If you have been reading about melanocortin receptor 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.
Updated 2025-09-09. Numbers and descriptions here follow the published literature rather than marketing material.
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.
The compound emerged from research programs in the 1980s that examined analogues of alpha-melanocyte-stimulating hormone for pigmentation and photoprotection. Investigators modified the native sequence to extend activity duration and potency. A related analogue, afamelanotide, was developed within the same broad line of inquiry and eventually gained approval in certain jurisdictions for a rare light-sensitivity condition. Melanotan-2 itself did not progress through the same regulatory route and has no approved therapeutic indication.
Melanocortin receptors comprise five subtypes with distinct tissue distributions and functions. Melanotan-2 is described in the literature as a non-selective agonist that engages several of these subtypes, including MC1R, MC3R, MC4R, and MC5R. MC1R is the subtype most directly linked to melanin production in skin cells. Because the compound is not subtype-selective, its observed effects in experimental settings are generally attributed to activity across multiple receptor pathways rather than to a single target.
| Property | Value | Notes |
|---|---|---|
| Compound class | Synthetic cyclic heptapeptide | Alpha-MSH analogue containing a D-phenylalanine residue |
| Molecular formula | C50H69N15O9 | Average molecular mass approximately 1024.2 g/mol |
| Appearance | White to off-white lyophilised powder | Normally supplied as a freeze-dried solid in a sealed vial |
| Solubility | Freely soluble in water and polar solvents | Dissolves readily in aqueous buffers and in alcohol-water mixtures |
| Receptor targets | MC1R, MC3R, MC4R, MC5R | Acts as a non-selective melanocortin receptor agonist |
On 25 March 2024 Shehbaz Sharif reconstituted the eight-member Council of Common Interests (CCI) as chairman after a notification was issued. The Prime Minister inducted Khawaja Asif (Defense), Amir Muqam (SAFRON), and Ishaq Dar (Foreign Affairs) into the Council. The composition of the CCI marked the first time a foreign minister had been designated a member, replacing the membership of the finance minister. Abdullah Niazi an editor at Profit claimed that Muhammad Aurangzeb's role in the Cabinet was being undermined by Ishaq Dar, further remarking that the inclusion of Khwaja Asif and Engineer Amir Muqam might indicate Shehbaz Sharif's focus on giving party loyalists greater influence. According to Mushtaq Ghumman, finance ministers were not always included in the CCI however energy and planning ministers were. In the previous Pakistan Democratic Movement (PDM) government under Shehbaz Sharif the finance minister was not included in the CCI. Attaullah Tarar on March 29 would state that “nobody has been replaced or substituted," referencing the constitutional procedure of the CCI. Summaries submitted by different ministries and provincial governments were returned for later resubmission following the re-constitution of the Council. CCI Secretary Omer Rasul stated that the summaries forwarded by ministries, divisions and provincial governments did not conform with the guidelines demarcated in Rules of Procedure of CCI (2010) and were ambiguous whether such cases fell within the purview of the CCI.
Sulfur assimilation is the process by which living organisms incorporate sulfur into their biological molecules. In plants, sulfate is absorbed by the roots and then transported to the chloroplasts by the transpiration stream where the sulfur are reduced to sulfide with the help of a series of enzymatic reactions. Furthermore, the reduced sulfur is incorporated into cysteine, an amino acid that is a precursor to many other sulfur-containing compounds. In animals, sulfur assimilation occurs primarily through the diet, as animals cannot produce sulfur-containing compounds directly. Sulfur is incorporated into amino acids such as cysteine and methionine, which are used to build proteins and other important molecules.
Alkylating agents are the oldest group of chemotherapeutics in use today. Originally derived from mustard gas used in World War I, there are now many types of alkylating agents in use. They are so named because of their ability to alkylate many molecules, including proteins, RNA and DNA. This ability to bind covalently to DNA via their alkyl group is the primary cause for their anti-cancer effects. DNA is made of two strands and the molecules may either bind twice to one strand of DNA (intrastrand crosslink) or may bind once to both strands (interstrand crosslink). If the cell tries to replicate crosslinked DNA during cell division, or tries to repair it, the DNA strands can break. This leads to a form of programmed cell death called apoptosis. Alkylating agents will work at any point in the cell cycle and thus are known as cell cycle-independent drugs. For this reason, the effect on the cell is dose dependent; the fraction of cells that die is directly proportional to the dose of drug. The subtypes of alkylating agents are the nitrogen mustards, nitrosoureas, tetrazines, aziridines, cisplatins and derivatives, and non-classical alkylating agents. Nitrogen mustards include mechlorethamine, cyclophosphamide, melphalan, chlorambucil, ifosfamide and busulfan. Nitrosoureas include N-Nitroso-N-methylurea (NMU), carmustine (BCNU), lomustine (CCNU) and semustine (MeCCNU), fotemustine and streptozotocin (STZ). Tetrazines include dacarbazine, mitozolomide and temozolomide. Aziridines include thiotepa, mitomycin and diaziquone (AZQ).
