Everything below concerns melanocortin receptor. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-01-28. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Analog of alpha-melanocyte-stimulating hormone |
| Primary receptor family | Melanocortin receptors MC1R through MC5R | Binding is not subtype-selective |
| Development period | 1980s | Synthesized during pigmentation and appetite research |
| Regulatory status | Not an approved medicine | No major regulator has authorized human use |
| Related compound | Afamelanotide | Linear analog studied for photoprotection |
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.
Melanotan-2 is a synthetic peptide designed as an analog of alpha-melanocyte-stimulating hormone, a signaling molecule produced in the pituitary and skin. Its structure is a linear chain of seven amino acids that folds into a ring through an internal lactam bridge joining two side chains. The compound is sometimes written as MT-II or MEL-2 in informal and commercial contexts. It belongs to the melanocortin peptide family, a group of short signaling molecules that share a conserved core sequence recognized by melanocortin receptors.
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.
1913: Canadian physician and chemist Maud Menten co-authored a paper on enzyme kinetics, leading to the development of the Michaelis–Menten kinetics equation. 1914–1918: During World War I, a team of seven British women chemists conducted pioneering research on chemical antidotes and weaponized gases. The project leader, Martha Annie Whiteley, was awarded the Order of the British Empire for her wartime contributions. 1914-1918: English botanist and mycologist Helen Gwynne-Vaughan was the first woman to be awarded a military DBE for her wartime service in January 1918. She served as Commandant of the Women's Royal Air Force (WRAF) from September 1918 until December 1919. 1914: British-born mycologist Ethel Doidge became the first woman in South Africa to receive a doctorate in any subject, receiving her doctorate of science degree from the University of the Good Hope. She wrote her thesis on "A bacterial disease of mango". 1916: Canadian horticulturist Isabella Preston became the first female professional plant hybridist in Canada, producing the George C. Creelman trumpet lily. Her lily later received an Award of Merit from the Royal Horticultural Society. 1916: Chika Kuroda became the first Japanese woman to earn a bachelor of science degree, studying chemistry at the Tohoku Imperial University. After graduation, she was subsequently appointed an assistant professor at the university. 1917: American zoologist Mary J. Rathbun received her PhD from the George Washington University.
Control of the process of gene transcription affects patterns of gene expression and, thereby, allows a cell to adapt to a changing environment, perform specialized roles within a multicellular organism, and maintain basic metabolic processes necessary for survival. The activity of RNAP is complex and highly regulated. In Escherichia coli bacteria, more than 100 transcription factors have been identified, which modify the activity of RNAP. RNAP can initiate transcription at specific DNA sequences known as promoters. It then produces an RNA chain, which is complementary to the template DNA strand. The process of adding nucleotides to the RNA strand is known as elongation; in eukaryotes, RNAP can build chains as long as 2.4 million nucleotides (the full length of the dystrophin gene). RNAP will preferentially release its RNA transcript at specific DNA sequences encoded at the end of genes, which are known as terminators. Products of RNAP include:
Pulmonary fibrosis may be a secondary effect of other diseases. Most of these are classified as interstitial lung diseases. Examples include autoimmune disorders, viral infections, and bacterial infections such as tuberculosis that may cause fibrotic changes in the lungs' upper or lower lobes and other microscopic lung injuries. But pulmonary fibrosis can also appear without any known cause. In that case, it is termed "idiopathic". Most idiopathic cases are diagnosed as idiopathic pulmonary fibrosis. This is a diagnosis of exclusion of a characteristic set of histologic/pathologic features known as usual interstitial pneumonia (UIP). In either case, a growing body of evidence points to a genetic predisposition in a subset of patients. For example, a mutation in surfactant protein C (SP-C) has been found in some families with a history of pulmonary fibrosis. Autosomal dominant mutations in the TERC or TERT genes, which encode telomerase, have been identified in about 15% of pulmonary fibrosis patients. Diseases and conditions that may cause pulmonary fibrosis as a secondary effect include:
Performance-enhancing substances (PESs), also known as performance-enhancing drugs (PEDs), are substances that are used to improve any form of activity performance in humans. Many substances, such as anabolic steroids, can be used to improve athletic performance and build muscle, which in most cases is considered cheating by organized athletic organizations. This usage is often referred to as doping. Athletic performance-enhancing substances are sometimes referred to as ergogenic aids. Cognitive performance-enhancing drugs, commonly called nootropics, are sometimes used by students to improve academic performance. Performance-enhancing substances are also used by military personnel to enhance combat performance.
