Everything below concerns cyclic heptapeptide. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-03-12. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Scientific discussion of Melanotan-2 spans pharmacology, dermatology, and public-health literature. Laboratory studies examine its receptor binding and cellular effects, while clinical reports describe outcomes observed after unregulated use. These two bodies of work differ in rigour and intent. Peer-reviewed trials of the compound as a medicine are limited, so much of the available information comes from case reports and surveillance data. Authors frequently note the gap between experimental findings and real-world use.
Reported observations after unregulated use include shifts in skin pigmentation and, in some accounts, unintended changes to moles and other lesions. Whether these outcomes are causally linked to the compound, and how often they occur, remain open questions because controlled data are scarce. The absence of standardised dosing and verified product purity complicates interpretation. Researchers have called for better surveillance and analytical characterisation of samples obtained outside regulated channels. Conclusions drawn from anecdotal evidence should be treated as provisional.
| 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 |
Published human data come mostly from small, short studies rather than large controlled trials. Reported outcomes include increased skin pigmentation and, in some reports, effects on appetite and libido, but sample sizes are small and follow-up is limited. Whether long-term use produces durable pigment changes or adverse effects is not established. Because products sold outside pharmacies are not standardized, the actual content of any given vial is often unknown. Independent testing of such material is uncommon.
Melanotan II is a synthetic cyclic heptapeptide analog derived from the core sequence of alpha-melanocyte-stimulating hormone. Researchers at the University of Arizona synthesized it during the 1980s while studying pigmentation and appetite signaling. The compound is not an approved medicine in any major jurisdiction and appears mainly in laboratory and research-chemical settings. Its structure incorporates a lactam bridge between side chains, which constrains the ring and slows enzymatic breakdown relative to the natural hormone.
Analytical confirmation of identity relies on mass spectrometry, most often coupled to liquid chromatography. Reversed-phase high-performance liquid chromatography separates the peptide from related impurities and provides a purity estimate based on peak area. Electrospray ionization mass spectrometry then confirms the expected molecular mass, while tandem mass spectrometry can map the fragment sequence. For research-grade material, these two techniques together form the standard minimum. Purity figures reported by vendors are frequently not traceable to an independent laboratory.
Independent verification is central to quality control because the compound is not produced under pharmaceutical manufacturing standards. Third-party laboratories can measure purity, identity, residual solvents, and microbial contamination, though the scope of testing varies between services. Reported analyses of vendor samples have shown batch-to-batch variation in peptide content and the presence of truncated or oxidized species. How much of this variation reflects synthesis conditions versus storage and shipping is not well characterized. No harmonized reference standard exists for the material as sold.
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.
Freeze-dried melanotan-2 is normally kept as a desiccated powder at minus twenty degrees Celsius or lower, shielded from light and moisture. Peptides of this size degrade through hydrolysis, oxidation and deamidation, and each pathway accelerates as temperature and water activity rise. Repeated freeze-thaw cycles promote aggregation and loss of material, so aliquoting a stock solution before freezing is standard laboratory practice. Once dissolved, the solution is markedly less stable than the powder. In laboratory work, solutions are generally refrigerated and used within days rather than kept for months.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, which separates the target peptide from truncated or oxidised impurities. Mass spectrometry, most often coupled to liquid chromatography, confirms molecular mass and detects substitutions that chromatography alone may miss. Amino acid analysis and peptide mapping supply additional structural evidence, while nuclear magnetic resonance is reserved for full structural confirmation. Laboratories that examine samples sold online report wide variation in actual content, with some vials containing little or none of the labelled material.
Melanotan-2 appears on the World Anti-Doping Agency prohibited list within the peptide hormone class, and several national regulators treat it as an unapproved prescription substance. Some countries restrict importation or sale for personal use. Because the compound is widely traded as a research chemical, the practical legal picture differs between jurisdictions and shifts over time. Human safety data covering long periods are limited, and whether repeated pigmentation changes carry any lasting risk to melanocytes remains an open question.
