This is a working overview of alpha-MSH, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-01-31. Anything still debated is marked as such rather than presented as settled.
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.
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-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.
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.
| 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 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.
In this series a panel of seven academics, journalists and historians named her among the group of people in the UK "whose actions during the reign of Elizabeth II have had a significant impact on lives in these islands and given the age its character". In 2015 Hodgkin's 1949 paper The X-ray Crystallographic Investigation of the Structure of Penicillin was honoured by a Citation for Chemical Breakthrough Award from the Division of History of Chemistry of the American Chemical Society presented to the University of Oxford (England). This research is notable for its groundbreaking use of X-ray crystallography to determine the structure of complex natural products, in this instance, of penicillin. Since 1999, the Oxford International Women's Festival has presented the annual Dorothy Hodgkin Memorial Lecture, usually in March, in honour of Hodgkin's work. The Lecture is a collaboration between Oxford AWiSE (Association for Women in Science & Engineering), Somerville College and the Oxford University Museum of Natural History.
=== Toxin removal === Following diagnosis, rapid removal of excess leucine from the body reduces the impact of the disease on development. Some methods of toxin removal include Exchange transfusion, hemodialysis, or hemofiltration. Exchange transfusion is an option to consider because it decreases high BCAA levels without disrupting the plasma repeatedly, however after exchange the BCAA levels will increase with the tissue storage releasing BCAAs. Hemodialysis is a safe and effective way to reduce elevated BCAA levels while correcting electrolyte and acid-base imbalances in an infant. Hemodialysis can be started as soon as a diagnosis is made when it is combined with dietary feeds that maintain recommended calorie and amino acid intake.
The deep veins of the lower limb include the common femoral vein, femoral vein, and the deep femoral vein; the popliteal vein, the tibial, and fibular veins. In the common femoral vein one valve is located above the saphenofemoral junction called the suprasaphenic valve. There are sometimes two valves in the same tract. In the femoral vein there are often three valves, the most constantly found valve is just below the joining of the deep femoral vein. The deep femoral vein and its perforators have valves. In the popliteal veins there are between one and three valves; in each posterior tibial vein there are between 8 and 19 valves, and in the anterior tibial veins there are between 8 and 11 valves. In the superficial veins there are between one and seven valves along the thigh portion of the great saphenous vein (GSV); two to six below the knee and one to four in the marginal veins of the foot. There is a valve at the termination of the GSV known as the terminal valve to prevent reflux from the femoral vein. A preterminal valve is located just below the openings of the tributaries to prevent reflux form these into the GSV. Incompetence of the GSV is a common cause of varicose veins. The valves also divide the column of blood into segments which helps move the blood unidirectionally to the heart. Their action is supported by the action of skeletal muscle pumps that contract and compress the veins. A skeletal muscle is confined in its fascia and contraction of the muscle which makes it wider results In compression on the vein that pushes the blood forward.
Sources: en.wikipedia.org
== Prevention == The primary prevention of bronchiolitis obliterans in people who have received either lung transplant or HSCT therapy is immunosuppression. In regards to post lung transplantation, the combination of calcineurin inhibitor combined with a purine synthesis inhibitor and a glucocorticoid is the general regimen used. People also have a baseline post-transplant lung function testing done in order to determine if their lung function is declining over time. People who are post-HSCT their immunosuppressive regimen typically includes methotrexate in combination with a calcineurin inhibitor to prevent GVHD, a risk factor for developing bronchiolitis obliterans.
=== Medical === Odontostomatology: gingivitis, stomatitis, glossitis, aphthous ulcers, dental surgery and oral ulceration due to radiation therapy. Otorhinolaryngology: glandular fever, pharyngitis, tonsillitis, post-tonsillectomy, radiation or intubation mucositis. It may be used alone or as an adjunct to other therapy giving the possibility of increased therapeutic effect with little risk of interaction. In some markets, the drug is supplied as an over-the-counter cream (Lonol in Mexico from Boehringer Ingelheim) used for topical treatment of musculoskeletal system disorders: sprains, strains, bursitis, tendinitis, synovitis, myalgia, periarthritis.
==== Breast crawl ==== According to studies cited by UNICEF, babies naturally follow a process that leads to a first breastfeed. Shortly after birth, the infant relaxes and makes small movements of the arms, shoulders, and head. If placed on the mother's abdomen, the baby gradually inches towards the breast, known as the breast crawl and begins to feed. After feeding, it is normal for a baby to remain latched to the breast while resting. This is sometimes mistaken for a lack of appetite. Without interruptions, all babies follow this process. Rushing, by picking up and moving the infant to the breast, or interrupting the process, such as removing the baby to be weighed, may complicate subsequent feeding. Activities such as weighing, measuring, bathing, needle-sticks, and eye prophylaxis wait until after the first feeding.
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.
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.