Everything below concerns cyclic heptapeptide. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-01-28. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Solid peptide material is generally stable when kept cold and dry. Common practice is storage at -20 degrees Celsius or lower, with desiccant and protection from light. Repeated freeze-thaw cycles and exposure to moisture are associated with degradation, aggregation, or loss of material. Once dissolved, stability depends on solvent, concentration, and temperature, and solutions are usually treated as short-lived unless stability data support longer periods. Handling notes typically emphasise minimising time at ambient temperature.
Identity and purity are assessed with chromatographic and mass spectrometric techniques. Reversed-phase high-performance liquid chromatography separates the target peptide from related impurities and degradation products, and the resulting retention time is compared against a reference standard. Mass spectrometry, often coupled to liquid chromatography, confirms molecular mass. Amino acid analysis or peptide mapping can provide additional sequence-level confirmation when required. Results are only as reliable as the reference materials used alongside them.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Analogue of alpha-melanocyte-stimulating hormone |
| Common synonyms | MT-II; melanotan 2 | No internationally accepted non-proprietary name |
| Typical presentation | Lyophilised powder in a sealed vial | Often supplied alongside a separate diluent |
| Regulatory status | Unapproved therapeutic substance | Customs seizure reported in several jurisdictions |
| Reported route in use | Subcutaneous injection | Self-administered outside clinical settings |
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.
Scientific discussion of Melanotan-2 spans pharmacology, dermatology, and public-health literature. Laboratory studies examine its receptor binding and cellular effects, while clinical reports describe outcomes observed after unregulated use. These two bodies of work differ in rigour and intent. Peer-reviewed trials of the compound as a medicine are limited, so much of the available information comes from case reports and surveillance data. Authors frequently note the gap between experimental findings and real-world use.
Reported observations after unregulated use include shifts in skin pigmentation and, in some accounts, unintended changes to moles and other lesions. Whether these outcomes are causally linked to the compound, and how often they occur, remain open questions because controlled data are scarce. The absence of standardised dosing and verified product purity complicates interpretation. Researchers have called for better surveillance and analytical characterisation of samples obtained outside regulated channels. Conclusions drawn from anecdotal evidence should be treated as provisional.
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.
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.
The BPC solicited bids for the restaurant's space, leasing it in January 2025 to a branch of the Jean-Georges restaurant, which planned to renovate the space for $12 million; the Bryant Park Grill's owner sued the BPC in April 2025 to prevent Jean-Georges from using its space. After a judge granted a temporary injunction, Bryant Park Grill indicated that it would not move out when its lease expired that month, which led to litigation over the restaurant's continued occupancy of its space.
== Bioengineering == Protein production, the generation of a pure protein Protein design, the design of new protein molecules from scratch Protein engineering, application of science, mathematics, and economics to the process of developing useful or valuable proteins
== Select publications == Müller, Thomas; Badu-Tawiah, Abraham; Cooks, R. Graham (2012). "Accelerated Carbon-Carbon Bond-Forming Reactions in Preparative Electrospray". Angewandte Chemie International Edition. 51 (47): 11832–11835. doi:10.1002/anie.201206632. ISSN 1521-3773. PMID 23042619. Badu-Tawiah, Abraham K.; Eberlin, Livia S.; Ouyang, Zheng; Cooks, R. Graham (2016). "Faculty Opinions recommendation of Chemical aspects of the extractive methods of ambient ionization mass spectrometry". Annual Review of Physical Chemistry. 64: 481–505. doi:10.1146/annurev-physchem-040412-110026. PMID 23331308. Damon, Deidre E.; Davis, Kathryn M.; Moreira, Camila R.; Capone, Patricia; Cruttenden, Riley; Badu-Tawiah, Abraham K. (10 February 2016). "Direct Biofluid Analysis Using Hydrophobic Paper Spray Mass Spectrometry". Analytical Chemistry. 88 (3): 1878–1884. doi:10.1021/acs.analchem.5b04278.s001. PMID 26730614.
Sources: en.wikipedia.org
Blixeprodil, also known by its developmental code name GM-1020 or as (R)-4-fluorodeschloroketamine ((R)-4-FDCK), is an NMDA receptor antagonist related to ketamine which is under development for the treatment of major depressive disorder, bipolar depression, and other depressive disorders. It is taken by mouth.
== Career == Wadden joined the University of Pennsylvania’s Department of Psychiatry as an instructor in 1981 and rose to full professor by 1994. From 1992 to 1993, he was Professor of Psychology and Director of Clinical Training at Syracuse University, where he also led the Center for Health and Behavior. Returning to Penn in 1994, he directed the Center for Weight and Eating Disorders until 2017. He was the first Albert J. Stunkard Professor in Psychiatry (2011–2021). He has also taught as Visiting Professor of Psychology at Haverford College (2013–2021) and Bryn Mawr College (2018–2019), offering courses on obesity and health psychology. In addition, he is Clinical Associate Professor at the Philadelphia College of Osteopathic Medicine. Wadden was president of The Obesity Society in 2005–2006 and has served as associate editor of its journal, Obesity (2010–2014; 2020–2025). He was also associate editor of Annals of Behavioral Medicine (1991–1993).
== I == Iatrogenic A condition unintentionally caused by medical treatment or diagnostic procedures. In neuroscience, may refer to nerve damage, seizures, or cognitive effects resulting from interventions. Ictal Relating to or occurring during a seizure or convulsion. Commonly used in the context of epilepsy, such as "ictal phase" versus "postictal phase." Imaging genetics A research field that combines brain imaging and genetics to investigate how genetic variation affects brain structure and function. Immunohistochemistry A technique that uses antibodies to detect specific proteins or antigens in tissue sections. Frequently used to visualize neuronal and glial markers. Implicit memory Unconscious memory of skills and procedures, such as riding a bike or playing an instrument. Associated with brain structures like the basal ganglia and cerebellum. Incus One of the three auditory ossicles in the middle ear that transmits sound vibrations from the malleus to the stapes. Independent component analysis (ICA) A computational method used to separate mixed signals into independent sources. Commonly used in EEG and fMRI to identify distinct brain activity patterns. Inferior colliculus A midbrain structure involved in auditory processing, particularly sound localization and reflexive responses to sound stimuli. Inferior olive A brainstem nucleus that sends climbing fiber inputs to the cerebellum and plays a critical role in motor learning and coordination.
Sources: en.wikipedia.org
No. No major regulatory agency has granted a marketing authorisation for melanotan II as a medicine. Products sold under this name are generally presented as laboratory reagents and are not subject to the batch-release testing applied to approved drugs.
It was developed in the 1980s by researchers investigating analogues of alpha-melanocyte-stimulating hormone for pigmentation and related endpoints. Early work included small human studies during the 1990s. Development did not progress to licensing, and the compound remained a research and grey-market item.
Peptides are prone to truncation, oxidation and aggregation during synthesis and handling. Without independent testing, a buyer cannot confirm the identity or the content of a vial. Analytical surveys of unapproved peptide products have repeatedly found discrepancies between label claims and measured composition.
Laboratory confirmation typically combines retention time matching on a chromatographic system with mass measurement. A reference standard of known identity is needed for a meaningful comparison. Sequence-level techniques can add further confirmation.