If you have been reading about regulatory status and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2025-08-15. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
Melanotan-2 has not received marketing authorisation from major regulatory agencies for any therapeutic indication. Several jurisdictions classify it as a prescription-only medicine or a controlled substance when supplied for human use. Because approved products do not exist, material sold online usually sits outside pharmaceutical supply chains and formal quality oversight. Regulators have issued public notices describing the compound as unapproved. Enforcement varies, and the legal position differs between countries, which complicates any single general statement about its status.
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.
| 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.
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.
Regulatory treatment varies by country. In the United States the peptide is not approved as a medicine, and products offered for human use may be treated as unapproved new drugs; some states also restrict sale. Australia, the United Kingdom, and European Union member states apply comparable restrictions to unapproved peptide products. Border agencies have seized shipments labelled as research chemicals. Classification may change over time, and the legal position for personal importation is not clearly settled in most published guidance.
Lyophilised melanotan-2 is supplied as a solid, which is more stable than a solution. The material is hygroscopic, so weighing is done quickly, in low humidity, with the container kept sealed. Reconstitution usually uses water for injection or bacteriostatic water, added down the wall of the vial to limit foaming. A reconstituted solution is held at 2 to 8 °C and kept away from light. Repeated freezing and thawing of the same vial is avoided because ice crystal formation and concentration effects degrade the peptide.
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.
Identity testing for a cyclic peptide of this size usually relies on reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The mass spectrum confirms molecular weight, while the chromatographic trace indicates the proportion of related impurities. Tandem mass spectrometry can provide sequence-level information when fragmentation data are compared against a reference standard. Nuclear magnetic resonance is sometimes used to confirm the lactam bridge, although it requires more material and greater operator expertise than routine chromatographic methods.
Lyophilised peptide powder is comparatively stable when kept dry, cold and protected from light. Once dissolved, the molecule is exposed to hydrolysis, oxidation and microbial growth, and degradation accelerates at higher temperatures and in alkaline solution. Repeated freeze-thaw cycles concentrate solutes and promote aggregation. Handling guidance for research peptides commonly clusters around freezer temperatures for powder and short refrigerated use for reconstituted solutions, with pH control and sterile technique applied throughout.
=== Topical use === Ophthalmology Topical prednisolone is mainly used in the ophthalmic pathway as eye drops in numerous eye conditions, including corneal injuries caused by chemicals, burns, and alien objects, inflammation of the eyes, mild to moderate non-infectious allergies, disorders of the eyelid, conjunctiva or sclera, ocular inflammation caused by operation and optic neuritis. Some side effects include glaucoma, blurred vision, eye discomfort, impaired recovery of injured site, scarring of the optic nerve, cataracts, and urticaria. However, their prevalence is not known. Prednisolone eye drops are contraindicated in individuals who develop hypersensitivity reactions against prednisolone, or individuals with the current conditions, such as tuberculosis of the eye, shingles affecting the eye, raised intraocular pressure, and eye infection caused by fungus. Prednisolone acetate ophthalmic suspension (eye drops) is prepared as a sterile ophthalmic suspension and used to reduce swelling, redness, itching, and allergic reactions affecting the eye. It has been explored as a treatment option for bacterial keratitis. Prednisolone eye drops are used in conjunctivitis caused by allergies and bacteria, marginal keratitis, uveitis, endophthalmitis, which is an infection of the eye involving the aqueous humor, Graves' ophthalmopathy, herpes zoster ocular infection, inflammation of the eye after surgery, and corneal injuries caused by chemicals, radiation, thermal burns, or penetration of foreign objects.
In a speech to the Scottish Labour Party conference in Edinburgh, Labour leader Sir Keir Starmer rules out a deal with the SNP "under any circumstances", and warns against complacency following the departure of Nicola Sturgeon as SNP leader and First Minister. 20 February – Finance Secretary Kate Forbes announces she is running in the Scottish National Party leadership election. 21 February Kate Forbes insists her campaign to become the next SNP leader has not been derailed after she lost the support of several colleagues following comments about same-sex marriage and having children outside marriage, both of which she is opposed to as a member of the Free Church of Scotland. MSPs vote 68–57 to approve the Scottish Government's budget for the 2023–24 financial year, which includes a tax rise for everyone in Scotland earning more than £43,662. 23 February – Sir Iain Livingstone announces he will retire as Chief Constable of Police Scotland in the summer after five years in the post. 24 February Nominations close for the SNP leadership election, with Kate Forbes, Ash Regan and Humza Yousaf having all reached the threshold of supporters to go forward into the contest. Two crew died after tugboat capsized & sank close to Greenock harbour. 25 February – Members of the Scottish Secondary Teachers' Association (SSTA) vote to accept a new pay offer from the Scottish Government, and announce they have suspended strike action scheduled for the following week. 28 February – Transgender rapist Isla Bryson is sentenced to eight years in prison with a further three years supervision.
Since iron is primarily required for hemoglobin, iron deficiency anemia is the primary clinical manifestation of iron deficiency. Iron-deficient people will suffer or die from organ damage well before their cells run out of the iron needed for intracellular processes like electron transport. Macrophages of the reticuloendothelial system store iron as part of the process of breaking down and processing hemoglobin from engulfed red blood cells. Iron is also stored as a pigment called hemosiderin, which is an ill-defined deposit of protein and iron, created by macrophages where excess iron is present, either locally or systemically, e.g., among people with iron overload due to frequent blood cell destruction and the necessary transfusions their condition calls for. If systemic iron overload is corrected, over time the hemosiderin is slowly resorbed by the macrophages.
