This is a working overview of melanotan-2, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
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.
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.
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.
| 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 |
== Further reading == Juretic, D., 2021. Bioenergetics: a bridge across life and universe. CRC Press. Lehninger, Albert L (1971). Bioenergetics: The Molecular Basis of Biological Energy Transformations (2nd ed.). Addison-Wesley. ISBN 0-8053-6103-0. Nicholls, David G.; Ferguson, Stuart J. (2002). Bioenergetics (3rd ed.). Academic Press. ISBN 0-12-518124-8. Green DE, Zande HD (September 1981). "Universal energy principle of biological systems and the unity of bioenergetics". Proc. Natl. Acad. Sci. U.S.A. 78 (9): 5344–7. Bibcode:1981PNAS...78.5344G. doi:10.1073/pnas.78.9.5344. PMC 348741. PMID 6946475.
Dislocations or subluxations (that is, partial dislocations) Sprains, tendinitis, or bursitis from activities. However, a 2018 study reports that while hypermobile individuals are more likely to suffer dislocations doing sports than non-hypermobile individuals, they are less likely to suffer muscle and tendon sprains. The overall chances of sports injury are not significantly different. Joint pain Back pain Joints that make clicking noises Chance of nerve compression disorders in the joints (such as carpal tunnel syndrome) "Growing pains" (as described in children in late afternoon or night)
Several types of cells support an action potential, such as plant cells, muscle cells, and the specialized cells of the heart (in which occurs the cardiac action potential). However, the main excitable cell is the neuron, which also has the simplest mechanism for the action potential. Neurons are electrically excitable cells composed, in general, of one or more dendrites, a single soma, a single axon and one or more axon terminals. Dendrites are cellular projections whose primary function is to receive synaptic signals. Their protrusions, known as dendritic spines, are designed to capture the neurotransmitters released by the presynaptic neuron. They have a high concentration of ligand-gated ion channels. These spines have a thin neck connecting a bulbous protrusion to the dendrite. This ensures that changes occurring inside the spine are less likely to affect the neighboring spines. The dendritic spine can, with rare exception (see LTP), act as an independent unit. The dendrites extend from the soma, which houses the nucleus, and many of the "normal" eukaryotic organelles. Unlike the spines, the surface of the soma is populated by voltage activated ion channels. These channels help transmit the signals generated by the dendrites. Emerging out from the soma is the axon hillock. This region is characterized by having a very high concentration of voltage-activated sodium channels. In general, it is considered to be the spike initiation zone for action potentials, i.e. the trigger zone. Multiple signals generated at the spines, and transmitted by the soma all converge here.
Since September 2021, private schools providing compulsory education can no longer be controlled by foreign entities or individuals. Only Chinese nationals may serve on their boards of directors. In 2023, the Patriotic Education Law was adopted, codifying the mandatory patriotic education program in the country.
Sources: en.wikipedia.org
== Adverse effects == Adverse drug reactions associated with the use of beta blockers include nausea, diarrhea, bronchospasm, dyspnea, cold extremities, exacerbation of Raynaud's syndrome, bradycardia, hypotension, heart failure, heart block, fatigue, dizziness, alopecia (hair loss), abnormal vision, hallucinations, insomnia, nightmares, sexual dysfunction, erectile dysfunction, alteration of glucose and lipid metabolism. Mixed α1/β-antagonist therapy is also commonly associated with orthostatic hypotension. Carvedilol therapy is commonly associated with edema. Due to the high penetration across the blood–brain barrier, lipophilic beta blockers, such as propranolol and metoprolol, are more likely than other less lipophilic beta blockers to cause sleep disturbances, such as insomnia, vivid dreams and nightmares. Adverse effects associated with β2-adrenergic receptor antagonist activity (bronchospasm, peripheral vasoconstriction, alteration of glucose and lipid metabolism) are less common with β1-selective (often termed "cardioselective") agents, but receptor selectivity diminishes at higher doses. Beta blockade, especially of the beta-1 receptor at the macula densa, inhibits renin release, thus decreasing the release of aldosterone. This causes hyponatremia and hyperkalemia. Hypoglycemia can occur with beta blockade because β2-adrenoceptors normally stimulate glycogen breakdown (glycogenolysis) in the liver and pancreatic release of the hormone glucagon, which work together to increase plasma glucose. Therefore, blocking β2-adrenoceptors lowers plasma glucose.
