The short version of afamelanotide fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-08-15 and is reviewed periodically as new material appears.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Synthetic cyclic heptapeptide |
| Molecular mass | Approximately 1024 g/mol | Depends on counter-ion content |
| Appearance | White to off-white powder | Commonly supplied as a lyophilised solid |
| Solubility | Freely soluble in water | Also dissolves in common aqueous buffers |
| Typical storage | -20 degrees Celsius, desiccated | Protect from light and repeated freeze-thaw |
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.
Regulatory treatment varies between countries. Several national medicines agencies have classified the peptide as unapproved, and customs authorities in some jurisdictions seize shipments on that basis. A few jurisdictions channel supply through prescription-only frameworks that do not list the substance by name. Because the material circulates mainly through online vendors, composition and purity are rarely verified before sale. Surveys of unapproved peptide products have reported labels that did not match measured content in a substantial fraction of samples.
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.
Receptor-binding studies classify melanotan II as a non-selective melanocortin agonist. It interacts with MC1R, MC3R, MC4R and MC5R, with reported affinities in the low nanomolar range and no strong subtype preference. Activation of MC1R on dermal melanocytes shifts pigment synthesis toward eumelanin, the dark polymer deposited in melanosomes and transferred to keratinocytes. Because the same peptide engages MC4R in the hypothalamus, it also appears in animal work on food intake and erectile response, which is why it is discussed in both pigment and metabolic research. Which receptor populations dominate after systemic exposure in humans is not fully established.
Two structural changes distinguish the synthetic peptide from the natural hormone. A norleucine residue replaces methionine at one position, and a D-configured phenylalanine replaces the natural L-form at another. Both substitutions slow enzymatic breakdown, which extends the molecule's persistence relative to the parent hormone. The lactam bridge further constrains the backbone into a stable conformation. These features are standard design strategies in peptide chemistry and are not unique to this compound; they appear across many research peptides built for improved stability.
The compound was developed in the late 1980s and early 1990s by academic researchers investigating melanocortin signaling and pigmentation. Early work explored whether synthetic analogs could reproduce effects of the natural hormone under controlled conditions. The molecule never advanced through the full regulatory pathway required for approval as a medicine. From the mid-2000s onward it appeared in unregulated consumer markets, often distributed through informal channels. That gap between research origins and commercial availability shapes how the compound is discussed today.
Melanotan-2 is a synthetic peptide designed as an analog of alpha-melanocyte-stimulating hormone, a signaling molecule produced in the pituitary and skin. Its structure is a linear chain of seven amino acids that folds into a ring through an internal lactam bridge joining two side chains. The compound is sometimes written as MT-II or MEL-2 in informal and commercial contexts. It belongs to the melanocortin peptide family, a group of short signaling molecules that share a conserved core sequence recognized by melanocortin receptors.
=== Order broker === Order brokers are third-party agents that display arrangement and bouquet product images and then transfer orders to affiliated local florists for fulfillment and hand delivery. Order broker customers pay additional service fees as well as local delivery charges, which are generally included in the price displayed with each product. Orders are sent to local florists for fulfillment via a floral wire service. The advantage of this service is the consolidation of purchases for delivery to multiple locations through a single website. The disadvantage is the customer cannot see or pick the fulfilling florist. Most florists also offer order brokering services for national and international delivery.
In two-dimensional structures like graphene, thermal and quantum fluctuations cause relative displacement, with fluctuations growing logarithmically with structure size as per the Mermin–Wagner theorem. This shows that the amplitude of long-wavelength fluctuations grows logarithmically with the scale of a 2D structure, and would therefore be unbounded in structures of infinite size. Local deformation and elastic strain are negligibly affected by this long-range divergence in relative displacement. It is believed that a sufficiently large 2D structure, in the absence of applied lateral tension, will bend and crumple to form a fluctuating 3D structure. Researchers have observed ripples in suspended layers of graphene, and it has been proposed that the ripples are caused by thermal fluctuations in the material. As a consequence of these dynamical deformations, it is debatable whether graphene is truly a 2D structure. These ripples, when amplified by vacancy defects, induce a negative Poisson's ratio into graphene, resulting in the thinnest auxetic material known so far. Graphene-nickel (Ni) composites, created through plating processes, exhibit enhanced mechanical properties due to strong Ni-graphene interactions inhibiting dislocation sliding in the Ni matrix.
=== Biosynthesis === Arginine is produced in organisms via de novo synthesis from glutamine, which has a simpler chemical structure. Arginine is also generated as an intermediate within the urea cycle but is consumed there to the same extent (i.e. there is no net production). In the urea cycle, the transient formation of arginine is a necessary step in the production and excretion of urea.
He noted that shed scabs (which might be spread via bedsheets or other fomites) often contain “large quantities of virus”, but suggested that the “apparent lack of infectiousness of scab associated virus” might be due to “encapsulation with inspissated pus”. Contaminated needles are the most common fomite that transmits HIV. Fomites from dirty needles also easily spread Hepatitis B.
== History == Zydis technology was developed by R.P. Scherer Corporation (currently owned by Catalent Pharma Solutions) in 1986. The technology's first commercial application was in August, 1993, when a new dosage form of Pepcidine (famotidine) from Merck & Co. was launched in Sweden. In November 1993 Imodium Lingual (loperamide) from Janssen Pharmaceutica was released in Germany with Zydis technology. In December, 1996, the Food and Drug Administration approved Claritin (loratadine) RediTabs from Schering-Plough, the first prescription drug with Zydis technology sold in the U.S.
