If you have been reading about alpha-MSH analog and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2026-04-17. Numbers and descriptions here follow the published literature rather than marketing 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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Typical storage temperature | -20 °C or below | For the lyophilised powder, desiccated |
| Storage form | Sealed vial, protected from light | Amber glass or foil-wrapped containers |
| Reconstituted stability | Short, refrigerate | Degradation accelerates in solution |
| Typical analytical method | Reversed-phase HPLC with mass spectrometry | Purity assessment plus identity confirmation |
| Common synonyms | Melanotan II, MT-II | Also written melanotan-2 |
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.
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.
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.
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 research on the compound remains limited. Much of the human data comes from small, early-stage studies rather than large controlled trials, and several questions about effects and variability between individuals remain open. Investigators have examined receptor activity, pigment pathways, and related physiological responses in laboratory and animal models. Findings from those models do not automatically translate to human outcomes. Reviews frequently note the scarcity of rigorous clinical evidence and call for better-characterized study material.
Because the substance circulates mainly through informal markets, verification is a recurring theme in technical discussion. Independent analyses have found that labeled content and actual content can diverge, and that purity varies between samples. Analytical laboratories use reversed-phase chromatography to separate components and mass spectrometry to confirm identity. Isotope-labeled internal standards improve quantification in complex matrices. Such methods describe what a sample contains but say nothing about its sterility, lawful status, or suitability for any use. Open questions remain about how consistently testing is applied across the supply chain.
Regulatory treatment of this peptide varies by country. It holds no marketing authorization as a medicine in the United States, the European Union, or most other jurisdictions. Some countries classify products containing it as prescription-only or unlicensed medicines, which restricts lawful supply. Authorities have issued public notices warning that unregulated products may contain undeclared or incorrect ingredients. The molecule also appears on prohibited lists for competitive sport. These measures address supply oversight rather than any approved therapeutic role.
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.
== Treatment == The most important measure is prevention – avoidance of the drugs and foods that cause hemolysis. Vaccination against some common pathogens (e.g. hepatitis A and hepatitis B) may prevent infection-induced attacks. In the acute phase of hemolysis, blood transfusions might be necessary, or even dialysis in acute kidney failure. Blood transfusion is an important symptomatic measure, as the transfused red cells are generally not G6PD deficient and will live a normal lifespan in the recipient's circulation. Those affected should avoid drugs such as aspirin. Some patients may benefit from the removal of the spleen (splenectomy), as this is an important site of red cell destruction. Folic acid should be used in any disorder featuring a high red cell turnover. Although vitamin E and selenium have antioxidant properties, their use does not decrease the severity of G6PD deficiency. AG1, a recently discovered small molecule, has been shown to increase the activity of the G6PD enzyme in the three common variants of the deficiency. Due to the absence of medications to treat G6PD, AG1 is a promising precursor in developing a pharmacological treatment effective for multiple G6PD enzymopathies.
== Calculation of Backbone and Side Chain Torsion Angles == Protein torsion angles are calculated for phi, psi, omega (which corresponds to the peptide bond) and chi1 (the first side chain torsion angle) using standard IUPAC definitions. These values are listed under four different column headers: PHI, PSI, OMEGA and CHI1. All torsion angles are reported in degrees. Torsion angles are a very useful indicator of the stereochemistry and the stereochemical quality of a protein structure, with most high-quality proteins exhibiting a relatively tight clustering of phi/psi angles and relatively little deviation in the omega angles.
Galip Asvat, a successful hair salon business owner, is a gay man born in Klerksdorp. He moved to Hillbrow, which was a haven for the LGBTQ community, in the early 2000s. One early morning in 2007, Asvat was ambushed and raped by three men in his apartment building. On his attack, he said, "They thought I was a woman, and when they found out I was a man, that's when they became even more violent." His beating was brutal, and the gang of men nearly cut off his genitals. Sizakele Sigasa, a lesbian activist living in Soweto, and her partner Salome Masooa were raped, tortured, and murdered in July 2007. South African lesbian-gay rights organizations, including the umbrella-group Joint Working Group, said the attack was driven by lesbophobia. Two other rape/murders of lesbians occurred in South Africa earlier in Summer 2007: Simangele Nhlapo, member of an HIV-positive support group was raped and murdered in June, along with her two-year-old daughter; and Madoe Mafubedu, age 16, was raped and stabbed to death. On 28 April 2008, 31-year-old soccer player Eudy Simelane was abducted, gang-raped and killed in KwaThema, her hometown near Johannesburg. Simelane was a star of the South Africa's acclaimed Banyana Banyana national female football squad, an avid equality rights campaigner, and one of the first women to live openly as a lesbian in KwaThema. On 24 April 2011, LGBTQ activist Noxolo Nogwaza was raped and murdered in KwaThema. In 2013, two writers from South African men's magazine FHM were fired as a result of corrective rape jokes they made on Facebook.
