This is a working overview of Melanotan II, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-09-01 and is reviewed periodically as new material appears.
Activity is attributed to agonism at melanocortin receptors, particularly MC1R and MC4R. Activation of MC1R on melanocytes increases melanin synthesis, which underlies the reported tanning effect. MC4R engagement in the central nervous system is linked to appetite suppression and to effects on sexual arousal reported in early clinical studies. Those studies were small and were not designed to establish efficacy or long-term safety. Receptor selectivity among the melanocortin subtypes is not absolute, which complicates attribution of any effect to a single pathway.
Regulatory treatment varies between countries. Several national medicines agencies have classified the peptide as unapproved, and customs authorities in some jurisdictions seize shipments on that basis. A few jurisdictions channel supply through prescription-only frameworks that do not list the substance by name. Because the material circulates mainly through online vendors, composition and purity are rarely verified before sale. Surveys of unapproved peptide products have reported labels that did not match measured content in a substantial fraction of samples.
Lyophilised melanotan-2 is supplied as a solid, which is more stable than a solution. The material is hygroscopic, so weighing is done quickly, in low humidity, with the container kept sealed. Reconstitution usually uses water for injection or bacteriostatic water, added down the wall of the vial to limit foaming. A reconstituted solution is held at 2 to 8 °C and kept away from light. Repeated freezing and thawing of the same vial is avoided because ice crystal formation and concentration effects degrade the peptide.
Reversed-phase high-performance liquid chromatography is the routine method for purity assessment. Peptides absorb near 214 nm because of the peptide bond, and a gradient of acetonitrile in water separates the intact peptide from deletion sequences, oxidised products, and earlier-eluting fragments at neutral pH. Electrospray ionisation mass spectrometry provides an orthogonal check: the measured mass must agree with the theoretical value. Amino acid analysis and peptide mapping confirm structure but are used less often. Reference standards remain scarce because the peptide is not described in any pharmacopoeia.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Analogue of alpha-melanocyte-stimulating hormone |
| Common synonyms | MT-II; melanotan 2 | No internationally accepted non-proprietary name |
| Typical presentation | Lyophilised powder in a sealed vial | Often supplied alongside a separate diluent |
| Regulatory status | Unapproved therapeutic substance | Customs seizure reported in several jurisdictions |
| Reported route in use | Subcutaneous injection | Self-administered outside clinical settings |
Melanotan-2 is a synthetic linear peptide built from seven amino acids arranged in a short chain. Its sequence is commonly written as Ac-Nle-Asp-His-D-Phe-Arg-Trp-Lys-NH2, which includes a modified N-terminus and an amidated C-terminus. The molecule belongs to the melanocortin family and acts as a receptor agonist. Structural features such as the D-phenylalanine residue and the Nle substitution are associated with increased stability against enzymatic degradation relative to the natural parent peptide.
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.
Lyophilized peptide powder is generally stored frozen, protected from light and moisture. Tryptophan residues are susceptible to oxidation, and the lactam bridge can hydrolyze under strongly acidic or basic conditions. Solutions prepared for laboratory work degrade faster than dry powder, and repeated freeze-thaw cycles accelerate loss. Common practice is to aliquot solutions before freezing and to avoid alkaline buffers. Reported stability windows vary with concentration, buffer, and temperature, so exact shelf lives are method-specific rather than universal.
Regulatory status differs by country, and in many places supplying the compound for human consumption is unlawful. Vendors frequently label material as intended for research use only, a designation that shifts stated purpose but does not create a legal pathway for personal use. Certificates of analysis accompanying such products vary widely in detail and provenance. Third-party testing exists but is voluntary, and results are rarely linked to a specific lot in a publicly verifiable way.
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, a naturally occurring peptide involved in pigmentation signalling. Its sequence incorporates modified residues that increase potency and extend biological activity relative to the native hormone. The compound binds receptors of the melanocortin family and is examined mainly in laboratory research. It does not occur naturally and exists only as a manufactured chemical entity produced by solid-phase synthesis.
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.
=== Surgery === The most effective treatment for obesity is bariatric surgery. The types of procedures include laparoscopic adjustable gastric banding, Roux-en-Y gastric bypass, vertical-sleeve gastrectomy, and biliopancreatic diversion. Surgery for severe obesity is associated with long-term weight loss, improvement in obesity-related conditions, and decreased overall mortality; however, improved metabolic health results from the weight loss, not the surgery. One study found a weight loss of between 14% and 25% (depending on the type of procedure performed) at 10 years, and a 29% reduction in all cause mortality when compared to standard weight loss measures. Complications occur in about 17% of cases and reoperation is needed in 7% of cases.
=== Musculoskeletal === Isotretinoin has a number of muscoloskeletal effects. Myalgia (muscular pain) and arthralgia (joint pain) are common side effects. Retinoids, such as high dose etretinate, are well known to cause bone changes, the most common type of which is hyperostotic changes (excessive bone growth), especially in growing children and adolescents. While excessive bone growth has been raised as a possible side effect of isotretinoin, a 2006 review found little evidence for this. Other problems include premature epiphyseal closure and calcification of tendons and ligaments. The bones of the spine and feet are most commonly affected. Risk factors for skeletal effects include older age, greater dosage, and longer course of treatment. Most bone changes cause no symptoms and may only be noticed using X-ray imaging.
