melanocortin receptor is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2026-02-21. Numbers and descriptions here follow the published literature rather than marketing material.
Published pharmacokinetic information is limited and comes mainly from small studies rather than registrational trials. Plasma half-life is usually described as short, on the order of tens of minutes, followed by rapid tissue distribution and clearance of the intact peptide. Metabolites and low concentrations of parent compound have been reported in urine, a detail relevant to anti-doping and forensic testing. Whether repeated exposure changes receptor sensitivity or clearance over time remains an open question. Values differ noticeably between analytical assays, so published numbers should be read as approximate rather than definitive.
Melanotan II is a synthetic cyclic heptapeptide with the sequence Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, corresponding to a molecular formula of C50H69N15O9 and a monoisotopic mass near 1024 daltons. It was designed as a structural analogue of alpha-melanocyte-stimulating hormone, a peptide hormone produced by cleavage of proopiomelanocortin. A lactam bridge between the aspartate and lysine side chains closes the ring, and the C-terminal amide removes a free carboxyl group. Both modifications increase resistance to enzymatic degradation compared with the linear parent hormone. Four substitutions distinguish it from afamelanotide, the linear analogue studied under the name melanotan I.
No regulatory authority has approved melanotan-2 for human use, and several countries classify it as a prescription-only or controlled substance, which restricts lawful supply. Material sold online is generally labelled as a research chemical and is not required to meet pharmaceutical standards of identity or purity. Published human data consist mainly of small uncontrolled studies, case reports and adverse-event notifications, so the evidence base is descriptive rather than confirmatory. Whether repeated melanocyte stimulation alters long-term naevus behaviour remains an open question that no completed trial has resolved.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Cyclic heptapeptide, C-terminally amidated |
| Approximate molecular mass | 1024 Da | Monoisotopic mass of the free peptide |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility class | Soluble in water and polar solvents | Also dissolves in neutral aqueous buffer |
| Common synonyms | Melanotan II, MT-II, MT-2 | Described as a melanocortin agonist in early literature |
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.
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.
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.
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.
In a TMU-LiCl mixture, stable isotropic solutions can be obtained up to a PPB polymer concentration of 14%. TMU also dissolves cellulose ester and swells other polymers such as polycarbonates, polyvinyl chloride, or aliphatic polyamides - usually at elevated temperature. Strong and hindered non-nucleophilic guanidine bases are accessible from TMU in a simple manner, which are in contrast to the fused amidine bases DBN or DBU not alkylated.
Achondroplasia is a type of autosomal dominant genetic disorder that is the most common cause of dwarfism. It is also the most common type of non-lethal osteochondrodysplasia or skeletal dysplasia. The prevalence is approximately 1 in 25,000 births. Achondroplastic dwarfs have short stature, with an average adult height of 131 cm (4 feet, 3 inches) for males and 123 cm (4 feet, 0 inches) for females. In achondroplasia the dwarfism is readily apparent at birth. Likewise, craniofacial abnormalities in the form of macrocephaly and mid-face hypoplasia are present at birth. The previous clinical findings differentiate between achondroplasia and pseudoachondroplasia in which dwarfism is not recognizable at birth and craniofacial abnormalities are not considered a disease feature. Plain radiography plays an additional and important role in the differential diagnosis of achondroplasia.