7 July Starmer makes his first visit to Scotland as prime minister, for a meeting with First Minister John Swinney. Lewis Hamilton of Mercedes takes his ninth victory at the British Grand Prix, breaking the record for the most wins at a single circuit and Grand Prix, and the most wins at a driver's home Grand Prix, bringing an end to a 56 winless race streak and making him the first driver to win a race after their 300th Grand Prix start. 8 July The Chancellor, Rachel Reeves, announces new housebuilding targets for England, and the loosening of planning rules to encourage more new homes. The ban on onshore wind in England is lifted. 9 July Minister Jim McMahon tells BBC News that the phrase "levelling-up" will be replaced with "local government" and that his department will now be named the Ministry of Housing, Communities and Local Government. Health Secretary Wes Streeting begins talks aimed at ending a long-running pay dispute with junior doctors in England. Starmer holds his second cabinet meeting, after telling England's regional mayors he will meet with them regularly to help growth across the UK. The first meeting of the 59th Parliament of the United Kingdom takes place. Vacuum manufacturer Dyson announces it is cutting a third of its UK workforce as part of a global restructuring strategy. 10 July Starmer travels to Washington, D.C., his first foreign trip as UK Prime Minister, to attend the 75th NATO summit.
In Marfan syndrome, the health of the eye can be affected in many ways, but the principal change is partial lens dislocation, where the lens is shifted out of its normal position. This occurs because of weakness in the ciliary zonules, the connective tissue strands that suspend the lens within the eye. The mutations responsible for Marfan syndrome weaken the zonules and cause them to stretch. The inferior zonules are most frequently stretched, resulting in the lens shifting upwards and outwards, but it can shift in other directions, as well. Nearsightedness (myopia), and blurred vision are common due to connective tissue defects in the eye. Farsightedness can also result particularly if the lens is highly subluxated. Subluxation (partial dislocation) of the lens can be detected clinically in about 60% of people with Marfan syndrome by the use of a slit-lamp biomicroscope. If the lens subluxation is subtle, then imaging with high-resolution ultrasound biomicroscopy might be used. Other signs and symptoms affecting the eye include increased length along an axis of the globe, myopia, corneal flatness, strabismus, exotropia, and esotropia. Those with MFS are also at a high risk for early glaucoma and early cataracts, as well as retinal detachment, the latter one of the reasons that people with Marfan may be advised to avoid contact sports and activities that risk falls.
Sources: en.wikipedia.org
– that is the probability of a molecule to have energy greater than or equal to E at the given temperature T. This exponential dependence of a reaction rate on temperature is known as the Arrhenius equation. The activation energy necessary for a chemical reaction to occur can be in the form of heat, light, electricity or mechanical force in the form of ultrasound. A related concept free energy, which also incorporates entropy considerations, is a very useful means for predicting the feasibility of a reaction and determining the state of equilibrium of a chemical reaction, in chemical thermodynamics. A reaction is feasible only if the total change in the Gibbs free energy is negative,
Witnesses included FDA officials. They looked into several areas: the delay in reporting by Menu Foods, the lack of federal inspections of pet food facilities, and incomplete reporting by the FDA since the start of the recall. During the hearing Senators Durbin and Byrd criticized the government's response during the recall. Durbin specifically criticized the lack of any regular inspection practices or quality control with regards to pet food safety. Senator Kohl criticized the FDA's communication to the public about recalled foods, noting that volunteer websites had more detailed and easier-to-access information about the extent of the problem and which specific foods are of concern than FDA's online resources which Kohl said was contradictory of itself at times, and which the FDA official giving testimony admitted to being difficult to navigate. On 18 April 2007, Senator Durbin and Representative DeLauro met with US FDA Commissioner von Eschenbach to discuss the additional rice protein recalls and learned that the Chinese government was blocking outside attempts to investigate the contamination. In response, they sent a letter to Zhou Wenzong, China's Ambassador to the United States saying in part that "contaminated batches of wheat gluten and rice protein responsible for these events were imported from China" and that "no level of melamine should be found in pet or human food" and asking for visas for inspectors from the United States.
== Spinal epidural space == In the spinal canal, the periosteal layer adheres to the inner surface of the spinal canal which is formed by the bodies of vertebrae. The meningeal layer lays over the spinal arachnoid mater. Between the vertebrae and the dural sheath is the spinal epidural space. Unlike the cranial epidural space, the spinal epidural space contains adipose tissue, the internal vertebral venous plexuses and the spinal nerve roots. The spinal epidural space spans the length of the spinal cord, from the foramen magnum superiorly to the sacral hiatus inferiorly. Epidural space is the smallest at the cervical region, measuring 1 to 2 mm. At L2 to L3, enlarges until 5 to 6 mm. It then enlarges progressively until lower lumbar and sacral region. However, some authors stated that it decreases in size after mid-lumbar region until 2 mm at S1 level.
Benzydamine (also known as Tantum Verde and branded in some countries as Maxtra Gargle, Difflam and Septabene), available as the hydrochloride salt, is a locally acting nonsteroidal anti-inflammatory drug (NSAID) with local anaesthetic and analgesic properties for pain relief and anti-inflammatory treatment of inflammatory conditions of the mouth and throat. It falls under class of chemicals known as indazoles.
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.
Major regulatory agencies have not approved it for any indication. Some countries permit it only under prescription frameworks, while others classify it as a controlled substance.