The short version of alpha-MSH fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-12-03 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.
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.
| 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.
Outside regulated medicine, melanotan II circulates through online vendors as a research chemical, often marketed for tanning. Products sold this way vary widely in purity, concentration, and labeling accuracy, and independent testing has documented discrepancies. Published reports describe both pigment effects and adverse reactions, including nausea, flushing, and darkening of existing moles. Long-term safety data are sparse, and no large controlled trial has established a risk profile. Questions about cumulative effects on melanocytes remain unresolved in the literature.
Melanotan II is a synthetic peptide analog modeled on alpha-melanocyte-stimulating hormone, a naturally occurring signaling peptide involved in pigmentation. Its structure is a cyclic heptapeptide containing two non-natural substitutions, norleucine at position four and D-phenylalanine at position seven. These modifications resist enzymatic breakdown and extend the molecule's activity relative to the native hormone. The compound binds melanocortin receptors and is studied mainly as a pharmacological tool rather than a therapeutic product. It has never received approval as a medicine in any major jurisdiction.
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.
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.
=== Decline === By 1987, the label began to see its commercial fortunes decline. Contributing to the decline were A&R problems with Shalamar, primarily, maintaining the group's identity and momentum as former members Hewett and Watley had departed and were having successful solo careers on other labels. The shifting musical directions of R&B, dance and popular music in general in the late 1980s and early 1990s also contributed to their decline.
This allows other ants to detect what task group (e.g., foraging or nest maintenance) other colony members belong to. In ant species with queen castes, when the dominant queen stops producing a specific pheromone, workers begin to raise new queens in the colony. Some ants produce sounds by stridulation, using the gaster segments and their mandibles. Sounds may be used to communicate with colony members or with other species.
Religious affiliation in West Germany decreased from the 1960s onward. Religious affiliation declined faster among Protestants than among Catholics, causing the Roman Catholic Church to overtake the EKD as the largest denomination in the country during the 1970s.
=== Middle Eastern culture === The scorpion is a culturally significant animal, appearing as a motif in art, especially in Islamic art in the Middle East. A scorpion motif is often woven into Turkish kilim flat-weave carpets, for protection from their sting. The scorpion is perceived both as an embodiment of evil and a protective force such as a dervish's powers to combat evil. In another context, the scorpion portrays human sexuality. Scorpions are used in folk medicine in South Asia, especially in antidotes for scorpion stings. One of the earliest occurrences of the scorpion in culture is its inclusion, as Scorpio, in the 12 signs of the Zodiac by Babylonian astronomers during the Chaldean period. In ancient Egypt, the goddess Serket was often depicted as a scorpion, one of several goddesses who protected the Pharaoh. Alongside serpents, scorpions are used to symbolize evil in the New Testament. In Luke 10:19 it is written, "Behold, I give unto you power to tread on serpents and scorpions, and over all the power of the enemy: and nothing shall by any means hurt you." Here, scorpions and serpents symbolize evil. Revelation 9:3 speaks of "the power of the scorpions of the earth."
== Other related disorders == When sIBM was originally described, the major feature noted was muscle inflammation. Two other disorders were also known to display muscle inflammation, and sIBM was classified along with them. They are dermatomyositis (DM) and polymyositis (PM) and all three illnesses were called idiopathic (of unknown origin) myositis or inflammatory myopathies. It appears that sIBM and polymyositis share some features, especially the initial sequence of immune system activation, however, polymyositis comes on over weeks or months, does not display the subsequent muscle degeneration and protein abnormalities as seen in IBM, and as well, polymyositis tends to respond well to treatments, IBM does not. IBM is often confused with (misdiagnosed as) polymyositis. Polymyositis that does not respond to treatment is likely IBM. Dermatomyositis shares a number of similar physical symptoms and histopathological traits as polymyositis, but exhibits a skin rash not seen in polymyositis or sIBM. It may have different root causes unrelated to either polymyositis or sIBM. Mutations in valosin-containing protein (VCP) cause multisystem proteinopathy (MSP), which can present (among others) as a rare form of inclusion body myopathy.
