If you have been reading about melanogenesis and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2026-05-27. Numbers and descriptions here follow the published literature rather than marketing material.
Melanotan II is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone, a naturally occurring peptide involved in pigmentation signalling. Its structure substitutes a lactam bridge between side chains to increase stability relative to the native hormone. The compound is also known by the shorthand MT-II and by several non-proprietary synonyms used in research catalogues. It is not an approved therapeutic product in any major jurisdiction; material sold under this name is typically offered as a laboratory reagent rather than as a medicine.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Analogue of alpha-melanocyte-stimulating hormone |
| Common synonyms | MT-II; melanotan 2 | No internationally accepted non-proprietary name |
| Typical presentation | Lyophilised powder in a sealed vial | Often supplied alongside a separate diluent |
| Regulatory status | Unapproved therapeutic substance | Customs seizure reported in several jurisdictions |
| Reported route in use | Subcutaneous injection | Self-administered outside clinical settings |
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.
The peptide acts as a non-selective agonist at melanocortin receptors, showing affinity for MC1R, MC3R, MC4R and MC5R. Activation of MC1R on melanocytes drives the conversion of tyrosine into melanin and shifts production toward the darker eumelanin form. MC4R signalling in the central nervous system is linked to appetite and energy balance, which helps explain why reduced food intake appeared in early human studies. Effects on MC4R and on vascular tone also account for the erectile responses recorded as unexpected findings in those same trials.
Receptor binding at MC1R on melanocytes raises intracellular cyclic AMP and increases expression of tyrosinase and related enzymes. The downstream result is greater synthesis of eumelanin, the dark pigment, without ultraviolet exposure acting as the trigger. The compound is not selective, however, and also engages MC3R, MC4R and MC5R, which are expressed in the central nervous system and elsewhere. That lack of selectivity is the explanation usually offered for effects reported outside pigmentation, including appetite suppression and nausea. Selectivity remains a central theme in comparative studies of related peptides.
Human data remain limited and mostly short-term. Reports describe small trials and observational accounts rather than large controlled studies, so questions about dose-response relationships and long-term effects on melanocytes stay open. Whether repeated exposure alters naevus behaviour is not settled in the published record. Researchers also note that self-administered use outside clinical settings makes actual exposure difficult to quantify. Statements about efficacy and safety should therefore be read as preliminary rather than established.
==== 1800–1899 ==== Double Taxation Relief (Taxes on Income) (Ghana) Order 1993 (S.I. 1993/1800) Double Taxation Relief (Taxes on Income) (India) Order 1993 (S.I. 1993/1801) Double Taxation Relief (Taxes on Income) (Uganda) Order 1993 (S.I. 1993/1802) Double Taxation Relief (Taxes on Income) (Ukraine) Order 1993 (S.I. 1993/1803) Army, Air Force and Naval Discipline Acts (Continuation) Order 1993 (S.I. 1993/1804) Films Co-Production Agreements (Amendment) Order 1993 (S.I. 1993/1805) Confiscation of the Proceeds of Drug Trafficking (Designated Countries and Territories) (Scotland) Amendment Order 1993 (S.I. 1993/1806) Criminal Justice (International Co-operation) Act 1990 (Enforcement of Overseas Forfeiture Orders) (Scotland) Amendment Order 1993 (S.I. 1993/1807) Development Board for Rural Wales (Transfer of Housing Stock) Regulations 1993 (S.I. 1993/1808) Civil Courts (Amendment) Order 1993 (S.I. 1993/1809) Local Government Superannuation (National Rivers Authority) Regulations 1993 (S.I. 1993/1810) Cardiothoracic Centre–Liverpool National Health Service Trust (Establishment) Amendment Order 1993 (S.I. 1993/1811) Civil Defence (General Local Authority Functions) Regulations 1993 (S.I. 1993/1812) Channel Tunnel (International Arrangements) Order 1993 (S.I. 1993/1813) Local Government Superannuation (Part-time Employees) Regulations 1993 (S.I. 1993/1814) Disclosure of Interests in Shares (Amendment) Regulations 1993 (S.I. 1993/1819) Partnerships and Unlimited Companies (Accounts) Regulations 1993 (S.I. 1993/1820) Income Tax (Interest Relief) (Qualifying Lenders) (No.
=== Tanning === Potassium alum is used in leather tanning, in order to remove moisture from the hide and prevent rotting. Unlike tannic acid, alum doesn't bind to the hide and can be washed out of it.