Still, the index closed at its all-time high of 24,121.74, for its first close above 24,000 points. The SENSEX closed at 25,019.51, for its first close above the 25,000 milestone on 5 June 2014 26,000, 7 July 2014- The SENSEX crossed record 26,000 level for the first time on 7 July 2014 and reached its peak of 26,123.55, before closing slightly lower at 26,100.08, in anticipation of strong reformatory budget by the new government. 27,000, 2 September 2014 - The SENSEX closed at 27,019.39, for its first close above the 27,000 level, on 2 September 2014. This is the sixth 1000-point milestone the index has crossed in 2014, tying a record set in 2007. 28,000, 5 November 2014 - The SENSEX crossed 28,000 mark, on 5 November 2014. One week later, on 12 November 2014, the index would close above the milestone for the first time. This is the seventh 1000-point milestone the index has crossed in 2014, breaking the six 1000-point record set in 2007. 29,000, 23 January 2015 - BSE Sensex today set a new high of 29,408 points and all-time closing high of 29,278.84, up 272.82 points 30,000, 4 March 2015 - The Sensex breaches 30000 mark following steps taken by the Reserve Bank of India in cutting the repo rates. 26 April 2017 - The SENSEX closed at 30,133.35, for its first close above the 30,000 level. 31,000, 26 May 2017- The SENSEX crossed record 31,000 level for the first time on 26 May 2017 and reached its peak of 31,074.07, before closing slightly lower at 31,028.21. 32,000, 13 July 2017 - The SENSEX closed at 32,037.38, for its first close above the 32,000 level, on 13 July 2017.
Sources: en.wikipedia.org
== Environmental impact == An unexpected negative environmental impact of chelating agents, as DTPA, is their toxicity for the activated sludges in the treatment of Kraft pulping effluents. Most of the DTPA worldwide production (several thousands of tons) is intended to avoid hydrogen peroxide decomposition by redox-active iron and manganese ions in the chlorine-free Kraft pulping processes (total chlorine free (TCF) and environmental chlorine free (ECF) processes). DTPA decreases the biological oxygen demand (BOD) of activated sludges and therefore their microbial activity.
=== International perspective === Rhodesia's Unilateral Declaration of Independence from the United Kingdom on 11 November 1965 was promptly condemned by the international community. The United Nations Security Council Resolution 216 of 12 November 1965 called "upon all States not to recognise this illegal racist minority regime in Southern Rhodesia." Rhodesia campaigned for international acceptance and invoked the doctrine of non-intervention in internal affairs as justification for rebuking external criticism of its internal policies. However, the emerging doctrine of self-determination in colonial situations meant that most nations regarded Rhodesia's self-declared independence as illegitimate. Zambia, formerly Northern Rhodesia, took a pragmatic approach towards Rhodesia. Kenneth Kaunda, heavily dependent on access through Rhodesia for his nation's copper ore exports, fuel, and power imports unofficially worked with the Rhodesian government. Rhodesia still allowed Zambia to export and import its goods through its territory to Mozambique ports, despite the Zambian government's official policy of hostility and non-recognition of the post-UDI Smith Administration. The United States, like all other Western nations, refused to recognise Rhodesia, but unlike others allowed its Consulate-General to function as a communications conduit between the US government in Washington, DC and the Rhodesian government in Salisbury. When Rhodesia set up the Rhodesian Information Office in Washington, DC, OAS nations loudly protested.
=== Diet === Diet may be a modifiable risk factor for the development of Alzheimer's disease, but more research needs to be conducted. The Mediterranean diet, and the DASH diet are both associated with less cognitive decline. A different approach has been to incorporate elements of both of these diets into one known as the MIND diet. Results from large-scale epidemiological studies and clinical trials have not demonstrated an independent role for most individual dietary components.
When adhered to a surface, neutrophil granulocytes have an average diameter of 12–15 micrometers (μm) in peripheral blood smears. In suspension, human neutrophils have an average diameter of 8.85 μm. With the eosinophil and the basophil, they form the class of polymorphonuclear cells, named for the nucleus's multilobulated shape (as compared to lymphocytes and monocytes, the other types of white cells). The nucleus has a characteristic lobed appearance, the separate lobes connected by chromatin. The nucleolus disappears as the neutrophil matures, which is something that happens in only a few other types of nucleated cells. Up to 17% of female human neutrophil nuclei have a drumstick-shaped appendage which contains the inactivated X chromosome. In the cytoplasm, the Golgi apparatus is small, mitochondria and ribosomes are sparse, and the rough endoplasmic reticulum is absent. The cytoplasm also contains about 200 granules, of which a third are azurophilic. Neutrophils will show increasing segmentation (many segments of the nucleus) as they mature. A normal neutrophil should have 3–5 segments. Hypersegmentation is not normal but occurs in some disorders, most notably vitamin B12 deficiency. This is noted in a manual review of the blood smear and is positive when most or all of the neutrophils have 5 or more segments.
Sources: en.wikipedia.org
No regulator in a major market has approved it for human use. It appears in research settings and in products marketed outside pharmacy channels. Legal status for personal possession varies by country.
Afamelanotide is a linear analog that has received approval in some jurisdictions for a specific photoprotection indication. Melanotan II is cyclic and less selective across melanocortin receptors. The two are related but are not interchangeable in regulatory or clinical terms.
A compound that activates several receptor subtypes may produce effects beyond pigmentation. Selectivity influences which tissues respond and shapes the side-effect profile described in reports. Designing subtype-selective analogs is a stated goal of melanocortin research.
No regulatory agency has authorised melanotan-2 as a medicine for any indication. It circulates mainly as a research chemical or through unregulated channels. As a result, identity, purity and content are not independently guaranteed.