Pribnow box Also –10 sequence or –10 element. A six-nucleotide consensus sequence, TATAAT, widely found in promoters of bacterial and phage genes. It is centered approximately 10 bases upstream of the transcription start site and serves as the binding site for RNA polymerase. See also TATA box.
Magnetic reconnection in highly conductive systems is important because it concentrates energy in time and space, such that gentle forces applied to a plasma over long periods of time can cause violent explosions and bursts of radiation. When the fluid cannot be considered completely conductive, but the other conditions for ideal MHD are satisfied, it is possible to use an extended model called resistive MHD. This includes an extra term in Ohm's law that models the collisional resistivity. Generally, MHD computer simulations are at least somewhat resistive because their computational grid introduces a numerical resistivity.
Sources: en.wikipedia.org
=== Computing === AAA, a level in the Web Content Accessibility Guidelines (WCAG) Advanced Amiga Architecture chipset Authentication, authorization, and accounting, a security framework ASCII adjust after addition, one of the Intel BCD opcodes for working with binary-coded decimal on x86 .aaa, the American Automobile Association's top-level Internet domain
=== Derivatives === Interest in cyclodextrins is enhanced because their host–guest behavior can be manipulated by chemical modification of the hydroxyl groups. O-Methylation and acetylation are typical conversions. Propylene oxide gives hydroxypropylated derivatives. The primary alcohols can be tosylated. The degree of derivatization is an adjustable, i.e. full methylation vs partial. Both β-cyclodextrin and methyl-β-cyclodextrin (MβCD) remove cholesterol from cultured cells. The methylated form MβCD was found to be more efficient than β-cyclodextrin. The water-soluble MβCD is known to form soluble inclusion complexes with cholesterol, thereby enhancing its solubility in aqueous solution. MβCD is employed for the preparation of cholesterol-free products: the bulky and hydrophobic cholesterol molecule is easily lodged inside cyclodextrin rings. MβCD is also employed in research to disrupt lipid rafts by removing cholesterol from membranes. Due to the covalent attachment of thiol groups to cyclodextrins high mucoadhesive properties can be introduced as these thiolated oligomers (thiomers) are capable of forming disulfide bonds with cysteine-rich subdomains of mucus glycoproteins. The gastrointestinal and ocular residence time of thiolated cyclodextrins is therefore substantially prolonged. Furthermore, thiolated cyclodextrins are actively taken up by target cells releasing their payload into the cytoplasma. The cellular uptake of various model drugs, for instance, was up to 20-fold improved by using thiolated α-cyclodextrin as carrier system.
Causes of T cell deficiency include lymphocytopenia of T cells and/or defects on function of individual T cells. Complete insufficiency of T cell function can result from hereditary conditions such as severe combined immunodeficiency (SCID), Omenn syndrome, and cartilage–hair hypoplasia. Causes of partial insufficiencies of T cell function include acquired immune deficiency syndrome (AIDS), and hereditary conditions such as DiGeorge syndrome (DGS), chromosomal breakage syndromes (CBSs), and B cell and T cell combined disorders such as ataxia-telangiectasia (AT) and Wiskott–Aldrich syndrome (WAS). The main pathogens of concern in T cell deficiencies are intracellular pathogens, including Herpes simplex virus, Mycobacterium and Listeria. Also, fungal infections are also more common and severe in T cell deficiencies.
Cartels have engaged in kidnapping, ransom, murder, robbery, and extortion of migrants traveling from Central America through Mexico on their way to the United States and Canada. Cartels have also forced migrants to join their organization and work for them, a situation that has been described as slavery. Mass graves have been also discovered in Mexico containing bodies of migrants. In 2011, 177 bodies were found in a mass grave in San Fernando, Tamaulipas, the same area where the bodies of 72 migrants were found in 2010, where most victims "died of blunt force trauma to the head." Cartels have also infiltrated the Mexican government's immigration agencies and attacked and threatened immigration officers. The National Human Rights Commission of Mexico (Comisión Nacional de los Derechos Humanos, CNDH) said that 11,000 migrants had been kidnapped in 6 months in 2010 by drug cartels.
== Biomarker == Fragments derived from the ANP precursor, including the signal peptide, NT-ProANP (N-terminal pro-ANP) and ANP, have been detected in human blood. ANP (28 residues long) is the active hormone while NT-proANP (98 residues) is the remaining part of proANP after cleavage by corin. ANP and associated peptides are used as biomarkers for cardiovascular diseases such as stroke, coronary artery disease, myocardial infarction and heart failure. A part of NT-proANP called mid-regional pro-atrial natriuretic peptide (MR-proANP) is a highly sensitive biomarker in heart failure. MR-proANP levels below 120 pmol/L can be used to effectively rule out acute heart failure. MR-proANP is measured using antibodies that bind to two consecutive parts of NT-proANP, residue number 53–72 and 73–90. In contrast, traditional NT-proANP measurement use antibodies that bind to the N-terminal of NT-proANP. In either case, antibodies are only able to determine the amount of peptides matching their epitope fragments. They largely cannot differentiate between a cleaved part (NT-proANP, ANP) and the uncleaved precursor (proANP). Large amounts of ANP secretion has been noted to cause electrolyte disturbances (hyponatremia) and polyuria. These indications can be a marker of a large atrial myxoma.
