If you have been reading about melanocortin 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.
Last reviewed on 2025-12-22. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
The compound emerged from research programs in the 1980s that examined analogues of alpha-melanocyte-stimulating hormone for pigmentation and photoprotection. Investigators modified the native sequence to extend activity duration and potency. A related analogue, afamelanotide, was developed within the same broad line of inquiry and eventually gained approval in certain jurisdictions for a rare light-sensitivity condition. Melanotan-2 itself did not progress through the same regulatory route and has no approved therapeutic indication.
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.
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.
| 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 |
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.
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.
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.
Research interest has centred on photoprotection and pigmentation, with a smaller body of work on appetite and sexual function. Published human data remain limited to small, frequently uncontrolled studies, and the compound has never received marketing approval from a national medicines regulator. Most laboratory work treats it as a pharmacological tool for probing melanocortin signalling in cell culture or animal models. Whether pigmentation changes observed in people translate into measurable protection against ultraviolet-induced DNA damage remains an open question.
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone, the naturally occurring peptide involved in pigmentation signalling. Its sequence is conventionally written as Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, with a lactam bridge joining the aspartate side chain to the lysine side chain. The empirical formula is C50H69N15O9 and the monoisotopic mass lies near 1023.5 daltons. N-terminal acetylation and the D-configured phenylalanine both increase resistance to enzymatic breakdown compared with the parent hormone.
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.
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.
== Brain and nervous system == Astrocytoma Anaplastic astrocytoma Brainstem glioma Choroid plexus carcinoma Craniopharyngioma Ependymoma Ganglioneuroma Glioblastoma Glioma Hemangioblastoma Medulloblastoma Meningioma Neuroblastoma Neurofibroma Oligodendroglioma Paraganglioma Pineal astrocytoma Pineocytoma Pineoblastoma Pituitary adenoma Pilocytic astrocytoma Primary central nervous system lymphoma Primitive neuroectodermal tumor Schwannoma Visual pathway and hypothalamic glioma
The researchers found no difference in post-workout plasma creatine kinase levels and muscle soreness, nor in cycling time to exhaustion. However, since chocolate milk is usually less expensive than commercial recovery beverages, the researchers concluded that chocolate milk "serves as a more convenient, cheaper ... recovery beverage option for many athletes". A May 2010 sports nutrition study concluded that "exercise recovery during short-term periods of heavy soccer training appears to be similar when isocaloric CM (Chocolate Milk) and CHO (Carbohydrate) beverages are consumed post-exercise". Yet another study in 2011 at Kean University in New Jersey concluded similar results in male soccer players, discovering that there was an increase in time to fatigue when chocolate milk was consumed. The Kean University study also viewed chocolate milk's effects on female soccer players undergoing morning and afternoon practices during preseason. They were either given the carbohydrate-electrolyte beverage or chocolate milk between morning and afternoon preseason practices. Following every afternoon practice, each athlete completed a shuttle run to fatigue. The study concluded that chocolate milk is just as beneficial as the carbohydrate-electrolyte beverage in promoting recovery in women.
==== Muslim Yibna, Early Islamic to Mamluk period ==== The Islamic historian al-Baladhuri (died 892 AD) describes Yibna as one of ten towns in Jund Filastin conquered by the Rashidun army led by 'Amr ibn al-'As in the early 7th century. Ibelin was first sacked by Saladin before his army was routed at the Battle of Montgisard in late 1177. In August 1187, it was retaken and burnt to the ground, and ceased for some time to form part of the Crusaders' kingdom.
=== Sheep wool === Wool from shearing sheep is a little-used yet promising renewable growing medium. In a study comparing wool with peat slabs, coconut fibre slabs, perlite and rockwool slabs to grow cucumber plants, sheep wool had a greater air capacity of 70%, which decreased with use to a comparable 43%, and water capacity that increased from 23% to 44% with use. Using sheep wool resulted in the greatest yield out of the tested substrates, while application of a biostimulator consisting of humic acid, lactic acid and Bacillus subtilis improved yields in all substrates.
