The short version of regulatory schedule fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-06-05 and is reviewed periodically as new material appears.
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.
Human data remain limited and mostly short-term. Reports describe small trials and observational accounts rather than large controlled studies, so questions about dose-response relationships and long-term effects on melanocytes stay open. Whether repeated exposure alters naevus behaviour is not settled in the published record. Researchers also note that self-administered use outside clinical settings makes actual exposure difficult to quantify. Statements about efficacy and safety should therefore be read as preliminary rather than established.
The material is commonly handled as a lyophilized powder in sealed vials. The solid dissolves readily in water and in polar organic solvents, producing a clear solution after reconstitution. Light, heat and repeated freeze-thaw cycles are the concerns most often raised in handling guidance, because peptide bonds and the constrained ring can degrade. Working solutions are generally prepared fresh, and material left in solution is treated as less stable than the dry form. These properties shape how laboratories store and aliquot reference material.
Identity and purity are assessed mainly by reversed-phase high-performance liquid chromatography with ultraviolet detection, often paired with mass spectrometry. Retention time supports identity, while the mass spectrum confirms the molecular weight of the intact peptide. Purity is frequently reported as a percentage of total peak area, a figure that depends on the wavelength, column and gradient used. Impurity profiling may also look for truncated sequences, oxidised forms and residual counterions. Amino acid analysis and peptide mapping provide orthogonal confirmation when required.
Regulatory status varies by jurisdiction, and the substance is frequently described as unapproved for therapeutic use. Some authorities classify it alongside prescription-only medicines or controlled categories, while others address it through general consumer protection rules. Analytical surveys have reported mismatches between label claims and measured content in products sold online, although the scope of such testing is limited. Whether these discrepancies are widespread remains an open question. Discussion in the literature therefore tends to combine chemistry, supply-chain observation and policy analysis.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic cyclic heptapeptide | Melanocortin receptor agonist |
| Molecular formula | C50H69N15O9 | Neutral form, mass near 1024.2 g/mol |
| Primary targets | MC1R, MC3R, MC4R, MC5R | Binding is non-selective across subtypes |
| Related compounds | Alpha-MSH, melanotan I, afamelanotide | Structurally or functionally related peptides |
| Common abbreviations | MT-II, MT-2 | Naming in the literature is not uniform |
Melanotan-2 is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone, the naturally occurring peptide involved in pigmentation signalling. Its sequence is conventionally written as Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, with a lactam bridge joining the aspartate side chain to the lysine side chain. The empirical formula is C50H69N15O9 and the monoisotopic mass lies near 1023.5 daltons. N-terminal acetylation and the D-configured phenylalanine both increase resistance to enzymatic breakdown compared with the parent hormone.
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.
Quality assessment of research-grade peptide rests mainly on reversed-phase high-performance liquid chromatography for purity and on mass spectrometry for identity confirmation. A single main peak above a stated threshold, commonly ninety-eight percent by peak area, is the usual release criterion applied by suppliers. Independent analyses commissioned by laboratories and consumer organisations have repeatedly reported discrepancies between label claims and measured content, including truncated sequences, residual trifluoroacetate, and lower-than-declared peptide mass. Those findings do not establish that every supplier is unreliable, but they indicate that purity figures printed on a vial are claims requiring verification rather than settled facts.
Regulatory treatment varies by jurisdiction and has changed over time. In several countries the peptide is handled as an unapproved prescription medicine, and import or sale for human use is restricted, while elsewhere it falls under poisons or controlled-substance schedules. Enforcement activity against online vendors has been reported in Australia, New Zealand, the United Kingdom and the United States. Scholarly writing discusses melanotan-2 chiefly as an experimental tool and as a case study in unregulated peptide supply, and its precise legal position in any given country should be checked against current national schedules.
In 2008, the International Union for Conservation of Nature (IUCN) completed a five-year Global Mammal Assessment for its IUCN Red List, which counted 5,488 species. According to research published in the Journal of Mammalogy in 2018, the number of recognized mammal species is 6,495, including 96 recently extinct.
