A practical reference on melanotan-2: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-01-13 and is reviewed periodically as new material appears.
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.
Receptor-binding studies classify melanotan II as a non-selective melanocortin agonist. It interacts with MC1R, MC3R, MC4R and MC5R, with reported affinities in the low nanomolar range and no strong subtype preference. Activation of MC1R on dermal melanocytes shifts pigment synthesis toward eumelanin, the dark polymer deposited in melanosomes and transferred to keratinocytes. Because the same peptide engages MC4R in the hypothalamus, it also appears in animal work on food intake and erectile response, which is why it is discussed in both pigment and metabolic research. Which receptor populations dominate after systemic exposure in humans is not fully established.
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.
Melanotan-2 is a synthetic cyclic heptapeptide designed as a structural analogue of alpha-melanocyte-stimulating hormone, the endogenous tridecapeptide that regulates pigment production. Two modifications distinguish it from the natural hormone: norleucine replaces methionine at the N-terminus, which limits oxidation, and a D-phenylalanine substitution raises receptor affinity. The ring is closed through an aspartate-lysine lactam bridge, giving the molecule a constrained conformation. The free base has a molecular mass near 1024 daltons, and commercial material is usually supplied as an acetate salt. It appears in the literature as a research peptide rather than an approved therapeutic agent.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Cyclic heptapeptide, C-terminally amidated |
| Approximate molecular mass | 1024 Da | Monoisotopic mass of the free peptide |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility class | Soluble in water and polar solvents | Also dissolves in neutral aqueous buffer |
| Common synonyms | Melanotan II, MT-II, MT-2 | Described as a melanocortin agonist in early literature |
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.
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.
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.
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.
=== PVP/PVA hydrogels for articular cartilage replacement === Poly(vinyl alcohol) (PVA) hydrogels were used in this study. It was difficult to meet the mechanical properties of articular cartilage using this hydrogel. There was no inflammatory or degenerative changes in articular cartilage or synovial membrane surround this artificial PVA cartilage. PVP hydrogels were also studied. They exhibit high hydrophilicity, biocompatibility, and complexing ability. When used as a blend of PVA/PVP hydrogel, they produced similar internal 3D structure and water content as natural articular cartilage. The best mechanical properties and friction system were blended hydrogel with 1 wt. % PVP. Due to the greater inter-chain hydrogen bonding, adding PVP to the pure PVA proved a better option. They acted exactly with a characteristic viscoelastic behavior of articular cartilage.
=== Shell collecting === The intricate color patterns of cone snails have made them one of the most popular species for shell collectors. Conus gloriamaris, also known as "Glory of the Seas", one of the most famous and sought-after seashells in past centuries, with only a few specimens in private collections. The rarity of this species' shells led to high market prices for the objects, until the habitat of this cone snail was discovered, which decreased prices dramatically.
=== Other === It was approved for treating ankylosing spondylitis, psoriatic arthritis, psoriasis, rheumatoid arthritis. Infliximab is also prescribed (out of indication) for the treatment of Behçet's disease. Infliximab is the most frequently used biological agent in treating relapsing polychondritis. Half of the patients saw benefit from this treatment, and a few other patients experienced infections that in some cases lead to death. There have been numerous case reports of the efficacy of infliximab in various inflammatory skin conditions diseases; the FDA approved infliximab for chronic severe plaque psoriasis in adults in September 2006. Infliximab has been used off-label in treating refractory sarcoidosis, where other treatments have not been effective. Infliximab has been tested in chronic obstructive pulmonary disease (COPD) but there was no evidence of benefit with the possibility of harm. Infliximab is indicated for steroid refractory checkpoint inhibitor induced colitis, at a dose of 5 to 10 mg/kg. Infliximab has been found to be a safe alternative treatment to a second dose of IVIG for Kawasaki Disease resistant to initial IVIG therapy, showing better outcomes in fever resolution and fewer severe adverse effects such as hemolytic anemia.
