Everything below concerns alpha-MSH analogue. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-04-09. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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 |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Analog of alpha-melanocyte-stimulating hormone |
| Primary receptor family | Melanocortin receptors MC1R through MC5R | Binding is not subtype-selective |
| Development period | 1980s | Synthesized during pigmentation and appetite research |
| Regulatory status | Not an approved medicine | No major regulator has authorized human use |
| Related compound | Afamelanotide | Linear analog studied for photoprotection |
The peptide was developed during the 1980s by researchers investigating melanocortin signalling and skin pigmentation pathways. Early work focused on analogues of alpha-melanocyte-stimulating hormone that would resist enzymatic breakdown more effectively than the parent molecule. Melanotan-2 emerged from that programme as a shortened, cyclised variant. Reports describing its synthesis and receptor activity later appeared in the scientific literature. Commercial availability grew through unregulated channels rather than through pharmaceutical approval.
Structurally, Melanotan-2 retains the core recognition motif of alpha-melanocyte-stimulating hormone while adding a lactam bridge that links two side chains and constrains the molecule into a ring. This modification lowers susceptibility to enzymatic degradation. The compound acts as an agonist at melanocortin receptors, particularly subtypes associated with melanin production. Because the same receptor family influences several physiological processes, researchers note that its activity is not confined to pigmentation alone. Receptor selectivity continues to be examined in published studies.
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.
hydrophobic Sometimes used interchangeably with lipophilic. Having a low solubility in or affinity for water or other polar solvents; describing a non-polar molecule, or a moiety or functional group within a molecule, which cannot form energetically favorable interactions with polar compounds and which therefore tends to "avoid" or be repulsed by such compounds, instead clustering together with other hydrophobic molecules or arranging itself in a way that minimizes its exposure to its polar surroundings. This phenomenon is not so much due to the affinity of the hydrophobic molecules for each other as it is a consequence of the strong intermolecular forces that allow polar compounds such as water molecules to bond with each other; hydrophobic species are unable to form alternative bonds of equivalent strength with the polar compounds, hence they tend to be excluded from aqueous solutions by the tendency of the polar solvent to maximize interactions with itself. Hydrophobicity is a major determinant of countless chemical interactions in biological systems, including the spatial conformations assumed by macromolecules such as proteins and lipids, the binding of ligands and substrates to proteins, and the structure and properties of lipid membranes. Contrast hydrophilic.
== Effectiveness == Drug companies nearly universally believe the ODA to be a success. Before Congress enacted the ODA in 1983 only 38 drugs were approved in the USA specifically to treat orphan diseases. In the US, from January 1983 to June 2004, a total of 1,129 different orphan drug designations have been granted by the Office of Orphan Products Development (OOPD) and 249 orphan drugs have received marketing authorization. In contrast, the decade prior to 1983 saw fewer than ten such products come to market. From the passage of the ODA in 1983 until May 2010, the FDA approved 353 orphan drugs and granted orphan designations to 2,116 compounds. As of 2010, 200 of the roughly 7,000 officially designated orphan diseases have become treatable. In 2010, drugmaker Pfizer established a division to focus specifically on the development of orphan drugs as other large pharmaceutical companies focused greater efforts on the orphan drug research. Some critics have questioned whether orphan drug legislation was the real cause of this increase (claiming that many of the new drugs were for disorders that were already being researched anyway, and would have had drugs developed regardless of the legislation), and whether the ODA has really stimulated the production of truly non-profitable drugs; the act also received some criticism for allowing some pharmaceutical companies to make a large profit off of drugs that have a small market but still sell for a high price.
=== Muscle repair === Stem cells have successfully been used to ameliorate healing in the heart after myocardial infarction in dogs. Adipose and bone marrow derived stem cells were removed and induced to a cardiac cell fate before being injected into the heart. The heart was found to have improved contractility and a reduction in the damaged area four weeks after the stem cells were applied. In 2007, a trial was underway for a patch made of a porous substance onto which the stem cells are "seeded" in order to induce tissue regeneration in heart defects. Tissue was regenerated and the patch was well incorporated into the heart tissue. This is thought to be due, in part, to improved angiogenesis and reduction of inflammation. Although cardiomyocytes were produced from the mesenchymal stem cells, they did not appear to be contractile. Other treatments that induced a cardiac fate in the cells before transplanting had greater success at creating contractile heart tissue. 2018 research, such as the European nTRACK research project, aims to demonstrate that multimodal nanoparticles can structurally and functionally track stem cell in muscle regeneration therapy. The idea is to label stem cells with gold nano-particles that are fully characterised for uptake, functionality, and safety. The labelled stem cells will be injected into an injured muscle and tracked using imaging systems. However, the system still needs to be demonstrated at lab scale.