Mescaline is used recreationally, spiritually, and medically. It is typically taken orally. The drug is used as a psychedelic at doses of 100 to 1,000 mg orally. Low doses are 100 to 200 mg, an intermediate or "good effect" dose is 500 mg, and a high (ego-dissolution) dose is 1,000 mg. However, doses of 800 mg and above orally are not well-tolerated due to side effects like severe nausea and vomiting. In his book PiHKAL (Phenethylamines I Have Known and Loved), Alexander Shulgin listed a dose range of 200 to 400 mg as the sulfate salt and 178 to 356 mg as the hydrochloride salt. Microdosing involves the use of daily mescaline doses of less than 75 mg. Mescaline has also been studied via intravenous injection, with assessed doses in the range of 500 to 750 mg as the sulfate salt. In addition to pure form, mescaline is used in the form of cacti such as peyote and the San Pedro cactus. Doses when mescaline is used in the form of fresh or dried cacti have also been described. In traditional peyote preparations, the top of the cactus is cut off, leaving the large tap root along with a ring of green photosynthesizing area to grow new heads. These heads are then dried to make disc-shaped buttons. Buttons are chewed to produce the effects or soaked in water to drink. However, the taste of the cactus is bitter, so modern users will often grind it into a powder and pour it into capsules to avoid having to taste it. The average 76 mm (3.0 in) peyote button contains about 25 mg mescaline. However, another source states that there is about 45 mg mescaline per peyote button on average.
Sources: en.wikipedia.org
== History == Pembrolizumab was invented by scientists at Organon after which they worked with Medical Research Council Technology (which became LifeArc) starting in 2006, to humanize the antibody; Schering-Plough acquired Organon in 2007, and Merck & Co. acquired Schering-Plough two years later. Inventors Gregory Carven, Hans van Eenennaam and Gradus Dulos were recognized as Inventors of the Year by the Intellectual Property Owners Education Foundation in 2016. The development program for pembrolizumab was seen as high priority at Organon, but low at Schering and later Merck. In early 2010, Merck terminated development and began preparing to out-license it. Later, in 2010, scientists from Bristol Myers Squibb published a paper in The New England Journal of Medicine showing that their checkpoint inhibitor, ipilimumab (Yervoy), had shown strong promise in treating metastatic melanoma and that a second Bristol Myers Squibb checkpoint inhibitor, nivolumab (Opdivo), was also promising. Merck at that time had little commitment or expertise in either oncology or immunotherapy, but understood the opportunity and reacted strongly, reactivating the program and filing its IND by the end of 2010. As one example, Martin Huber was one of the few senior people at Merck with strong experience in lung cancer drug development, but had been promoted to senior management and was no longer involved in product development. He stepped down from his role to lead clinical development of pembrolizumab for lung cancer.
β-Hydroxy β-methylglutaryl-CoA (HMG-CoA), also known as 3-hydroxy-3-methylglutaryl coenzyme A, is an intermediate in the mevalonate and ketogenesis pathways. It is formed from acetyl CoA and acetoacetyl CoA by HMG-CoA synthase. The research of Minor J. Coon and Bimal Kumar Bachhawat in the 1950s at University of Illinois led to its discovery. HMG-CoA is a metabolic intermediate in the metabolism of the branched-chain amino acids, which include leucine, isoleucine, and valine. Its immediate precursors are β-methylglutaconyl-CoA (MG-CoA) and β-hydroxy β-methylbutyryl-CoA (HMB-CoA). HMG-CoA reductase catalyzes the conversion of HMG-CoA to mevalonic acid, a necessary step in the biosynthesis of cholesterol.
The South African Border War, also known as the Namibian War of Independence, and sometimes denoted in South Africa as the Angolan Bush War, was a largely asymmetric conflict that occurred in Namibia (then South West Africa), Zambia, and Angola from 26 August 1966 to 21 March 1990. It was fought between the South African Defence Force (SADF) and the People's Liberation Army of Namibia (PLAN), an armed wing of the South West African People's Organisation (SWAPO). The South African Border War was closely intertwined with the Angolan Civil War.
Sources: en.wikipedia.org
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.
It was developed in the 1980s by researchers investigating analogues of alpha-melanocyte-stimulating hormone for pigmentation and related endpoints. Early work included small human studies during the 1990s. Development did not progress to licensing, and the compound remained a research and grey-market item.
Peptides are prone to truncation, oxidation and aggregation during synthesis and handling. Without independent testing, a buyer cannot confirm the identity or the content of a vial. Analytical surveys of unapproved peptide products have repeatedly found discrepancies between label claims and measured composition.
It is a synthetic cyclic heptapeptide and an analogue of alpha-melanocyte-stimulating hormone. The molecule is produced by chemical synthesis rather than extracted from a biological source.