Everything below concerns MC1R. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-10-01. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Melanotan II is a synthetic cyclic heptapeptide that acts as an agonist at melanocortin receptors. It was designed as a structural analogue of alpha-melanocyte-stimulating hormone, the endogenous peptide involved in pigment production. The analogue carries a lactam bridge that constrains the ring and slows enzymatic breakdown relative to the native hormone. In research literature it appears under several abbreviations, and naming conventions are not fully standardized. Published descriptions usually place it within the broader melanocortin agonist family.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Free base; salt forms add to total mass |
| Molecular mass | About 1024 daltons | Calculated for the free base |
| Structural class | Cyclic heptapeptide | Contains D-phenylalanine and norleucine |
| Parent hormone | Alpha-melanocyte-stimulating hormone | Endogenous tridecapeptide of 13 residues |
| Receptor profile | Non-selective melanocortin agonist | Interacts with MC1R, MC3R, MC4R and MC5R |
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.
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.
UO2 + 4 HF → UF4 + 2 H2O (500 °C, endothermic) UF4 + F2 → UF6 (350 °C, endothermic) The resulting UF6, a white solid, is highly reactive (by fluorination), easily sublimes (emitting a vapor that behaves as a nearly ideal gas), and is the most volatile compound of uranium known to exist. Uranium hexafluorides (IV) and (V) can be used to make several hexafluorouranates, as they are anions (UF6- and UF62-). They bond with alkali metals, certain transition metals, and other non-metal compounds. One method of preparing uranium tetrachloride (UCl4) is to directly combine chlorine with either uranium metal or uranium hydride. The reduction of UCl4 by hydrogen produces uranium trichloride (UCl3) while the higher chlorides of uranium are prepared by reaction with additional chlorine. All uranium chlorides react with water and air. Bromides and iodides of uranium are formed by direct reaction of, respectively, bromine and iodine with uranium or by adding UH3 to those element's acids. Known examples include: UBr3, UBr4, UI3, and UI4. UI5 has never been prepared. Uranium oxyhalides are water-soluble and include UO2F2, UOCl2, UO2Cl2, and UO2Br2. Stability of the oxyhalides decrease as the atomic weight of the component halide increases.
== Function == Hepatokines are hormone-like proteins secreted by hepatocytes, and many have been associated with extra-hepatic metabolic regulation. Through processes like autocrinem, paracrinem, and endocrine signaling, hepatokines can influence metabolic processes. Hepatocytes can secrete multiple hepatokines into the blood. In particular, these hepatokines, similar to hypothalamic hormones and insulin, are structurally polypeptides, and proteins and are transcribed and expressed by specific genes. The liver may emit hepatokines to influence energy homeostasis and inflammation under pressure on the metabolism like long-term starvation or over-nutrition. If the liver is unable to fulfill this process, the corresponding disease develops like fatty liver disease from, "impaired hepatic insulin-sensitizing substance production." Hepatokines signal energy status and help regulate nutrient availability to multiple peripheral tissues and the central nervous system (CNS). Hepatokines have been described to be involved in the regulation of energy and nutrient metabolism by acting directly on the liver or on distal target tissues. These proteins regulate glucose and lipid metabolism in the liver but also in the skeletal muscle or the adipose tissue. It is now clear that a single session of exercise is accompanied by the production of liver-secreted proteins. Hepatokines can also mediate the beneficial effects of chronic exercise or, at least, represent biomarkers of training-induced metabolic improvements.
Also, a marine reserve is established in Sagay City, which protects the marine life and reefs of Carbin and Maca, making it a popular draw for marine life enthusiasts. Dauin is known for its beach resorts and Apo Island, a famous diving spot and marine reserve in Negros Oriental. The city of Dumaguete is popular amongst students, largely because of its presence as a university city in the region. Bais has since then become a tourist spot for whale and dolphin watching, due to its coastline touching the Tañon Strait. Antulang Beach Resort and Tambobo Bay, as well as the inland Lake Balanan serve as three important attractions in the town of Siaton. Situated within the towns of Sibulan, San Jose and Valencia is the Balinsasayao Twin Lakes Natural Park, which serves as an important draw for tourists going to inland Negros Oriental.
Sources: en.wikipedia.org
=== Diet === Dietary management involves reducing both the digestible energy levels and the total non-structural carbohydrate (NSC) level of feed. NSC include starches, single sugars, and fructans, whereas cellulose and hemicelluloses are structural carbohydrates. High NSC levels cause a glucose and insulin spike following feeding, and may worsen insulin resistance. Current recommendations for NSC levels are less than 10% of the diet on a dry matter basis. Pasture is often eliminated from the diet, since digestible energy levels from grazing are not easily measured and pasture carbohydrates can trigger laminitis. It may be introduced back into the diet following improvement of insulin sensitivity. In horses with mild insulin resistance, this is often the case once obesity is resolved. However, pasture access should be restricted to those times of day when grass NSC levels are lowest, such as early morning, and never following a frost, which stresses the grass and results in accumulation of water-soluble carbohydrates. Horses are best managed by only allowing short grazing periods—less than 1 hour since they can rapidly ingest grass, or confining them to a limited turn-out area or by use of a grazing muzzle. Horses with severe IR, that have recurrent laminitis, are not recommended to return to pasture. Hay low in NSC is provided in place of pasture. Ideally, hay should be tested and purchased based on known NSC levels, only using hays less than 10% NSC.
=== NP-40 lysis buffer === It may be the most widely used lysis buffer. The solubilizing agent is NP-40, which can be replaced by other detergents at different concentrations. Since NP-40 is a nonionic detergent, this lysis buffer has a milder effect than RIPA buffer. It can be used when protein functions are to be retained with minimal disruption. Recipe:
Without interactions between the compounds there would be no enthalpy of mixing and the entropy of mixing would be ideal. The ideal entropy of mixing of multiple pure compounds is always positive (the term -T∙ΔS is negative) and ΔG would be negative for all compositions, causing complete miscibility. Therefore, the fact that miscibility gaps are observed can only be explained by interaction. In the case of polymer solutions, polymer-polymer, solvent-solvent and polymer-solvent interactions have to be taken into account. A model for the phenomenological description of polymer phase diagrams was developed by Flory and Huggins (see Flory–Huggins solution theory). The resulting equation for the change of Gibbs energy consists of a term for the entropy of mixing for polymers and an interaction parameter that describes the sum of all interactions.
Sources: en.wikipedia.org
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.
Melanotan-1, also called afamelanotide, is a linear analogue with greater selectivity for MC1R and has received approval in some jurisdictions for a specific photosensitivity disorder. Melanotan-2 is cyclic, less selective, and reaches central receptors more readily. The two are often confused in online discussion despite different pharmacology and regulatory status.
Alpha-MSH is an endogenous tridecapeptide derived from pro-opiomelanocortin. Melanotan-2 reproduces its core receptor-binding sequence inside a shortened, stabilised ring. The result is a molecule with a longer effective half-life and higher potency than the parent hormone.
It is a synthetic cyclic heptapeptide and a non-selective melanocortin receptor agonist. Structurally it is modelled on alpha-melanocyte-stimulating hormone, a peptide that occurs naturally in the body.