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 2026-06-20 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.
Melanotan II binds several melanocortin receptor subtypes rather than a single target. MC1R on melanocytes drives melanin synthesis, while MC3R and MC4R participate in energy balance, appetite, and sexual response pathways. This lack of selectivity explains why reported effects extend beyond skin darkening. Substitutions at positions four and seven, including norleucine and D-phenylalanine, increase potency and resistance to peptidases. Understanding which receptor mediates which effect remains an active area of investigation.
Published human data come mostly from small, short studies rather than large controlled trials. Reported outcomes include increased skin pigmentation and, in some reports, effects on appetite and libido, but sample sizes are small and follow-up is limited. Whether long-term use produces durable pigment changes or adverse effects is not established. Because products sold outside pharmacies are not standardized, the actual content of any given vial is often unknown. Independent testing of such material is uncommon.
| 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 |
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.
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.
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.
Scabies (, SKAY-beez; also sometimes known as the seven-year itch) is a contagious human skin infestation by the tiny (0.2–0.45 mm) mite Sarcoptes scabiei, variety hominis. The word is from Latin: scabere, lit. 'to scratch'. It is a particular public health problem in crowded settings such as care homes, schools, refugee camps, prisons, and hospitals. The most common symptoms are severe itchiness and a pimple-like rash. Occasionally, tiny burrows may appear on the skin from eggs that are about to hatch. In a first-ever infection, the infected person usually develops symptoms within three weeks. During a second infection, symptoms may begin within 24 hours. These symptoms can be present across most of the body or just in certain areas such as the wrists, between fingers, or along the waistline. The head may be affected, but this is typically only in young children. The itch is often worse at night. Scratching may cause skin breakdown and an additional bacterial infection in the skin. Various names have been given to this condition and the name "seven year itch" has been recorded in many documents from the 1800s. Although the 1952 play The Seven Year Itch and modern treatment methods have generally changed this name to refer to human relationships, the condition was historically very difficult to treat. Scabies is caused by infection with the female mite Sarcoptes scabiei var. hominis, an ectoparasite. The mites burrow into the skin to live and deposit eggs. The symptoms of scabies are due to an allergic reaction to the mites.
Enzymatic specificity provides useful insight into enzyme structure, which ultimately determines and plays a role in physiological functions. Specificity studies also may provide information of the catalytic mechanism. Specificity is important for novel drug discovery and the field of clinical research, with new drugs being tested for its specificity to the target molecule in various rounds of clinical trials. Drugs must contain as specific as possible structures in order to minimize the possibility of off-target affects that would produce unfavorable symptoms in the patient. Drugs depend on the specificity of the designed molecules and formulations to inhibit particular molecular targets. Novel drug discovery progresses with experiments involving highly specific compounds. For example, the basis that drugs must successfully be proven to accomplish is both the ability to bind the target receptor in the physiological environment with high specificity and also its ability to transduce a signal to produce a favorable biological effect against the sickness or disease that the drug is intended to negate.
== Honors == In 2021, Akagha was nominated for the Golden Joystick Awards in the category of Best Performer for voicing the character Julianna Blake in Deathloop. For the same role, she was also nominated for Best Performance at The Game Awards 2021, and for the Great White Way Award for Best Acting in a Game at the New York Game Awards 2022.
== Physical interpretation == The term Dω/Dt on the left-hand side is the material derivative of the vorticity vector ω. It describes the rate of change of vorticity of the moving fluid particle. This change can be attributed to unsteadiness in the flow (∂ω/∂t, the unsteady term) or due to the motion of the fluid particle as it moves from one point to another ((u ∙ ∇)ω, the convection term). The term (ω ∙ ∇) u on the right-hand side describes the stretching or tilting of vorticity due to the flow velocity gradients. Note that (ω ∙ ∇) u is a vector quantity, as ω ∙ ∇ is a scalar differential operator, while ∇u is a nine-element tensor quantity. The term ω(∇ ∙ u) describes stretching of vorticity due to flow compressibility. It follows from the Navier-Stokes equation for continuity, namely
Sources: en.wikipedia.org
Trypanothione is an unusual form of glutathione containing two molecules of glutathione joined by a spermidine (polyamine) linker. It is found in parasitic protozoa such as leishmania and trypanosomes. These protozoal parasites are the cause of leishmaniasis, sleeping sickness and Chagas' disease. Trypanothione was discovered by Alan Fairlamb. Its structure was proven by chemical synthesis. It is present mainly in the Kinetoplastida but can be found in other parasitic protozoa such as Entamoeba histolytica. Since this thiol is absent from humans and is essential for the survival of the parasites, the enzymes that make and use this molecule are targets for the development of new drugs to treat these diseases. Trypanothione-dependent enzymes include reductases, peroxidases, glyoxalases and transferases. Trypanothione-disulfide reductase (TryR) was the first trypanothione-dependent enzyme to be discovered (EC 1.8.1.12). It is an NADPH-dependent flavoenzyme that reduces trypanothione disulfide. TryR is essential for survival of these parasites both in vitro and in the human host. A major function of trypanothione is in the defence against oxidative stress. Here, trypanothione-dependent enzymes such as tryparedoxin peroxidase (TryP) reduce peroxides using electrons donated either directly from trypanothione, or via the redox intermediate tryparedoxin (TryX). Trypanothione-dependent hydrogen peroxide metabolism is particularly important in these organisms because they lack catalase.
