The short version of melanocortin receptor fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-04-17 and is reviewed periodically as new material appears.
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.
Scientific discussion of Melanotan-2 spans pharmacology, dermatology, and public-health literature. Laboratory studies examine its receptor binding and cellular effects, while clinical reports describe outcomes observed after unregulated use. These two bodies of work differ in rigour and intent. Peer-reviewed trials of the compound as a medicine are limited, so much of the available information comes from case reports and surveillance data. Authors frequently note the gap between experimental findings and real-world use.
Reported observations after unregulated use include shifts in skin pigmentation and, in some accounts, unintended changes to moles and other lesions. Whether these outcomes are causally linked to the compound, and how often they occur, remain open questions because controlled data are scarce. The absence of standardised dosing and verified product purity complicates interpretation. Researchers have called for better surveillance and analytical characterisation of samples obtained outside regulated channels. Conclusions drawn from anecdotal evidence should be treated as provisional.
Melanotan-2 has not received marketing authorisation from major regulatory agencies for any therapeutic indication. Several jurisdictions classify it as a prescription-only medicine or a controlled substance when supplied for human use. Because approved products do not exist, material sold online usually sits outside pharmaceutical supply chains and formal quality oversight. Regulators have issued public notices describing the compound as unapproved. Enforcement varies, and the legal position differs between countries, which complicates any single general statement about its status.
| 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 |
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.
Analytical confirmation of identity relies on mass spectrometry, most often coupled to liquid chromatography. Reversed-phase high-performance liquid chromatography separates the peptide from related impurities and provides a purity estimate based on peak area. Electrospray ionization mass spectrometry then confirms the expected molecular mass, while tandem mass spectrometry can map the fragment sequence. For research-grade material, these two techniques together form the standard minimum. Purity figures reported by vendors are frequently not traceable to an independent laboratory.
Independent verification is central to quality control because the compound is not produced under pharmaceutical manufacturing standards. Third-party laboratories can measure purity, identity, residual solvents, and microbial contamination, though the scope of testing varies between services. Reported analyses of vendor samples have shown batch-to-batch variation in peptide content and the presence of truncated or oxidized species. How much of this variation reflects synthesis conditions versus storage and shipping is not well characterized. No harmonized reference standard exists for the material as sold.
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.
A dog is of a very hot nature: he should therefore never be without clean water by him, that he may drink when he is thirsty. In regard to their food, carrion is by no means proper for them. It must hurt their sense of smelling, on which the excellence of these dogs greatly depends. Barley meal, the dross of wheatflour, or both mixed together, with broth or skim'd milk, is very proper food. For change, a small quantity of greaves from which the tallow is pressed by the chandlers, mixed with their flour; or sheep's feet well baked or boiled, are a very good diet, and when you indulge them with flesh it should always be boiled. In the season of hunting your dogs, it is proper to feed them in the evening before, and give them nothing in the morning you take them out, except a little milk. If you stop for your own refreshment in the day, you should also refresh your dogs with a little milk and bread. In 1833, The Complete Farrier gave similar but far more extensive advice on feeding dogs:
Mannich reaction, resulting in, e.g., voacamine Michael reaction (villalstonine) Condensation of aldehydes with amines (toxiferine) Oxidative addition of phenols (dauricine, tubocurarine) Lactonization (carpaine).
Most often, when symptoms occur it is because of compression of structures near the thymus, such as the superior vena cava or the upper respiratory tract; when lymph nodes are affected it is often in the mediastinum and neck groups. Such tumours are often detected with a biopsy that is subject to immunohistochemistry. This will show the presence of clusters of differentiation, cell surface proteins – namely CD30, with CD19, CD20 and CD22, and with the absence of CD15. Other markers may also be used to confirm the diagnosis. Treatment usually includes the typical regimens of CHOP or EPOCH or other regimens; regimens generally including cyclophosphamide, an anthracycline, prednisone, and other chemotherapeutics; and potentially also a stem cell transplant.
