alpha-MSH analog is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-07-21. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Melanotan II binds several melanocortin receptor subtypes rather than a single target. MC1R on melanocytes drives melanin synthesis, while MC3R and MC4R participate in energy balance, appetite, and sexual response pathways. This lack of selectivity explains why reported effects extend beyond skin darkening. Substitutions at positions four and seven, including norleucine and D-phenylalanine, increase potency and resistance to peptidases. Understanding which receptor mediates which effect remains an active area of investigation.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Free base; salt forms differ |
| Molecular weight | Approximately 1024 g/mol | Calculated for the free base |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility | Soluble in water and polar solvents | Poorly soluble in non-polar solvents |
| Typical storage | -20 degrees Celsius, dry, protected from light | Refers to the solid form |
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.
Two structural changes distinguish the synthetic peptide from the natural hormone. A norleucine residue replaces methionine at one position, and a D-configured phenylalanine replaces the natural L-form at another. Both substitutions slow enzymatic breakdown, which extends the molecule's persistence relative to the parent hormone. The lactam bridge further constrains the backbone into a stable conformation. These features are standard design strategies in peptide chemistry and are not unique to this compound; they appear across many research peptides built for improved stability.
The compound was developed in the late 1980s and early 1990s by academic researchers investigating melanocortin signaling and pigmentation. Early work explored whether synthetic analogs could reproduce effects of the natural hormone under controlled conditions. The molecule never advanced through the full regulatory pathway required for approval as a medicine. From the mid-2000s onward it appeared in unregulated consumer markets, often distributed through informal channels. That gap between research origins and commercial availability shapes how the compound is discussed today.
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.
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.
==== Impact of the Tokyo Code (1993) ==== The Tokyo Code of 1993 extended the provisions for conserving names to all species, not just those of major economic importance. This change in the International Code of Botanical Nomenclature allowed for the conservation of names that would promote nomenclatural stability. Despite this provision, no formal proposal was made to conserve the name Parmotrema chinense, and thus it did not gain widespread acceptance. David Hawksworth's 2004 study brought significant clarity to the taxonomic confusion. He rediscovered Osbeck's original material in Linnaeus' herbarium and identified it as belonging to Parmotrema tinctorum, not Parmotrema perlatum. Hawksworth demonstrated that Lichen chinensis was not validly published because it lacked a proper description and was linked with an expression of doubt by Osbeck. Hawksworth's work led to the reinstatement of the name Parmotrema perlatum, confirming that Hudson's name was legitimate and should continue to be used. This resolution was based on the original typification by Hale and the invalid publication status of Lichen chinensis. Recent studies suggest that the circumscription of Parmotrema perlatum may need to be revised. Research utilising DNA sequencing has uncovered cryptic diversity within the genus Parmotrema, indicating that traditional phenotype-based identification methods may underestimate species diversity. Specifically, the genetic analysis of P. perlatum and related species revealed multiple distinct lineages that were previously grouped under a single nominal taxon.
== Regulation == Betamethasone dipropionate was patented by Merck in 1987, as an augmented cream/lotion, Diprolene in the U.S., and Disprosone in Europe. These patents expired in 2003 and 2007 respectively leading to generic production of betamethasone dipropionate. During this time other topical corticosteroids such as triamcinolone acetonide and clobetasol propionate also became available as generic creams. Merck filed for "pediatric exclusivity" in 2001 launching a clinical trial to prove betamethasone dipropionate's safety and efficacy for use in pediatrics. Betamethasone has also been used in the formulation of combination products such as Luxiq, Lotrisone and Taclonex.
12 September – Bill Wilson, lawyer and judge, judge of the Court of Appeal (2007–2008) and Supreme Court (2008–2010), King's Counsel (since 1996) (born 1946). 13 September – Stan Simpson, wool scientist (WRONZ) and science administrator, director of WRONZ (1978–1992) (born 1933). 14 September – Barry Roberts, cricketer (Northern Districts) (born 1946). 16 September Judy Tinnock, tennis player, Wimbledon mixed doubles semi-finalist (1954) (born 1931). Jack Williams, cricketer (Canterbury) (born 1931). 17 September Tenick Dennison, paediatrician, conservationist and ornithologist (born 1927). Jim Easton, oldest living man in New Zealand (108 years, 279 days), oldest living Australian World War II veteran (born 1916). Dame Joan Metge, social anthropologist (University of Auckland, Victoria University of Wellington), Te Rangi Hiroa Medal (1997) (born 1930). 20 September – Tui Te Rupe, Paralympic marathon runner (1988) (born 1943). 21 September Stu Freebairn, rugby union player (Manawatu, national team) (born 1932). William E. Shepard, religious studies academic (University of Canterbury) (born 1933). 22 September Ian Farquhar, maritime historian, businessman and local politician, chair of the Otago Harbour Board (1980–1983) (born 1931). Grant Hawke, Māori leader (Ngāti Whātua Ōrākei) (born 1944). 23 September Bruce Morrison, cricketer (Wellington, national team) (born 1933). Sir Tumu Te Heuheu, Māori leader, paramount chief of Ngāti Tūwharetoa (since 1997) (born 1941). 25 September Glynn Jones, physicist (University of Canterbury) (born 1936).
