A practical reference on melanotan II: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-06-11. Anything still debated is marked as such rather than presented as settled.
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.
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.
| 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 |
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.
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.
No regulatory authority has approved melanotan-2 for human use, and several countries classify it as a prescription-only or controlled substance, which restricts lawful supply. Material sold online is generally labelled as a research chemical and is not required to meet pharmaceutical standards of identity or purity. Published human data consist mainly of small uncontrolled studies, case reports and adverse-event notifications, so the evidence base is descriptive rather than confirmatory. Whether repeated melanocyte stimulation alters long-term naevus behaviour remains an open question that no completed trial has resolved.
Melanotan-2 is a synthetic cyclic heptapeptide designed as a structural analogue of alpha-melanocyte-stimulating hormone, the endogenous tridecapeptide that regulates pigment production. Two modifications distinguish it from the natural hormone: norleucine replaces methionine at the N-terminus, which limits oxidation, and a D-phenylalanine substitution raises receptor affinity. The ring is closed through an aspartate-lysine lactam bridge, giving the molecule a constrained conformation. The free base has a molecular mass near 1024 daltons, and commercial material is usually supplied as an acetate salt. It appears in the literature as a research peptide rather than an approved therapeutic agent.
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.
In physics, the first law of thermodynamics is an expression of the conservation of total energy of a system. The increase of the energy of a system is equal to the sum of work done on the system and the heat added to that system:
Narrowly most residents included an owner-occupier in their household, with 23.17% of households owning their house outright, and a further 31.33% owning with a mortgage. 10.59% were in local authority housing, with a further 13.29% renting from a housing association, or other registered social landlord. The 2021 census found that the borough has England and Wales's lowest proportion of people born in the UK, at 43.9%. The borough of Brent is extremely ethnically diverse, having changed greatly since 1951. In the 2011 census, those who identified as White British made up 18% of the borough's population. 18% identified as other White, 5% were of mixed heritage, those of South Asian heritage comprised about 33%, those of African and Caribbean heritage about 19%, and other ethnic groups about 7%. White ethnicities were relatively high in the wards of Mapesbury (straddling Willesden Green and Cricklewood), Brondesbury Park, Queen's Park and Kilburn. Black ethnicities in highest proportion were in Stonebridge, Harlesden and Kensal Green wards. Asian ethnicities in highest proportion were in the wards of Alperton, Wembley Central and Kenton. Those who ethnically identify as BAME (Black, Asian and minority Ethnic) was as high as 86% in Wembley Central – one of the highest in London – and most other Brent wards have a majority BAME population. Queen's Park had the lowest BAME proportion, at 37.0%. Brent has the highest proportion of Irish residents in Britain, with 4% of the population.
The combination of an estrogen and oral or vaginal progesterone has been found to improve cardiovascular health in women in early menopause but not in women in late menopause. Estrogen therapy has a favorable influence on the blood lipid profile, which may translate to improved cardiovascular health. The addition of oral or vaginal progesterone has neutral or beneficial effects on these changes. This is in contrast to various progestins, which are known to antagonize the beneficial effects of estrogens on blood lipids. Progesterone, both alone and in combination with an estrogen, has been found to have beneficial effects on skin and to slow the rate of skin aging in postmenopausal women. In the French E3N-EPIC observational study, the risk of diabetes was significantly lower in women on menopausal hormone therapy, including with the combination of an oral or transdermal estrogen and oral progesterone or a progestin.
On 26 November 2018, the mayor of Moscow, Sergey Sobyanin, participated in the ceremony to launch the cable car above the Moskva River. This car connects the Luzhniki sports complex with Sparrow Hills and Kosygin Street. The trip from the viewpoint on Vorobyovy Gory to Luzhniki Stadium takes only five minutes, rather than 20 minutes by car.
Sources: en.wikipedia.org
== Drug interactions == Both dalfopristin and quinupristin are extensively hepatically metabolized, excreted from the feces, and serve as an inhibitor of cytochrome P450 (CYP) 3A4 enzyme pathway. Caution should be taken with concommitent use with drugs metabolized by the CYP3A4 pathway. Concomitant use of quinupristin/dalfopristin with cyclosporine for 2–5 days has shown to result in a two-fold increase in cyclosporine levels. No adverse effects have been seen in patients with hepatic impairment and no recommendations by the manufacturer have been made for dose reduction of quinupristin/dalfopristin in this patient population.
He served as President of the Kedah Tuberculosis Association, visiting Indian workers on rubber plantations to treat the disease, while she volunteered in the Kedah Family Planning Association. With the money from his medical practice, Mahathir indulged in his entrepreneurial streak and invested in property development, tin mining, a franchised petrol station, and a shop to do quick printing–sometimes to rescue Malay businessmen in trouble. He helped found the Malay Chamber of Commerce and served as its director.
== Uses == Fritillaria extracts are used in traditional Chinese medicine under the name chuan bei mu, and in Latin, bulbus fritillariae cirrhosae. The bulbs of Fritillaria roylei have been used as antipyretics and expectorants. Lilium bulbs, particularly Lanzhou lily (Lilium davidii) are used as food in China and other parts of Asia. Calochortus bulbs were eaten by Native Americans and as a famine food by Mormon settlers. During World War II, starvation conditions in the Netherlands (Hongerwinter, hunger winter 1944) led to Tulipa bulbs being used as food. Other members of the family used for food include Clintonia (leaves), Medeola (roots), Erythronium (corms), and Fritillaria (bulbs).
frameshift mutation A type of mutation in a nucleic acid sequence caused by the insertion or deletion of a number of nucleotides that is not divisible by three. Because of the triplet nature by which nucleotides code for amino acids, a mutation of this sort causes a shift in the reading frame of the nucleotide sequence, resulting in the sequence of codons downstream of the mutation site being completely different from the original.
== Legislation == The plight of patients with rare diseases became an important political issue in the late 1970s and early 1980s. The US government was subject to pressure from activist groups such as NORD and many others. The chief sponsor of the bill (H.R. 5238) was Henry Waxman (sometimes referred to as the author of the Act), chairman of the Energy and Commerce Subcommittee on Health. It passed the House of Representatives on 14 December 1982, and was similarly approved by voice vote in the Senate on 17 December. On 4 January 1983, President Ronald Reagan signed the ODA into law. Under the ODA drugs, vaccines, and diagnostic agents would qualify for orphan status if they were intended to treat a disease affecting less than 200,000 American citizens. In order to encourage the development of drugs for orphan diseases, the ODA included a number of incentives including seven-year market exclusivity for companies that developed orphan drug, tax credits equal to half of the development costs, later changed to a fifteen-year carry-forward provision and a three-year carry-back that can be applied in profitable year, grants for drug development, fast-track approvals of drugs indicated for rare diseases, and expanded access to the Investigational New Drug Program. The law was also later amended to waive user fees charged under PDUFA. Market exclusivity is particularly appealing to pharmaceutical firms as an incentive to pursue orphan drug development.
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. No major regulatory agency has granted a marketing authorisation for melanotan II as a medicine. Products sold under this name are generally presented as laboratory reagents and are not subject to the batch-release testing applied to approved drugs.