CoviVac – COVID vaccine Cytestrol acetate – antiestrogen, cytostatic antineoplastic agent Deltaran (delta sleep-inducing peptide) – alcohol withdrawal treatment Dilept (GZR-123) – antipsychotic, neurotensin analogue Diucifon – leprostatic agent Emoxypine (Mexidol; Mexifin) – actoprotector, antioxidant EpiVacCorona – COVID vaccine Eprobemide (Befol) – antidepressant, reversible inhibitor of monoamine oxidase A Ethacizine (ethacyzine; Ethacizin) – antiarrhythmic agent Fabomotizole (Afobazole) – anxiolytic Feprosidnine (Sydnophen) – amphetamine derivative, psychostimulant Fluacizine (Phtorazisin) – tricyclic antidepressant, phenothiazine Fluorothiazinone (CL-55; Ftortiazinon) – investigational antibiotic Fotretamine (Fotrin) – alkylating antineoplastic agent, immunosuppressant Gamofen (gamophen; amphetamine–GABA) – amphetamine derivative, GABATooltip γ-aminobutyric acid analogue, central agent, central depressant Gidazepam (hydazepam, hidazepam) – atypical benzodiazepine, anxiolytic, TSPOTooltip translocator protein agonist/ligand Gludantan (gludantane) – adamantane, antiparkinsonian agent, antidepressant Glufimet (RGPU-238; dimethyl 3-phenylglutamate) – GABATooltip γ-aminobutyric acid and phenibut analogue Glutaron (RGPU-135; neuroglutamine, neuroglutam; β-phenylglutamate; 3-phenylglutamate) – glutamate analogue, psychostimulant, antidepressant, anxiolytic, neuroprotective Hemantane (hymantane) – adamantane, antiparkinsonian agent Hopantenic acid (homopantothenic acid; N-pantoyl-GABA; Pantogam) – central depressant, GABATooltip γ-aminobutyric acid analogue Ipidacrine (Neiromidin) – acetylcholinesterase inhibitor Latrepirdine (dimebolin; Dimebon) – antihistamine, antiserotonergic, nootropic Mecigestone (pentarane B) – progestin Megestrol caproate (MGC) – progestin Meldonium (Mildronate) – anti-ischemia agent Menthyl isovalerate (validolum; Extravalerianic, Validol, Valofin, Menthoval) – anxiolytic Mesocarb (Sidnocarb, Sydnocarb, Synocarb) – amphetamine derivative, psychostimulant Methylphenatine – amphetamine derivative, psychostimulant Methylphenylpiracetam – racetam, sigma σ1 receptor positive allosteric modulator α-Methyltryptamine (αMT; Indopan) – tryptamine derivative, antidepressant Metralindole (Inkazan) – antidepressant, reversible inhibitor of monoamine oxidase A Moracizine (moricizine; Ethmozine) – antiarrhythmic agent Nooglutyl (Nooglutil; N-5-hydroxynicotinoyl-L-glutamate) – nootropic Orenetide (BP101; Libicore; Desirix; Thr-Lys-Pro-Arg-Pro) – investigational small peptide, sexual enhancer Pabofen (pabophen; amphetamine–PABA) – amphetamine derivative, antihypoxic agent Pentarane A (D'6-pentarane) – progestin Phemerazole (femerazol; 5-phenyl-3-methylpyrazole) – sedative, hypnotic, anticonvulsant, muscle relaxant, mammary stimulant Phenatine (phenatin; Fenatine; amphetamine–niacin; N-nicotinoylamphetamine) – amphetamine derivative, psychostimulant, hypotensive agent Phenazepam – benzodiazepine, anxiolytic, sedative, hypnotic Phenibut (β-phenyl-GABA; Anvifen, Fenibut, Noofen; Citrocard, RGPU-147) – central depressant, anxiolytic, GABATooltip γ-aminobutyric acid analogue, gabapentinoid N-Phenylacetyl-L-prolylglycine ethyl ester (omberacetam; Noopept) – nootropic, racetam, cyclic glycine-proline prodrug Phenylphenamine (phenylamphetamine) – amphetamine derivative Phenylpiracetam (fonturacetam; Phenotropil, Actitropil, Carphedon) – psychostimulant, nootropic, racetam Phenylpiracetam hydrazide (fonturacetam hydrazide) – anticonvulsant, racetam Picamilon (N-nicotinoyl-GABA, pycamilon, and pikamilon) – anxiolytic, GABATooltip γ-aminobutyric acid analogue Pipofezine (Azafen, Azaphen) – tricyclic antidepressant Pirlindole (Lifril, Pyrazidol) – antidepressant, reversible inhibitor of monoamine oxidase A, serotonin–norepinephrine reuptake inhibitor Polymethylsiloxane polyhydrate (PMSPH; methylsilicic acid hydrogel; Enterosgel) – enterosorbent Propylphenamine (propylamphetamine; possibly N-propylamphetamine) – amphetamine derivative Prospidium chloride (prospidine) – cytostatic, anti-inflammatory agent Pyridoxiphen (amphetamine–pyridoxine; pyridoxylamphetamine) – amphetamine derivative, sympatholytic, hypotensive agent Quifenadine (Phencarol, Fencarol) – antihistamine RGPU-95 (p-chlorophenylpiracetam) – antidepressant, anxiolytic, racetam RGPU-207 (cyclic GABA derivative) – GABATooltip γ-aminobutyric acid analogue, mitochondrial modulator, racetam RGPU-260 – GABATooltip γ-aminobutyric acid analogue, cardiac stimulant Riamilovir (Triazavirin) – antiviral RU-1205 – analgesic, kappa opioid receptor agonist Selank – tuftsin analogue, nootropic, anxiolytic