cyclic heptapeptide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-04-27 and is reviewed periodically as new material appears.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Belongs to the melanocortin agonist family |
| Key substitutions | Nle4 and D-Phe7 | Improve resistance to enzymatic degradation |
| Molecular formula | C50H69N15O9 | Approximately 1024 g/mol |
| Regulatory status | Not approved as a medicine | Distributed as a research chemical |
| Common synonyms | Melanotan II, MT-II, MT-2 | Spelling varies across sources |
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.
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 II is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone, a naturally occurring peptide involved in pigmentation signalling. Its structure substitutes a lactam bridge between side chains to increase stability relative to the native hormone. The compound is also known by the shorthand MT-II and by several non-proprietary synonyms used in research catalogues. It is not an approved therapeutic product in any major jurisdiction; material sold under this name is typically offered as a laboratory reagent rather than as a medicine.
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.
== Biography == Woodroof was born in Dallas, Texas, on February 3, 1950, to Garland Odell Woodroof (March 17, 1917, in Texas – December 3, 1983, in Dallas) and Willie Mae Hughes (November 25, 1917, in Oklahoma – November 19, 1996, in Dallas). His first marriage was to Mary Etta Pybus on June 28, 1969, in Dallas; they had a daughter. They divorced on March 23, 1972. On May 6, 1972, he married a woman named Rory S. Flynn in Dallas. They divorced on May 21, 1973. He then married Brenda Shari Robin on October 4, 1982, in Lubbock. They divorced on March 4, 1986, after he was diagnosed with HIV. It was recorded that Woodroof had a mercurial personality. One reporter writes that "Woodroof took guns to his doctor’s office, prompting Steven Pounders to 'fire him as a patient.'" Woodroof later sent the doctor roses, and the doctor took him back. Woodroof was said to have lost all his friends after they found out he was HIV-positive. The movie Dallas Buyers Club depicts Woodroof as holding homophobic views prior to contracting HIV. Other people who knew Woodroof said that he did not harbor anti-gay beliefs and was openly bisexual. He was a member of the Dallas Gay Alliance.
The death of his brother-in-law, John Gardner, from tetanus led to an interest in treating the disease, which he pursued in collaboration with Paul Fildes and H. E. Harding. He also researched the structure and function of the lymphatic system with Pullinger, and continued his studies of contraception with Harry Carleton that had begun at London Hospital. Florey's son Charles du Vé was born in Sheffield on 11 September 1934, but for a time Florey's relationship with Ethel had deteriorated to the point where they were communicating in writing and contemplating a legal separation. This was regarded as a serious matter; no Oxford fellow divorced without resigning his fellowship until the 1950s.
Gingras research focuses on the development of experimental and bioinformatics approaches for functional proteomics, with a focus on protein-protein and proximity interactions. She applies these tools to the study of signaling pathways in health and disease and in mapping the physical organization of the dynamic proteome. Some of her work focuses on the consequence of disease-associated mutations on the interactions established by proteins. In addition to proteomics, Gingras laboratory has interest in studying human protein phosphatase and their systematic interactions and has now expanded into the field of systems biology.
Sources: en.wikipedia.org
The poem revolves around an isolated and anxious man who runs throughout the city, his anxiety and fears taking on the personified image of a grandiose beast that has the makeup of a dragon and lion. While not inherently stated, the beast is likely that of a decadent form of a sphinx due to its appearance and grand nature.
In the blockchain, bitcoins are linked to specific strings called addresses. Most often, an address encodes a hash of a single public key. Creating such an address involves generating a random private key and then computing the corresponding address. This process is almost instant, but the reverse (finding the private key for a given address) is nearly impossible. Publishing such a bitcoin address does not risk its private key, and it is extremely unlikely to accidentally generate a used key with funds. To use bitcoins, owners need their private key to digitally sign transactions, which are verified by the network using the public key, keeping the private key secret. An address may encode the hash of a bitcoin script that specifies more complex requirements to spend the funds. One common example is "multisig", in which multiple distinct private keys must mutually sign any transaction that attempts to spend the funds. Bitcoin transactions use a Forth-like scripting language, involving one or more inputs and outputs. When sending bitcoins, a user specifies the recipients' addresses and the amount for each output. This allows sending bitcoins to several recipients in a single transaction. To prevent double-spending, each input must refer to a previous unspent output in the blockchain. Using multiple inputs is similar to using multiple coins in a cash transaction. As in a cash transaction, the sum of inputs can exceed the intended sum of payments. In such a case, an additional output can return the change back to the payer.
