If you have been reading about MC1R 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 2026-01-10. Numbers and descriptions here follow the published literature rather than marketing material.
Structurally, Melanotan-2 retains the core recognition motif of alpha-melanocyte-stimulating hormone while adding a lactam bridge that links two side chains and constrains the molecule into a ring. This modification lowers susceptibility to enzymatic degradation. The compound acts as an agonist at melanocortin receptors, particularly subtypes associated with melanin production. Because the same receptor family influences several physiological processes, researchers note that its activity is not confined to pigmentation alone. Receptor selectivity continues to be examined in published studies.
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.
Regulatory status differs by country, and in many places supplying the compound for human consumption is unlawful. Vendors frequently label material as intended for research use only, a designation that shifts stated purpose but does not create a legal pathway for personal use. Certificates of analysis accompanying such products vary widely in detail and provenance. Third-party testing exists but is voluntary, and results are rarely linked to a specific lot in a publicly verifiable way.
Identity testing for a synthetic peptide relies on several complementary methods. Reversed-phase high-performance liquid chromatography separates the target from related impurities and reports purity as a percentage of total peak area. Mass spectrometry confirms molecular mass and can reveal deletions or truncations. Amino acid analysis and peptide mapping provide sequence-level confirmation, while counter-ion content and residual solvents are measured separately. A purity figure alone does not establish identity, so a complete dataset combines chromatographic and spectrometric evidence.
Lyophilized peptide powder is generally stored frozen, protected from light and moisture. Tryptophan residues are susceptible to oxidation, and the lactam bridge can hydrolyze under strongly acidic or basic conditions. Solutions prepared for laboratory work degrade faster than dry powder, and repeated freeze-thaw cycles accelerate loss. Common practice is to aliquot solutions before freezing and to avoid alkaline buffers. Reported stability windows vary with concentration, buffer, and temperature, so exact shelf lives are method-specific rather than universal.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Synthetic cyclic heptapeptide |
| Molecular mass | Approximately 1024 g/mol | Depends on counter-ion content |
| Appearance | White to off-white powder | Commonly supplied as a lyophilised solid |
| Solubility | Freely soluble in water | Also dissolves in common aqueous buffers |
| Typical storage | -20 degrees Celsius, desiccated | Protect from light and repeated freeze-thaw |
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.
Melanocortin receptors comprise five subtypes with distinct tissue distributions and functions. Melanotan-2 is described in the literature as a non-selective agonist that engages several of these subtypes, including MC1R, MC3R, MC4R, and MC5R. MC1R is the subtype most directly linked to melanin production in skin cells. Because the compound is not subtype-selective, its observed effects in experimental settings are generally attributed to activity across multiple receptor pathways rather than to a single target.
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.
Lyophilised melanotan-2 is supplied as a solid, which is more stable than a solution. The material is hygroscopic, so weighing is done quickly, in low humidity, with the container kept sealed. Reconstitution usually uses water for injection or bacteriostatic water, added down the wall of the vial to limit foaming. A reconstituted solution is held at 2 to 8 °C and kept away from light. Repeated freezing and thawing of the same vial is avoided because ice crystal formation and concentration effects degrade the peptide.
Reversed-phase high-performance liquid chromatography is the routine method for purity assessment. Peptides absorb near 214 nm because of the peptide bond, and a gradient of acetonitrile in water separates the intact peptide from deletion sequences, oxidised products, and earlier-eluting fragments at neutral pH. Electrospray ionisation mass spectrometry provides an orthogonal check: the measured mass must agree with the theoretical value. Amino acid analysis and peptide mapping confirm structure but are used less often. Reference standards remain scarce because the peptide is not described in any pharmacopoeia.
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.
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.
Contrary to common belief, lactic acid accumulation does not actually cause the burning sensation we feel when we exhaust our oxygen and oxidative metabolism, but in actuality, lactic acid in presence of oxygen recycles to produce pyruvate in the liver which is known as the Cori cycle. Substrates produce metabolic fatigue by being depleted during exercise, resulting in a lack of intracellular energy sources to fuel contractions. In essence, the muscle stops contracting because it lacks the energy to do so.