=== Prevention === Prevention relies on a farm to plate approach involving the whole supply chain anchored in risk analysis and good hygiene practices. Internationally, the Codex Alimentarius General Principles of Food Hygiene provide the foundation for national food safety systems and industry controls. These guidelines are then implemented through various prerequisite programs and HACCP (Hazard Analysis and Critical Control Point) which identify, monitor, and control hazards at specific steps in production. For consumers and food service businesses, evidence-based guidance involves four key steps: Clean, Separate, Cook, Chill. These techniques reduce cross-contamination and ensure lethal heat treatment and rapid refrigeration. Since supply chains are complex, it is critical to prioritize monitoring high-risk foods, such as minimally processed fresh produce, and modifying controls such as, agricultural water safety, manure management, worker hygiene, and post-harvest sanitation. Overall, strengthening surveillance and rapid information-sharing through a One Health lens by linking human, animal, and environmental data, improves outbreak detection and targeted interventions. This is a priority of the WHO Global Strategy for Food Safety 2022–2030.
60th Academy Awards: Best Supporting Actor, nomination, for Street Smart (1987) 62nd Academy Awards: Best Actor, nomination, for Driving Miss Daisy (1989) 67th Academy Awards: Best Actor, nomination, for The Shawshank Redemption (1994) 77th Academy Awards: Best Supporting Actor, win, for Million Dollar Baby (2004) 82nd Academy Awards: Best Actor, nomination, for Invictus (2009) Freeman has been nominated for five Golden Globe Awards, winning one for Best Actor in Driving Miss Daisy (1989). He has also been nominated for three Screen Actors Guild Awards, winning one for Outstanding Performance by a Male Actor in a Supporting Role in Million Dollar Baby (2004). He earned an Obie Award for each theater role in Coriolanus (1979), Mother Courage and Her Children (1980), and Driving Miss Daisy (1987–90).
Sources: en.wikipedia.org
The emu has a prominent place in Australian Aboriginal mythology, including a creation myth of the Yuwaalaraay and other groups in New South Wales who say that the sun was made by throwing an emu's egg into the sky; the bird features in numerous aetiological stories told across a number of Aboriginal groups. One story from Western Australia holds that a man once annoyed a small bird, who responded by throwing a boomerang, severing the arms of the man and transforming him into a flightless emu. The Kurdaitcha man of Central Australia is said to wear sandals made of emu feathers to mask his footprints. Many Aboriginal language groups throughout Australia have a tradition that the dark dust lanes in the Milky Way represent a giant emu in the sky. Several of the Sydney rock engravings depict emus, and the birds are mimicked in Indigenous dances. Hunting emus, known as kari in the Kaurna language, features in the major Dreaming story of the Kaurna people of the Adelaide region about the ancestor hero Tjilbruke. The emu is popularly but unofficially considered as a faunal emblem – the national bird of Australia. It appears as a shield bearer on the Coat of arms of Australia with the red kangaroo, and as a part of the Arms also appears on the Australian 50-cent coin. It has featured on numerous Australian postage stamps, including a pre-federation New South Wales 100th Anniversary issue from 1888, which featured a 2 pence blue emu stamp, a 36-cent stamp released in 1986, and a $1.35 stamp released in 1994.
==== Various conditions ==== More recently, ALDH2 has been implicated in a number of pathways beyond alcohol metabolism. ALDH2 dysfunction is supposedly associated with a variety of human diseases including diabetes, neurodegenerative diseases, cardiovascular diseases and stroke, cancer, Fanconi anemia, pain, osteoporosis, and the process of aging. The inactivating ALDH2 rs671 polymorphism, present in up to 8% of the global population and in up to 50% of the East Asian population, is associated with increased risk of cardiovascular conditions such as coronary artery disease, alcohol-induced cardiac dysfunction, pulmonary arterial hypertension, heart failure and drug-induced cardiotoxicity.
