Everything below concerns melanotan-2. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-12-02. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Regulatory status varies by jurisdiction, and the substance is frequently described as unapproved for therapeutic use. Some authorities classify it alongside prescription-only medicines or controlled categories, while others address it through general consumer protection rules. Analytical surveys have reported mismatches between label claims and measured content in products sold online, although the scope of such testing is limited. Whether these discrepancies are widespread remains an open question. Discussion in the literature therefore tends to combine chemistry, supply-chain observation and policy analysis.
The material is commonly handled as a lyophilized powder in sealed vials. The solid dissolves readily in water and in polar organic solvents, producing a clear solution after reconstitution. Light, heat and repeated freeze-thaw cycles are the concerns most often raised in handling guidance, because peptide bonds and the constrained ring can degrade. Working solutions are generally prepared fresh, and material left in solution is treated as less stable than the dry form. These properties shape how laboratories store and aliquot reference material.
Identity and purity are assessed mainly by reversed-phase high-performance liquid chromatography with ultraviolet detection, often paired with mass spectrometry. Retention time supports identity, while the mass spectrum confirms the molecular weight of the intact peptide. Purity is frequently reported as a percentage of total peak area, a figure that depends on the wavelength, column and gradient used. Impurity profiling may also look for truncated sequences, oxidised forms and residual counterions. Amino acid analysis and peptide mapping provide orthogonal confirmation when required.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | Melanotan II; MT-II; N-acetyl-norleucyl-cyclo[Asp-His-D-Phe-Arg-Trp-Lys] amide | Naming follows peptide convention; the numeral distinguishes it from melanotan-1 |
| Molecular formula | C50H69N15O9 | Includes the lactam bridge; no counter-ion assumed |
| Monoisotopic mass | 1023.53 Da | Free base; salts and counter-ions shift the observed value |
| Appearance | White to off-white lyophilised powder | Batch-to-batch colour variation is not itself proof of impurity |
| Typical analytical method | RP-HPLC purity determination with ESI-MS identity confirmation | Retention time alone does not establish sequence identity |
Receptor binding at MC1R on melanocytes raises intracellular cyclic AMP and increases expression of tyrosinase and related enzymes. The downstream result is greater synthesis of eumelanin, the dark pigment, without ultraviolet exposure acting as the trigger. The compound is not selective, however, and also engages MC3R, MC4R and MC5R, which are expressed in the central nervous system and elsewhere. That lack of selectivity is the explanation usually offered for effects reported outside pigmentation, including appetite suppression and nausea. Selectivity remains a central theme in comparative studies of related peptides.
Human data remain limited and mostly short-term. Reports describe small trials and observational accounts rather than large controlled studies, so questions about dose-response relationships and long-term effects on melanocytes stay open. Whether repeated exposure alters naevus behaviour is not settled in the published record. Researchers also note that self-administered use outside clinical settings makes actual exposure difficult to quantify. Statements about efficacy and safety should therefore be read as preliminary rather than established.
Melanotan II is a synthetic cyclic heptapeptide that acts as an agonist at melanocortin receptors. It was designed as a structural analogue of alpha-melanocyte-stimulating hormone, the endogenous peptide involved in pigment production. The analogue carries a lactam bridge that constrains the ring and slows enzymatic breakdown relative to the native hormone. In research literature it appears under several abbreviations, and naming conventions are not fully standardized. Published descriptions usually place it within the broader melanocortin agonist family.
Regulatory treatment varies by country. In the United States the peptide is not approved as a medicine, and products offered for human use may be treated as unapproved new drugs; some states also restrict sale. Australia, the United Kingdom, and European Union member states apply comparable restrictions to unapproved peptide products. Border agencies have seized shipments labelled as research chemicals. Classification may change over time, and the legal position for personal importation is not clearly settled in most published guidance.
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.
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.
== Genetics == The enzyme is coded by the gene with the symbol MTHFR on chromosome 1 location p36.3 in humans. There are DNA sequence variants (genetic polymorphisms) associated with this gene. In 2000 a report brought the number of polymorphisms up to 24. Two of the most investigated are C677T (rs1801133) and A1298C (rs1801131) single nucleotide polymorphisms (SNPs). While multiple published studies have drawn relationships between these SNPs and a wide variety of diseases, the American College of Medical Genetics has issued an official Practice Guideline recommending against testing or reporting on these two variants, citing "Recent meta-analyses have disproven an association between hyperhomocysteinemia and risk for coronary heart disease and between MTHFR polymorphism status and risk for venous thromboembolism. There is growing evidence that MTHFR polymorphism testing has minimal clinical utility.". However, a more recent study has shown that the presence of the C677T and/or A1298C polymorphisms may have a critical impact on leukemic cell response to MYC-targeting therapies. This study demonstrates that MTHFR deficiency indeed increases leukemic cell resistance to a variety of MYC-targeting pharmacological agents, including BET protein small-molecule inhibitors.
