The short version of melanotan-2 fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-02-20 and is reviewed periodically as new material appears.
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.
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.
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.
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 |
|---|---|---|
| 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 |
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.
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.
These plaques are the main causes of heart attacks, strokes, and other serious medical problems, leading to the association of so-called LDL cholesterol (actually a lipoprotein) with the term "bad" cholesterol. HDL particles are thought to transport cholesterol back to the liver, either for excretion or for other tissues that synthesize hormones, in a process known as reverse cholesterol transport (RCT). Large numbers of HDL particles correlates with better health outcomes, whereas low numbers of HDL particles is associated with atheromatous disease progression in the arteries.
In September 2025, facing threats from Trump to deploy the National Guard in Baltimore, Moore and Baltimore mayor Brandon Scott announced plans to increase partnership between the Baltimore Police Department, Maryland State Police, and Maryland Transportation Authority Police in high-risk areas of the city. In October 2025, Moore signed onto an amicus brief supporting a legal challenge against Trump's deployment of the National Guard for civil law enforcement in various U.S. cities.
UPMC Eye & Ear Institute is located in the Oakland neighborhood of Pittsburgh and is conjoined with the medical complex housing UPMC Presbyterian, UPMC Montefiore, the University of Pittsburgh School of Medicine, and associated medical research towers. UPMC Ear & Eye Institute is one of a few centers in the nation dedicated entirely to the management of problems related to otolaryngology and ophthalmology.
Livestock are not usually given opioids due to a stand down period where an animal cannot be used for milking or slaughter following administration and strict regulations that require precise record keeping on administration of opioids.
== Structure and reactivity == κ-Bungarotoxin has a single polypeptide chain consisting of 66 amino acids. The overall weight of this chain is 7313 DA. Two single polypeptide chains can arrange together into a dimer. The subunit of the dimer consists of three main chain loops. These loops have a rotation of 178.6 degrees. Overall, κ-bungarotoxin has ten beta strands. This forms a six stranded antiparallel beta sheet configuration[8]. This is formed by three out of the five beta strands of each subunit of the dimer. Arg 34 is at the top of the central loop for each subunit. The outer strand of loop III is involved in an antiparallel arrangement. The κ-bungarotoxin dimer can make disulfide bonds, hydrogen bonds and van der Waals connections.
Sources: en.wikipedia.org
== Preparation == Home drying of vegetables, fruit and meat can be carried out with electrical dehydrators (household appliances) or by sun-drying or by wind. Preservatives such as potassium metabisulfite, BHA, or BHT may be used, but are not required. However, dried products without these preservatives may require refrigeration or freezing to ensure safe storage for a long time. Industrial food dehydration is often accomplished by freeze-drying. In this case, food is flash frozen and put into a reduced-pressure system which causes the water to sublimate directly from the solid to the gaseous phase. Although freeze-drying is more expensive than traditional dehydration techniques, it also mitigates the change in flavor, texture, and nutritional value. In addition, another widely used industrial method of drying of food is convective hot air drying. Industrial hot air dryers are simple and easy to design, construct and maintain. More so, it is very affordable and has been reported to retain most of the nutritional properties of food if dried using appropriate drying conditions. Hurdle technology is the combination of multiple food preservation methods. Hurdle technology uses low doses of multiple food preservation techniques in order to ensure food is not only safe but is desirable visually and texturally.
=== First endosymbiosis === Eukaryotic algae are polyphyletic thus their origin cannot be traced back to a single hypothetical common ancestor. It is thought that they came into existence when photosynthetic coccoid cyanobacteria got phagocytized by a unicellular heterotrophic eukaryote (a protist), giving rise to double-membranous primary plastids. Such symbiogenic events (primary symbiogenesis) are believed to have occurred more than 1.5 billion years ago during the Calymmian period, early in Boring Billion, but it is difficult to track the key events because of so much time gap. Primary symbiogenesis gave rise to three divisions of archaeplastids, namely the Viridiplantae (green algae and later plants), Rhodophyta (red algae) and Glaucophyta ("grey algae"), whose plastids further spread into other protist lineages through eukaryote-eukaryote predation, engulfments and subsequent endosymbioses (secondary and tertiary symbiogenesis). This process of serial cell "capture" and "enslavement" explains the diversity of photosynthetic eukaryotes. The oldest undisputed fossil evidence of eukaryotic algae is Bangiomorpha pubescens, a red alga found in rocks around 1047 million years old.
Afamelanotide (brand name Scenesse) has been approved for the treatment of erythropoietic protoporphyria in Europe and is also being investigated as a method of photoprotection in the treatment of polymorphous light eruption, actinic keratosis and squamous cell carcinoma (a form of skin cancer). An additional analogue called melanotan II causes enhanced libido and erections in most male test subjects and arousal with corresponding genital involvement in most female test subjects. Bremelanotide (formerly PT-141) which stemmed from melanotan II research is currently under development for its aphrodisiac effects. These effects are mediated by actions in the hypothalamus on neurons that express MC3 and MC4 receptors.
== Characterization == Solution precipitation as a core synthesis technique produces homogenous-sized nanoparticles, which can be advantageous in controlling specific physical properties such as surface tension and packing density of the atoms in a crystalline lattice structure. The most common methods of characterizing nanoparticle size distribution and morphology of the core in aquasomes include scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In a study by Kommimeni et al. in 2012, researchers employed TEM to verify that the ceramic particles were spherical and also in the acceptable nano-range for aquasomes. The carbohydrate coating size can also be characterized using SEM and TEM, but Fourier-transform infrared spectroscopy (FTIR) is commonly utilized to check for the presence of the coat. In a study by Kommimeni et al. in 2020, FTIR was used to confirm the presence of the coating by analyzing the IR spectra bands that correspond to the functional groups of either the core or the sugar coat. The bioactive drug loaded onto the aquasome can be characterized in a variety of ways depending on the molecular classification of the drug. In Kossovsky et al. in 1996, which studied the effect of insulin as the bioactive drug of interest, immunogold labeling was employed. Through this technique, the different binding efficiencies of carbohydrate coatings for insulin were able to be observed.
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 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.