This is a working overview of melanotan-2, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-06-29. Anything still debated is marked as such rather than presented as settled.
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.
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.
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 |
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==== On-farm efficiency ==== On-farm, precision agriculture technologies can minimize inputs required for a given yield. For example, variable-rate application (VRA) technologies can apply precise amounts of water, fertilizer, pesticide, herbicide, etc. A number of empirical studies find that VRA improves input use efficiency. Using VRA alongside geo-spatial mapping, farmers can apply inputs to hyper-localized regions of their farm, sometimes down to the individual plant level. Reducing input use lowers costs and lessens negative environmental impacts. Furthermore, empirical evidence indicates precision agriculture technologies can increase yields. On U.S. peanut farms, guidance systems are associated with a 9% increase in yield, and soil maps are associated with a 13% increase in yield. One study in Argentina found that a precision agriculture approach based on crop physiological principles could result in 54% higher farm output. Digital agriculture can improve the allocative efficiency of physical capital within and between farms. Often touted as "Uber for tractors," equipment-sharing platforms like Hello Tractor, WeFarmUp, MachineryLink Solutions, TroTro Tractor, and Tringo facilitate farmer rental of expensive machinery, an on-demand model with parallels to Public transport. These platforms are an example of agricultural Fleet management, often coordinated with Fleet management software. By facilitating a market for equipment sharing, telematics technology ensures fewer tractors sit idle and allows owners to make extra income.
=== Unfolding and translocation === After a protein has been ubiquitinated, it is recognized by the 19S regulatory particle in an ATP-dependent binding step. The substrate protein must then enter the interior of the 20S subunit to come in contact with the proteolytic active sites. Because the 20S particle's central channel is narrow and gated by the N-terminal tails of the α ring subunits, the substrates must be at least partially unfolded before they enter the core. The passage of the unfolded substrate into the core is called translocation and necessarily occurs after deubiquitination. For an idealized substrate, translocation drives deubiquitination. However, the order in which substrates are deubiquitinated and unfolded is not yet clear. Which of these processes is the rate-limiting step in the overall proteolysis reaction depends on the specific substrate; for some proteins, the unfolding process is rate-limiting, while deubiquitination is the slowest step for other proteins. The extent to which substrates must be unfolded before translocation is suggested to be around 20 amino acid residues by the atomic structure of the substrate-engaged 26S proteasome in the deubiquitylation-compatible state, but substantial tertiary structure, and in particular nonlocal interactions such as disulfide bonds, are sufficient to inhibit degradation. The presence of intrinsically disordered protein segments of sufficient size, either at the protein terminus or internally, has also been proposed to facilitate efficient initiation of degradation.
Hyperosmolar hyperglycemic state (HHS), also known as hyperosmolar non-ketotic state (HONK), is a complication of diabetes mellitus in which high blood sugar results in high osmolarity without significant ketoacidosis. Symptoms include signs of dehydration, weakness, leg cramps, vision problems, and an altered level of consciousness. Onset is typically over days to weeks. Complications may include seizures, disseminated intravascular coagulopathy, mesenteric artery occlusion, or rhabdomyolysis. The main risk factor is a history of diabetes mellitus type 2. Occasionally it may occur in those without a prior history of diabetes or those with diabetes mellitus type 1. Triggers include infections, stroke, trauma, certain medications, and heart attacks. Diagnosis is based on blood tests finding a blood sugar greater than 30 mmol/L (600 mg/dL), osmolarity greater than 320 mOsm/kg, and a pH above 7.3. Initial treatment generally consists of intravenous fluids to manage dehydration, intravenous insulin in those with significant ketones, low molecular weight heparin to decrease the risk of blood clotting, and antibiotics among those in whom there are concerns of infection. The goal is a slow decline in blood sugar levels. Potassium replacement is often required as the metabolic problems are corrected. Efforts to prevent diabetic foot ulcers are also important. It typically takes a few days for the person to return to baseline. While the exact frequency of the condition is unknown, it is relatively common. Older people are most commonly affected.
Sources: en.wikipedia.org
) of the wildtype virus to be between 2.39 and 3.44. This means each infection from the virus is expected to result in 2.39 to 3.44 new infections when no members of the community are immune and no preventive measures are taken. The reproduction number may be higher in densely populated conditions such as those found on cruise ships. Human behaviour affects the R0 value and hence estimates of R0 differ between different countries, cultures, and social norms. For instance, one study found relatively low R0 (~3.5) in Sweden, Belgium and the Netherlands, while Spain and the US had significantly higher R0 values (5.9 to 6.4, respectively). The R0 values for later variants were significantly higher, with the Omicron lineage exhibiting the highest R0 by far. The Omicron BA.1 variant had an estimated R0 of around ~9.5, while the Omicron BA.4 and BA.5 subvariants and later lineages were estimated by some studies to have an R0 reaching or even exceeding 20, which would give them an R0 exceeding that of the Measles virus.
Presence of AIDS with low pretreatment CD4 count, typically <100 cells/microL. An exception is in the setting of Mycobacterium tuberculosis infection, which can be reactivated with CD4 cells >200 cells/microL. Decrease in HIV-1 RNA levels from baseline or increase in CD4 count after starting ART No evidence of drug-resistant infection, bacterial superinfection, adverse drug reaction, patient non-adherence, or reduced serum drug levels (from drug-drug interactions or malabsorption). Clinical symptoms consistent with an inflammatory condition Temporal association between initiation of ART and symptom onset The differential diagnosis of IRIS is broad given its varied presentation. Conditions that can present similarly to IRIS are: adverse drug effects, progression of initial OI caused by medication resistance or patient non-adherence, and development of a new OI.
=== Carlton Football Club === In 2018, Stanton joined the Carlton Football Club in an assistant coaching role as a development coach. He also plays for the Banyule Bears in the Northern Football League who were eliminated in their preliminary final after they were beaten by the Lower Plenty Jabba's. In August 2021, at the end of the 2021 season, Stanton was sacked by Carlton as an assistant coach, due to a clean-out at the club, after an extensive review of the club's football operations.
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=== Catheterization === Right heart catheterization is the test used to test for elevated diastolic ventricular pressures. This test is more invasive and would be performed after inconclusive endomyocardial biopsy samples.
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.