== Sports == Maccabi Yavne is the city's major football club. During the 1980s the club played in the top division and in 1985 won the Toto Cup. Today they are in Liga Leumit. The basketball team, Elitzur Yavne, have also played in the Liga Leumit since 2007. Omri Casspi, the first Israeli to play in the National Basketball Association, grew up in the city and played for some of its teams.
== Advantages == Space optimization: Vertical farming and advanced control technologies maximize the use of limited spaces. Resource management: Reduced water and fertilizer consumption through the recycling of nutrient solutions. Protection for sensitive species: Controlled conditions shield plants from climatic extremes, pests and diseases. Hydrozones lie at the intersection of urban agriculture innovations, environmental concerns, and biodiversity conservation efforts. Notable examples include specialized botanical gardens, cultivation facilities for threatened endemic species, and domestic spaces for advanced horticulture enthusiasts.
Lore [pronounced "Lo'-re," rhymes with "story"] Rogers was born in the town of Patten, Maine. His father, Col. Luther B. Rogers, was a veteran of the Civil War, and became a partner in a prominent lumbering operation called Ayer and Rogers. Lore's mother, Mary Elizabeth Barker Rogers, bore seven children, and it is said she might have become a "remarkable journalist" had she been given the chance. In an unpublished autobiography, she described the children
In the 17th century the Italian Marcello Malpighi used microscopes to study tiny biological entities; some regard him as the founder of the fields of histology and microscopic pathology. Malpighi analyzed several parts of the organs of bats, frogs and other animals under the microscope. While studying the structure of the lung, Malpighi noticed its membranous alveoli and the hair-like connections between veins and arteries, which he named capillaries. His discovery established how the oxygen breathed in enters the blood stream and serves the body. In the 19th century histology was an academic discipline in its own right. The French anatomist Xavier Bichat introduced the concept of tissue in anatomy in 1801, and the term "histology" (German: Histologie), coined to denote the "study of tissues", first appeared in a book by Karl Mayer in 1819. Bichat described twenty-one human tissues, which can be subsumed under the four categories currently accepted by histologists. The usage of illustrations in histology, deemed as useless by Bichat, was promoted by Jean Cruveilhier. In the early 1830s Purkynĕ invented a microtome with high precision. During the 19th century many fixation techniques were developed by Adolph Hannover (solutions of chromates and chromic acid), Franz Schulze and Max Schultze (osmic acid), Alexander Butlerov (formaldehyde) and Benedikt Stilling (freezing).
Sources: en.wikipedia.org
Further investigations showed that the babies had not been injected with the potassium via IV method, but instead, that they had received the injections in their backs and with clothes on while they were in the resuscitation room. On the same day that police announced the arrest of nurse Brenda Agüero, the minister of health of Córdoba, Diego Cardozo, resigned from his position after heavy criticism for his handling of the case. Cardozo said that he had presented his resignation with the goal of helping clarify and serve justice in the case. Governor Juan Schiaretti assigned the ministry to María Gabriela Barbás. In February 2023, the head of the hospital, 70-year-old Liliana Asís, was arrested and accused of concealing the unnatural deaths of the babies from the authorities. She was granted house arrest in May 2023 due to her deteriorating health while in prison. Along with Asís, more officials and local politicians were indicted for either concealment or wrongdoing.
