The short version of research chemical fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-08-18. Anything still debated is marked as such rather than presented as settled.
Pharmacologically, melanotan-2 behaves as a non-selective agonist across the melanocortin receptor family. Binding at MC1R on dermal melanocytes promotes eumelanin synthesis, which underlies the tanning response described in early human work. Activity at the centrally expressed MC4R receptor is associated with reported effects on appetite and erectile function. Because the peptide does not discriminate strongly among receptor subtypes, attributing any single observed effect to one receptor pathway is generally not possible without selective antagonists or receptor knockout models.
Research interest has centred on photoprotection and pigmentation, with a smaller body of work on appetite and sexual function. Published human data remain limited to small, frequently uncontrolled studies, and the compound has never received marketing approval from a national medicines regulator. Most laboratory work treats it as a pharmacological tool for probing melanocortin signalling in cell culture or animal models. Whether pigmentation changes observed in people translate into measurable protection against ultraviolet-induced DNA damage remains an open question.
Regulatory status differs by country, and in many places supplying the compound for human consumption is unlawful. Vendors frequently label material as intended for research use only, a designation that shifts stated purpose but does not create a legal pathway for personal use. Certificates of analysis accompanying such products vary widely in detail and provenance. Third-party testing exists but is voluntary, and results are rarely linked to a specific lot in a publicly verifiable way.
Identity testing for a synthetic peptide relies on several complementary methods. Reversed-phase high-performance liquid chromatography separates the target from related impurities and reports purity as a percentage of total peak area. Mass spectrometry confirms molecular mass and can reveal deletions or truncations. Amino acid analysis and peptide mapping provide sequence-level confirmation, while counter-ion content and residual solvents are measured separately. A purity figure alone does not establish identity, so a complete dataset combines chromatographic and spectrometric evidence.
Lyophilized peptide powder is generally stored frozen, protected from light and moisture. Tryptophan residues are susceptible to oxidation, and the lactam bridge can hydrolyze under strongly acidic or basic conditions. Solutions prepared for laboratory work degrade faster than dry powder, and repeated freeze-thaw cycles accelerate loss. Common practice is to aliquot solutions before freezing and to avoid alkaline buffers. Reported stability windows vary with concentration, buffer, and temperature, so exact shelf lives are method-specific rather than universal.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | Melanotan II; MT-II; N-acetyl-norleucyl-cyclo[Asp-His-D-Phe-Arg-Trp-Lys] amide | Naming follows peptide convention; the numeral distinguishes it from melanotan-1 |
| Molecular formula | C50H69N15O9 | Includes the lactam bridge; no counter-ion assumed |
| Monoisotopic mass | 1023.53 Da | Free base; salts and counter-ions shift the observed value |
| Appearance | White to off-white lyophilised powder | Batch-to-batch colour variation is not itself proof of impurity |
| Typical analytical method | RP-HPLC purity determination with ESI-MS identity confirmation | Retention time alone does not establish sequence identity |
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.
Regulatory treatment varies by country. In the United States, melanotan-2 is not approved for any indication, and products marketed for human use fall outside the approved drug framework. Some other jurisdictions have placed it under prescription controls or listed it as a prohibited or restricted substance. Online listings frequently describe the material as a research chemical, a category that does not carry the same manufacturing and labelling requirements as approved medicines.
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.
== The Sabres years (1958–1964) == The Sabres's popularity in the Central New York region prompted them to record a single ("Seaweed" (written by Ron Lauback) b/w "The McCoy" a Ventures song) which received airplay on WNDR radio in 1962 ("Seaweed" was produced by Joe Raposo at Raposo Studios). The Sabres played all the regional teen dances and even backed up Bobby Vee at The Three Rivers Inn one time for DJ Peter C. Cavenaugh The band changed its name to The Jazzmen in 1963, but split the following year. The British Invasion having rendered their Instrumental sound out of fashion. During this time Ron also graduated from Syracuse University (1964) and took a job with Bristol Laboratories (now known as Bristol-Myers Squibb).