=== Traumatic === Frictional keratosis: This typically presents as white plaques on the oral mucosa due to mechanical trauma. When the cause of frictional keratosis is removed the white patch may resolve. Hyperplastic reactive lesions or nodular swellings: These occur in the oral mucosa due to low grade inflammation or trauma. They develop where the mucosa is subjected to chronic minor irritants, mechanical or infective. They most frequently occur on the buccal mucosa (inner cheek) along the occlusal line where the teeth meet and the gingivae (the mucosa which covers the gums); reactive nodules occurring here are specifically categorised as epulides instead of polyps. Also the alveolar ridge (the gum where the teeth erupt up from, or if missing, where they used to be) and the hard palate (roof of the mouth). The most common are fibrous nodules called fibroepithelial polyps and epulides. Other hyperplastic reactive hyperplastic lesions include those associated with dentures, and papillomas. However, they are all similar in cause and nature, the overproduction of the cells of the mucosa, primarily the epithelial cells, also fibrous myxoid and low inflamed tissue due to irritation. Fibroepithelial polyps are usually pale, firm to touch, and painless but further irritation can cause abrasion and then ulceration or bleeding. They are sometimes be called fibroma, such as leaf fibroma, a fibroepithelial polyp often occurring under a denture and appears flattened.
Sources: en.wikipedia.org
=== Biomedical applications === Ethyl carbamate was originally used as an antineoplastic agent, hypnotic, sclerosing agent, adjunct to sulfonamide therapy, and topical bactericide. It was discovered to be carcinogenic in 1943 and largely ineffective at treating multiple myeloma, according to a study published in 1966. It was removed from the market in the US, UK and Canada in 1963 and was classified as a 2B carcinogen by the IARC in 1974. However, its use in Japan as a co-solvent in water for dissolving water-insoluble analgesics used for post-operation pain, at doses estimated to be at levels that are carcinogenic in mice, continued until 1975. Miller has suggested that this may have been the "largest number (millions) of humans exposed to the largest doses of a pure carcinogen that is on record" and called for studies to determine the effects on Japanese cancer rates to be performed. Ethyl carbamate continues to be used as an anaesthetic in animal experiments, with more than 100 animal studies using ethyl carbamate published each year. One advantage of using ethyl carbamate is that it has a very long duration of action, with some adult rats remaining anaesthetised 24 hours after administration of the drug. It also does not depress neuronal activity in the cortex to the same extent as isoflurane.
=== Bacterial susceptibility === Cefuroxime axetil treats infections against methicillin-, oxacillin- and penicillin-sensitive bacterial strains. Cefuroxime axetil does not work against enterococci. Gram-positive aerobic microorganisms
=== November === 1 November – Alan Bickers, civil engineer and local government officer, chief executive of Tauranga City Council (1986–1995), president of IPENZ (1991–1992), chair of Transit New Zealand (2000–2004) (born 1945). 2 November – John Walker, plant biochemist (University of Canterbury) (born 1932). 4 November – Robert Taylor, Hall of Fame musician (Dragon) and songwriter ("This Time", "Magic") (born c. 1951). (death announced on this date) 7 November Patrick Brontë, military historian (born 1970). Bruce Malcolm, rower, lawn bowls player, local politician, trade union official and sports administrator, national men's pairs bowls champion (1990), Port Chalmers Borough Councillor (1968–1977), president of New Zealand Watersiders' Union (1982–1995), president of Otago Rugby Football Union (1988), national men's bowls selector (1998–2008) (born 1935). Roger McClay, politician, MP for Taupo (1981–1984) and Waikaremoana (1984–1996), Minister of Youth Affairs (1990–1996), Commissioner for Children (1998–2003) (born 1945). Lee Tamahori, film director (Once Were Warriors, Die Another Day, Along Came a Spider) (born 1950). 8 November – Gary Williams, cricketer (Otago), table tennis player (Bermuda national team), and sports administrator, chair of Table Tennis New Zealand (2015–2018) (born 1953). 9 November Stephen Clarke, information manager and public servant, Chief Archivist (2020–2022) (born 1970). Susan Skerman, artist (born 1928).
Sources: en.wikipedia.org
No. No major regulatory agency has granted a marketing authorisation for melanotan II as a medicine. Products sold under this name are generally presented as laboratory reagents and are not subject to the batch-release testing applied to approved drugs.
It was developed in the 1980s by researchers investigating analogues of alpha-melanocyte-stimulating hormone for pigmentation and related endpoints. Early work included small human studies during the 1990s. Development did not progress to licensing, and the compound remained a research and grey-market item.
Peptides are prone to truncation, oxidation and aggregation during synthesis and handling. Without independent testing, a buyer cannot confirm the identity or the content of a vial. Analytical surveys of unapproved peptide products have repeatedly found discrepancies between label claims and measured composition.
Low temperature slows hydrolysis and oxidation, the two main routes by which the peptide backbone and side chains are modified. A lyophilised powder stored at −20 °C is more stable than one kept at room temperature, and once the material is dissolved the degradation rate rises, making refrigeration more important.