Melanotan II is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2026-04-02. Numbers and descriptions here follow the published literature rather than marketing material.
The compound was developed in the late 1980s and 1990s by academic researchers investigating photoprotection. The rationale held that stimulating melanin production might reduce ultraviolet damage to skin and lower skin cancer risk. Early work examined receptor binding, pigment response, and short-term tolerability in small studies. That program did not produce an approved drug, and formal development stalled after early-phase trials. Whether induced pigmentation confers meaningful photoprotection remains an open question.
Outside regulated medicine, melanotan II circulates through online vendors as a research chemical, often marketed for tanning. Products sold this way vary widely in purity, concentration, and labeling accuracy, and independent testing has documented discrepancies. Published reports describe both pigment effects and adverse reactions, including nausea, flushing, and darkening of existing moles. Long-term safety data are sparse, and no large controlled trial has established a risk profile. Questions about cumulative effects on melanocytes remain unresolved in the literature.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Belongs to the melanocortin agonist family |
| Key substitutions | Nle4 and D-Phe7 | Improve resistance to enzymatic degradation |
| Molecular formula | C50H69N15O9 | Approximately 1024 g/mol |
| Regulatory status | Not approved as a medicine | Distributed as a research chemical |
| Common synonyms | Melanotan II, MT-II, MT-2 | Spelling varies across sources |
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.
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.
== Overview == Dependent origination is a philosophically complex concept, subject to a large variety of explanations and interpretations. As the interpretations often involve specific aspects of dependent origination, they are not necessarily mutually exclusive to each other. Dependent origination can be contrasted with the classic Western concept of causation in which an action by one thing is said to cause a change in another thing. Dependent origination instead views the change as being caused by many factors, not just one or even a few. The principle of dependent origination has a variety of philosophical implications.
== Channel blockers == P-type calcium channel blockers act to impede the flow of calcium. The blocking of calcium currents may cause the organism to experience impaired functioning and viability. These effects can lead to various diseases which are described in more detail in the section below. The pore of P-type calcium channels are sensitive to compounds that can be divided into three groups:
== First published posthumously == De Profundis (written 1895–97, in Reading Gaol). Expurgated edition published 1905; suppressed portions 1913, expanded version in The Letters of Oscar Wilde (1962). The Rise of Historical Criticism (written while at college). First published in 1905 (Sherwood Press, Hartford, CT), privately printed. Reprinted in Miscellanies, the last volume of the First Collected Edition (1908). The First Collected Edition (Methuen & Co., 14 volumes) appeared in 1908 and contained many previously unpublished works. The Second Collected Edition (Methuen & Co., 12 volumes) appeared in installments between 1909–11 and contained several other unpublished works. The Letters of Oscar Wilde (written 1868–1900). Published in 1962. Republished as The Complete Letters of Oscar Wilde (2000), with letters discovered since 1962 and new annotations by Merlin Holland. The Women of Homer (written 1876, while at college). First published in Oscar Wilde: The Women of Homer (2008) by the Oscar Wilde Society.
Sources: en.wikipedia.org
Bombesin-like peptides comprise a large family of peptides which were initially isolated from amphibian skin, where they stimulate smooth muscle contraction. They were later found to be widely distributed in mammalian neural and endocrine cells. The amphibian peptides which belong to this family are currently classified into three subfamilies; the Bombesin group, which includes bombesin and alytesin; the Ranatensin group, which includes ranatensins, litorin, and Rohdei litorin; and the Phyllolitorin group, which includes Leu(8)- and Phe(8)-phyllolitorins. In mammals and birds two categories of bombesin-like peptides are known, gastrin-releasing peptide (GRP), which stimulates the release of gastrin as well as other gastrointestinal hormones, and neuromedin B (NMB), a neuropeptide whose function is not yet clear. Bombesin-like peptides, like many other active peptides, are synthesized as larger protein precursors that are enzymatically converted to their mature forms. The final peptides are eight to fourteen residues long.
Anwar's conviction drew criticism from the international community. US Secretary of State Madeleine Albright defended Anwar as a "highly respectable leader" who was "entitled to due process and a fair trial" and met with Anwar's wife, Wan Azizah Wan Ismail. Wan Azizah had formed a liberal opposition party, the National Justice Party (Keadilan) to contest in the 1999 election. UMNO lost 18 seats and two state governments. By July 2001, Mahathir had reached his 20th year in power but discouraged grand celebrations. Around the same time, Mahathir established the Women's Affairs Ministry and proposed an amendment to Article 8(2) of the Federal Constitution to include "sex" as a prohibited ground for discrimination, ensuring women's equal rights. He also launched Puteri Umno, urging party members to support and nurture the new women's wing. In May 2002, Mahathir officially opened the PETRONAS Petroleum Industry Complex (PPIC) in Kerteh, a world-class integrated petroleum hub developed by Petronas that attracted significant foreign investment. During the same time, he also approved Malaysian Chinese Association (MCA) President Ling Liong Sik's proposal to establish Universiti Tunku Abdul Rahman (UTAR). During his tenure, Mahathir proposed sending a Malaysian into space, and on 7 August 2003, he officially announced the astronaut programme. This initiative came to fruition in 2007, when Sheikh Muszaphar Shukor became the first Malaysian astronaut to travel to the International Space Station aboard a Soyuz spacecraft under an arrangement with Russia.
=== Genetic stability === In order for there to be genetic stability within a marijuana strain the breeder has to go through selection and breeding, pinpointing the dominant and recessive genes within the two strains being crossed. After analyzing offspring with the preferred traits a breeder is looking for, the breeder will select the preferred traits and continue to breed those offspring to create the desired final product. Selection is a crucial process for a breeder to create a strain, especially if a client is looking for something with specific plant traits the breeder has to ensure that the hybrid's genetic traits have been closed in enough so unwanted traits aren't expressed in future harvests.
Sources: en.wikipedia.org
Here, when a = b, Poiseuille flow for circular pipe is recovered and when a → ∞, plane Poiseuille flow is recovered. More explicit solutions with cross-sections such as snail-shaped sections, sections having the shape of a notch circle following a semicircle, annular sections between homofocal ellipses, annular sections between non-concentric circles are also available, as reviewed by Ratip Berker.
== External links == Overview at colostate.edu Nosek, Thomas M. "Section 6/6ch2/s6ch2_27". Essentials of Human Physiology. Archived from the original on 2016-03-24. Enteroglucagon at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
==== England (1920, 1923, 1925, 1935, 1938, 1946) ==== Constance Long arranged for Jung to deliver a seminar in Cornwall in 1920. Another seminar was held in 1923, this one organized by Jung's British protégé Helton Godwin Baynes (known as "Peter") (1882–1943), and another in 1925.
Sources: en.wikipedia.org
It is a synthetic cyclic peptide designed as an analog of alpha-melanocyte-stimulating hormone. It acts on melanocortin receptors and is best known from research into pigmentation. It is not an approved pharmaceutical product.
No regulatory agency has approved it for any indication. It is encountered as a research chemical sold outside pharmaceutical supply chains. Products marketed this way are not subject to the manufacturing and labeling requirements that apply to approved drugs.
Reports describe increased skin pigmentation as well as side effects such as nausea, flushing, and changes to existing moles. Much of the evidence comes from small studies and case reports rather than large trials. The long-term safety profile is therefore uncertain.
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.