Semax – ACTHTooltip adrenocorticotropic hormone fragment analogue, nootropic, neuroprotective, neurorestorative Sodium polydihydroxyphenylene thiosulfonate (Hypoxen) – antihypoxic agent Sputnik Light – COVID vaccine Sputnik V – COVID vaccine Sulfozinum (sulfazin) – pyrogenic and pain-inducing agent used in psychiatry, for instance psychosis Temgicoluril (tetramethylglycoluril; Adaptol, Mebicar, Mebicarum, Mebikar) – anxiolytic Testifenon (testiphenon, testiphenone, chlorphenacyl dihydrotestosterone ester) – androgen/anabolic steroid, cytostatic antineoplastic agent Tetrindole – antidepressant, reversible inhibitor of monoamine oxidase A Thiophenatine (N-thionicotinoylamphetamine) – amphetamine derivative Tipindole – serotonin antagonist and monoamine oxidase inhibitor Tolibut (β-(4-methylphenyl)-GABA)) – anxiolytic, analgesic, neuroprotective, GABATooltip γ-aminobutyric acid and phenibut analogue Traneurocin (cycloprolylglycine; CPG; NA-831) – racetam-like neuroprotective, neurogenic, nootropic, and anxiolytic Trimeperidine – opioid analgesic Umifenovir (Arbidol) – antiviral Vishnevsky liniment – topical wound medication Phenamine (Fenamin), a psychostimulant, is not specifically a Russian drug but is rather the Russian name for amphetamine.
=== Synthetic analogues === Many vitamin B1 analogues, such as Benfotiamine, fursultiamine, and sulbutiamine, are synthetic derivatives of thiamine. Most were developed in Japan in the 1950s and 1960s as forms that were intended to improve absorption compared to thiamine. Some are approved for use in some countries as a drug or non-prescription dietary supplement for treatment of diabetic neuropathy or other health conditions.
=== Human mutations === 341 mutations in human OTC have been reported. At least 259 of these mutations are considered to be disease-causing mutations. 149 of these mutations are known to cause onset of hyperammonemia during the first weeks of life. 70 manifest as hyperammonemia in male patients later in life. Most of the mutations occur in known functional motifs, such as the SMG loop or CP binding domains.
Sources: en.wikipedia.org
where p0 is called total pressure, and q is dynamic pressure. Many authors refer to the pressure p as static pressure to distinguish it from total pressure p0 and dynamic pressure q. In Aerodynamics, L.J. Clancy writes: "To distinguish it from the total and dynamic pressures, the actual pressure of the fluid, which is associated not with its motion but with its state, is often referred to as the static pressure, but where the term pressure alone is used it refers to this static pressure." The simplified form of Bernoulli's equation can be summarized in the following memorable word equation:
=== Luteal phase === Immediately after the LH surge and subsequent ovulation, estradiol concentrations drop and the corpus luteum develops. Towards the end of luteal phase, GnSAF production in the small antral follicles increases steadily. FSH does not stimulate GnSAF production in the corpus luteum, so GnSAF bioactivity is low after ovulation, until the intercycle rise in FSH occurs.
== Disadvantages == Consistently producing ligand-targeted liposomes through traditional methods is difficult. The process can be tedious, challenging to control and result in a poorly defined system. Using the 'post-insertion' technique—in which Micelles formed from PEG-linked ligands are incubated with pre-formed, drug-loaded, non-targeted liposomes to combine and form LTLs—can limit the associated manufacturing challenges. When using certain ligands, such as antibodies, the risk for an immunological reaction poses a risk. Liposome design including size, charge, morphology, composition, surface characteristics, and dose size can all influence the immune response to administered LTLs. The ligands used can elicit an immune response when introduced into the body. For example, when peptide ligands such as CDX are used for brain-targeted delivery systems, they are immunogenic and trigger an immune response. Complement Activation-Related Pseudo-allergies (CARPA) is a hypersensitivity syndrome that can be triggered when LTLs activate the innate immune system and the complement system. CARPA can cause many side effects including anaphylaxis, cardiopulmonary distress, and facial swelling. These side effects have the potential to be severe, which generates concern when administering LTLs to patients with health problems, especially cardiovascular issues. This reaction can be reduced by slowing infusion rates or incorporating the use of allergy medicines like antihistamines into the treatment regimen.