Chemical information, Clinical information and Biochemical information. The chemical data includes >40,000 metabolite structures with detailed descriptions, extensive chemical classifications, synthesis information and observed/calculated chemical properties. It also contains nearly 10,000 experimentally measured NMR, GC-MS and LC/MS spectra from more than 1,100 different metabolites. The clinical information includes data on >10,000 metabolite-biofluid concentrations, metabolite concentration information on more than 600 different human diseases and pathway data for more than 200 different inborn errors of metabolism. The biochemical information includes nearly 6,000 protein (and DNA) sequences and more than 5,000 biochemical reactions that are linked to these metabolite entries. The HMDB supports a wide variety of online queries including text searches, chemical structure searches, sequence similarity searches and spectral similarity searches. This makes it particularly useful for metabolomic researchers who are attempting to identify or understand metabolites in clinical metabolomic studies. The first version of the HMDB was released in Jan. 1 2007 and was compiled by scientists at the University of Alberta and the University of Calgary. At that time, they reported data on 2,500 metabolites, 1,200 drugs and 3,500 food components. Since then these scientists have greatly expanded the collection. The version 3.5 of the HMDB contains >16,000 endogenous metabolites, >1,500 drugs and >22,000 food constituents or food metabolites.
== Further reading == Als, Hilton (Summer 2012). "Wallace Shawn, The Art of Theater No. 17". The Paris Review. Summer 2012 (201). Higgins, J. (2012). "The End of Room-Space: Domesticity and the Absent Audience in Wallace Shawn's the Fever". Journal of Dramatic Theory and Criticism. 26 (2): 57–74. doi:10.1353/dtc.2012.0017. S2CID 191948394. King, W. D. (1997). Writing Wrongs: The Work of Wallace Shawn. Philadelphia: Temple University Press. ISBN 1-56639-517-8. Shawn, Wallace, "The End of a Village", The New York Review of Books, vol. LXXI, no 15 (3 October 2024), pp. 16–17.
Tregs derived from CD25+Foxp3high progenitors protect from experimental auto-immune encephalomyelitis, whereas those derived from CD25+Foxp3low progenitors protect from T-cell induced colitis. Mature CD25+Foxp3+ Tregs can be also divided into two different subsets based on the expression level of CD25, GITR, and PD-1. Tregs expressing low amounts of CD25, GITR and PD-1 limit the development of colitis by promoting the conversion of conventional CD4+ T cells into pTreg. Tregs highly expressing CD25, GITR and PD-1 are more self-reactive and control lymphoproliferation in peripheral lymph nodes - they may have the ability to protect against autoimmune disorders. Foxp3+ Treg generation in the thymus is delayed by several days compared to Teff cells and does not reach adult levels in either the thymus or periphery until around three weeks post-partum. Treg cells require CD28 co-stimulation and B7.2 expression is largely restricted to the medulla, the development of which seems to parallel the development of Foxp3+ cells. It has been suggested that the two are linked, but no definitive link between the processes has yet been shown. TGF-β is not required for Treg functionality, in the thymus, as thymic Tregs from TGF-β insensitive TGFβRII-DN mice are functional.
The first use of titanium as an implantable material was by Bothe, Beaton and Davenport in 1940, who observed how close the bone grew to titanium screws, and the difficulty they had in extracting them. Bothe et al. were the first researchers to describe what would later be called osseointegration (a name that would be marketed later on by Per-Ingvar Brånemark). In 1951, Gottlieb Leventhal implanted titanium rods in rabbits. Leventhal's positive results led him to believe that titanium represented the ideal metal for surgery. In the 1950s research was being conducted at Cambridge University in England on blood flow in living organisms. These workers devised a method of constructing a chamber of titanium which was then embedded into the soft tissue of the ears of rabbits. In 1952 the Swedish orthopaedic surgeon, Per-Ingvar Brånemark, was interested in studying bone healing and regeneration. During his research time at Lund University he adopted the Cambridge designed "rabbit ear chamber" for use in the rabbit femur. Following the study, he attempted to retrieve these expensive chambers from the rabbits and found that he was unable to remove them. Brånemark observed that bone had grown into such close proximity with the titanium that it effectively adhered to the metal. Brånemark carried out further studies into this phenomenon, using both animal and human subjects, which all confirmed this unique property of titanium. Leonard Linkow, in the 1950s, was one of the first to insert titanium and other metal implants into the bones of the jaw.