== Active site and mechanism of catalysis == The active site of eqolosin contains a distinctive glutamic acid and glutamine catalytic dyad which are involved in substrate binding and catalysis. These residues act as a nucleophile, with the glutamic acid serving as a general acid in the first phase of the reaction, donating a proton to the carbonyl oxygen in the peptide bond of the substrate. One or two water molecules may be involved in the reaction supplying a hydroxyl group, and the glutamic acid further donates a proton to the amide nitrogen, resulting in breakage of the peptide bond. The glutamine then returns the glutamic acid to its initial state.
If the temperature is too low, the primer may bind imperfectly. If it is too high, the primer may not bind at all. A typical annealing temperature is about 3–5 °C below the Tm of the primers used. Stable hydrogen bonds between complementary bases are formed only when the primer sequence very closely matches the template sequence. During this step, the polymerase binds to the primer-template hybrid and begins DNA formation. Extension/Elongation: The temperature at this step depends on the DNA polymerase used; the optimum activity temperature for the thermostable DNA polymerase of Taq polymerase is approximately 75–80 °C (167–176 °F), though a temperature of 72 °C (162 °F) is commonly used with this enzyme. In this step, the DNA polymerase synthesizes a new DNA strand complementary to the DNA template strand by adding free dNTPs from the reaction mixture that is complementary to the template in the 5'-to-3' direction, condensing the 5'-phosphate group of the dNTPs with the 3'-hydroxy group at the end of the nascent (elongating) DNA strand. The precise time required for elongation depends both on the DNA polymerase used and on the length of the DNA target region to amplify. As a rule of thumb, at their optimal temperature, most DNA polymerases polymerize a thousand bases per minute. Under optimal conditions (i.e., if there are no limitations due to limiting substrates or reagents), at each extension/elongation step, the number of DNA target sequences is doubled.
Kellogg (1860–1951) worked for him for many years until, in 1906, he broke away, bought the rights to Cornflakes, and set up the Kellogg Toasted Corn Flake Company. William Kellogg discarded the health food concept, opting for heavy advertising and commercial taste appeal. Later, his signature on every package became the company trademark.
By 1948, Lilly employees worked in 35 countries, most of them as sales representatives in Latin America, Asia, and Africa. After three generations of Lilly family leadership under company founder, Col. Eli Lilly, his son, Josiah K. Lilly Sr., and two grandsons, Eli Lilly Jr. and Josiah K. Lilly Jr., the company announced a reorganization in 1944 that prepared the way for future expansion and the eventual separation of company management from its ownership. In 1945, Lilly began a major expansion effort that included two manufacturing operations in Indianapolis. The company purchased the massive Curtiss-Wright propeller plant on Kentucky Avenue, west of the company's McCarty Street operation. When renovation was completed in mid-1947, the Kentucky Avenue location manufactured antibiotics and capsules and housed the company's shipping department. By 1948, Lilly employed nearly 7,000 people. After World War II, patents and research records belonging to IG Farben, which included Farbwerke Hoechst, were confiscated by the Allies. The U.S. Department of Commerce made the expropriated patent rights available to American pharmaceutical companies for $1; Lilly acquired the rights to methadone. In 1947, Lilly became the first distributor of methadone in the United States and marketed it under the trade name Dolophine. Methadone is an analgesic that is also widely used in the treatment of opioid use disorder.
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 regulator in a major market has approved it for human use. It appears in research settings and in products marketed outside pharmacy channels. Legal status for personal possession varies by country.