A practical reference on MC1R: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-01-05 and is reviewed periodically as new material appears.
Early published reports described melanotan-2 as a tanning agent without sun protection, which means darkening is not the same as protection against ultraviolet radiation. Later studies explored the peptide in erectile dysfunction, hemorrhagic shock, and some skin conditions. No regulator in the United States or Europe has approved it for clinical use. Many products labelled melanotan-2 are sold without approval and their identity and purity are unverified. Its long-term safety in humans remains an open question.
Melanotan-2, also written Melanotan II, is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone. Its sequence is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, and the lactam bridge between the aspartate and lysine side chains constrains the peptide into a ring. This structural change increases receptor affinity and metabolic stability relative to the native hormone. The compound was created in the 1980s as a research tool for studying pigmentation biology.
Melanocytes are the pigment-producing cells of the skin, and they carry melanocortin-1 receptors on their surface. When the receptor is activated, cyclic adenosine monophosphate rises inside the cell and raises the activity of enzymes such as tyrosinase, which increases melanin output. Melanotan-2 binds melanocortin-1 receptors in vitro and in animal models, and this binding is generally described as the basis for the tanning effect. Other receptors account for different effects: melanocortin-4 receptors contribute to appetite and erectile signalling, while melanocortin-3 and melanocortin-5 receptors contribute to energy balance and exocrine function.
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.
Human data remain limited and mostly short-term. Reports describe small trials and observational accounts rather than large controlled studies, so questions about dose-response relationships and long-term effects on melanocytes stay open. Whether repeated exposure alters naevus behaviour is not settled in the published record. Researchers also note that self-administered use outside clinical settings makes actual exposure difficult to quantify. Statements about efficacy and safety should therefore be read as preliminary rather than established.
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.
| Property | Value | Notes |
|---|---|---|
| Compound class | Synthetic cyclic heptapeptide | Alpha-MSH analogue containing a D-phenylalanine residue |
| Molecular formula | C50H69N15O9 | Average molecular mass approximately 1024.2 g/mol |
| Appearance | White to off-white lyophilised powder | Normally supplied as a freeze-dried solid in a sealed vial |
| Solubility | Freely soluble in water and polar solvents | Dissolves readily in aqueous buffers and in alcohol-water mixtures |
| Receptor targets | MC1R, MC3R, MC4R, MC5R | Acts as a non-selective melanocortin receptor agonist |
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.
The peptide acts as a non-selective agonist at melanocortin receptors, showing affinity for MC1R, MC3R, MC4R and MC5R. Activation of MC1R on melanocytes drives the conversion of tyrosine into melanin and shifts production toward the darker eumelanin form. MC4R signalling in the central nervous system is linked to appetite and energy balance, which helps explain why reduced food intake appeared in early human studies. Effects on MC4R and on vascular tone also account for the erectile responses recorded as unexpected findings in those same trials.
Melanotan-2 is frequently confused with afamelanotide, a linear analogue authorised in the European Union for erythropoietic protoporphyria. The two compounds differ in chain length, ring structure and receptor selectivity, so findings for one cannot be transferred directly to the other. Published controlled human data on melanotan-2 remain sparse, and much of what circulates online derives from small studies or unpublished reports. Questions about effect size, dose-response behaviour and long-term safety therefore remain unresolved.
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-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.
The peptide was developed during the 1980s by researchers investigating melanocortin signalling and skin pigmentation pathways. Early work focused on analogues of alpha-melanocyte-stimulating hormone that would resist enzymatic breakdown more effectively than the parent molecule. Melanotan-2 emerged from that programme as a shortened, cyclised variant. Reports describing its synthesis and receptor activity later appeared in the scientific literature. Commercial availability grew through unregulated channels rather than through pharmaceutical approval.
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.
