Everything below concerns lyophilized powder. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-03-07. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
Handling guidance for melanotan II follows general practice for small synthetic peptides rather than a product-specific monograph. Lyophilized powder is typically kept at minus twenty degrees Celsius or colder, protected from light and moisture, because warmth and humidity accelerate degradation. Once reconstituted, solutions are usually refrigerated and used within a short window, as hydrolysis and microbial growth both become concerns. Repeated freeze-thaw cycles are generally avoided. These conventions come from laboratory peptide chemistry and not from formal stability studies on this specific compound.
| 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 |
Melanotan-2 is frequently confused with afamelanotide, a linear analogue authorised in the European Union for erythropoietic protoporphyria. The two compounds differ in chain length, ring structure and receptor selectivity, so findings for one cannot be transferred directly to the other. Published controlled human data on melanotan-2 remain sparse, and much of what circulates online derives from small studies or unpublished reports. Questions about effect size, dose-response behaviour and long-term safety therefore remain unresolved.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone. Its sequence incorporates a lactam bridge that constrains the peptide into a ring, which increases resistance to enzymatic breakdown relative to the natural hormone. Researchers at the University of Arizona synthesised the compound in the late 1980s and early 1990s while studying pigmentation pathways. It has never received marketing approval from any national medicines regulator. In the scientific literature it is usually described as a laboratory research reagent rather than a therapeutic product.
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.
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.
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.
Routine characterisation relies on reversed-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres, using a C18 column and a water-acetonitrile gradient containing trifluoroacetic acid. Electrospray ionisation mass spectrometry confirms the expected molecular mass and can reveal truncated or oxidised by-products that co-elute poorly. Sequence and stereochemistry require additional work, such as peptide mapping or amino acid analysis, because a chromatographic purity figure alone does not distinguish a diastereomer from the target peptide. Independent testing of research-grade material frequently shows measured content below the stated label, so a certificate of analysis is best read together with the method that produced it.
Melanotan-2 is handled in the laboratory as a lyophilised powder that dissolves readily in water, dimethyl sulfoxide and dimethylformamide, with limited solubility in ethanol. Stock solutions prepared in an organic solvent often precipitate when diluted into aqueous buffer, so gradual dilution with mixing is standard practice. The peptide carries a tryptophan residue and a histidine residue, both sensitive to oxidation and to alkaline conditions. Working solutions are therefore kept near neutral to slightly acidic pH, protected from light, and consumed within the same working session whenever that is practical.
== Poets == Dannie Abse, poet and physician Al Alvarez, poet Marc Bolan (born Mark Feld; 30 September 1947 – 16 September 1977); guitarist, singer, songwriter and poet; in 1969, wrote a collection of poems entitled The Warlock of Love; of Russian Jewish and Polish Jewish ancestry, Bolan was pioneer of glam rock movement in early 1970s with T. Rex; was inducted into the Rock and Roll Hall of Fame in 2020. Ivor Cutler, poet, humorist, musician Aviva Dautch, poet Elaine Feinstein, poet, writer, biographer Rose Fyleman, children's writer Karen Gershon, German-born poet Yvonne Green, (8 April 1957 – 16 April 2024) was an English poet, translator, writer and barrister. She was an Orthodox Jew, of Bukharian Jewish ancestry. Her first pamphlet, Boukhara, was published in 2007 and won The Poetry Business 2007 Book & Pamphlet Competition. Her first full-length collection, The Assay was published in 2010 and as a result of an award from Celia Atkin and Lord Gavron was translated into Hebrew in 2013, under the title HaNisuyi and published in Israel by Am Oved. Philip Hobsbaum, poet Jenny Joseph, poet Denise Levertov (1923-1997), British-born, naturalised American poet, feminist and anti-war activist. Amy Levy, poet and novelist Mina Loy (1882–1966); of Hungarian Jewish ancestry; artist, writer, poet, playwright, novelist, painter, designer, and bohemian; first-generation modernist; her poetry admired by T. S.
==== Orthopedics ==== As of 2017, use of mesenchymal stem cells (MSCs) derived from adult stem cells was under preliminary research for potential orthopedic applications in bone and muscle trauma, cartilage repair, osteoarthritis, intervertebral disc surgery, rotator cuff surgery, and musculoskeletal disorders, among others. Other areas of orthopedic research for uses of MSCs include tissue engineering and regenerative medicine.
