Melanotan II comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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 |
|---|---|---|
| Common synonyms | Melanotan II; MT-II; N-acetyl-norleucyl-cyclo[Asp-His-D-Phe-Arg-Trp-Lys] amide | Naming follows peptide convention; the numeral distinguishes it from melanotan-1 |
| Molecular formula | C50H69N15O9 | Includes the lactam bridge; no counter-ion assumed |
| Monoisotopic mass | 1023.53 Da | Free base; salts and counter-ions shift the observed value |
| Appearance | White to off-white lyophilised powder | Batch-to-batch colour variation is not itself proof of impurity |
| Typical analytical method | RP-HPLC purity determination with ESI-MS identity confirmation | Retention time alone does not establish sequence identity |
Sleep deprivation (skipping a night's sleep) has been found to improve symptoms of depression in 40–60% of patients. Partial sleep deprivation in the second half of the night may be as effective as an all night sleep deprivation session. Improvement may last for weeks, though the majority (50–80%) relapse after recovery sleep. Shifting or reduction of sleep time, light therapy, antidepressant drugs, and lithium have been found to potentially stabilize sleep deprivation treatment effects.
(For a renovation that began in 1999, the RATP, the Paris transportation authority, restored the entrances to two slightly different shades: at sites with a lot of vegetation, vert wagon ('train-car green'), the dark green used for Parisian public works at the turn of the 20th century, and at fully urban sites, a slightly bluer shade, vert allemand ('German green').) He designed standardized components, including railing cartouches incorporating the letter "M" and signs in his own distinctive lettering reading "Métropolitain" or, at narrow entrances, "Métro"; later the use of the lettering was extended to a holder for a system map and for advertising (porte-plan) with the station name above. In addition to speed (the first set of entrances were installed within six months of their design) and relatively low cost in manufacture and adaptation to different sizes and locations of entrances, all of this gave the system a stylistic identity.
In 1913 the structure of sodium chloride was determined by William Henry Bragg and his son William Lawrence Bragg. This revealed that there were six equidistant nearest neighbours for each atom, demonstrating that the constituents were not arranged in molecules or finite aggregates, but instead as a network with long-range crystalline order. Many other inorganic compounds were also found to have similar structural features. These compounds were soon described as being constituted of ions rather than neutral atoms, but proof of this hypothesis was not found until the mid-1920s, when X-ray reflection experiments (which detect the density of electrons), were performed. Principal contributors to the development of a theoretical treatment of ionic crystal structures were Max Born, Fritz Haber, Alfred Landé, Erwin Madelung, Paul Peter Ewald, and Kazimierz Fajans. Born predicted crystal energies based on the assumption of ionic constituents, which showed good correspondence to thermochemical measurements, further supporting the assumption.
Developments in Britain helped to alienate the white Rhodesian population from the former mother country, namely Queen Elizabeth II's 1966 speech to the Parliament of Jamaica where she endorsed majority rule and her attempt in 1968 to block the hanging of what Rhodesians perceived as Zimbabwean nationalist terrorists. Until late 1969, Rhodesia still recognised Queen Elizabeth II as head of state, even though it opposed the British government itself for hindering its goals of independence. However she refused to accept the title Queen of Rhodesia and eventually the Smith government abandoned their attempts to remain loyal to the British Crown. In a 1969 referendum, a majority of the electorate voted to declare Rhodesia an independent republic. The hope being that this move would facilitate recognition as an independent state by the international community, but the issue of white minority rule remained and continued to hinder this effort, and like the UDI before it, the proclamation of a republic lacked international recognition. The British public overall viewed the issue of Rhodesia and UDI as a distant and anachronistic one that they cared relatively little about and saw any expedient response to it by their government as satisfactory. Most Britons saw the end of Rhodesia's white supremacist timocracy as inevitable and justified. Although the majority Britons opposed military intervention against the renegade Rhodesian state, this opinion was not uniformly held.