== Computing, Internet and information technology == Files-11 (On-Disk Structure), a DEC filesystem Office of Digital Strategy, Executive Branch of the White House OpenDocument Spreadsheet file format Online dating service Operational data store, an intermediate data warehouse for databases OpenDNSSEC, a security extension of DNS Protocol Optical data storage a technology for storing information
Sources: en.wikipedia.org
=== White House event === To commemorate the 250th anniversary of the United States, the UFC held a historic mixed martial arts event entited UFC Freedom 250 on the grounds of the White House in June 2026, marking the first professional sporting event ever staged at the presidential residence. The event was first announced by US President Donald Trump on July 3, 2025, during a rally at the Iowa State Fairgrounds: On August 29, 2025, UFC CEO Dana White confirmed via social media that plans for the event had been finalized, stating, "We had the meeting at the White House... The White House fight is on." On October 6, 2025, President Trump announced that the event would take place on June 14, 2026, coinciding with his 80th birthday.
== T == Celia White Tabor (1918–2012). American biochemist at the NIH, expert on the biosynthesis of polyamines. Herbert Tabor (1918–2020). American biochemist at NIH who studied the function of polyamines and their role in human health and disease. He was editor-in-chief of the Journal of Biological Chemistry for nearly 40 years. Member Natl. Acad. Sci. USA. Charles Tanford (1921–2009). American protein chemist at Duke University, known for analysis of the hydrophobic effect. Member Natl. Acad. Sci. USA. Ignacio Tinoco Jr. (1930–2016). American chemist at UC Berkeley, known for his pioneering work on RNA folding. Member Natl. Acad. Sci. USA. Arne Tiselius FRS (foreign associate) (1902–1971). Swedish biochemist at the University of Uppsala, who developed protein electrophoresis. Nobel Prize for Chemistry (1948). Foreign associate Natl. Acad. Sci. USA. Victor Trikojus CBE (1902–1985). Australian biochemist, head of the School of Biochemistry at the University of Melbourne (1943–1968). Joint discoverer of triiodothyronine (T3) with Frank Hird in 1948. Chen-Lu Tsou (邹承鲁 Zou Chenglu in Pinyin, 1923–2006). Chinese biochemist at the Academia Sinica, known for work on enzyme inactivation kinetics, and even more as the "face of Chinese biochemistry" for many years in the west. Member of the Academia Sinica.
=== Molar mass of cellulose === In the pulp and paper industry, molar mass is traditionally measured with a method where the intrinsic viscosity (dL/g) of the pulp sample is measured in cupriethylenediamine (Cuen). The intrinsic viscosity [η] is related to the weight-average molar mass (in daltons) by the Mark–Houwink equation: [η] = 0.070 Mw0.70. However, it is typical to cite [η] values directly in dL/g, as the "viscosity" of the cellulose, confusingly as it is not a viscosity.
== Urea cycle disorders == Urea cycle disorders are rare and affect about one in 35,000 people in the United States. Genetic defects in the enzymes involved in the cycle can occur, which usually manifest within a few days after birth. The recently born child will typically experience varying bouts of vomiting and periods of lethargy. Ultimately, the infant may go into a coma and develop brain damage. New-borns with UCD are at a much higher risk of complications or death due to untimely screening tests and misdiagnosed cases. The most common misdiagnosis is neonatal sepsis. Signs of UCD can be present within the first 2 to 3 days of life, but the present method to get confirmation by test results can take too long. This can potentially cause complications such as coma or death. Urea cycle disorders may also be diagnosed in adults, and symptoms may include delirium episodes, lethargy, and symptoms similar to that of a stroke. On top of these symptoms, if the urea cycle begins to malfunction in the liver, the patient may develop cirrhosis. This can also lead to sarcopenia (the loss of muscle mass). Mutations lead to deficiencies of the various enzymes and transporters involved in the urea cycle, and cause urea cycle disorders. If individuals with a defect in any of the six enzymes used in the cycle ingest amino acids beyond what is necessary for the minimum daily requirements, then the ammonia that is produced will not be able to be converted to urea. These individuals can experience hyperammonemia, or the build-up of a cycle intermediate.
