Everything below concerns cyclic heptapeptide. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-02-24. 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 peptide analog modeled on alpha-melanocyte-stimulating hormone, a naturally occurring signaling peptide involved in pigmentation. Its structure is a cyclic heptapeptide containing two non-natural substitutions, norleucine at position four and D-phenylalanine at position seven. These modifications resist enzymatic breakdown and extend the molecule's activity relative to the native hormone. The compound binds melanocortin receptors and is studied mainly as a pharmacological tool rather than a therapeutic product. It has never received approval as a medicine in any major jurisdiction.
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.
Receptor studies place melanotan-2 among non-selective melanocortin agonists, binding MC1R, MC3R, MC4R and MC5R rather than a single subtype. Activation of MC1R on cutaneous melanocytes raises tyrosinase activity and shifts pigment synthesis toward eumelanin, which is darker and more photostable than pheomelanin. Central receptors, particularly MC4R, are associated with appetite suppression and with reported effects on sexual function. Because subtype selectivity is low, the same molecule engages pigment, metabolic and vascular pathways at once, and this breadth is a common explanation offered for the range of adverse events described in user reports.
| 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 |
In 1848, Thomas Beecham launched his Beecham's Pills laxative in England, giving birth to the Beecham Group. In 1859, Beecham opened its first factory in St Helens, Lancashire. By the 1960s, Beecham was extensively involved in pharmaceuticals and consumer products such as Macleans toothpaste, Lucozade and synthetic penicillin research.
== Works == Gish, Duane T. 15 Scopus Publishers. Gish, Duane T. (1972). Speculations and Experiments on the Origins of Life. New Leaf Pr. ISBN 0-89051-010-5. Gish, Duane T. (1972). Evidence against evolution. Wheaton, Ill: Tyndale House Publishers. ISBN 0-8423-0790-7. Gish, Duane T. (1986) [1972]. Evolution, the fossils say no!. San Diego, Calif: Institute for Creation Research Publishing. ISBN 0-89051-057-1. Gish, Duane T. (1973). Have You Been... Brainwashed?. Seattle, Washington: Life Messengers. p. 32. OCLC 10930514. Hillestad, George M.; Morris, Henry; Gish, Duane T. (1974). Creation: acts, facts, impacts. San Diego, Calif: ICR Pub. Co. ISBN 0-89051-020-2. Gish, Duane T. (1977). Dinosaurs: Those Terrible Lizards. Green forest, Arkansas: Master Books. ISBN 0-89051-039-3. Rohrer, Donald H.; Gish, Duane T. (1978). Up with creation!: ICR acts/facts/impacts, 1976-1977. San Diego, California: Creation-Life Publishers. ISBN 0-89051-048-2. Gish, Duane T.; Wilson, Clifford (1981). Manipulating life, where does it stop?: Genetic engineering. Green Forest, Arkansas: Master Books. ISBN 0-89051-071-7. Gish, Duane T. (1985). Evolution: the challenge of the fossil record. San Diego, Calif: Creation-Life Publishers. ISBN 0-89051-112-8. Gish, Duane T. (1988). Creationist Research 1964-1988. Creation Research Society. ISBN 0-940384-06-X. Bonnie Snellenberger; Gish, Duane T.; D Dish; Earl Snellenberger (1990). The Amazing Story of Creation: From Science and the Bible. Green Forest, Arkansas: Master Books. ISBN 0-89051-120-9.
Additionally, protein binding triggers a metachromatic reaction, evidenced by the emergence of a species that absorbs light around 595 nm, indicative of the unprotonated form This dye creates strong noncovalent bonds with the proteins, via electrostatic interactions with the amino and carboxyl groups, as well as Van Der Waals interactions. Only the molecules that bind to the proteins in solution exhibit this change in absorption, which eliminates the concern that unbound molecules of the dye might contribute to the experimentally obtained absorption reading. This process is more beneficial since it is less pricey than other methods, easy to use, and has high sensitivity of the dye for protein. After 5 minutes of incubation, the absorbance can be read at 595 nm using a spectrophotometer or a mobile smartphone camera (RGBradford method). This assay is one of the fastest assays performed on proteins. The total time it takes to set up and complete the assay is under 30 minutes. The entire experiment is done at room temperature. The Bradford protein assay can measure protein quantities as little as 1 to 20 μg. It is an extremely sensitive technique. The dye reagent is a stable ready to use product prepared in phosphoric acid. It can remain at room temperature for up to 2 weeks before it starts to degrade. Protein samples usually contain salts, solvents, buffers, preservatives, reducing agents and metal chelating agents. These molecules are frequently used for solubilizing and stabilizing proteins.
Sources: en.wikipedia.org
There is much research currently underway looking at ways to protect the nerve (neuroprotection) or even regenerate new fibers within the optic nerve. So far there is no evidence in human studies that the so-called neuroprotectors have any beneficial effect in NAION. However, there is a new current clinical trial for the treatment of NAION in the United States with plans to include sites in India, Israel, Germany and Australia (see NORDICclinicaltrials.com and https://clinicaltrials.gov/). This trial will test the use of a synthetic siRNA that blocks caspase 2, an important enzyme in the apoptosis cycle. In addition to such research, patents have been applied for by Pfizer, The University of Southern California, Otsuka Pharmaceutical and other individual inventors for innovations related to the treatment of anterior ischemic optic neuropathy. In recent years, pentoxifylline has emerged as a potential treatment option for NAION and other diseases involving ocular ischemia. Pentoxifylline has been shown to reduce erythrocyte rigidity, resulting in decreased blood viscosity and increased flow velocity. Animal studies have demonstrated that pentoxifylline can inhibit TNF and, in turn, prevent retinal ganglion cell death and axonal degeneration associated with optic neuropathy in a dose-dependent manner.
== Clinical significance == Because insulin is one of, if not the most important, regulators of glucokinase synthesis, diabetes mellitus of all types diminishes glucokinase synthesis and activity by a variety of mechanisms. Glucokinase activity is sensitive to the oxidative stress of cells, especially the beta cells. At least 497 mutations of the human glucokinase gene GCK have been discovered, that can change the efficiency of glucose binding and phosphorylation, increasing or decreasing the sensitivity of beta cell insulin secretion in response to glucose, and producing clinically significant hyperglycemia or hypoglycemia.
=== Energy expenditure === The Na+/K+-ATPase is an active enzyme. It uses energy from ATP to move ions against their concentration gradient. In fact, all cells expend a large fraction of the ATP they produce (typically 30% and up to 70% in nerve cells) to maintain their required cytosolic Na and K concentrations. For neurons, the Na+/K+-ATPase can be responsible for up to three-fourths of the cell's energy expenditure. In many types of tissue, ATP consumption by the Na+/K+-ATPases have been related to glycolysis. This was first discovered in red blood cells (Schrier, 1966), but has later been evidenced in renal cells, smooth muscles surrounding the blood vessels, and cardiac cells which compose Purkinje fibers. Recently, glycolysis has also been shown to be of particular importance for Na+/K+-ATPase in skeletal muscles, where inhibition of glycogen breakdown (a substrate for glycolysis) leads to reduced Na+/K+-ATPase activity and lower force production.
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 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.