This is a working overview of Melanotan II, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-04-09 and is reviewed periodically as new material appears.
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.
Receptor-binding studies classify melanotan II as a non-selective melanocortin agonist. It interacts with MC1R, MC3R, MC4R and MC5R, with reported affinities in the low nanomolar range and no strong subtype preference. Activation of MC1R on dermal melanocytes shifts pigment synthesis toward eumelanin, the dark polymer deposited in melanosomes and transferred to keratinocytes. Because the same peptide engages MC4R in the hypothalamus, it also appears in animal work on food intake and erectile response, which is why it is discussed in both pigment and metabolic research. Which receptor populations dominate after systemic exposure in humans is not fully established.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Cyclic heptapeptide, C-terminally amidated |
| Approximate molecular mass | 1024 Da | Monoisotopic mass of the free peptide |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility class | Soluble in water and polar solvents | Also dissolves in neutral aqueous buffer |
| Common synonyms | Melanotan II, MT-II, MT-2 | Described as a melanocortin agonist in early literature |
The peptide was developed during the 1980s by researchers investigating melanocortin signalling and skin pigmentation pathways. Early work focused on analogues of alpha-melanocyte-stimulating hormone that would resist enzymatic breakdown more effectively than the parent molecule. Melanotan-2 emerged from that programme as a shortened, cyclised variant. Reports describing its synthesis and receptor activity later appeared in the scientific literature. Commercial availability grew through unregulated channels rather than through pharmaceutical approval.
Structurally, Melanotan-2 retains the core recognition motif of alpha-melanocyte-stimulating hormone while adding a lactam bridge that links two side chains and constrains the molecule into a ring. This modification lowers susceptibility to enzymatic degradation. The compound acts as an agonist at melanocortin receptors, particularly subtypes associated with melanin production. Because the same receptor family influences several physiological processes, researchers note that its activity is not confined to pigmentation alone. Receptor selectivity continues to be examined in published studies.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone, a naturally occurring peptide involved in pigmentation signalling. Its sequence incorporates modified residues that increase potency and extend biological activity relative to the native hormone. The compound binds receptors of the melanocortin family and is examined mainly in laboratory research. It does not occur naturally and exists only as a manufactured chemical entity produced by solid-phase synthesis.
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.
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 treatment varies by country. In the United States, melanotan-2 is not approved for any indication, and products marketed for human use fall outside the approved drug framework. Some other jurisdictions have placed it under prescription controls or listed it as a prohibited or restricted substance. Online listings frequently describe the material as a research chemical, a category that does not carry the same manufacturing and labelling requirements as approved medicines.
Solid peptide material is generally stable when kept cold and dry. Common practice is storage at -20 degrees Celsius or lower, with desiccant and protection from light. Repeated freeze-thaw cycles and exposure to moisture are associated with degradation, aggregation, or loss of material. Once dissolved, stability depends on solvent, concentration, and temperature, and solutions are usually treated as short-lived unless stability data support longer periods. Handling notes typically emphasise minimising time at ambient temperature.
Identity and purity are assessed with chromatographic and mass spectrometric techniques. Reversed-phase high-performance liquid chromatography separates the target peptide from related impurities and degradation products, and the resulting retention time is compared against a reference standard. Mass spectrometry, often coupled to liquid chromatography, confirms molecular mass. Amino acid analysis or peptide mapping can provide additional sequence-level confirmation when required. Results are only as reliable as the reference materials used alongside them.
=== Carbonyl protecting groups === The most common protecting groups for carbonyls are acetals and typically cyclic acetals with diols. The runners-up used are also cyclic acetals with 1,2‑hydroxythiols or dithioglycols – the so-called O,S– or S,S-acetals.
=== Prescription trends === Between 1998 and 2017, along with imipramine, amitriptyline was the most commonly prescribed first antidepressant for children aged 5–11 years in England. It was also the most prescribed antidepressant (along with fluoxetine) for 12- to 17-year-olds.
=== Economics === In December 2019, the US FDA approved a generic version of apixaban produced jointly by Mylan and Micro Labs. BMS and Pfizer worked quickly to block generics from being created, and in August 2020, they won a patent infringement lawsuit against Sigmapharm, Sunshine Lake, and Unichem, after previously settling patent cases against 25 other companies. In September 2021, a Federal Circuit Court upheld the ruling. The result is that apixaban generics will most likely not be available in the United States until at least 2026, but possibly 2031. In July 2022, the Canadian generic drug company, Apotex Inc., obtained approval for marketing of apixaban. Pfizer reported revenue of US$6.747 billion for Eliquis in 2023. Apixaban is one of ten medications covered by price negotiations in the US under the Inflation Reduction Act. The negotiations, conducted by the Centers for Medicare & Medicaid Services, apply to pricing for Medicare recipients. The results of the negotiations were announced in August 2024, and Medicare's negotiated price for a 30-day supply of Eliquis is $231, a 56% decrease from the 2023 list price of $521. The pricing is set to take effect in 2026.
The most common applications are as an ingredient in dietary supplement, in cosmetics, as flavoring for foods, such as turmeric-flavored beverages in South and Southeast Asia, and as coloring for foods, such as curry powders, mustards, butters, and cheeses. As a food additive for orange-yellow coloring in prepared foods, its E number is E 100 in the European Union. It is also approved by the U.S. FDA to be used as a food coloring in US.