In the 1918 general election, Lloyd George, hailed as "the Man Who Won the War", led his coalition into a khaki election. Lloyd George and the Conservative leader Bonar Law wrote a joint letter of support to candidates to indicate they were considered the official Coalition candidates—this "coupon", as it became known, was issued against many sitting Liberal MPs, often to devastating effect, though not against Asquith himself. The coalition won a massive victory: Labour increased their position slightly, but the Asquithian Liberals were decimated. Those remaining Liberal MPs who were opposed to the Coalition Government went into opposition under the parliamentary leadership of Sir Donald MacLean who also became Leader of the Opposition. Asquith, who had appointed MacLean, remained as overall Leader of the Liberal Party even though he lost his seat in 1918. Asquith returned to Parliament in 1920 and resumed leadership. Between 1919 and 1923, the anti-Lloyd George Liberals were called Asquithian Liberals, Wee Free Liberals or Independent Liberals. Lloyd George was increasingly under the influence of the rejuvenated Conservative party who numerically dominated the coalition. In 1922, the Conservative backbenchers rebelled against the continuation of the coalition, citing, in particular, Lloyd George's plan for war with Turkey in the Chanak Crisis, and his corrupt sale of honours. He resigned as prime minister and was succeeded by Bonar Law.
(Despite this being how it works in theory, hair samples from dark areas of liver chestnut and dark red chestnut horses were found to contain both types of melanin.) In general, alleles that create fully functional MC1R proteins are inherited dominantly and result in a black-based coat color ("E"), while mutated alleles that create "dysfunctional" MC1R are recessive and result in a lighter coat color ("e"). Normally MC1R would bind to the Melanocyte-stimulating hormone (MSH) which is released by the pituitary gland and stimulates the production and release of melanin in skin and hair. Red hair color in horses ("e") is created by a missense mutation in the code for MC1R, which results in a protein that cannot bind to MSH. When only mutant copies ("e) of the gene are available, non-functional MC1R proteins are produced. As a result, no black pigment is deposited into the hair and the entire coat is red-based. However, the skin of chestnut horses is still generally black, unless affected by other genes. Some chestnut foals are also born with lighter eyes and lightened skin, which darken not long after birth. This is not the same as the blue eyes and pink skin seen at birth in foals carrying the champagne gene. It is a genetic mechanism not fully understood, but may be related to the pheomelanistic characteristics of "e". Though "E" allows the production of black pigment, it can also allow for red pigment in some parts of the animal as seen in bay horses.
The emperors Leo III (r. 717–741) and Constantine V (r. 741–775) were effective leaders, both in government and warfare. They withstood continued Arab attacks, as well as civil war and natural disasters. Constantine's success reestablished the state as a major regional power. Leo's reign produced the Ekloge ton nomon, a code of law that evolved that of Justinian I. He also continued to reform the theme system in order to lead offensive campaigns against the Muslims, culminating in a notable victory in 740. Constantine overcame an early civil war against his brother-in-law Artabasdos, created stability against the new Abbasid Caliphate, campaigned successfully against the Bulgars, and continued to make administrative and military reforms. Both emperors supported iconoclast policies opposing the veneration of religious images, which had them later vilified by biased authors, creating issues that continue to impact modern scholarship; Constantine's reign also saw the loss of Ravenna to the Lombards, and the beginning of a split from the Roman papacy. In 780, Empress Irene assumed power as regent for her son Constantine VI. Although she was a capable administrator who restored the veneration of icons, the empire was destabilised by her conflict with her son. The Bulgars and Abbasids inflicted numerous defeats on the Byzantine armies, and the papacy crowned Charlemagne as Roman emperor in 800. In 802, the unpopular Irene was overthrown by Nikephoros I; he reformed the empire's administration but died in battle against the Bulgars in 811.
Sources: en.wikipedia.org
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.
It is shorter than the native hormone and carries a cyclic constraint that improves stability. These changes raise receptor potency and slow breakdown relative to the naturally occurring peptide.
Published accounts date its development to the 1980s, when researchers were generating analogues of melanocyte-stimulating hormone. That work aimed to produce more stable compounds for studying pigmentation biology.
Dry powder is usually held frozen, shielded from light, and kept away from moisture. Desiccant packaging limits hydrolysis during storage. Solutions are typically aliquoted and frozen once, because repeated thawing shortens useful life.