The first description of a comprehensive annotation system was published in 1995 by The Institute for Genomic Research, which performed the first complete sequencing and analysis of the genome of a free-living (non-symbiotic) organism, the bacterium Haemophilus influenzae. The system identifies the genes encoding all proteins, transfer RNAs, ribosomal RNAs, in order to make initial functional assignments. The GeneMark program trained to find protein-coding genes in Haemophilus influenzae is constantly changing and improving. Following the goals that the Human Genome Project left to achieve after its closure in 2003, the ENCODE project was developed by the National Human Genome Research Institute. This project is a collaborative data collection of the functional elements of the human genome that uses next-generation DNA-sequencing technologies and genomic tiling arrays, technologies able to automatically generate large amounts of data at a dramatically reduced per-base cost but with the same accuracy (base call error) and fidelity (assembly error).
== The Holocaust == On 6 March 1943, Eva and her parents were transported to the Theresienstadt Ghetto in Terezín, where her father was separated from her and her mother. In Terezín, she worked in agriculture, so she was able to go into the ghetto and managed to make contact with her father. In December 1943, she and her mother were transferred to the Auschwitz concentration camp, where she stayed until June 1944. After six months of horrible conditions at Auschwitz, Eva and her mother were unexpectedly recognized as able to work and were relocated to the Dessauer Ufer camp of the Neuengamme concentration camp in Hamburg, where she experienced better conditions. Her final transport was without her mother to Bergen-Belsen concentration camp in April 1945, which was liberated the same month.
Sources: en.wikipedia.org
During the 2026 AFL Season, Essendon parted ways with senior coach Brad Scott, despite him having a year remaining on his contract. The Club's board cited a "lack of progress" and failure to meet key performance indicators as the primary reasons for his termination. This decision followed a severe downturn in on-field performance, in which the Bombers recorded only one victory from a 24-game period, spanning the 2025 and 2026 Seasons. Following Brad Scott's departure, assistant coach Dean Solomon was appointed interim senior coach for the remainder of the season.
One theory is that because bisphosphonates are preferentially deposited in bone with high turnover, it is possible that the levels of bisphosphonate within the jaw are selectively elevated. To date, there have been no reported cases of bisphosphonate-associated complications within bones outside the craniofacial skeleton.
The aromatic acids 3-phenylpropionic acid (3PPA) and 3-(4-hydroxyphenyl)propionic acid (HPPA) are important commodities used in the chemical, pharmaceutical, and food industrial sectors. A biosynthetic route to synthetize these compounds was designed by combining the Escherichia coli phenylalanine pathway with non-native enzymes like tyrosine ammonia lyase (TAL) and the clostridial EnoR. The full pathway was assembled in Escherichia coli, which led to the production of HPPA and cinnamyl alcohol. Optimization of individual enzyme expression levels produced 3PPA and HPPA with a concentration of 367 and 225 mg/L, in this case the oxygen-sensitive EnoRs were catalytically active under the microaerophilic fermentation conditions. The 2-methylsuccinic acid (2-MSA) is used to synthetize polymers that have application as bioplastics, cosmetic solvents and coatings. A pathway for its synthesis was designed using Escherichia coli, combining native pyruvate and acetyl-CoA biosynthesis with methanogenic citramalate synthase (CimA), isopropylmalate isomerase (LeuCD), and the ER YqjM or KpnER from Klebsiella pneumoniae. The successful production of 2-MSA was achieved with a concentration of 0.96 g/L using KpnER.
Furthermore, they demanded protection for the Danish language in Schleswig (the dominant language in almost a quarter of Schleswig had changed from Danish to German since the beginning of the 19th century). A liberal constitution for Holstein was not seriously considered in Copenhagen, since it was well known that the political élite of Holstein were more conservative than Copenhagen's. Representatives of German-minded Schleswig-Holsteiners demanded that Schleswig and Holstein be unified and allowed its own constitution and that Schleswig join Holstein as a member of the German Confederation. These demands were rejected by the Danish government in 1848, and the Germans of Holstein and Southern Schleswig rebelled.
Sources: en.wikipedia.org
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.
Afamelanotide is the linear analogue [Nle4-D-Phe7]-alpha-MSH, sometimes called melanotan I, while melanotan II is cyclic and carries three further substitutions. The two are distinct molecules and are not interchangeable in analytical testing.
Binding to the four melanocortin receptor subtypes is well documented in vitro. The relative contribution of each subtype to whole-body effects in humans is far less certain.
No regulatory agency has authorised melanotan-2 as a medicine for any indication. It circulates mainly as a research chemical or through unregulated channels. As a result, identity, purity and content are not independently guaranteed.