=== Medical === Dihydromorphine is used for the management of moderate to severe pain such as that occurring in cancer; however, it is less effective in treating neuropathic pain and is generally considered inappropriate and ineffective for psychological pain.
The metabolome is the complete set of small-molecule chemicals found within a biological sample. The biological sample can be a cell, a cellular organelle, an organ, a tissue, a tissue extract, a biofluid or an entire organism. The small molecule chemicals found in a given metabolome may include both endogenous metabolites that are naturally produced by an organism (such as amino acids, organic acids, nucleic acids, fatty acids, amines, sugars, vitamins, co-factors, pigments, antibiotics, etc.) as well as exogenous chemicals (such as drugs, environmental contaminants, food additives, toxins and other xenobiotics) that are not naturally produced by an organism. In other words, there is both an endogenous metabolome and an exogenous metabolome. The endogenous metabolome can be further subdivided to include a "primary" and a "secondary" metabolome (particularly when referring to plant or microbial metabolomes). A primary metabolite is directly involved in the normal growth, development, and reproduction. A secondary metabolite is not directly involved in those processes, but usually has important ecological function. Secondary metabolites may include pigments, antibiotics or waste products derived from partially metabolized xenobiotics. The study of the metabolome is called metabolomics.
== Efficacy == The use of lasers in treating periodontal disease has been seen by some dental professionals as controversial. The American Academy of Periodontology stated in 1999 that it was "not aware of any randomized blinded controlled longitudinal clinical trials, cohort or longitudinal studies, or case-controlled studies indicating that 'laser excisional new attachment procedure (or Laser ENAP)' or 'laser curettage' offers any advantageous clinical result not achieved by traditional periodontal therapy. Moreover, published studies suggest that use of lasers for ENAP procedures and/or gingival curettage could render root surfaces and adjacent alveolar bone incompatible with normal cell attachment and healing." A 2015 systematic review from the AAP regeneration workshop acknowledged peer-reviewed studies reporting periodontal regeneration, and further suggested that the LANAP protocol's minimally invasive nature may offer advantages in the regeneration of defects where minimal soft tissue change is required. The AAP consumer information page on laser therapy for gum disease notes that lasers can be used to treat periodontal disease and that controlled studies have reported similar results to some other treatment options (including scaling and root planing alone), and also states that different laser wavelengths have different applications in periodontal treatment.
N-acetyl Aspartate (NAA): with its major resonance peak at 2.02 ppm, decrease in levels of NAA indicate loss or damage to neuronal tissue, which results from many types of insults to the brain. Its presence in normal conditions indicates neuronal and axonal integrity. Choline: with its major peak at 3.2 ppm, choline is known to be associated with membrane turnover, or increase in cell division. Increased choline indicates increase in cell production or membrane breakdown, which can suggest demyelination or presence of malignant tumors. Creatine and phosphocreatine: with its major peak at 3.0 ppm, creatine marks metabolism of brain energy. Gradual loss of creatine in conjunction with other major metabolites indicates tissue death or major cell death resulting from disease, injury or lack of blood supply. Increase in creatine concentration could be a response to cranialcerebral trauma. Absence of creatine may be indicative of a rare congenital disease. Lipids: with their major aliphatic peaks located in the 0.9–1.5 ppm range, increase in lipids is seen is also indicative of necrosis. These spectra are easily contaminated, as lipids are not only present in the brain, but also in other biological tissue such as the fat in the scalp and area between the scalp and skull. Lactate: Is an AX3 system which results in a doublet (two symmetric peaks) centered about 1.31 ppm, and a quartet (four peaks with relative peak heights of 1:2:2:1) centered about 4.10 ppm.