=== Carious versus sound dentin for dentinal bonding === Some caries excavation methods lead to leaving caries-affected dentin behind to serve as the bonding substrate, mostly in indirect pulp capping. It is reported that the immediate bond strengths to caries-affected dentin are 20-50% lower than to sound dentin, and even lower with caries-infected dentin. How does caries progression correlates with this? First, it reduces mineral content, increases porosity and changes the dentinal collagen structure and its distribution too. These changes can cause a significant reduction in the mechanical properties in dentin e.g. hardness, stiffness, tensile strength, modulus of elasticity, and shrinkage during drying, which makes dentin in and under hybrid layer more prone to cohesive failures under occlusal forces. Lower mineral content of the caries-affected dentin will allow phosphoric acid or acidic monomers to demineralize matrix more deeply than in normal dentin, which results in even more residual water in exposed collagen matrix.
=== General references === Daxer, Albert; Misof, Klaus; Grabner, Barbara; Ettl, Armin; Fratzl, Peter (1998). "Collagen fibrils in the human corneal stroma: Structure and aging". Investigative Ophthalmology & Visual Science. 39 (3): 644–8. PMID 9501878. Daxer, Albert; Fratzl, Peter (1997). "Collagen fibril orientation in the human corneal stroma and its implication in keratoconus". Investigative Ophthalmology & Visual Science. 38 (1): 121–9. PMID 9008637. Fratzl, Peter; Daxer, Albert (1993). "Structural transformation of collagen fibrils in corneal stroma during drying. An x-ray scattering study". Biophysical Journal. 64 (4): 1210–4. Bibcode:1993BpJ....64.1210F. doi:10.1016/S0006-3495(93)81487-5. PMC 1262438. PMID 8494978.
Sources: en.wikipedia.org
Relf's Philadelphia Gazette and Daily Advertiser reported that "Baron de Homboldt arrived in this city on Wednesday night." Meanwhile, Humboldt himself wasted no time in getting in touch with the President. He wrote the following in French on May 24:
An open-faced, or Lépine, watch, is one in which the case lacks a metal cover to protect the crystal. It is typical for an open-faced watch to have the pendant located at 12:00 and the sub-second dial located at 6:00. Occasionally, a watch movement intended for a hunting case (with the winding stem at 3:00 and sub second dial at 6:00) will have an open-faced case. Such watch is known as a "sidewinder." Alternatively, such a watch movement may be fitted with a so-called conversion dial, which relocates the winding stem to 12:00 and the sub-second dial to 3:00. After 1908, watches approved for railroad service were required to be cased in open-faced cases with the winding stem at 12:00.
=== Non-selective peptide toxins === ω-Grammotoxin SIA is a peptide toxin derived from the venom of the spider Grammostola spatulata. It acts to modify the P-type channel gating. ω-PnTx3-3, PnTx3-3, and phonetoxin IIA are all toxins from the spider Phonoetrica nigriventer which act to block the current through the P-type calcium channels. DW13.3 is a peptide toxin from the spider Filistata hibernalis and it is composed of 74 amino acids. It also functions to block the current through P-type calcium channels. ω-Conotoxins are derived from the venom of cone snails. ω-Conotoxin MVIIC acts within the hippocampal CA1 pyramidal neurons to block the P-type channels. Also, within the hippocampal CA3 neurons, this toxin blocks synaptic transmission. Its effects are slow. Calcicludine is from venom of Dendroaspis angusticeps, which is a green mamba. It has the ability to voltage-dependently block P-type channels. Kurotoxin is from venom of the scorpion Parabuthus. In neurons in the thalamus, kurtoxin decreases high threshold calcium currents, however, in the Purkinje cells, it increases the calcium currents.
Sources: en.wikipedia.org
Silver salts have antiseptic properties. In 1881 Credé introduced a method known as Credé's prophylaxis, which used of dilute (2%) solutions of silver nitrate in newborn babies' eyes at birth to prevent contraction of gonorrhea from the mother, which could cause blindness via ophthalmia neonatorum. (Modern antibiotics are now used instead). Fused silver nitrate, shaped into sticks, was traditionally called "lunar caustic". It is used as a cauterizing agent, for example to remove granulation tissue around a stoma. General Sir James Abbott noted in his journals that in India in 1827 it was infused by a British surgeon into wounds in his arm resulting from the bite of a mad dog to cauterize the wounds and prevent the onset of rabies. Silver nitrate is used to cauterize superficial blood vessels in the nose to help prevent nosebleeds. Dentists sometimes use silver nitrate-infused swabs to heal oral ulcers. Silver nitrate is used by some podiatrists to kill cells located in the nail bed. The Canadian physician C. A. Douglas Ringrose researched the use of silver nitrate for sterilization procedures, believing that silver nitrate could be used to block and corrode the fallopian tubes. The technique was ineffective.