Sources: en.wikipedia.org
Indeed, at least four people have died in the course of either preparation for or institution of bone marrow transplantation for EB, out of only a small group of patients treated so far. The mechanism of action of this therapy is unclear as hematopoietic stem cells are not thought to contribute to epithelial lineages. Rather, it is speculated that cross-correction from tissue-resident graft-derived immune cells contributes to the observed clinical benefit. A pilot study performed in 2015 suggests that systemic granulocyte-colony stimulating factor (G-CSF) may promote increased wound healing in people with dystrophic EB. Transplanting skin derived from genetically modified stem cells onto the wound surfaces has been studied with a report of improvements in one person. A 2017 clinical trial with male RDEB (recessive dystrophic EB) patients conducted successful grafting of type VII gene corrected keratinocytes (COL7A1 gene correction using retrovirus transduction), without any serious adverse effects. Type VII collage formation was observed at the dermis-epidermis junction in significant amounts. A 2020 study demonstrated the safe allogenic grafting of acellular dermal matrix/scaffolds in EB patients without any observed infection or necrosis and instead noted fewer required dressing changes, promoted wound healing, pain reduction, and an overall improvement in the quality of life of the patients. In 2022, a pharmaceutical gel made out of birch bark extract from Betula pendula and Betula pubescens was approved by the European Union as a treatment for epidermolysis bullosa.
=== Exercise Therapy === Exercise based rehab is commonly used in the conservative management of tendinopathy. Strengthening exercises targeting the affected tendon, including eccentric, concentric, and isometric contractions, are frequently prescribed in clinical practice. Eccentric loading exercises, which involve muscle contraction while the muscle lengthens, are the most commonly used interventions for conditions such as patellar tendinopathy. A systematic review of randomized controlled trials involving individuals with chronic patellar tendinopathy found low- to very-low-quality evidence regarding the benefits of exercise compared with no treatment, glucocorticoid injections, or surgery. While exercise programs may reduce pain in some cases, studies have generally shown little or no difference in long-term function, pain outcomes, or return-to-sport rates when compared with other interventions.
== Pathology == Mutations in the PLOD1 gene have been linked to kyphoscoliotic Ehlers–Danlos syndrome (kEDS, in the past EDS VI).Mutations in the PLOD2 gene have been linked to Bruck syndrome in humans. A deficiency in its cofactor vitamin C is associated with scurvy.
=== Systemic lupus erythematosus === Systemic lupus erythematosus, referred to simply as lupus, is a systemic autoimmune disease that affects multiple organs, including the skin, joints, kidneys, and the nervous system. It is characterized by a widespread loss of immune tolerance. The disease is characterized by periods of flares and remissions, and symptoms range from mild to severe. Women, especially those of childbearing age, are disproportionately affected.
==== Deposition ==== The extracellular matrix of bone is laid down by osteoblasts, which secrete both collagen and ground substance. These cells synthesise collagen alpha polypeptide chains and then secrete collagen molecules. The collagen molecules associate with their neighbors and crosslink via lysyl oxidase to form collagen fibrils. At this stage, they are not yet mineralized, and this zone of unmineralized collagen fibrils is called "osteoid". Around and inside collagen fibrils calcium and phosphate eventually precipitate within days to weeks becoming then fully mineralized bone with an overall carbonate substituted hydroxyapatite inorganic phase. In order to mineralise the bone, the osteoblasts secrete alkaline phosphatase, some of which is carried by vesicles. This cleaves the inhibitory pyrophosphate and simultaneously generates free phosphate ions for mineralization, acting as the foci for calcium and phosphate deposition. Vesicles may initiate some of the early mineralization events by rupturing and acting as a centre for crystals to grow on. Bone mineral may be formed from globular and plate structures, and via initially amorphous phases.
Sources: en.wikipedia.org
The lyophilised solid is best kept cold, dry and dark, typically at minus twenty degrees Celsius. Moisture and repeated warming cycles are the main causes of degradation. Solutions prepared from the powder are less stable and are normally used quickly.
Reversed-phase liquid chromatography assesses purity, while mass spectrometry confirms molecular mass and detects sequence errors. Amino acid analysis and peptide mapping add structural detail. These techniques are complementary rather than interchangeable.
It is listed as a prohibited peptide hormone by the World Anti-Doping Agency. No medicines regulator has approved it for human use. Import and sale rules vary by country.
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.