For services to 31 Squadron Royal Air Force Association. Henry Ashley Edwards, Consultant Anaesthetist, Ysbyty Gwynedd. For services to the Welsh Medical Committee. The Reverend John Gisborne Charteris Eldrid. For services to the Samaritans. Geoffrey Kenyon Elliott. For services to Forestry and to Wood Science. Robert William Elliott, Chairperson and Director, Wiltshire & Swindon Users' Network, and Chairperson, The Jumbulance Group. For services to disabled people in Wiltshire. David John Ellis, Grade 6, Ministry of Defence. Andrew James Erving, Grade 7, Foreign and Commonwealth Office. George Stanley Etchells, Member, Rotherham Metropolitan Borough Council. For services to Local Government. Eric Magnus Eunson, lately General Manager, Power System Development, National Grid Company plc. For services to the Electricity Industry. David Roger Evans. For services to Agriculture in Wales. Gwynne Howard Neill Evans, lately Grade 6, Department for Education and Employment. David Roger Evans. For services to Agriculture in Wales. John Ivan Ellis Farmer, Honorary Show Director, All England Jumping Course, Hickstead. For services to Show Jumping. William Harold Faulkner, Headteacher, Montrose Academy. For services to Education. David Alan Fawcett. For humanitarian services in the Caribbean. Ronald Paul Feeney, Governor 2, Her Majesty's Prison Stafford. Professor Christine Elizabeth Fell, Professor of Early English Studies, University of Nottingham. For services to Early English. John Ronald Fenner, Chairman, British Urban Regeneration Association.
Sources: en.wikipedia.org
=== Mechanism of action === Heparin binds to the enzyme inhibitor antithrombin (AT), causing a conformational change that results in its activation through an increase in the flexibility of its reactive site loop. The activated AT then inactivates thrombin, factor Xa and other proteases. The rate of inactivation of these proteases by AT can increase by up to 1000-fold due to the binding of heparin. Heparin binds to AT via a specific pentasaccharide sulfation sequence contained within the heparin polymer:
Nebraska Senator Vickie McDonald responded with "Anytime anything's on YouTube it's an issue," and "Legislators, parents, grandparents, we need to be on top of these things," McDonald proposed Schedule I listing Salvia divinorum as part of their Controlled Substances Act, under which possession of salvia would have been considered a Class IV felony with a penalty of up to five years and trafficking would have fallen under a Class III felony with up to a 20 year penalty. In Massachusetts, YouTube videos were shown by a retired police officer to public health and judiciary committees as evidence in favor of outlawing it there. The issue has been raised of whether the salvia videos are in breach of YouTube's own community guidelines, which ask users not to "cross the line" and post videos showing "bad stuff" like "drug abuse". The question is considered as particularly problematical as the videos may be something of an enforcement grey area.
Dendritic cell therapy provokes anti-tumor responses by causing dendritic cells to present tumor antigens to lymphocytes, which activates them, priming them to kill other cells that present the antigen. Dendritic cells are antigen-presenting cells (APCs) in the mammalian immune system. In cancer treatment, they aid cancer antigen targeting. The only approved cellular cancer therapy based on dendritic cells is sipuleucel-T. One method of inducing dendritic cells to present tumor antigens is by vaccination with autologous tumor lysates or short peptides (small parts of the protein that correspond to the protein antigens on cancer cells). These peptides are often given in combination with adjuvants (highly immunogenic substances) to increase the immune and anti-tumor responses. Other adjuvants include proteins or other chemicals that attract and/or activate dendritic cells, such as granulocyte-macrophage colony-stimulating factor (GM-CSF). The most common sources of antigens used for dendritic cell vaccine in glioblastoma (GBM) as an aggressive brain tumor were whole tumor lysate, CMV antigen RNA and tumor-associated peptides like EGFRvIII. Dendritic cells can also be activated in vivo by making tumor cells express GM-CSF. This can be achieved by either genetically engineering tumor cells to produce GM-CSF or by infecting tumor cells with an oncolytic virus that expresses GM-CSF. Another strategy is to remove dendritic cells from the blood of a patient and activate them outside the body.
Sources: en.wikipedia.org
It is a synthetic cyclic peptide designed as an analog of alpha-melanocyte-stimulating hormone. It acts on melanocortin receptors and is best known from research into pigmentation. It is not an approved pharmaceutical product.
No regulatory agency has approved it for any indication. It is encountered as a research chemical sold outside pharmaceutical supply chains. Products marketed this way are not subject to the manufacturing and labeling requirements that apply to approved drugs.
Reports describe increased skin pigmentation as well as side effects such as nausea, flushing, and changes to existing moles. Much of the evidence comes from small studies and case reports rather than large trials. The long-term safety profile is therefore uncertain.
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.