alpha-MSH 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 2026-02-04. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Melanocytes are the pigment-producing cells of the skin, and they carry melanocortin-1 receptors on their surface. When the receptor is activated, cyclic adenosine monophosphate rises inside the cell and raises the activity of enzymes such as tyrosinase, which increases melanin output. Melanotan-2 binds melanocortin-1 receptors in vitro and in animal models, and this binding is generally described as the basis for the tanning effect. Other receptors account for different effects: melanocortin-4 receptors contribute to appetite and erectile signalling, while melanocortin-3 and melanocortin-5 receptors contribute to energy balance and exocrine function.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Melanocortin receptor agonist |
| Molecular formula | C50H69N15O9 | Neutral form, mass near 1024.2 g/mol |
| Primary targets | MC1R, MC3R, MC4R, MC5R | Binding is non-selective across subtypes |
| Related compounds | Alpha-MSH, melanotan I, afamelanotide | Structurally or functionally related peptides |
| Common abbreviations | MT-II, MT-2 | Naming in the literature is not uniform |
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.
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.
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.
No regulatory authority has approved melanotan-2 for human use, and several countries classify it as a prescription-only or controlled substance, which restricts lawful supply. Material sold online is generally labelled as a research chemical and is not required to meet pharmaceutical standards of identity or purity. Published human data consist mainly of small uncontrolled studies, case reports and adverse-event notifications, so the evidence base is descriptive rather than confirmatory. Whether repeated melanocyte stimulation alters long-term naevus behaviour remains an open question that no completed trial has resolved.
RCH=CH2 + H2 → RCH2−CH3 (R = alkyl) Another route to alkanes is hydrogenolysis, which entails cleavage of C-heteroatom bonds using hydrogen. In industry, the main substrates are organonitrogen and organosulfur impurities, i.e. the heteroatoms are N and S. The specific processes are called hydrodenitrification and hydrodesulfurization:
== Medical uses == Second generation cephalosporins are more effective in treating Gram-negative bacilli compared to first generation cephalosporins, which have a greater coverage for Gram-positive cocci. Also, it has been reported that cefuroxime is resistant to hydrolysis by β-lactamases produced by Gram-negative bacteria. Some medical uses are:
This hypothesis was opposed by French palaeontologist Marcellin Boule, who authored several publications starting in 1908 describing the French Neanderthal specimen La Chapelle-aux-Saints 1 ("The Old Man") as a slouching, ape-like creature distantly related to modern man. Boule's ideas would define discussions of Neanderthals for some time. Boule suggested two different lineages existed in Ice Age Europe: a more evolved one descending from the British Piltdown Man (a hoax) to the French Grimaldi Man (a Cro-Magnon) which would culminate with modern Europeans; and a less evolved dead-end lineage leading from the German Heidelberg Man to Neanderthal Man. As the focus of human origins shifted from Europe to East Asia ("Out of Asia" hypothesis) by the 1930s and 40s with discoveries such as Java Man and Peking Man (as well as the marginalisation of Piltdown Man), the question of a "Neanderthal phase" in human evolution once again became a topic of discussion. The definition of "Neanderthal" expanded to include several anatomically variable specimens around the Old World. In the contextual debate between monogenism and polycentrism, some specimens were described as "progressive" Neanderthals which would evolve into some local subspecies of H. sapiens (polycentricism), while the "classic" Neanderthals of the Western European Würm glaciation would not. In the 1970s, with the formulation of cladistics and the consequent refinement of the anatomical definitions of species, this "global morphological pattern" fell apart.
Sources: en.wikipedia.org
By far the most widely used compound in this field is 2-cyanoacrylic acid ethyl ester, while 2-cyanoacrylic acid methyl ester and allyl cyanoacrylate are used to a lesser extent. Cyanoacrylate adhesives are also applied in medicine for wound closure as an alternative to suturing. However, short-chain alkyl esters (e.g., methyl cyanoacrylate) frequently cause adverse effects, particularly inflammation; therefore, different compounds are employed in medical applications than in technical uses. In particular, butyl cyanoacrylate and 2-octyl cyanoacrylate are predominantly used. Nitriles are used as electrolyte additives in lithium batterys. For example, the addition of 1,3,6-hexanetricarbonitrile leads to a significant performance improvement compared with a corresponding battery without such an additive. The mechanism of action of nitrile additives has not yet been fully elucidated.
=== Hemoglobin synthesis and function === PLP aids in the synthesis of hemoglobin, by serving as a coenzyme for the enzyme aminolevulinic acid synthase. It also binds to two sites on hemoglobin to enhance the oxygen binding of hemoglobin.