Sources: en.wikipedia.org
==== MeSH D12.776.210.500.600 – myosins ==== MeSH D12.776.210.500.600.100 – myosin heavy chains MeSH D12.776.210.500.600.200 – myosin light chains MeSH D12.776.210.500.600.300 – myosin subfragments MeSH D12.776.210.500.600.465 – myosin type i MeSH D12.776.210.500.600.470 – myosin type ii MeSH D12.776.210.500.600.470.249 – cardiac myosins MeSH D12.776.210.500.600.470.249.249 – atrial myosins MeSH D12.776.210.500.600.470.249.500 – ventricular myosins MeSH D12.776.210.500.600.470.374 – nonmuscle myosin type iia MeSH D12.776.210.500.600.470.500 – nonmuscle myosin type iib MeSH D12.776.210.500.600.470.750 – skeletal muscle myosins MeSH D12.776.210.500.600.470.875 – smooth muscle myosins
Flutamide acts as a selective, competitive, silent antagonist of the androgen receptor (AR). Its active form, hydroxyflutamide, has between 10- and 25-fold higher affinity for the AR than does flutamide, and hence is a much more potent AR antagonist in comparison. However, at high concentrations, unlike flutamide, hydroxyflutamide is able to weakly activate the AR. Flutamide has far lower affinity for the AR than do steroidal antiandrogens like spironolactone and cyproterone acetate, and it is a relatively weak antiandrogen in terms of potency by weight, but the large dosages at which flutamide is used appear to compensate for this. In accordance with its selectivity for the AR, flutamide does not interact with the progesterone, estrogen, glucocorticoid, or mineralocorticoid receptor, and possesses no intrinsic progestogenic, estrogenic, glucocorticoid, or antigonadotropic activity. However, it can have some indirect estrogenic effects via increased levels of estradiol secondary to AR blockade, and this involved in the gynecomastia it can produce. Because flutamide does not have any estrogenic, progestogenic, or antigonadotropic activity, the medication does not cause menstrual irregularities in women. This is in contrast to steroidal antiandrogens like spironolactone and cyproterone acetate. Similarly to nilutamide, bicalutamide, and enzalutamide, flutamide crosses the blood–brain barrier and exerts central antiandrogen actions.
== Standards and regulations == The Codex Alimentarius represents the global standard for irradiation of food, in particular under the WTO-agreement. Regardless of treatment source, all processing facilities must adhere to safety standards set by the International Atomic Energy Agency (IAEA), Codex Code of Practice for the Radiation Processing of Food, Nuclear Regulatory Commission (NRC), and the International Organization for Standardization (ISO). More specifically, ISO 14470 and ISO 9001 provide in-depth information regarding safety in irradiation facilities. All commercial irradiation facilities contain safety systems which are designed to prevent exposure of personnel to radiation. The radiation source is constantly shielded by water, concrete, or metal. Irradiation facilities are designed with overlapping layers of protection, interlocks, and safeguards to prevent accidental radiation exposure. Meltdowns are unlikely to occur due to low heat production from sources used.
In advanced cases, bulging of the cornea can result in a localized rupture of Descemet's membrane, an inner layer of the cornea. Aqueous humor from the eye's anterior chamber seeps into the cornea before Descemet's membrane reseals. The patient experiences pain and a sudden severe clouding of vision, with the cornea taking on a translucent milky-white appearance known as a corneal hydrops. Although disconcerting to the patient, the effect is normally temporary and after a period of six to eight weeks, the cornea usually returns to its former transparency. The recovery can be aided nonsurgically by bandaging with an osmotic saline solution. Although a hydrops usually causes increased scarring of the cornea, occasionally it will benefit a patient by creating a flatter cone, aiding the fitting of contact lenses. Corneal transplantation is not usually indicated during corneal hydrops.
=== Other biosynthetic pathways === Carbamoyl phosphate is a carbamate mixed anhydride that is an intermediate in the urea cycle and the biosynthesis of pyrimidines. 5-carboxyamino-1-(5-phospho-D-ribosyl)imidazole (N5-CAIR), a carbamate derivative of aminoimidazole, is an intermediate in the biosynthesis of inosine. Both carbamates are produced via reaction of −NH2 groups with carboxyphosphate (HO−C(O)−OPO2−3).
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 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.