==== Cardiovascular tissues ==== Cardiovascular regenerative medicine focuses on repairing damaged myocardial tissue, heart valves, and peripheral blood vessels, primarily targeting ischemic heart disease and congenital heart defects. Because adult mammalian cardiomyocytes possess highly restricted proliferative capacity, therapeutic strategies utilize engineered cardiac patches, cell-seeded hydrogels, and decellularized extracellular matrix (ECM) components to stimulate localized myocardial repair after a myocardial infarction. Clinical and pre-clinical research focuses heavily on using induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and vascular endothelial cells embedded within porous, biomimetic polymeric scaffolds to ensure functional electrical coupling and host tissue integration. Additionally, tissue-engineered vascular grafts (TEVGs) are investigated as synthetic or bio-resorbable alternatives for coronary artery bypass surgery, where scaffold porosity is precisely tuned to allow host cell infiltration, smooth muscle cell remodeling, and functional neovascularization without inducing thrombosis.
The Bard Gorlen series "Catamounts" (September 1996, The Magazine of Fantasy and Science Fiction) "Childrun" (August 2008, The Magazine of Fantasy and Science Fiction) "Quickstone" (March 2009, The Magazine of Fantasy and Science Fiction) "Bemused" (September/October 2013, The Magazine of Fantasy and Science Fiction) "Rooksnight" (May/June 2014, The Magazine of Fantasy and Science Fiction) "Catamounts" (Reprint) (August 2013, Lightspeed) "Belweather" (September 2013, Lightspeed) "Stillborne" (November/December 2017, The Magazine of Fantasy and Science Fiction) "Weeper" (September/October 2020, The Magazine of Fantasy and Science Fiction) "Underneath the Oversea" (November 2020)
== Discovery == In 1839, the German anatomist Hermann Friedrich Stannius discovered a pair of novel structures inside the kidneys of sturgeon and bony fishes. He believed that they were a kind of adrenal gland (found in mammals) in these fishes. In 1896, the French physiologist A. Petit demonstrated that removal of one of the structures led to degeneration of the other. He suggested that these structures were endocrine organs. In 1908, the Italian zoologist Ercole Giacomini was the first to describe that these structures were present only in fishes which lack a parathyroid gland. He distinguished and named them "posterior interrenal" from the anterior portion of the kidney, which he named "anterior interrenal". A French Physiologist M. Fontaine reported that the corpuscles were responsible for controlling calcium level in the blood. In 1971 Peter K.T. Pang of Yale University showed in the male killifish, Fundulus heteroclitus, that the corpuscles control calcium metabolism. He found that removal of the corpuscle led to development of kidney stone and increase in serum calcium level. By the mid 1970s, it was confirmed that the corpuscles secrete a factor that can reduce calcium level, similar to calcitonin but completely different. and Pang gave the prospective name "hypocalcin". The chemical compound was isolated in 1986 from sockeye salmon (Oncorhynchus nerka), and since it was from a teleost, it was called "teleocalcin". A better isolation was reported in 1988 from different species, including European eel, tilapia, goldfish, and carp.
Psylocke is the alias of two connected characters appearing in American comic books published by Marvel Comics, commonly in association with the X-Men. Both characters are depicted as mutants, a subspecies of humans born with an "X-gene" that grants superhuman abilities. In the primary continuity of the Marvel Universe, the first and best-known incarnation of Psylocke is Betsy Braddock (created by Chris Claremont and Herb Trimpe), a British telepath who was introduced as a supporting character for her twin brother Brian in 1976. Betsy adopts the codename "Psylocke" upon joining the X-Men in 1986, and three years later takes on the appearance of a Japanese woman and the abilities of a ninja in a story written by Claremont and illustrated by Jim Lee. This redesign was retroactively revealed in 1993 as the result of a body swap with the ninja assassin Kwannon (created by Fabian Nicieza and Andy Kubert). Following 29 years of publication history, both women were returned to their respective bodies, and Betsy assumed the mantle of Captain Britain from her brother while Kwannon became the second Psylocke. The Ultimate Universe features two versions of Psylocke: Sai and Kanon Sainouchi (both created by Peach Momoko). In addition to their presence in numerous X-related team titles over the decades, both iterations of Psylocke have been featured in various limited series and one-shots. In 1997, Betsy Braddock, as Psylocke, appeared in the 4-issue team-up series Psylocke and Archangel: Crimson Dawn.