== In the aquarium == The minimum tank size requirement for the Ember tetras is at least 10 gallons with few live aquarium plants. Ember tetras should be kept in acidic water with a pH near 6.6, and although their native habitat has very soft water, they have adapted quite well to a wide range of hardness (5–17 dGH). The recommended temperature range is 23–29 °C (73–84 °F). Ideally their tank should contain live plants , a darker substrate, and open water for swimming. Ember tetras should be kept in groups of at least 6, though the recommended number is 9–10, in order to promote schooling. They appreciate a heavily planted aquarium ideally with a small area shaded from direct light, and will spend a lot of time swimming through planted areas, which also offer some protection for their fry. Ember tetras will school with other tetras, such as the neon tetra, but may become stressed by the presence of significantly larger fish. These fish swim at the middle level of the aquarium, and they do not feed from the bottom of the tank. Therefore, it is recommended that they are kept with other bottom dwelling fish (such as pygmy corydoras) so that leftover food is then eaten up off the substrate and not left to waste. Ember tetras can be fed a variety of foods, including flake, frozen, and freeze dried food. Small live foods like worms and brine shrimp are also recommended, as they bring out the fish's colors. In a well maintained heavily planted aquarium, ember tetras have been known to live ten years or more.
=== Sepsis === IGFBP-3 has been implicated in the regulation of cell growth, immune response, and endothelial integrity. In patients with sepsis, reduced serum levels of IGFBP-3 have been associated with increased mortality and greater immune suppression. A 2025 prospective study on 139 patients with microbiologically confirmed sepsis found that baseline IGFBP-3 concentrations below 10.64 pg/mL were independently associated with higher 30-day (28% vs. 10%) and 1-year mortality (69% vs. 35%) compared to patients with higher levels. These patients also exhibited lower lymphocyte counts, increased interleukin-6 levels, and more frequent polymicrobial infections, suggesting a phenotype characterized by immunosuppression and gut barrier dysfunction. IGFBP-3 had an area under the ROC curve (AUROC) of 0.70 for predicting 1-year mortality, outperforming other biomarkers such as CRP, procalcitonin, IL-6, and lactate. When added to clinical models including age and SOFA score, IGFBP-3 significantly improved prognostic accuracy up to 365 days. Preclinical studies support its immunomodulatory and anti-apoptotic roles, and therapeutic strategies targeting the IGF-1/IGFBP-3 axis are under investigation.
==== Other nuclear receptors ==== DHEA does not bind to or activate the progesterone, glucocorticoid, or mineralocorticoid receptors. Other nuclear receptor targets of DHEA besides the androgen and estrogen receptors include the PPARα, PXR, and CAR. However, whereas DHEA is a ligand of the PPARα and PXR in rodents, it is not in humans. In addition to direct interactions, DHEA is thought to regulate a handful of other proteins via indirect, genomic mechanisms, including the enzymes CYP2C11 and 11β-HSD1 – the latter of which is essential for the biosynthesis of the glucocorticoids such as cortisol and has been suggested to be involved in the antiglucocorticoid effects of DHEA – and the carrier protein IGFBP1.
Sources: en.wikipedia.org
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.
Activation of MC1R increases pigment synthesis independently of ultraviolet exposure, which is the mechanism usually cited for darkening without sun exposure. Ultraviolet light still influences skin response through separate biological pathways.
Because the peptide binds several melanocortin receptor subtypes, its effects are not confined to pigmentation. This complicates interpretation of both intended and unintended outcomes reported in studies.
The dry powder is more stable during transport and storage than a solution. It also allows a known amount of material to be reconstituted at a chosen concentration.