=== Auto-ponderomotive guide === An auto-ponderomotive guide is an electrostatic counterpart to a Paul trap. The electron beam is directed into an area of segmented electrodes with alternating negative and positive static voltages placed at half a periodicity
Sources: en.wikipedia.org
November 14, 2008: Eurozone Taken as a whole the Eurozone officially slips under, pushed down by recessions in Germany and Italy for its first recession since its creation in 1999. These 15 countries are: Austria, Belgium, Cyprus, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, Malta, Netherlands, Portugal, Slovenia, Spain. On January 1, 2009, Slovakia adopted the euro, and so is now part of the Eurozone. Though the Eurozone suffers from recession as a whole, Belgium, France, Greece, and Slovakia still have better growth.
The evidence for the effectiveness of non-pharmacological interventions for chronic pain is insufficient to recommend such interventions alone, however their use in combination with medications may be reasonable. There is some evidence that aquatic therapy is a beneficial intervention. The spasticity associated with MS can be difficult to manage because of the progressive and fluctuating course of the disease. Although there is no firm conclusion on the efficacy in reducing spasticity, PT interventions can be a safe and beneficial option for patients with multiple sclerosis. Physical therapy including vibration interventions, electrical stimulation, exercise therapy, standing therapy, and radial shock wave therapy (RSWT), were beneficial for limiting spasticity, helping limit excitability, or increasing range of motion.
== Epitope design == The whole peptide vaccine is to mimic the epitope of an antigen, so epitope design is the most important stage of vaccine development and requires an accurate understanding of the amino acid sequence of the immunogenic protein interested. The designed epitope is expected to generate strong and long-period immuno-response against the pathogen. The followings are the points to consider when designing the epitope:
light red or dark pink, being perfused with new capillary loops or "buds"; soft to the touch; moist; bumpy (granular) in appearance, due to punctate hemorrhages; pulsatile on palpation; painless when healthy;
Administration of ethinylestradiol diminishes the secretion of luteinizing hormone and follicle-stimulating hormone from the pituitary, leading to stabilization of the endometrial surface of the uterus. An levonorgestrel containing intrauterine device (IUD) can also be placed to reduce heavy menstrual bleeding in VWD. Desmopressin is generally safe, with mild side effects of low blood pressure and flushing possible. Very rare side effects include hyponatremia (low sodium) and cardiovascular complications. The incidence of hyponatremia can be reduced by limiting water intake to 1.5 liters for 1 day after receiving desmopressin. For patients with VWD scheduled for surgery and cases of VWD disease complicated by clinically significant hemorrhage, human-derived medium purity factor VIII concentrates, which also contain von Willebrand factors, are available for prophylaxis and treatment. Humate P, Alphanate, Wilate and Koate HP are commercially available for prophylaxis and treatment of VWD, and have varying levels of factor VIII. Products with higher VWF:RCo/FVIII ratios allow for more frequent dosing of VWF if needed, without the risk of accumulation to supranormal levels of FVIII. Recombinant factor VIII products contain insignificant quantity of VWF, so are not clinically useful as standalone therapy for VWD. Risks of thrombosis, development of alloantibodies, and allergic reactions including anaphylaxis must be considered when administering these preparations. Such risks have emerged as the main concerns in factor replacement therapies as infectious risks have diminished.
Sources: en.wikipedia.org
No. It is a synthetic analogue carrying four amino acid changes, a lactam ring and an amidated C-terminus. The natural hormone is a linear thirteen-amino-acid peptide processed from proopiomelanocortin.
Afamelanotide is the linear analogue [Nle4-D-Phe7]-alpha-MSH, sometimes called melanotan I, while melanotan II is cyclic and carries three further substitutions. The two are distinct molecules and are not interchangeable in analytical testing.
Binding to the four melanocortin receptor subtypes is well documented in vitro. The relative contribution of each subtype to whole-body effects in humans is far less certain.
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.