oil/fat {\displaystyle {{\textrm {W}}_{\textrm {oil/fat}}}} is the weight of sample, in g. For example, standard methods for determination of SV of vegetable and animal fats are as follows: The SV can also be calculated from the fatty acid composition as determined by gas chromatography (AOCS Cd 3a-94). Handmade soap makers who aim for bar soap use sodium hydroxide (NaOH), commonly known as lye, rather than KOH (caustic potash) which produces soft paste, gel or liquid soaps. In order to calculate the lye amount needed to make bar soap, KOH values of SV can be converted to NaOH values by dividing KOH values by the ratio of the molecular weights of KOH and NaOH (1.403). The theoretical SV of a pure triglyceride molecule can be calculated by the following equation (where MW is its molecular weight):
Topical nonsteroidal anti-inflammatory drugs provide pain relief in common conditions such as muscle sprains and overuse injuries. Since the side effects are also lesser, topical preparations could be preferred over oral medications in these conditions. Some novel and investigational analgesics include subtype-selective voltage-gated sodium channel blockers such as funapide and raxatrigine, as well as multimodal agents such as ralfinamide. Audioanalgesia Electroanalgesia Pain management Patient-controlled analgesia Pain in babies Congenital analgesia (insensitivity to pain)
Prognosis varies with the type of amyloidosis and the affected organ system. Prognosis for untreated AL cardiac amyloidosis is poor, with a median survival of six months. More specifically, AL amyloidosis can be classified as stage I, II or III based on cardiac biomarkers like Nt-proBNP and cardiac troponin. Survival diminishes with increasing stage, but recent advancements in treatments have improved median survival rates for stages I, II, and III, to 91.2, 60, and 7 months respectively. Outcomes in a person with AA amyloidosis depend on the underlying disease, organ(s) affected, and correlate with the concentration of serum amyloid A protein. People with ATTR, mutant ATTR and wild-type ATTR have a better prognosis when compared to people with AL and may survive for over a decade. Survival time is not associated with gender or age, however, some measures of reduced heart function are associated with a shorter survival time. Senile systemic amyloidosis was determined to be the primary cause of death for 70% of people over 110 who have been autopsied.
In a topological transcriptome analysis, researchers profiled important proteins of the non-small cell lung cancer regulatory network and determined that TMEM125 exhibited different topological characteristics across cancerous and normal conditions, suggesting its criticality in lung cancer networks. This is consistent with post-translational modification analysis; TMEM125 phosphorylation suggests it may be involved in a signal transduction pathway or as a receptor protein. Additionally, its myristoylation sites suggests its involvement in signal transduction, apoptosis, and alternative extracellular protein export. TMEM125 was identified as a tetraspanin cell adhesion molecule enriched in oligodendrocytes, suggesting it may play a role in myelination. Additionally, its expression was not observed in differentiating oligodendrocytes in vitro, but was detected in oligodendrocytes from treated rat brains, which suggests its expression is regulated by the presence of axons.
Sources: en.wikipedia.org
G-protein-coupled receptor oligomerisation is a widespread phenomenon. One of the best-studied examples is the metabotropic GABAB receptor. This so-called constitutive receptor is formed by heterodimerization of GABABR1 and GABABR2 subunits. Expression of the GABABR1 without the GABABR2 in heterologous systems leads to retention of the subunit in the endoplasmic reticulum. Expression of the GABABR2 subunit alone, meanwhile, leads to surface expression of the subunit, although with no functional activity (i.e., the receptor does not bind agonist and cannot initiate a response following exposure to agonist). Expression of the two subunits together leads to plasma membrane expression of functional receptor. It has been shown that GABABR2 binding to GABABR1 causes masking of a retention signal of functional receptors.
Orthologs of the human TBR1 gene have been identified in chimpanzee, dog, cow, rat, mouse, and zebrafish. In mice, TBR1 has been found to function in development of the brain, eye, immune system, mesoderm, and placenta. It is also involved in glutamatergic neuronal differentiation in the developing mouse brain. It was discovered that Tbr-1 is expressed by postmitotic cortical neurons in mice and in humans. One target gene of TBR1 in the mouse brain is RELN or Reelin. Tbr-1 mutant mice have been found to have reduced RELN expression, resulting in improper neuronal migration, particularly in Cajal-Retzius cells of the marginal zone. Other studies in mice have found that TBR1 is a repressor or Fezf2. It has also been found to negatively regulate corticospinal tract formation.
The vaginal environment is slightly acidic, with pH ranging from 3.8 - 4.5 based on multiple factors such as age, natural bacteria, and stage of menstrual cycle. Due to the variety in possible pH values, this poses an interesting consideration for drug delivery. Absorption and release of drugs is often influenced by pH, so if the pH is changing through the menstrual cycle, different combinations could be needed at different times to achieve the most effective drug delivery system.