Sources: en.wikipedia.org
===== Light collector ===== Using graphene as a photoactive material requires its bandgap to be 1.4–1.9 eV. In 2010, single cell efficiencies of nanostructured graphene-based PVs of over 12% were achieved. According to P. Mukhopadhyay and R. K. Gupta organic photovoltaics could be "devices in which semiconducting graphene is used as the photoactive material and metallic graphene is used as the conductive electrodes". In 2008, chemical vapor deposition produced graphene sheets by depositing a graphene film made from methane gas on a nickel plate. A protective layer of thermoplastic is laid over the graphene layer and the nickel underneath is then dissolved in an acid bath. The final step is to attach the plastic-coated graphene to a flexible polymer sheet, which can then be incorporated into a PV cell. Graphene/polymer sheets range in size up to 150 square centimeters and can be used to create dense arrays. Silicon generates only one current-driving electron for each photon it absorbs, while graphene can produce multiple electrons. Solar cells made with graphene could offer 60% conversion efficiency.
=== Music and the culture industry === Adorno criticized jazz and popular music, viewing it as part of the culture industry that contributes to the present sustainability of capitalism by rendering it "aesthetically pleasing" and "agreeable." In his early essays for the Vienna-based journal Anbruch, Adorno claimed that musical progress is proportional to the composer's ability to constructively address the possibilities and limitations contained within what he called the "musical material." For Adorno, twelve-tone serialism constitutes a decisive, historically developed method of composition. The objective validity of composition, according to him, rests with neither the composer's genius nor the work's conformity with prior standards but with the way in which the work coherently expresses the dialectic of the material. In this sense, the contemporary absence of composers of the status of Bach or Beethoven is not the sign of musical regression; instead, new music is to be credited with laying bare aspects of the musical material previously repressed: The musical material's liberation from number, the harmonic series and tonal harmony. Thus, historical progress is achieved only by the composer who "submits to the work and seemingly does not undertake anything active except to follow where it leads." Because historical experience and social relations are embedded within this musical material, it is to the analysis of such material that the critic must turn.
=== Release of GSTs as an indication of organ damage === The high intracellular concentrations of GSTs coupled with their cell-specific cellular distribution allows them to function as biomarkers for localising and monitoring injury to defined cell types. For example, hepatocytes contain high levels of alpha GST and serum alpha GST has been found to be an indicator of hepatocyte injury in transplantation, toxicity and viral infections. Similarly, in humans, renal proximal tubular cells contain high concentrations of alpha GST, while distal tubular cells contain pi GST. This specific distribution enables the measurement of urinary GSTs to be used to quantify and localise renal tubular injury in transplantation, nephrotoxicity and ischaemic injury. In rodent pre-clinical studies, urinary and serum alpha GST have been shown to be sensitive and specific indicators of renal proximal tubular and hepatocyte necrosis respectively.