Sources: en.wikipedia.org
The mistreatment of Arias' supporters sparked public outrage, and led to Noriega being suspended for ten days, an item of information that was picked up by the U.S. intelligence services. In 1966, Noriega was again involved in a violent incident, allegedly raping a 13-year-old girl and beating her brother. After this, Torrijos transferred Noriega to a remote posting.
=== Initial concerns and industry response === In 1997, in response to mounting concern over the serious side effects of ephedra, the FDA proposed a ban on products containing 8 mg or more of ephedrine alkaloids and stricter labeling of low-dose ephedra supplements. The FDA also proposed that ephedra labels be required to disclose the health risks of ephedra, such as heart attack, stroke, and death. In response, the supplement industry created a public relations group, the Ephedra Education Council, to oppose the changes, and commissioned a scientific review by a private consulting firm, which reported that Ephedra was safe. The Ephedra Education Council also attempted to block the publication of a study confirming wide discrepancies between the labeled potency of supplements and the actual amount of ephedra in the product. Metabolife, makers of the best-selling brand of ephedra supplement, had received over 14,000 complaints of adverse events associated with its product. These reports were not initially provided to the FDA. Co-founder of Metabolife, Michael Ellis, was sentenced in 2008 to six months in federal prison for his failure to report adverse effects from his company's products to the FDA. Senators Orrin Hatch (R. Utah) and Tom Harkin (D. Iowa), authors of the Dietary Supplements Health and Education Act, questioned the scientific basis for the FDA's proposed labeling changes and suggested that the number of problems reported were insufficient to warrant regulatory action.
=== Notable individuals === Alfredo Ferrari was an Italian automotive engineer, the eldest son of automaker Enzo Ferrari, and the planned heir to his father's sports car company, Ferrari. Alfredo died of DMD on 30 June 1956 at the age of 24. Rapper and disability rights advocate Darius Weems had the disease and used his notoriety to raise awareness and funds for treatment, as seen in the documentary Darius Goes West (2007). He died at the age of 27 in 2016. In 2024, Netflix released a documentary film about a young man with the disease, The Remarkable Life of Ibelin. The film explores the life of Mats Steen and the impact he had on his World of Warcraft guild Starlight, where Mats spent much of his time.
5 and Savings) Order 1993 (S.I. 1993/1186) Friendly Societies Act 1992 (Consequential Provisions) (No. 2) Regulations 1993 (S.I. 1993/1187) Serbia and Montenegro (United Nations Sanctions) Order 1993 (S.I. 1993/1188) Export of Goods (Control) (Croatian and Bosnian Territories) Order 1993 (S.I. 1993/1189) Education (Schools) Act 1992 (Commencement No. 2 and Transitional Provision) Order 1993 (S.I. 1993/1190) Lothian Region (Electoral Arrangements) Order 1993 (S.I. 1993/1191) Injuries in War (Shore Employments) Compensation (Amendment) Scheme 1993 (S.I. 1993/1192) Electricity (Standards of Performance) Regulations 1993 (S.I. 1993/1193) Diseases of Animals (Approved Disinfectants) (Amendment) Order 1993 (S.I. 1993/1194) Serbia and Montenegro (United Nations Sanctions) (Dependent Territories) Order 1993 (S.I. 1993/1195) Sea Fish Licensing (Time at Sea) (Principles) Order 1993 (S.I. 1993/1196) Third Country Fishing (Enforcement) Order 1993 (S.I. 1993/1197) Police (Amendment) (No. 2) Regulations 1993 (S.I. 1993/1198) Lincolnshire County Council (Tattershall Bridge Reconstruction) Scheme 1991 Confirmation Instrument 1993 (S.I. 1993/1199)
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.