Diffusion force caused by a concentration gradient - all particles tend to diffuse from higher concentration to lower. Electrostatic force caused by electrical potential gradient - cations like protons H+ tend to diffuse down the electrical potential, from the positive (P) side of the membrane to the negative (N) side. Anions diffuse spontaneously in the opposite direction. These two gradients taken together can be expressed as an electrochemical gradient. Lipid bilayers of biological membranes, however, are barriers for ions. This is why energy can be stored as a combination of these two gradients across the membrane. Only special membrane proteins like ion channels can sometimes allow ions to move across the membrane (see also: Membrane transport). In the chemiosmotic hypothesis a transmembrane ATP synthase is central to convert energy of spontaneous flow of protons through them into chemical energy of ATP bonds. Hence researchers created the term proton-motive force (PMF), derived from the electrochemical gradient mentioned earlier. It can be described as the measure of the potential energy stored (chemiosmotic potential) as a combination of proton and voltage (electrical potential) gradients across a membrane. The electrical gradient is a consequence of the charge separation across the membrane (when the protons H+ move without a counterion, such as chloride Cl−).
Sources: en.wikipedia.org
=== Tocopherols === Alpha-tocopherol is a fat-soluble antioxidant functioning within the glutathione peroxidase pathway, and protecting cell membranes from oxidation by reacting with lipid radicals produced in the lipid peroxidation chain reaction. This removes the free radical intermediates and prevents the oxidation reaction from continuing. The oxidized α-tocopheroxyl radicals produced in this process may be recycled back to the active reduced form through reduction by other antioxidants, such as ascorbate, retinol or ubiquinol. Other forms of vitamin E have their own unique properties; for example, γ-tocopherol is a nucleophile that can react with electrophilic mutagens. It is also more easily deactivated by CYP4F2 hydroxylation.
Another class of common electrophiles are aryl and heterocyclic halides, especially bromides and iodides. Aryl triflates and sulfonates are also couple to a wide variety of organostannane reagents. Triflates tend to react comparably to bromides in the Stille reaction. Acyl chlorides are also used as coupling partners and can be used with a large range of organostannane, even alkyl-tin reagents, to produce ketones (see example below). However, it is sometimes difficult to introduce acyl chloride functional groups into large molecules with sensitive functional groups. An alternative developed to this process is the Stille-carbonylative cross-coupling reaction, which introduces the carbonyl group via carbon monoxide insertion.
Antimicrobial peptides generally have a net positive charge, allowing them to interact with the negatively charged molecules exposed on bacteria and cancer cell surfaces, such as phospholipid phosphatidylserine, O-glycosylated mucins, sialylated gangliosides, and heparin sulfates. The mechanism of action of these peptides varies widely but can be simplified into two categories: membranolytic and non-membranolytic antimicrobial peptides. The disruption of membranes by membranolytic antimicrobial peptides can be described by four models:
GvpA is a gas vesicle structural protein found in different phyla of bacteria and archaea for example in Halobacterium salinarum or Haloferax mediterranei. Gas vesicles are small, hollow, gas filled protein structures found in several cyanobacterial and archaebacterial microorganisms. They allow the positioning of the bacteria at a favourable depth for growth. GvpA associates with GvpC, to build up gas vesicles, hollow protein structures which are used by planktonic organisms to perform vertical migration. GvpA makes up most of the structure, as so called "ribs", rigid β-sheets, whereas GvpC stabilizes the vesicle against collapse by crosslinking as α-helices.
Sources: en.wikipedia.org
No. Melanotan-2 is manufactured synthetically. The naturally occurring peptide in the same family is alpha-melanocyte-stimulating hormone, which the body produces as part of normal endocrine and neural signalling.
Both are synthetic analogues derived from the same parent hormone. Reference descriptions usually characterise afamelanotide as more selective for the MC1R subtype, whereas melanotan-2 is reported to interact with a wider range of melanocortin receptors.
Early studies explored melanocortin signalling and pigmentation, which later led to informal use of the label tanning peptide. That label is not a regulatory category and does not imply approved status for any purpose.
No regulator in a major market has approved it for human use. It appears in research settings and in products marketed outside pharmacy channels. Legal status for personal possession varies by country.