British model. The centre of this coat of arms and royal standard included the original arms of Hanover, which consisted of the two lions of the Brunswick, the rampant lion with hearts of Lüneburg and the horse of Hanover, surmounted by the Imperial Crown of the Holy Roman Empire for the Holy Roman office of Archbannerbearer/Archtreasurer. As Hanover was no longer ruled by the British monarchs, the arms of Hanover were simultaneously removed from the British coat of arms and royal standard, so it was no longer identical with that of the Kingdom of Hanover.
=== Fosfomycin === Several antimicrobial drugs have been tested for the effective treatment of CRE. Fosfomycin is an antimicrobial agent that acts to inhibit UDP-N-acetylglucosamine enolpyruvyl transferase (MurA) which catalyzes one of the early steps of bacterial cell wall synthesis, and is effective against gram-negative and -positive aerobic bacteria, such as CRE. A meta-analysis of 17 studies investigating the clinical effectiveness of fosfomycin in four multidrug-resistant strains of Enterobacteriaceae found 11 which reported that over 90% of bacterial isolates were susceptible to fosfomycin. The elevated level of antimicrobial activity by fosfomycin can be attributed to the fact that resistance to this antibiotic in Enterobacteriaceae is chromosomally encoded and not plasmid-mediated. This causes a decreased capacity for survival in the bacteria. Bacteria that are naturally resistant to fosfomycin are less robust and less pathogenic.
== Etymology == BmK is the abbreviation for Buthus martensi Karsch, an old name for the scorpion that is the source of BmKAEP; AEP is an abbreviation for anti-epilepsy peptide. At the NCBI Protein Database, the full name of this peptide is listed as "Toxin BmKAEP".
The adoption of -gate to suggest the existence of a scandal was promoted by William Safire, the conservative New York Times columnist and former Nixon administration speechwriter. As early as September 1974, he wrote of "Vietgate", a proposed pardon of the Watergate criminals and Vietnam War draft dodgers. Subsequently, he coined numerous -gate terms, including Billygate, Briefingate, Contragate, Deavergate, Debategate, Doublebillingsgate (of which he later said "My best [-gate coinage] was the encapsulation of a minor ... scandal as doublebillingsgate"), Frankiegate, Franklingate, Genschergate, Housegate, Iraqgate, Koreagate, Lancegate, Maggiegate, Nannygate, Raidergate, Scalpgate, Travelgate, Troopergate, and Whitewatergate. The New York magazine suggested that his aim in doing so was "rehabilitating Nixon by relentlessly tarring his successors with the same rhetorical brush – diminished guilt by association". Safire himself later said to author Eric Alterman that he "may have been seeking to minimize the relative importance of the crimes committed by his former boss with this silliness". The usage has spread into languages other than English; examples of -gate being used to refer to local political scandals have been reported from Argentina, Germany, South Korea, Hungary, Greece and the former Yugoslavia. The term is also used in Mandarin Chinese with the suffix -mén (simplified Chinese: 门; traditional Chinese: 門; lit. 'door', 'gate'). Some commentators have characterized this use of the -gate suffix as a snowclone.
Now perhaps it's a pretty well kept secret that one of the most uninspiring acts of the University of Cambridge over this past century was to turn down Francis Crick when he applied to be the Professor of Genetics, in 1958. Now there may have been a series of arguments, which led them to reject Francis. It was really saying, don't push us to the frontier. The apparently "pretty well kept secret" had already been recorded in Soraya De Chadarevian's Designs For Life: Molecular Biology After World War II, published by Cambridge University Press in 2002. His major contribution to molecular biology in Cambridge is well documented in The History of the University of Cambridge: Volume 4 (1870 to 1990), which was published by CUP in 1992. According to the University of Cambridge's genetics department official website, the electors of the professorship could not reach consensus, prompting the intervention of then University Vice-Chancellor Lord Adrian. Lord Adrian first offered the professorship to a compromise candidate, Guido Pontecorvo, who refused, and is said to have offered it then to Crick, who also refused. In 1976, Crick took a sabbatical year at the Salk Institute for Biological Studies in La Jolla, California. Crick had been a nonresident fellow of the Institute since 1960. Crick wrote, "I felt at home in Southern California." After the sabbatical, Crick left Cambridge to continue working at the Salk Institute. He was also an adjunct professor at the University of California, San Diego. He taught himself neuroanatomy and studied many other areas of neuroscience research.
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide modelled on alpha-melanocyte-stimulating hormone. A lactam bridge links two side chains, forming a ring that stabilises the molecule against proteolysis. It belongs to the broader melanocortin peptide family.
No national medicines agency has approved melanotan-2 for clinical use. Afamelanotide, a related but distinct peptide, holds a marketing authorisation in the European Union for a rare photosensitivity disorder. Melanotan-2 itself is handled as a laboratory chemical.
Its broad activity across melanocortin receptors makes it a tool for probing pigmentation, appetite and vascular signalling. Early trials recorded skin darkening and other effects that were not the original focus of the work. Those observations generated hypotheses that later studies have examined.
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.