People can also develop CJD because they carry a mutation of the gene that codes for the prion protein (PRNP), located on chromosome 202p12-pter. This occurs in only 10–15% of all CJD cases. In sporadic cases, the misfolding of the prion protein is a process that is hypothesized to occur as a result of the effects of aging on cellular machinery, explaining why the disease often appears later in life. An EU study determined that "87% of cases were sporadic, 8% genetic, 5% iatrogenic and less than 1% variant." Testing for CJD has historically been problematic, due to the nonspecific nature of early symptoms and difficulty in safely obtaining brain tissue for confirmation. The diagnosis may initially be suspected in a person with rapidly progressing dementia, particularly when it is also found with the characteristic medical signs and symptoms such as involuntary muscle jerking, difficulty with coordination/balance and walking, and visual disturbances. Further testing can support the diagnosis and may include:
2023 Analytical Scientist the Power List - Leaders and Advocates 2020 Society for Glycobiology Molecular and Cellular Proteomics (MCP) / American Society for Biochemistry and Molecular Biology (ASBMB) Lectureship Award 2019 inaugural winner of the US Human Proteome Organization Lifetime Achievement in Proteomics Award 2019 Analytical Scientist the Power List 2017 American Society for Mass Spectrometry John B. Fenn Award for a Distinguished Contribution in Mass Spectrometry 2016 American Association for the Advancement of Science Fellow 2015 Human Proteome Organization Distinguished Service Award 2015 German Mass Spectrometry Society (Deutsche Gesellschaft für Massenspektrometrie, DGMS) Wolfgang Paul Lecture 2013 Boston University The William Fairfield Warren Distinguished Professorship 2011 American Chemical Society Fellow 2010 American Chemical Society Frank H. Field and Joe L. Franklin Award for Outstanding Achievement in Mass Spectrometry 2009 International Mass Spectrometry Foundation Thomson Medal 2008 Human Proteome Organization Discovery in Proteomic Sciences Award
Sources: en.wikipedia.org
Alza Corporation was an American pharmaceutical and medical systems company. Founded in 1968 by Dr. Alejandro Zaffaroni; the company's name is a portmanteau of his name. Alza was a major pioneer in the field of drug delivery systems, bringing over 20 prescription pharmaceutical products to market, and employing about 10,000 people during 20 years. In 2001, Alza was acquired by Johnson & Johnson via a stock-for-stock transaction worth US$10.5 billion. The company owns the patents on the following delivery platforms: Alzamer Depot D-Trans DUROS implant E-Trans electrotransport OROS (Osmotic Release Oral System) Macroflux transdermal system Stealth liposomal
Infant formulas made with soy protein phytoestrogens are considered safe alternatives to formulas containing dairy ingredients, which may be excluded for infants with galactosemia and hereditary lactose intolerance. Some reviews express the opinion that more research is needed to answer the question of what effect phytoestrogens may have on infants, but their authors did not find any adverse effects. Studies conclude there are no adverse effects in human growth, development, or reproduction as a result of the consumption of soy-based infant formula compared to conventional cow-milk formula. The American Academy of Pediatrics states: "although isolated soy protein-based formulas may be used to provide nutrition for normal growth and development, there are few indications for their use in place of cow milk-based formula. These indications include (a) for infants with galactosemia and hereditary lactase deficiency (rare) and (b) in situations in which a vegetarian diet is preferred."
Sensory evoked potentials (SEP) are recorded from the central nervous system following stimulation of sense organs, for example, visual evoked potentials elicited by a flashing light or changing pattern on a monitor, auditory evoked potentials by a click or tone stimulus presented through earphones), or tactile or somatosensory evoked potential (SSEP) elicited by tactile or electrical stimulation of a sensory or mixed nerve in the periphery. Sensory evoked potentials have been widely used in clinical diagnostic medicine since the 1970s, and also in intraoperative neurophysiology monitoring (IONM), also known as surgical neurophysiology. There are three kinds of evoked potentials in widespread clinical use: auditory evoked potentials, usually recorded from the scalp but originating at brainstem level; visual evoked potentials, and somatosensory evoked potentials, which are elicited by electrical stimulation of peripheral nerve. Examples of SEP usage include:
Both the formation and degradation of amylopectin is important to the metabolic processes of organisms. Amylopectin is one of the two dominant components of starch, and starch is a successful storage molecule for energy. Because of this, it is synthesized and broken down in most plants and cyanobacteria. In fact, amylopectin seems to rival glycogen, the energy storage molecule in animals, because it is able to store more glucose units and henceforth more energy. The synthesis of amylopectin depends on the combined efforts of four different enzymes:
Sources: en.wikipedia.org
No. It is a laboratory-made peptide, while the natural hormone is alpha-melanocyte-stimulating hormone, a longer peptide produced by the pituitary gland and by skin cells. Melanotan-2 mimics only a short active region of that hormone and contains non-natural residues such as D-phenylalanine.
No approved regulatory indication exists in major markets. An approval exists for a different peptide, afamelanotide, which is used for a rare photosensitivity disorder called erythropoietic protoporphyria. Melanotan-2 itself remains a research compound with no cleared clinical role.
Melanocortin-1 receptors on melanocytes are the receptor most closely linked to pigment production. The peptide is not selective, however, and also activates melanocortin-3, melanocortin-4, and melanocortin-5 receptors. That lack of selectivity is the usual explanation offered for both its range of observed effects and its off-target effects.
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.