Sources: en.wikipedia.org
the Scottish Parliament, with 129 members elected under the additional member system every five years, and each called Member of the Scottish Parliament (MSP; Scottish Gaelic: Ball Pàrlamaid na h-Alba, BPA; Scots: Memmer o the Scots Pairliament, MSP) the Northern Ireland Assembly, with 90 members each known as Member of the Legislative Assembly (MLA; Irish: Comhalta den Tionól Reachtach, CTR; Ulster-Scots: Laa-Makkan Forgaitherar, LMF). (Between 1921 and 1973, Northern Ireland was governed by the bicameral Parliament of Northern Ireland. Members of its lower house, the House of Commons of Northern Ireland, were known as Member of Parliament.) the Senedd (Welsh Parliament), with 60 elected members called Member of the Senedd (English - MS); Welsh: Aelod o'r Senedd, AS) the London Assembly, with 25 members elected under the additional member system every four years, called Members of the London Assembly (AM) MPs are elected in general elections and by-elections to represent constituencies, and may remain MPs until Parliament is dissolved. "If it has not been dissolved earlier, a Parliament dissolves at the beginning of the day that is the fifth anniversary of the day on which it first met." (Dissolution and Calling of Parliament Act 2022). A candidate to become an MP must be a British or Irish or Commonwealth citizen, be at least 18 years of age (reduced from 21 in 2006), and not be a public official or officeholder, as set out in the schedule to the Electoral Administration Act 2006.
== Pollution tolerance == Xanthoria parietina is highly resistant to air pollution, including heavy metals, nitrogen compounds, and ozone. Laboratory experiments have shown that it tolerates exposure to air contaminants and bisulfite ions with little or no damage. It is also resistant to heavy metal contamination and nitrogen pollution. The mechanisms underlying this tolerance involve multiple protective systems. The parietin layer in the upper cortex acts as a hydrophobic barrier, reducing the penetration of toxic metal ions into the photobiont cells. Experimental studies have shown that parietin-deficient thalli experience greater physiological stress when exposed to heavy metals. Parietin also contributes to ozone tolerance; fumigation experiments revealed that samples containing parietin recovered photosynthetic efficiency and chlorophyll integrity more quickly than those without it, suggesting an antioxidant function in addition to its role as a light-screening pigment. Furthermore, reactive oxygen species (ROS) levels induced by ozone exposure were significantly higher in parietin-deficient samples, reinforcing its role in oxidative stress mitigation. The hydration state of X. parietina influences its ozone sensitivity. Dry thalli suffer less damage and recover more quickly than hydrated ones, likely because reduced gas exchange limits ozone penetration. This factor helps explain the lichen's resilience in Mediterranean climates, where it often remains desiccated during periods of high ozone pollution.
===== State ===== Most states also have laws regulating pseudoephedrine. The states of Alabama, Arizona, Arkansas, California, Colorado, Delaware, Florida, Georgia, Hawaii (as of May 1, 2009) Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana (as of August 15, 2009), Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Jersey, North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia and Wisconsin have laws requiring pharmacies to sell pseudoephedrine "behind the counter." Though the drug can be purchased without a prescription, states can limit the number of units sold and can collect personal information from purchasers. The states of Oregon and Mississippi previously required a prescription for the purchase of products containing pseudoephedrine. However, as of 1 January 2022, these restrictions have been repealed. The state of Oregon reduced the number of methamphetamine lab seizures from 448 in 2004 (the final full year before implementation of the prescription only law) to a new low of 13 in 2009. The decrease in meth lab incidents in Oregon occurred largely before the prescription-only law took effect, according to a NAMSDL report titled Pseudoephedrine Prescription Laws in Oregon and Mississippi.
== Personal life == In 2004, Wolpaw was diagnosed with ulcerative colitis. Expecting his condition to require a departure from the company, he spoke with managing director Gabe Newell, who surprised him by offering an extended leave with pay. "Your job is to get better," Newell said. "That is your job description at Valve. So go home to your wife and come back when you are better."
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.
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.