In the United States, heroin is not accepted as medically useful. Its classification as a Schedule I drug means it has "no currently accepted medical use and a high potential for abuse." Under the generic name diamorphine, heroin is prescribed as a strong pain medication in the United Kingdom, where it is administered via oral, subcutaneous, intramuscular, intrathecal, intranasal or intravenous routes. It may be prescribed for the treatment of acute pain, such as in severe physical trauma, myocardial infarction, post-surgical pain and chronic pain, including end-stage terminal illnesses. In other countries it is more common to use morphine or other strong opioids in these situations. The UK's National Institute for Health and Clinical Excellence has produced guidance on the management of caesarean section, which recommends the use of intrathecal or epidural diamorphine for post-operative pain relief. For women who have had intrathecal opioids including diamorphine, there should be a minimum hourly observation of respiratory rate, sedation and pain scores for at least 12 hours if risk factors for respiratory depression are present. Women should be offered diamorphine (up to 0.3mg intrathecally) for intra- and postoperative analgesia because it reduces the need for supplemental analgesia after a caesarean section. Epidural diamorphine (up to 3mg) is a suitable alternative. Diamorphine continues to be widely used in palliative care in the UK, where it is commonly given by the subcutaneous route, often via a syringe driver if patients cannot easily swallow morphine solution.
Sources: en.wikipedia.org
Although one-letter symbols are included in the table, IUPAC–IUBMB recommend that "Use of the one-letter symbols should be restricted to the comparison of long sequences". The one-letter notation was chosen by IUPAC-IUB based on the following rules:
=== Exercise Therapy === Exercise based rehab is commonly used in the conservative management of tendinopathy. Strengthening exercises targeting the affected tendon, including eccentric, concentric, and isometric contractions, are frequently prescribed in clinical practice. Eccentric loading exercises, which involve muscle contraction while the muscle lengthens, are the most commonly used interventions for conditions such as patellar tendinopathy. A systematic review of randomized controlled trials involving individuals with chronic patellar tendinopathy found low- to very-low-quality evidence regarding the benefits of exercise compared with no treatment, glucocorticoid injections, or surgery. While exercise programs may reduce pain in some cases, studies have generally shown little or no difference in long-term function, pain outcomes, or return-to-sport rates when compared with other interventions.
==== Other procedures ==== Orthokeratology is a method using specialized hard or rigid gas-permeable contact lenses to transiently reshape the cornea in order to improve the refractive state of the eye or reduce the need for eyeglasses and contact lenses. In 2009, researchers at the University of Pittsburgh Medical center demonstrated that stem cell collected from human corneas can restore transparency without provoking a rejection response in mice with corneal damage. For corneal epithelial diseases such as Stevens Johnson Syndrome, persistent corneal ulcer etc., the autologous contralateral (normal) suprabasal limbus derived in vitro expanded corneal limbal stem cells are found to be effective as amniotic membrane based expansion is controversial. For endothelial diseases, such as bullous keratopathy, cadaver corneal endothelial precursor cells have been proven to be efficient. Recently emerging tissue engineering technologies are expected to be capable of making one cadaver-donor's corneal cells be expanded and be usable in more than one patient's eye. One such technique has been reported to be safe and efficacious in a clinical pilot study with long term follow-up.
== External links == Collagen+type+III at the U.S. National Library of Medicine Medical Subject Headings (MeSH) "COL3A1". Ehlers Danlos Syndrome Variant Database. Archived from the original on 2021-01-26. Retrieved 2018-12-05. "Report for CCDS2297.1". Consensus Coding Sequence (CDS) Database. National Center for Biotechnology Information (NCBI).
== Development == There are many cell types that contribute to the development of the various types of extracellular matrix found in the plethora of tissue types. The local components of ECM determine the properties of the connective tissue. Fibroblasts are the most common cell type in connective tissue ECM, in which they synthesize, maintain, and provide a structural framework; fibroblasts secrete the precursor components of the ECM, including the ground substance. Chondrocytes are found in cartilage and produce the cartilaginous matrix. Osteoblasts are responsible for bone formation.
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.
Major regulatory agencies have not approved it for any indication. Some countries permit it only under prescription frameworks, while others classify it as a controlled substance.