== Further reading == García-Colín, L.S.; Velasco, R.M.; Uribe, F.J. (August 2008). "Beyond the Navier–Stokes equations: Burnett hydrodynamics". Physics Reports. 465 (4): 149–189. Bibcode:2008PhR...465..149G. doi:10.1016/j.physrep.2008.04.010.
Sources: en.wikipedia.org
NF-kappa+B at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Sankar Ghosh (2006). Handbook of Transcription Factor NF-κB. Boca Raton: CRC. ISBN 978-0-8493-2794-0. Thomas D Gilmore. "The Rel/NF-κB Signal Transduction Pathway". Boston University. Retrieved 2007-12-02.
=== Naming conventions === The first part of an intein name is based on the scientific name of the organism in which it is found, and the second part is based on the name of the corresponding gene or extein. For example, the intein found in Thermoplasma acidophilum and associated with vacuolar ATPase subunit A (VMA) is called "Tac VMA". Normally, as in this example, just three letters suffice to specify the organism, but there are variations. For example, additional letters may be added to indicate a strain. If more than one intein is encoded in the corresponding gene, the inteins are given a numerical suffix starting from 5′ to 3′ or in order of their identification (for example, "Msm dnaB-1"). The segment of the gene that encodes the intein is usually given the same name as the intein, but to avoid confusion the name of the intein proper is usually capitalized (e.g., Pfu RIR1-1), whereas the name of the corresponding gene segment is italicized (e.g., Pfu rir1-1). A different disambiguating convention is to place a lowercase "i" after the source protein name, e.g. "Msm DnaBi1".
== Applications == Capillary electrophoresis may be used for the simultaneous determination of the ions NH4+,, Na+, K+, Mg2+ and Ca2+ in saliva. One of the main applications of CE in forensic science is the development of methods for amplification and detection of DNA fragments using polymerase chain reaction (PCR), which has led to rapid and dramatic advances in forensic DNA analysis. DNA separations are carried out using thin CE 50-mm fused silica capillaries filled with a sieving buffer. These capillaries have excellent capabilities to dissipate heat, permitting much higher electric field strengths to be used than slab gel electrophoresis. Therefore, separations in capillaries are rapid and efficient. Additionally, the capillaries can be easily refilled and changed for efficient and automated injections. Detection occurs via fluorescence through a window etched in the capillary. Both single-capillary and capillary-array instruments are available with array systems capable of running 16 or more samples simultaneously for increased throughput. A major use of CE by forensic biologists is typing of STR from biological samples to generate a profile from highly polymorphic genetic markers which differ between individuals. Other emerging uses for CE include the detection of specific mRNA fragments to help identify the biological fluid or tissue origin of a forensic sample.
=== Central bankers === In a joint public statement released the day after Powell announced the subpoenas and investigation, former Federal Reserve Chairs Alan Greenspan, Ben Bernanke, and Janet Yellen, former U.S. Secretaries of the Treasury Henry Paulson, Timothy Geithner, Robert Rubin, and Jacob Lew, economists Glenn Hubbard, Kenneth Rogoff, and Jared Bernstein with others in defense of Powell that argued that the investigation was "an unprecedented attempt to use prosecutorial attacks to undermine [the Federal Reserve's] independence", and that "This is how monetary policy is made in emerging markets with weak institutions, with highly negative consequences for inflation and the functioning of their economies more broadly". In an interview with CNBC, Yellen further condemned the investigation and stated that Trump's demands for the Federal Reserve to cut its interest rates to lower interest payments on the national debt "is the road to a banana republic." Likewise, New York Federal Reserve Bank President John C. Williams, Chicago Federal Reserve Bank President Austan Goolsbee, Minneapolis Federal Reserve Bank President Neel Kashkari, and Atlanta Federal Reserve Bank President Raphael Bostic publicly criticized the investigation as undermining the Federal Reserve's independence while speaking in defense of Powell's personal character, echoing concerns about potentially higher inflation, and asserting that the investigation is about the central bank's monetary policies rather than the cost overruns of the renovation projects.
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide and a non-selective melanocortin receptor agonist. Structurally it is modelled on alpha-melanocyte-stimulating hormone, a peptide that occurs naturally in the body.
Activation of MC1R increases pigment synthesis independently of ultraviolet exposure, which is the mechanism usually cited for darkening without sun exposure. Ultraviolet light still influences skin response through separate biological pathways.
Because the peptide binds several melanocortin receptor subtypes, its effects are not confined to pigmentation. This complicates interpretation of both intended and unintended outcomes reported in studies.
No. It is a laboratory-made peptide, while the natural hormone is alpha-melanocyte-stimulating hormone, a longer peptide produced by the pituitary gland and by skin cells. Melanotan-2 mimics only a short active region of that hormone and contains non-natural residues such as D-phenylalanine.