18,000 hospitalizations 120 deaths (0.5 deaths per 100,000 inhabitants) 2.1 million lost days off work 1.2 million doctor consultations 300,000 prescriptions for antibiotics. Most foodborne disease outbreaks in Australia have been linked to raw or minimally cooked eggs or poultry. The Australian Food Safety Information Council estimates that one third of cases of food poisoning occur in the home.
=== Environmental activism === In 2004, Freeman helped form the Grenada Relief Fund to aid people affected by Hurricane Ivan on the island of Grenada. The fund has since become PLANIT NOW, an organization that seeks to provide preparedness resources for people living in areas affected by hurricanes and severe storms. In 2014, he narrated a clip titled What's Possible which had its debut at the United Nations climate summit. Freeman has donated to the Mississippi Horse Park in Starkville, Mississippi, part of Mississippi State University and Freeman has several horses that he takes there. After learning about the decline of honeybees, Freeman decided to turn his 124-acre ranch into a bee sanctuary in July 2014 beginning with 26 beehives. Freeman is a supporter of Oceana and ocean conservation.
Sources: en.wikipedia.org
Under reducing conditions, the blue-colored methylene blue cation (MB+) gains 1H+ and 2e− to become the electrically neutral and colorless leucomethylene blue (LMB). The redox midpoint potential E0' is +0.01 V. The redox properties can be seen in a classical demonstration of chemical kinetics in general chemistry, the "blue bottle" experiment. Typically, a solution is made of glucose (dextrose), methylene blue, and sodium hydroxide. Upon shaking the bottle, oxygen oxidizes methylene blue, and the solution turns blue. The dextrose will gradually reduce the methylene blue to its colorless, reduced form. Hence, when the dissolved dextrose is entirely consumed, the solution will turn blue again. In the mitochondrial electron transport chain, reduced methylene blue (MBH2) directly reduces cytochrome c rather than to oxygen, limiting the formation of superoxide. Methylene blue has been shown to directly accept electrons from NADH, NADPH, and FADH2.
=== Tandem fusion === The proteins of interest are simply connected end-to-end via fusion of N or C termini between the proteins. This provides a flexible bridge structure allowing enough space between fusion partners to ensure proper folding. However, the N or C termini of the peptide are often crucial components in obtaining the desired folding pattern for the recombinant protein, making simple end-to-end conjoining of domains ineffective in this case. For this reason, a protein linker is often needed to maintain the functionality of the protein domains of interest.
== Function == Angiogenin is a key protein implicated in angiogenesis in normal and tumor growth. Angiogenin interacts with endothelial and smooth muscle cells resulting in cell migration, invasion, proliferation and formation of tubular structures. Ang binds to actin of both smooth muscle and endothelial cells to form complexes that activate proteolytic cascades which upregulate the production of proteases and plasmin that degrade the laminin and fibronectin layers of the basement membrane. Degradation of the basement membrane and extracellular matrix allows the endothelial cells to penetrate and migrate into the perivascular tissue. Signal transduction pathways activated by Ang interactions at the cellular membrane of endothelial cells produce extracellular signal-related kinase1/2 (ERK1/2) and protein kinase B/Akt. Activation of these proteins leads to invasion of the basement membrane and cell proliferation associated with further angiogenesis. The most important step in the angiogenesis process is the translocation of Ang to the cell nucleus. Once Ang has been translocated to the nucleus, it enhances rRNA transcription by binding to the CT-rich (CTCTCTCTCTCTCTCTCCCTC) angiogenin binding element (ABE) within the upstream intergenic region of rDNA, which subsequently activates other angiogenic factors that induce angiogenesis. However, angiogenin is unique among the many proteins that are involved in angiogenesis in that it is also an enzyme with an amino acid sequence 33% identical to that of bovine pancreatic ribonuclease (RNase A).