An example of a depsipeptide drug is the anticancer agent romidepsin, a known histone deacetylase inhibitor (HDACi). It was first isolated as a fermentation product from the soil bacterium Chromobacterium violaceum by the Fujisawa Pharmaceutical Company. Streptogramins, specifically streptogramin B, are depsipeptides that bind to the 50S subunit of bacterial ribosomes. Etamycin was shown in preliminary data in 2010 to have potent activity against MRSA in a mouse model. Several depsipeptides from Streptomyces exhibit antimicrobial activity. These form a new, potential class of antibiotics known as acyldepsipeptides (ADEPs). ADEPs target and activate casein lytic protease (ClpP) to initiate uncontrolled peptide and unfolded protein degradation, killing many Gram-positive bacteria. Depsipeptides can be formed through a Passerini reaction.
==== Serotonin reuptake enhancer ==== Tianeptine is no longer labelled a selective serotonin reuptake enhancer (SSRE) antidepressant. Tianeptine had been found to bind to the same allosteric site on the serotonin transporter (SERT) as conventional TCAs. However, whereas conventional TCAs inhibit serotonin reuptake by the SERT, tianeptine appeared to enhance it. This seems to be because of the unique C3 amino heptanoic acid side chain of tianeptine, which, in contrast to other TCAs, is thought to lock the SERT in a conformation that increases affinity for and reuptake (Vmax) of serotonin. As such, tianeptine was thought to act a positive allosteric modulator of the SERT, or as a "serotonin reuptake enhancer". Although tianeptine was originally found to have no effect in vitro on monoamine reuptake, release, or receptor binding, upon acute and repeated administration, tianeptine decreased the extracellular levels of serotonin in rat brain without a decrease in serotonin release, leading to a theory of tianeptine enhancing serotonin reuptake. The (−)-enantiomer is more active in this sense than the (+)-enantiomer. However, more recent studies found that long-term administration of tianeptine does not elicit any marked alterations (neither increases nor decreases) in extracellular levels of serotonin in rats. However, coadministration of tianeptine and the selective serotonin reuptake inhibitor fluoxetine inhibited the effect of tianeptine on long-term potentiation in hippocampal CA1 area.
== Translational readthrough == Stop codon suppression or translational readthrough occurs when in translation a stop codon is interpreted as a sense codon, that is, when a (standard) amino acid is 'encoded' by the stop codon. Mutated tRNAs can be the cause of readthrough, but also certain nucleotide motifs close to the stop codon. Translational readthrough is very common in viruses and bacteria, and has also been found as a gene regulatory principle in humans, yeasts, bacteria and drosophila. This kind of endogenous translational readthrough constitutes a variation of the genetic code, because a stop codon codes for an amino acid. In the case of human malate dehydrogenase, the stop codon is read through with a frequency of about 4%. The amino acid inserted at the stop codon depends on the identity of the stop codon itself: Gln, Tyr, and Lys have been found for the UAA and UAG codons, while Cys, Trp, and Arg for the UGA codon have been identified by mass spectrometry. Extent of readthrough in mammals have widely variable extents, and can broadly diversify the proteome and affect cancer progression.
Enantiomers of a chiral drug often interact in an enantioselective way in a chiral environment. This may be offered by different biotic substances (viz. proteins, nucleic acids, phospholipids and oligosaccharides). They are made up of chiral building blocks that are put together in space in handed conformations. These biological targets function as receptors for the drug enantiomers. So, at the binding sites of these receptors, enantiomers will be seen as different chemical species. The three point attachment model (Easson & Stedman model) can be used to see how chiral discrimination works. Figure depicts how the enantiomers of a drug interact with receptors in a way that depends on the drug's shape. This model was made for chiral drugs with a single stereogenic center. It says that there are three binding sites in the receptor (B', C' and D') that match the drug's pharmacophoric groups (B, C, D). A three-point fit (good fit) is possible for the eutomer at BB', CC' and DD'(Fig. A). Even though the distomer is the wrong enantiomer, it can fit either a one-point interaction (bad fit), or a two-point attachment (CC' and DD') with the same receptor site as shown in (Fig. B). Eutomer is the version that works the way you want it to, and distomer is the version that doesn't work or works in a way you don't want it to. Most of the time, the mirror-image versions have different binding affinities. In the eutomer, the ligands or moiety around a stereogenic element have more binding energy than in the distomer.