Serous: Clear straw colored liquid that drains from the wound. This is a normal part of the healing process. Serosanguineous: Small amount of blood is present in the drainage; it is pink in color due to the presence of red blood cells mixed with serous drainage. This is a normal part of the healing process. Sanguineous: This type of drainage contains red blood due to trauma of blood vessels, this may occur while cleaning the wound. Sanguineous drainage is abnormal. Hemorrhaging: This type of drainage contains frank blood from a leaking blood vessel. This will require emergency treatment to control the bleed. This type of drainage is abnormal. Purulent drainage: This type of drainage is malodorous and can be yellow, gray, or greenish in color. This is an indication of an infection.
Sources: en.wikipedia.org
=== 1991 === January 1991 – Money transfers from the Czech Republic budget to the Slovak Republic are stopped, beginning the process that would lead to Velvet Divorce. February 28, 1991 – End of Gulf War. March 3, 1991 – Estonia and Latvia hold an independence referendum with a majority voting to restore independence. March 31, 1991 – Georgia holds an independence referendum resulting in a majority of Georgians voting in favour of Georgia becoming independent from the Soviet Union. May 1, 1991 – The Republic of China abolishes the Temporary Provisions against the Communist Rebellion which was in place during the Chinese Civil War. May 19, 1991 – Croatia holds an independence referendum resulting in a majority of Croatians voting in favour of Croatia seeking independence from Yugoslavia. May 24, 1991 – End of Eritrean War of Independence in Ethiopia. June 27, 1991 – Beginning of the Yugoslav Wars in Slovenia. June 28, 1991 – Comecon is dissolved. July 1, 1991 – The Warsaw Pact is dissolved. July 10, 1991 – Boris Yeltsin becomes president of Russia. July 31, 1991 – Ratification of START I treaty between United States and the Soviet Union. August 19, 1991 – Start of the Soviet Union coup d'état attempt. August 21, 1991 – The Soviet Union coup d'état is dissolved. August 24, 1991 – Gorbachev resigns from the post of General Secretary of the Communist Party of the Soviet Union. September 6, 1991 – The Soviet Union recognizes the independence of the Baltic States.
In late January, several CDC websites, pages, and datasets related to HIV and STI prevention, and LGBT and youth health became unavailable for viewing. In mid-February, around 1,300 CDC employees were laid off. In April, it was reported that among the reductions were the elimination of the Freedom of Information Act team, the Division of Violence Prevention, labs involved in testing for antibiotic resistance, and the team responsible for recalls of hazardous infant products. Additional cuts affected the technology branch of the Center for Forecasting and Outbreak Analytics, which was established during the COVID-19 pandemic. On June 25, 2025, Kennedy announced that the U.S. was stopping its donations to the Gavi vaccine alliance, until Gavi can better demonstrate vaccine safety. The United States had been providing approximately 13 percent of Gavi's budget. On August 5, 2025, Secretary Kennedy announced that he was stopping 22 vaccine projects using mRNA technology, including Covid, RSV, and bird flu. A critic of this funding halt pointed out that mRNA vaccines have the potential for faster roll-out. On December 5, 2025, it was no longer systematically recommended for newborns of mothers having never gotten Hepatitis B to get vaccinated against this infection. The memos sparked indignation among most health experts. On February 24, 2026, more than a dozen U.S.
=== Morphology === Vernix is composed of mobile corneocytes embedded in an amorphous lipid matrix. Precise biological mechanisms leading to its formation are poorly understood. The cells are polygonal or ovoid in shape, malleable, and lack nuclei; typical thickness is 1-2 μm. Nuclear ghosts are frequently observed and Acid Phosphatase Activity is nonuniform. Keratin filaments build a scaffold like structure which form a water-storage area. As opposed to stratum corneum, the vernix corneocytes lack desmosomal attachment and the lipid layer is more disordered.
Brenner has developed targeted, quantitative analysis of the NAD+ metabolome and made fundamental contributions to NAD metabolism including discovery of nicotinic acid riboside-dependent NAD synthesis, elucidating the mechanism of synthesis of nicotinic acid adenine dinucleotide phosphate, and discovering multiple conditions in which NAD metabolism is dysregulated in disease. Brenner is active in translating NR technologies to treat and prevent human conditions that disturb the NAD system including cancer diabetic and chemotherapeutic peripheral neuropathy, heart failure, central brain injury, inflammation, mitochondrial myopathy pellagra, and infections such as coronavirus infection Brenner's work included the first human trial of NR in 2016, which demonstrated safe oral availability as an NAD+ precursor, thereby creating the foundational intellectual property for the NAD boosting industry. Though Brenner was the first to show that NR increases SIR2 activity, improves gene silencing, and can extend yeast lifespan, his work has not emphasized sirtuins or nonspecific anti-aging claims and instead emphasizes how NR repairs inflammatory conditions and metabolic stresses that dysregulate NAD+ and NADPH.
Sources: en.wikipedia.org
No. It is a synthetic analogue carrying four amino acid changes, a lactam ring and an amidated C-terminus. The natural hormone is a linear thirteen-amino-acid peptide processed from proopiomelanocortin.
Afamelanotide is the linear analogue [Nle4-D-Phe7]-alpha-MSH, sometimes called melanotan I, while melanotan II is cyclic and carries three further substitutions. The two are distinct molecules and are not interchangeable in analytical testing.
Binding to the four melanocortin receptor subtypes is well documented in vitro. The relative contribution of each subtype to whole-body effects in humans is far less certain.
Low temperature slows hydrolysis and oxidation, the two main routes by which the peptide backbone and side chains are modified. A lyophilised powder stored at −20 °C is more stable than one kept at room temperature, and once the material is dissolved the degradation rate rises, making refrigeration more important.