=== EC 1.2.1 With NAD+ or NADP+ as acceptor === EC 1.2.1.1: deleted, replaced by EC 1.1.1.284, S-(hydroxymethyl)glutathione dehydrogenase and EC 4.4.1.22, S-(hydroxymethyl)glutathione synthase EC 1.2.1.2: Now EC 1.17.1.9, formate dehydrogenase EC 1.2.1.3: aldehyde dehydrogenase (NAD+) EC 1.2.1.4: aldehyde dehydrogenase (NADP+) EC 1.2.1.5: aldehyde dehydrogenase (NAD(P)+) EC 1.2.1.6: deleted (was benzaldehyde dehydrogenase) EC 1.2.1.7: benzaldehyde dehydrogenase (NADP+) EC 1.2.1.8: betaine-aldehyde dehydrogenase EC 1.2.1.9: glyceraldehyde-3-phosphate dehydrogenase (NADP+) EC 1.2.1.10: acetaldehyde dehydrogenase (acetylating) EC 1.2.1.11: aspartate-semialdehyde dehydrogenase EC 1.2.1.12: glyceraldehyde-3-phosphate dehydrogenase (phosphorylating) EC 1.2.1.13: glyceraldehyde-3-phosphate dehydrogenase (NADP+) (phosphorylating) EC 1.2.1.14: Now EC 1.1.1.205, IMP dehydrogenase EC 1.2.1.15: malonate-semialdehyde dehydrogenase EC 1.2.1.16: succinate-semialdehyde dehydrogenase [NAD(P)+] EC 1.2.1.17: glyoxylate dehydrogenase (acylating) EC 1.2.1.18: malonate-semialdehyde dehydrogenase (acetylating) EC 1.2.1.19: aminobutyraldehyde dehydrogenase EC 1.2.1.20: glutarate-semialdehyde dehydrogenase EC 1.2.1.21: glycolaldehyde dehydrogenase EC 1.2.1.22: lactaldehyde dehydrogenase EC 1.2.1.23: 2-oxoaldehyde dehydrogenase (NAD+) EC 1.2.1.24: succinate-semialdehyde dehydrogenase (NAD+) EC 1.2.1.25: branched-chain α-keto acid dehydrogenase system EC 1.2.1.26: 2,5-dioxovalerate dehydrogenase EC 1.2.1.27: methylmalonate-semialdehyde dehydrogenase (CoA-acylating) EC 1.2.1.28: benzaldehyde dehydrogenase (NAD+) EC 1.2.1.29: aryl-aldehyde dehydrogenase EC 1.2.1.30: aryl-aldehyde dehydrogenase (NADP+) EC 1.2.1.31: L-aminoadipate-semialdehyde dehydrogenase EC 1.2.1.32: aminomuconate-semialdehyde dehydrogenase EC 1.2.1.33: (R)-dehydropantoate dehydrogenase EC 1.2.1.34: Now EC 1.1.1.131, mannuronate reductase EC 1.2.1.35: Now EC 1.1.1.203, uronate dehydrogenase EC 1.2.1.36: retinal dehydrogenase EC 1.2.1.37: Now EC 1.17.1.4, xanthine dehydrogenase EC 1.2.1.38: N-acetyl-γ-glutamyl-phosphate reductase EC 1.2.1.39: phenylacetaldehyde dehydrogenase EC 1.2.1.40: part of EC 1.14.13.15, cholestanetriol 26-monooxygenase EC 1.2.1.41: glutamate-5-semialdehyde dehydrogenase EC 1.2.1.42: hexadecanal dehydrogenase (acylating) EC 1.2.1.43: Now EC 1.17.1.10, formate dehydrogenase (NADP+) EC 1.2.1.44: cinnamoyl-CoA reductase EC 1.2.1.45: Now EC 1.1.1.312, 2-hydroxy-4-carboxymuconate semialdehyde hemiacetal dehydrogenase EC 1.2.1.46: formaldehyde dehydrogenase EC 1.2.1.47: 4-trimethylammoniobutyraldehyde dehydrogenase EC 1.2.1.48: long-chain-aldehyde dehydrogenase EC 1.2.1.49: 2-oxoaldehyde dehydrogenase (NADP+) EC 1.2.1.50: long-chain-fatty-acyl-CoA reductase EC 1.2.1.51: pyruvate dehydrogenase (NADP+) EC 1.2.1.52: deleted 2025 (was oxoglutarate dehydrogenase (NADP+)) EC 1.2.1.53: 4-hydroxyphenylacetaldehyde dehydrogenase EC 1.2.1.54: γ-guanidinobutyraldehyde dehydrogenase EC 1.2.1.55: Now EC 1.1.1.279, (R)-3-hydroxyacid-ester dehydrogenase EC 1.2.1.56: Now EC 1.1.1.280, (S)-3-hydroxyacid-ester dehydrogenase EC 1.2.1.57: butanal dehydrogenase EC 1.2.1.58: phenylglyoxylate dehydrogenase (acylating) EC 1.2.1.59: glyceraldehyde-3-phosphate dehydrogenase (NAD(P)+) EC 