KALYANKAR GD, MEISTER A (1959). "Enzymatic synthesis of carnosine and related beta-alanyl and gamma-aminobutyryl peptides". J. Biol. Chem. 234 (12): 3210–8. doi:10.1016/S0021-9258(18)69651-6. PMID 14404206. Stenesh JJ; Winnick T (1960). "Carnosine–anserine synthetase of muscle. 4. Partial purification of the enzyme and further studies of β-alanyl peptide synthesis". Biochem. J. 77 (3): 575–581. doi:10.1042/bj0770575. PMC 1205078. PMID 16748858.
Sources: en.wikipedia.org
Because of the practical and, in particular, the financial scale of the program needed, the NCI decided to seek association with a pharmaceutical company, and in August 1989, it published a Cooperative Research and Development Agreement (CRADA) offering its current stock and supply from current bark stocks, and proprietary access to the data so far collected, to a company willing to commit to providing the funds to collect further raw material, isolate taxol, and fund a large proportion of clinical trials. In the words of Goodman and Welsh, authors of a substantial scholarly book on taxol, "The NCI was thinking, not of collaboration, ... but of a hand-over of taxol (and its problems)". Although the offer was widely advertised, only four companies responded to the CRADA, including the American firm Bristol-Myers Squibb (BMS), which was selected as the partner in December 1989. The choice of BMS later became controversial and was the subject of Congressional hearings in 1991 and 1992. While it seems clear the NCI had little choice but to seek a commercial partner, there was also controversy about the terms of the deal, eventually leading to a report by the General Accounting Office in 2003, which concluded the NIH had failed to ensure value for money. In related CRADAs with the USDA and Department of the Interior, Bristol-Myers Squibb was given exclusive first refusal on all Federal supplies of Taxus brevifolia. This exclusive contract lead to some criticism for giving BMS a "cancer monopoly".
== History == Surgery was used to treat hyperthyroidism until the advent of drug therapies in the 1940s. In 1942, thiourea was used by Edwin B. Astwood to treat a patient with the condition. He later published evidence that thiouracil was more effective and began a search for analogues with higher potency and less toxicity. In 1949 he published his work on thiamazole which showed its superiority to previous therapies. The compound had been known since 1889, and was developed as a drug by Eli Lilly and Company under the trade name Tapazole.
The new photosynthetic plants (along with their algal relatives) accelerated the rise in atmospheric oxygen started by the cyanobacteria, changing the ancient oxygen-free, reducing, atmosphere to one in which free oxygen has been abundant for more than 2 billion years. Among the important botanical questions of the 21st century are the role of plants as primary producers in the global cycling of life's basic ingredients: energy, carbon, oxygen, nitrogen and water, and ways that our plant stewardship can help address the global environmental issues of resource management, conservation, human food security, biologically invasive organisms, carbon sequestration, climate change, and sustainability.
A photograph of the deceased in good health is often sought to guide the embalmer's hand in restoring the body to a more lifelike appearance. Blemishes and discolorations (such as bruises, in which the discoloration is not in the circulatory system, and cannot be removed by arterial injection) occasioned by the last illness, the settling of blood, or the embalming process itself are also dealt with at this time (although some embalmers utilize hypodermic bleaching agents, such as phenol-based cauterants, during injection to lighten discoloration and allow easier cosmeticizing). It is also common for the embalmer to perform minor restoration of the deceased's appearance with tissue building chemicals and a hypodermic syringe. Tissue building chemicals (Tissue Builders) become solid with the introduction of liquids such as water or interstitial fluids. Commonly the area where the sphenoid and temporal bones meet; this can also be referred to the temples. In the event of trauma or natural depressions on the face or hands, tissue builder can also be utilised to return those regions of the face to the expectations of the family.
Saccharopine is an intermediate in the metabolism of amino acid lysine. It is a precursor of lysine in the alpha-aminoadipate pathway which occurs in fungi and euglenids. In mammals and seed plants saccharopine is an intermediate in the degradation of lysine, formed by condensation of lysine and alpha-ketoglutarate.
Sources: en.wikipedia.org
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.
No approved regulatory indication exists in major markets. An approval exists for a different peptide, afamelanotide, which is used for a rare photosensitivity disorder called erythropoietic protoporphyria. Melanotan-2 itself remains a research compound with no cleared clinical role.
Melanocortin-1 receptors on melanocytes are the receptor most closely linked to pigment production. The peptide is not selective, however, and also activates melanocortin-3, melanocortin-4, and melanocortin-5 receptors. That lack of selectivity is the usual explanation offered for both its range of observed effects and its off-target effects.
No. Melanotan-2 is manufactured synthetically. The naturally occurring peptide in the same family is alpha-melanocyte-stimulating hormone, which the body produces as part of normal endocrine and neural signalling.