Sources: en.wikipedia.org
=== Drowsiness === Clonazepam, like other benzodiazepines, may impair a person's ability to drive or operate machinery. The central nervous system depressing effects of the drug can be intensified by alcohol consumption, so alcohol should be avoided while taking this medication. Benzodiazepines have been shown to cause dependence. Patients dependent on clonazepam should be slowly titrated off under the supervision of a qualified healthcare professional to reduce the intensity of withdrawal or rebound symptoms.
Etoxadrol (CL-1848C) is a dissociative anaesthetic drug that has been found to be an NMDA antagonist and produce similar effects to PCP in animals. Etoxadrol, along with another related drug dexoxadrol, were developed as analgesics for use in humans, but development was discontinued in the late 1970s after patients reported side effects such as nightmares and hallucinations.
== History == Students Michael Schrader, Livio Valenti, Kathryn Kosuda, and Patrick Ho started Vaxess in December 2011, based on a technology created by David Kaplan and Fiorenzo Omenetto. Schrader graduated with an MBA from Harvard Business School in 2012. Valenti attended the John F. Kennedy School of Government. Kosuda had been a Harvard postdoctoral fellow in chemistry, and Patrick Ho had earned a J.D in 2012. In 2012, Vaxess was awarded $25,000 from Harvard Business School for Harvard's Business Plan Contest in the Business Ventures Track. Vaxess Technologies was a semi-finalist for MIT's $100K Entrepreneurship Competition in the Life Sciences section. In 2012, it won the Harvard President's Challenge in the Global Health section and was awarded $70,000. The company was selected as a finalist for two 2013 MassTLC Awards, Start-Up to Watch and Innovative Technology of the Year: Healthcare/Life Sciences. In May 2013, Vaxess received $3.75M in funding from Norwich Ventures and an undisclosed amount of money from angel investor Jeffrey Walker. In August 2013, the company announced that it would be moving out of Harvard's Innovation Lab to a new location at LabCentral in Cambridge. In December 2013, the Massachusetts Life Sciences Center awarded $1.5M to local startups. Vaxess received $1M of that amount which is the most that the MLSC's Accelerator Loan Program will lend to one organization.
=== 1980s and 1990s === Pritzker first became involved in politics while an undergraduate student at Duke University, volunteering for Terry Sanford's 1986 campaign for the U.S. Senate. After graduating from Duke in 1987, Pritzker moved to Washington, D.C., to work on Capitol Hill. He served on the legislative staffs of Congressman Tom Lantos of California and Senator Alan J. Dixon of Illinois, focusing on trade and transportation issues. After his career as a staffer, Pritzker founded Democratic Leadership for the 21st Century, a national organization dedicated to attracting voters under 40 to the Democratic Party, in 1991. Anticipating that Sidney Yates, the longtime Democratic incumbent in Illinois's 9th congressional district, might retire instead of seeking reelection, Pritzker laid the groundwork for possible 1994 and 1996 campaigns for his seat. Each time, there was public speculation about whether Yates would retire, but he ultimately ran for reelection. Each time, after Yates announced his intention to run, Pritzker abandoned his plans to run. Pritzker established a campaign committee in 1993. By the end of the 1996 cycle, the committee had raised more than $120,000 and spent most of this money on operating expenditures.
== See also == List of commanders of 82nd Airborne Division (United States) 82nd Airborne Division War Memorial Museum United States military beret flash Geneviève Duboscq Medal of Honor: Airborne Monica Lin Brown World War II combat jump airfields: RAF Balderton RAF Barkston Heath RAF Chalgrove RAF Cottesmore RAF Folkingham RAF Merryfield RAF Membury RAF North Witham RAF Ramsbury RAF Saltby RAF Spanhoe International:
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.
Major regulatory agencies have not approved it for any indication. Some countries permit it only under prescription frameworks, while others classify it as a controlled substance.