==== MeSH E05.196.401 – electrophoresis ==== MeSH E05.196.401.153 – electrophoresis, agar gel MeSH E05.196.401.153.150 – comet assay MeSH E05.196.401.190 – electrophoresis, capillary MeSH E05.196.401.190.500 – electrophoresis, microchip MeSH E05.196.401.200 – electrophoresis, cellulose acetate MeSH E05.196.401.220 – electrophoresis, gel, pulsed-field MeSH E05.196.401.250 – electrophoresis, gel, two-dimensional MeSH E05.196.401.319 – electrophoresis, paper MeSH E05.196.401.319.670 – nucleotide mapping MeSH E05.196.401.319.670.100 – blotting, northern MeSH E05.196.401.319.670.150 – blotting, southern MeSH E05.196.401.319.720 – peptide mapping MeSH E05.196.401.402 – electrophoresis, polyacrylamide gel MeSH E05.196.401.402.236 – electrophoresis, disc MeSH E05.196.401.402.250 – electrophoresis, gel, two-dimensional MeSH E05.196.401.485 – electrophoresis, starch gel MeSH E05.196.401.500 – electrophoretic mobility shift assay MeSH E05.196.401.568 – immunoelectrophoresis MeSH E05.196.401.568.250 – counterimmunoelectrophoresis MeSH E05.196.401.568.520 – immunoelectrophoresis, two-dimensional MeSH E05.196.401.663 – isoelectric focusing
Sources: en.wikipedia.org
The mean improvement in scores with dextromethorphan/bupropion was statistically significant but not clinically significant relative to placebo at all assessed timepoints including at the end of week 1, although at the end of the study some patients did have clinically significant improvement. In Study 2 (STRIDE-1), dextromethorphan/bupropion was compared with bupropion alone in another randomized controlled trial. The dose of bupropion in the study was lower than the target dose recommended for clinical practice. In this study, dextromethorphan/bupropion showed significantly greater improvement than bupropion alone in the first two weeks of treatment but not by week 6 of treatment in people with major depressive disorder. The baseline scores were 33.4 points with dextromethorphan/placebo and 33.2 points with placebo, while the score reductions at week 1 were 5.2 points on the MADRS with dextromethorphan/bupropion and 3.6 points with bupropion (a 1.6-point difference), at week 2 were 8.0 points with dextromethorphan/bupropion and 6.1 points with bupropion (a 1.9-point difference), and at week 6 were 11.6 points with dextromethorphan/bupropion and 9.4 points with bupropion (a 2.2-point difference). On the basis of this trial, the FDA concluded that dextromethorphan contributes to the apparent antidepressant effects of dextromethorphan/bupropion.
== Early life and education == Born in Karachi, Pakistan, Butler completed his higher secondary education at Adamjee Science College and received his MBBS from Aga Khan University in 1990. He moved to the United States for further medical training, earning a MPH from the Harvard T.H. Chan School of Public Health in 1998 and an MBA from Emory University's Goizueta Business School in 2015. Butler completed his residency in primary care internal medicine at Yale University, where he also served as Chief Resident. His specialization includes a fellowship in cardiovascular disease and an additional fellowship in Advanced Heart Failure & Transplantation from Vanderbilt University. He pursued additional specialization in cardiac imaging at Massachusetts General Hospital, Harvard University.
=== The Robertson Memorial Volume (1932) === In January 1932, a special volume of The Australian Journal of Experimental Biology and Medical Science, of which Robertson was not only a founder, but its editor until his death (AE.2), was published in his memory, containing contributions from former students, colleagues, and/or associates:Martin, Sir Charles & Marston, Hedley R. (eds), The Robertson Memorial Volume, The Australian Journal of Experimental Biology and Medical Science, Vol.9, No.1, (January 1932), pp. 1-246. (see: AC.6)
== History == President Dr. Arif Alvi granted approval for the reconstitution of the NEC on 8 June 2022, in accordance with the guidelines outlined in Article 156 of the Constitution. The NEC consists of a total of 13 members, led by the Prime Minister of Pakistan, who serves as the chairman. In addition to the chief ministers from all provinces, the council includes various federal ministers and nominated representatives from different political parties and provinces.
== History == In 1989, work by the groups of Joseph T. Coyle and Ronald Schnaar showed in a neuronal cell line that excess exposure to glutamate or lowered cystine causes a decrease in glutathione levels, an accumulation in intracellular peroxides, and cytotoxicity. Later work by Pamela Maher and David Schubert noted the distinction of this cell death process from apoptosis, describing it as oxidative glutamate toxicity or oxytosis. In 2012, a study by Brent Stockwell and Scott Dixon characterized the iron dependence of this cell death process and coined the term ferroptosis. Oxytosis and ferroptosis are now thought to be the same cell death mechanism. Other early studies regarding the connection between iron and lipid peroxidation, cystine deprivation and oxidative cell death, the activity and importance of glutathione peroxidase 4 (GPX4), and the identification of small molecules that induce ferroptosis were key to the eventual characterization of ferroptosis.
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone, containing seven amino acids with a lactam ring and a D-configured phenylalanine residue. It is supplied as a lyophilised powder for laboratory research.
The natural hormone is a linear tridecapeptide that is rapidly degraded in circulation. Melanotan-2 is shortened, cyclised, N-terminally acetylated, and carries a D-amino acid substitution, all of which slow enzymatic breakdown.
No national medicines regulator has approved melanotan-2 for therapeutic or cosmetic use. In several jurisdictions it is treated as an unapproved prescription medicine, and its legal classification differs from country to country.
The dry powder is more stable during transport and storage than a solution. It also allows a known amount of material to be reconstituted at a chosen concentration.