Sources: en.wikipedia.org
In phase one, the dosages of noggin, a regulator protein, as well as rhBMP-2 were properly calibrated, and in phase two these proteins carried on synthetic calcium phosphate matrix (CPM) were then injected into the ACL region. The results of this procedure also demonstrated an improvement in the collagen fiber formation between the tendon and the bone. Hence, all three treatments were seen to improve the efficacy of tendon-to-bone healing via the different bone growth factors: SHMSP, bone protein, and rhBMP-2.
Women in the Mexican drug war have been participants and civilians. They have served for or been harmed by all belligerents. There have been female combatants in the military, police, cartels, and gangs. Women officials, judges, prosecutors, lawyers, paralegals, reporters, business owners, social media influencers, teachers, and non-governmental organizations directors and workers have also been involved in different capacities. Women citizens and foreigners, including migrants, have been raped, tortured, and murdered in the conflict. Cartels and gangs fighting in the conflict carry out sex trafficking in Mexico as an alternative source of profits. Some members of criminal organizations also abduct women and girls for sexual slavery and carry out sexual assault of migrants from Latin America to the United States. Groups of women known as madres buscadoras ('searching mothers') have become prominent for organizing searches for disappeared relatives, and their work has uncovered unmarked mass graves that provide evidence of widespread disappearances.
== Research and teaching == Strobel's research focuses on the biophysics and biochemistry of catalytic RNAs, including riboswitches and peptidyl transferase. His group developed the early methods of Nucleotide Analog Interference Mapping, used to determine the importance of particular functional groups in a structured RNA molecule. Strobel's group solved the x-ray crystal structure of the full length Azoarcus Group I catalytic intron, the glmS ribozyme, and the c-di-GMP riboswitch. He has also collaborated with the Thomas A. Steitz lab at Yale on structural studies toward better understanding the mechanism of ribosomal peptide synthesis. He was twice named a HHMI professor to promote undergraduate science education. With this award he instituted an undergraduate research course, the Rainforest Expedition and Laboratory, which explored microbial and chemical diversity in the world's rainforests as a means to inspire undergraduate students in the sciences. He has led groups of undergraduate students into the rainforest over spring break to hunt for novel endophytes that live inside plants. Following fieldwork, students then isolated microbes and tested them for interesting properties, discovering a variety of organisms including novel fungi with new biological and chemical properties, including Pestalotiopsis microspora, of which some strains degrade polyurethane.
The (+)- and (−)-enantiomers of menthol are the most stable among these based on their cyclohexane conformations. With the ring itself in a chair conformation, all three bulky groups can orient in equatorial positions. The two crystal forms for racemic menthol have melting points of 28 °C and 38 °C. Pure (−)-menthol has four crystal forms, of which the most stable is the α form, the familiar broad needles.
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide analogue of alpha-melanocyte-stimulating hormone, containing seven amino acids with a lactam ring and a D-configured phenylalanine residue. It is supplied as a lyophilised powder for laboratory research.
The natural hormone is a linear tridecapeptide that is rapidly degraded in circulation. Melanotan-2 is shortened, cyclised, N-terminally acetylated, and carries a D-amino acid substitution, all of which slow enzymatic breakdown.
No national medicines regulator has approved melanotan-2 for therapeutic or cosmetic use. In several jurisdictions it is treated as an unapproved prescription medicine, and its legal classification differs from country to country.
Dry powder is usually held frozen, shielded from light, and kept away from moisture. Desiccant packaging limits hydrolysis during storage. Solutions are typically aliquoted and frozen once, because repeated thawing shortens useful life.