==== Humans ==== Gene therapy uses genetically modified viruses to deliver genes which can cure disease in humans. Although gene therapy is still relatively new, it has had some successes. It has been used to treat genetic disorders such as severe combined immunodeficiency, and Leber's congenital amaurosis. Treatments are also being developed for a range of other currently incurable diseases, such as cystic fibrosis, sickle cell anemia, Parkinson's disease, cancer, diabetes, heart disease and muscular dystrophy. These treatments only effect somatic cells, meaning any changes would not be inheritable. Germline gene therapy results in any change being inheritable, which has raised concerns within the scientific community. In 2015, CRISPR was used to edit the DNA of non-viable human embryos. In November 2018, He Jiankui announced that he had edited the genomes of two human embryos, in an attempt to disable the CCR5 gene, which codes for a receptor that HIV uses to enter cells. He said that twin girls, Lulu and Nana, had been born a few weeks earlier and that they carried functional copies of CCR5 along with disabled CCR5 (mosaicism) and were still vulnerable to HIV. The work was widely condemned as unethical, dangerous, and premature.
== Further developments == Given the widespread usage of the AIDA diabetes simulation software, there has been considerable interest worldwide in updates to the program. Work has been reported in the scientific literature into the incorporation of lispro (Humalog)-like rapidly acting insulin analogues, and the glargine (Lantus) very long-acting insulin analogue, into the freeware diabetes simulator. Further information can be found in the medical / scientific literature. A beta release of AIDA [v4.5c (beta)] incorporating lispro, regular, NPH and glargine insulins is available for download from the AIDA website. AIDA v4.5c (beta) is still undergoing testing / further development but has been available without charge from the AIDA website since 2012.
Sources: en.wikipedia.org
Like perlite, vermiculite is a mineral that has been superheated until it has expanded into light pebbles. Vermiculite holds more water than perlite and has a natural "wicking" property that can draw water and nutrients in a passive hydroponic system. If too much water and not enough air surrounds the plants roots, it is possible to gradually lower the medium's water-retention capability by mixing in increasing quantities of perlite.
Polymeric drug delivery systems have overcome challenges due to their biodegradability, biocompatibility, and anti-toxicity. Materials such as collagen, chitosan, cellulose, and poly (lactic-co-glycolic acid) have been implemented extensively for drug delivery to organs such as eye, nose, kidneys, lungs, intestines, skin and brain. Future work is focused on reducing toxicity, improving biocompatibility, expanding assembly techniques Hydrogels have been considered as vehicles for drug delivery. They can also be made to mimic animal mucosal tissues to be used for testing mucoadhesive properties. They have been examined for use as reservoirs in topical drug delivery; particularly ionic drugs, delivered by iontophoresis. Biomimetic physical barrier that separates T cells from tumors, potentially allowing them to regain strength before resuming immunotherapy.
== Clinical significance == Progression of epithelial cancer often relies on deep and regional lymph node invasion. The lamina propria, being one of the barriers to the submucosa, is an area where epithelial cancer invasion is of significance since lymphatic invasion is an independent predictor of lymph node metastasis, especially in gastric cancer. As soon as the tumors breach the basement membrane and reach the lamina propria, they are exposed to lymphatics which may increase the rate of metastasis and cancer progression. Deeper invasion into the submucosa will increase the exposure to lymphatics. Long-standing inflammation is a risk factor for the development of cancer. The lamina propria macrophages when under much stress release pro-inflammatory signals that may lead to increased probability of developing cancer. An example of this is the overactivation of the IL-6/STAT3 pathway, which has been linked to colitis-associated cancer.
Sources: en.wikipedia.org
No regulator in a major market has approved it for human use. It appears in research settings and in products marketed outside pharmacy channels. Legal status for personal possession varies by country.
Afamelanotide is a linear analog that has received approval in some jurisdictions for a specific photoprotection indication. Melanotan II is cyclic and less selective across melanocortin receptors. The two are related but are not interchangeable in regulatory or clinical terms.
A compound that activates several receptor subtypes may produce effects beyond pigmentation. Selectivity influences which tissues respond and shapes the side-effect profile described in reports. Designing subtype-selective analogs is a stated goal of melanocortin research.
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.