Sources: en.wikipedia.org
A study at Duke University found that decline in muscle strength as part of the aging process can be attributed to a decline in glutaminase, and that restoring it in the muscles of aged mice improved muscle function. A study at the University of California, San Francisco identified the accumulation of the protein FTL1 as the main driver of brain aging. An experiment found that removing it from the brains of elderly mice reversed age-related decline while introducing it into the brains of young mice immediately aged their brains. Researchers Tel Aviv University, Bar-Ilan University, and the National Institute on Aging reported reversing key signs of age-related decline in the livers of aged mice by boosting levels of Sirtuin 6. Researchers at Texas A&M University reported reversing signs of brain aging by using extracellular vesicles loaded with microRNAs to reduce inflammation by means of a nasal spray to bypass the blood–brain barrier. Two studies at Mass General Brigham found that the health of the thymus in adulthood is one of the strongest predictors of longevity, cardiovascular health, and cancer survival including response to immunotherapy in adulthood. Scientists at the Leibniz Institute on Aging identified declining levels of phosphatidylcholine as a driver of age-related mitochondrial dysfunction and loss of cellular energy. They found that boosting phosphatidylcholine resulted in more youthful mitochondrial performance in aging organisms.
Affibody molecules are small, robust proteins engineered to bind to a large number of target proteins or peptides with high affinity, imitating monoclonal antibodies, and are therefore a member of the family of antibody mimetics. Affibody molecules are used in biochemical research and are being developed as potential new biopharmaceutical drugs. These molecules can be used for molecular recognition in diagnostic and therapeutic applications.
== Structure == These proteins are characterized by having three disulfide bonds in a characteristic motif. Some family members have an additional disulfide bond also in a conserved location. All of these proteins have a helical segment (corresponding to B chain in insulin) followed by a variable-length chain, followed by a domain (A chain in insulin) with two helices pinned against each other via a disulfide bond. These two regions are linked by two or three disulfide bonds. Amongst the different proteins in the family, very little of the sequence is conserved except for the disulfide bonds. The variable-length chains may exhibit large inter-species variation even when the remainder of the sequence is highly conserved; and as is in the case of insulin, sometimes the variable length chain is cleaved out by secretory endoproteases, leaving a two-chain protein held together by disulfide bonds.
=== General and cited references === Chinn, George M., ed. (1987). The Machine Gun: History, Evolution, and Development of Manual, Automatic, and Airborne Repeating Weapons (PDF). Vol. V. Ann Arbor, Michigan: Edward Brothers Publishing Co. Retrieved 28 April 2019.
Sources: en.wikipedia.org
=== Discovery of GLP-2 actions leading to Short Bowel Syndrome treatments === In 1996, Drucker also discovered the first biological actions for GLP-2, demonstrating that it augmented crypt cell proliferation and expansion of the mucosal epithelium in the small bowel of mice and rats. He subsequently identified and characterized a DPP-4-resistant molecule, teduglutide, that was ultimately developed and approved for the treatment of short bowel syndrome in adults and children, a disorder in which fluids are poorly absorbed after resection of the small intestine.
Molybdenum is the 54th most abundant element in the Earth's crust with an average of 1.5 parts per million and the 25th most abundant element in the oceans, with an average of 10 parts per billion; it is the 42nd most abundant element in the Universe. The Soviet Luna 24 mission discovered a molybdenum-bearing grain (1 × 0.6 μm) in a pyroxene fragment taken from Mare Crisium on the Moon. The comparative rarity of molybdenum in the Earth's crust is offset by its concentration in a number of water-insoluble ores, often combined with sulfur in the same way as copper, with which it is often found. Though molybdenum is found in such minerals as wulfenite (PbMoO4) and powellite (CaMoO4), the main commercial source is molybdenite (MoS2). Molybdenum is mined as a principal ore and is also recovered as a byproduct of copper and tungsten mining. The world's production of molybdenum was 250,000 tonnes in 2011, the largest producers being China (94,000 t), the United States (64,000 t), Chile (38,000 t), Peru (18,000 t) and Mexico (12,000 t). The total reserves are estimated at 10 million tonnes, and are primarily concentrated in China (4.3 Mt), the US (2.7 Mt) and Chile (1.2 Mt). By continent, 93% of the world's molybdenum production is distributed approximately evenly among North America, South America (mainly Chile), and China. Europe and the rest of Asia (mostly Armenia, Russia, Iran and Mongolia) produce the remainder.
In DNA, fraying occurs when non-complementary regions exist at the end of an otherwise complementary double-strand of DNA. However, branched DNA can occur if a third strand of DNA is introduced and contains adjoining regions able to hybridize with the frayed regions of the pre-existing double-strand. Although the simplest example of branched DNA involves only three strands of DNA, complexes involving additional strands and multiple branches are also possible. Branched DNA can be used in nanotechnology to construct geometric shapes, see the section on uses in technology below.
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide and an analogue of alpha-melanocyte-stimulating hormone. The molecule is produced by chemical synthesis rather than extracted from a biological source.
It is shorter than the native hormone and carries a cyclic constraint that improves stability. These changes raise receptor potency and slow breakdown relative to the naturally occurring peptide.
Published accounts date its development to the 1980s, when researchers were generating analogues of melanocyte-stimulating hormone. That work aimed to produce more stable compounds for studying pigmentation biology.
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.