==== MeSH D12.776.210.500.600 – myosins ==== MeSH D12.776.210.500.600.100 – myosin heavy chains MeSH D12.776.210.500.600.200 – myosin light chains MeSH D12.776.210.500.600.300 – myosin subfragments MeSH D12.776.210.500.600.465 – myosin type i MeSH D12.776.210.500.600.470 – myosin type ii MeSH D12.776.210.500.600.470.249 – cardiac myosins MeSH D12.776.210.500.600.470.249.249 – atrial myosins MeSH D12.776.210.500.600.470.249.500 – ventricular myosins MeSH D12.776.210.500.600.470.374 – nonmuscle myosin type iia MeSH D12.776.210.500.600.470.500 – nonmuscle myosin type iib MeSH D12.776.210.500.600.470.750 – skeletal muscle myosins MeSH D12.776.210.500.600.470.875 – smooth muscle myosins
Sources: en.wikipedia.org
5α-Reductase inhibitors (5-ARIs), also known as dihydrotestosterone (DHT) blockers, are a class of medications with antiandrogenic effects which are used primarily in the treatment of enlarged prostate and scalp hair loss. They are also sometimes used to treat excess hair growth in women and as a component of hormone therapy for transgender women. These agents inhibit the enzyme 5α-reductase, which is involved in the metabolic transformations of a variety of endogenous steroids. 5-ARIs are most known for preventing conversion of testosterone, the major androgen sex hormone, to the more potent androgen dihydrotestosterone (DHT), in certain androgen-associated disorders.
== Further reading == World Health Organization publications: Safety and nutritional adequacy of irradiated food, WHO, Geneva, 1994 High-dose irradiation: Wholesomeness of food irradiated with doses above 10 kGy, WHO, Geneva, 1999, Technical Report Series No. 890 Facts about Food Irradiation, A series of Fact Sheets from the International Consultative Group on Food Irradiation (ICGFI), 1999, IAEA, Vienna, Austria at the Wayback Machine (archived 2006-03-16) Diehl, J.F., Safety of irradiated foods, Marcel Dekker, N.Y., 1995 (2. ed.) Satin, M., Food irradiation, Technomic, Lancaster, 1996 (2. ed.) Urbain, W.M., Food irradiation, Academic Press, Orlando, 1986 Molins, R. (ed.), Food irradiation – Principles and applications, Wiley Interscience, N.Y., 2001 Sommers, C.H. and Fan, X. (eds.), Food Irradiation Research and Technology, Blackwell Publishing, Ames, IA, 2006 The Food That Would Last Forever : Understanding the Dangers of Food Irradiation, by Gary Gibbs, Garden City Park, N.Y. : Avery Pub. Group, c1993 anon., Food Irradiation: Available Research Indicates That Benefits Outweigh Risks, RCED-00-217, August 24, 2000, Government Accountability Office, United States General Accounting Office, Resources, Community, and Economic Development Division, Washington, D.C. 20548 "Food Irradiation" Farkas, József; Mohácsi-Farkas, Csilla (March 2011). "History and future of food irradiation". Trends in Food Science & Technology. 22 (2–3): 121–126. doi:10.1016/j.tifs.2010.04.002.
=== By Dyson === Freeman Dyson at The New York Review of Books (content for subscribers only) "Heretical thoughts about science & society", essay by Freeman Dyson [8.7.2007] Templeton Prize acceptance lecture 2000, by Freeman Dyson Imagined Worlds by Freeman Dyson, 1996: Chapter 1 Video Interview of Freeman Dyson discussing Bogus Climate Models on YouTube A radio interview with Freeman Dyson Archived 7 August 2020 at the Wayback Machine Aired on the Lewis Burke Frumkes Radio Show in 2009. Suzan Mazur interviewing Dyson, 2012, CounterPunch "Pushing the Boundaries – A Conversation with Freeman Dyson" Archived 17 August 2016 at the Wayback Machine, Ideas Roadshow, 2014 Freeman Dyson and Gregory Benford: Forseeing the Next 35 Years – Where Will We Be in 2054? on YouTube, Arthur C. Clarke Center for Human Imagination, February 2019. A 'Rebel' Without a Ph.D.
== Flow control == There are various ways to control the fluid flow in the channels. They include changing the channel width and length, altering the wettability of the paper, diverting some fluid through a parallel channel, or changing the viscosity of the fluid. The flow in PADs can be turned off with dissolvable sugar bridges, Corona discharge treatment to alter a coating on the paper from a hydrophobic to hydrophilic state, or the use of an expandable polymer triggered by the flow to close the flow path.
Sources: en.wikipedia.org
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.
The natural hormone is a linear tridecapeptide that is rapidly degraded in circulation. Melanotan-2 is shortened, cyclised, N-terminally acetylated, and carries a D-amino acid substitution, all of which slow enzymatic breakdown.
No national medicines regulator has approved melanotan-2 for therapeutic or cosmetic use. In several jurisdictions it is treated as an unapproved prescription medicine, and its legal classification differs from country to country.
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.