1.2.1.60: 5-carboxymethyl-2-hydroxymuconic-semialdehyde dehydrogenase EC 1.2.1.61: 4-hydroxymuconic-semialdehyde dehydrogenase EC 1.2.1.62: 4-formylbenzenesulfonate dehydrogenase EC 1.2.1.63: 6-oxohexanoate dehydrogenase EC 1.2.1.64: 4-hydroxybenzaldehyde dehydrogenase (NAD+) EC 1.2.1.65: salicylaldehyde dehydrogenase EC 1.2.1.66: Now EC 1.1.1.306, S-(hydroxymethyl)mycothiol dehydrogenase EC 1.2.1.67: vanillin dehydrogenase EC 1.2.1.68: coniferyl-aldehyde dehydrogenase EC 1.2.1.69: fluoroacetaldehyde dehydrogenase EC 1.2.1.70: glutamyl-tRNA reductase EC 1.2.1.71: succinylglutamate-semialdehyde dehydrogenase EC 1.2.1.72: erythrose-4-phosphate dehydrogenase EC 1.2.1.73: sulfoacetaldehyde dehydrogenase EC 1.2.1.74: abieta-7,13-dien-18-al dehydrogenase EC 1.2.1.75: malonyl CoA reductase (malonate semialdehyde-forming) EC 1.2.1.76: succinate-semialdehyde dehydrogenase (acylating) EC 1.2.1.77: 3,4-dehydroadipyl-CoA semialdehyde dehydrogenase (NADP+) EC 1.2.1.78: 2-formylbenzoate dehydrogenase EC 1.2.1.79: succinate-semialdehyde dehydrogenase (NADP+) EC 1.2.1.80: long-chain acyl-[acyl-carrier-protein] reductase EC 1.2.1.81: sulfoacetaldehyde dehydrogenase (acylating) EC 1.2.1.82: β-apo-4′-carotenal oxygenase EC 1.2.1.83: 3-succinoylsemialdehyde-pyridine dehydrogenase EC 1.2.1.84: alcohol-forming fatty acyl-CoA reductase EC 1.2.1.85: 2-hydroxymuconate-6-semialdehyde dehydrogenase EC 1.2.1.86: geranial dehydrogenase EC 1.2.1.87: propanal dehydrogenase (CoA-propanoylating) EC 1.2.1.88: L-glutamate γ-semialdehyde dehydrogenase EC 1.2.1.89: D-glyceraldehyde dehydrogenase (NADP+) EC 1.2.1.90: glyceraldehyde-3-phosphate dehydrogenase [NAD(P)+] EC 1.2.1.91: 3-oxo-5,6-dehydrosuberyl-CoA semialdehyde dehydrogenase EC 1.2.1.92: 3,6-anhydro-α-L-galactose dehydrogenase EC 1.2.1.93: formate dehydrogenase (NAD+, ferredoxin). Now EC 1.17.1.11, formate dehydrogenase (NAD+, ferredoxin) * EC 1.2.1.94: farnesal dehydrogenase EC 1.2.1.95: L-2-aminoadipate reductase EC 1.2.1.96: 4-hydroxybenzaldehyde dehydrogenase (++) EC 1.2.1.97: 3-sulfolactaldehyde dehydrogenase EC 1.2.1.98: 2-hydroxy-2-methylpropanal dehydrogenase EC 1.2.1.99: 4-(γ-glutamylamino)butanal dehydrogenase EC 1.2.1.100: 5-formyl-3-hydroxy-2-methylpyridine 4-carboxylic acid 5-dehydrogenase EC 1.2.1.101: L-tyrosine reductase EC 1.2.1.102: isopyridoxal dehydrogenase (5-pyridoxate-forming) EC 1.2.1.103: [amino-group carrier protein]-6-phospho-L-2-aminoadipate reductase EC 1.2.1.104: pyruvate dehydrogenase system EC 1.2.1.105: 2-oxoglutarate dehydrogenase system EC 1.2.1.106: [amino-group carrier protein]-5-phospho-L-glutamate reductase EC 1.2.1.107: glyceraldehyde-3-phosphate dehydrogenase (arsenate-transferring)
=== Age-Related and Pathological Changes === Deposition of secondary cementum may alter the diameter and shape of the apical foramen over time. Pathological conditions such as periodontal diseases can cause widening or resorption of the apical foramen.
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.
The lyophilized powder is generally held at minus twenty degrees Celsius or below, away from light and moisture. Reconstituted solutions are typically refrigerated and used quickly. These practices derive from general peptide handling rather than a formal stability study.