Alpha-MSH raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-05-16. Anything still debated is marked as such rather than presented as settled.
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.
Melanotan-2 is a synthetic peptide designed as an analog of alpha-melanocyte-stimulating hormone, a signaling molecule produced in the pituitary and skin. Its structure is a linear chain of seven amino acids that folds into a ring through an internal lactam bridge joining two side chains. The compound is sometimes written as MT-II or MEL-2 in informal and commercial contexts. It belongs to the melanocortin peptide family, a group of short signaling molecules that share a conserved core sequence recognized by melanocortin receptors.
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.
| 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 II is a synthetic cyclic heptapeptide analog derived from the core sequence of alpha-melanocyte-stimulating hormone. Researchers at the University of Arizona synthesized it during the 1980s while studying pigmentation and appetite signaling. The compound is not an approved medicine in any major jurisdiction and appears mainly in laboratory and research-chemical settings. Its structure incorporates a lactam bridge between side chains, which constrains the ring and slows enzymatic breakdown relative to the natural hormone.
Melanotan II binds several melanocortin receptor subtypes rather than a single target. MC1R on melanocytes drives melanin synthesis, while MC3R and MC4R participate in energy balance, appetite, and sexual response pathways. This lack of selectivity explains why reported effects extend beyond skin darkening. Substitutions at positions four and seven, including norleucine and D-phenylalanine, increase potency and resistance to peptidases. Understanding which receptor mediates which effect remains an active area of investigation.
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 vegetative body of the lichen, the thallus, is foliose (leafy) and typically less than 8 centimetres (3.1 in) wide. The lobes of the thallus are 1–4 mm (rarely up to 7 mm) in diameter, and flattened, though in African populations the lobes tend to be smaller than those in temperate areas, typically 0.5–2.0 mm wide. The upper surface is some shade of yellow, orange, or greenish yellow, becoming almost green when growing in shaded situations. The lower surface is white, has a cortex, and sparse pale rhizines or hapters that help attach the thallus to its substrate. The vegetative reproductive structures soredia and isidia are absent in this species. X. parietina reproduces primarily through sexual reproduction via apothecia (fruiting bodies). Apothecia typically develop about 2–4 mm behind the growing edge of the thallus and take 12–18 months to reach maturity. Mature apothecia typically measure between 1.5 and 2.6 mm in diameter, though in rare cases they can reach up to 4.3 mm. They can comprise between 0–87% of a thallus's dry weight, with most thalli dedicating 10–30% of their biomass to these reproductive structures. The apothecia can release spores at rates of up to 50 per minute under humid conditions. The production of apothecia appears to be independent of the thallus's directional aspect (north, south, east, or west facing), meaning that sunlight exposure does not significantly influence reproductive effort.
Thus, by constriction of blood vessels, mainly those located in the nasal passages, pseudoephedrine causes a decrease in the symptoms of nasal congestion. Activation of β2-adrenergic receptors produces relaxation of the smooth muscle of the bronchi, causing bronchial dilation and in turn decreasing congestion (although not fluid) and difficulty breathing. Pseudoephedrine is less potent as a sympathomimetic and psychostimulant than ephedrine. Clinical studies have found that pseudoephedrine is about 3.5- to 4-fold less potent than ephedrine as a sympathomimetic agent in terms of blood pressure increases and 3.5- to 7.2-fold less potent as a bronchodilator. Pseudoephedrine is also said to have much less central effect than ephedrine and to be only a weak psychostimulant. Blood vessels in the nose are around five times more sensitive than the heart to the actions of circulating epinephrine (adrenaline), which may help to explain how pseudoephedrine at the low doses used in over-the-counter products can produce nasal decongestion with minimal effects on the heart. Compared to dextroamphetamine, pseudoephedrine is about 30 to 35 times less potent as a norepinephrine releasing agent and 80 to 350 times less potent as a dopamine releasing agent in vitro. Pseudoephedrine is a very weak reversible inhibitor of monoamine oxidase (MAO) in vitro, including both MAO-A and MAO-B (Ki = 1,000–5,800 μM). It is far less potent in this action than other agents like dextroamphetamine and moclobemide.
All nuclear data not otherwise stated is from the standard source: There are 42 known isotopes of polonium (84Po), all radioactive, stretching from 186Po to 227Po. The isotopes 210 through 218 occur naturally in the four principal decay chains. In terms of curies they are mostly of even mass number, coming from uranium-238 and thorium-232, with smaller amounts of 211 and 215 from uranium-235, and very little with mass number 213 coming from neptunium-237, and much less with mass number 217 coming from a rare branch of the neptunium decay chain. 210Po has the longest half-life by far (138.376 days) and is, therefore, the most abundant by far in terms of moles or mass. It is also the most easily synthesized isotope, by neutron capture on natural bismuth, and so by far the most abundant artificial isotope as well. Two other isotopes have longer lives: 209Po with a half-life of 124 years and 208Po with a half-life of 2.898 years. Both are made by using a cyclotron to bombard bismuth with protons.
Sources: en.wikipedia.org
=== Commemorations === The Australian National Boer War Memorial Committee organises events to mark the war on 31 May each year. In Canberra, a commemorative service is usually held at the St John the Baptist Church in Reid. Floral tributes are laid for the dead.
Bovine serum albumin (BSA or "Bovine Fraction V") is a serum albumin protein derived from cows. It is often used as a protein concentration standard in lab experiments. The nickname "Fraction V" refers to albumin being the fifth fraction of the original Edwin Cohn purification methodology that made use of differential solubility characteristics of plasma proteins. By manipulating solvent concentrations, pH, salt levels, and temperature, Cohn was able to pull out successive "fractions" of blood plasma. The process was first commercialized with human albumin for medical use and later adopted for production of BSA.
At this stage another galectin, galectin-3, interacts with TRIM16 to guide selective autophagy of damaged lysosomes. TRIM16 gathers ULK1 and principal components (Beclin 1 and ATG16L1) of other complexes (Beclin 1-VPS34-ATG14 and ATG16L1-ATG5-ATG12) initiating autophagy, many of them being under negative control of mTOR directly such as the ULK1-ATG13 complex, or indirectly, such as components of the class III PI3K (Beclin 1, ATG14 and VPS34) since they depend on activating phosphorylations by ULK1 when it is not inhibited by mTOR. These autophagy-driving components physically and functionally link up with each other integrating all processes necessary for autophagosomal formation: (i) the ULK1-ATG13-FIP200/RB1CC1 complex associates with the LC3B/GABARAP conjugation machinery through direct interactions between FIP200/RB1CC1 and ATG16L1, (ii) ULK1-ATG13-FIP200/RB1CC1 complex associates with the Beclin 1-VPS34-ATG14 via direct interactions between ATG13's HORMA domain and ATG14, (iii) ATG16L1 interacts with WIPI2, which binds to PI3P, the enzymatic product of the class III PI3K Beclin 1-VPS34-ATG14. Thus, mTOR inactivation, initiated through GALTOR upon lysosomal damage, plus a simultaneous activation via galectin-9 (which also recognizes lysosomal membrane breach) of AMPK that directly phosphorylates and activates key components (ULK1, Beclin 1) of the autophagy systems listed above and further inactivates mTORC1, allows for strong autophagy induction and autophagic removal of damaged lysosomes.
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.
It is a synthetic seven-amino-acid peptide modeled on alpha-melanocyte-stimulating hormone. It carries two non-natural substitutions and a cyclic bridge that increase its stability relative to the natural hormone. It circulates as a research chemical and is not an approved medicine.