A practical reference on alpha-MSH analogue: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-01-12. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C50H69N15O9 | Synthetic cyclic heptapeptide |
| Molecular mass | Approximately 1024 g/mol | Depends on counter-ion content |
| Appearance | White to off-white powder | Commonly supplied as a lyophilised solid |
| Solubility | Freely soluble in water | Also dissolves in common aqueous buffers |
| Typical storage | -20 degrees Celsius, desiccated | Protect from light and repeated freeze-thaw |
Receptor studies place melanotan-2 among non-selective melanocortin agonists, binding MC1R, MC3R, MC4R and MC5R rather than a single subtype. Activation of MC1R on cutaneous melanocytes raises tyrosinase activity and shifts pigment synthesis toward eumelanin, which is darker and more photostable than pheomelanin. Central receptors, particularly MC4R, are associated with appetite suppression and with reported effects on sexual function. Because subtype selectivity is low, the same molecule engages pigment, metabolic and vascular pathways at once, and this breadth is a common explanation offered for the range of adverse events described in user reports.
No regulatory authority has approved melanotan-2 for human use, and several countries classify it as a prescription-only or controlled substance, which restricts lawful supply. Material sold online is generally labelled as a research chemical and is not required to meet pharmaceutical standards of identity or purity. Published human data consist mainly of small uncontrolled studies, case reports and adverse-event notifications, so the evidence base is descriptive rather than confirmatory. Whether repeated melanocyte stimulation alters long-term naevus behaviour remains an open question that no completed trial has resolved.
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.
It has a Ki of over 10,000 nM (and thus negligible affinity) for β-adrenergic, H1, and mACh. Toxicity depends on the route of administration; the LD50s in mice were 300 mg/kg for the oral route, 160 mg/kg for intraperitoneal, and 56 mg/kg intravenous.
In August 2010, he was cast in the role of "The Man in Black" in 2011's X-Men spin-off, X-Men: First Class, directed by Matthew Vaughn. In 2012, he starred in the romantic comedy The Oranges alongside Hugh Laurie and Leighton Meester and appeared in the action film Chinese Zodiac. He provided the voice of Wiser the Owl in the 2013 animated film Dorothy of Oz. He appeared in Miramax's 2016 supernatural thriller, The 9th Life of Louis Drax.
Certain regulatory measures are in place to minimize RBC storage lesion – including a maximum shelf life (currently 42 days), a maximum auto-hemolysis threshold (currently 1% in the US, 0.8% in Europe), and a minimum level of post-transfusion RBC survival in vivo (currently 75% after 24 hours). However, all of these criteria are applied in a universal manner that does not account for differences among units of product. For example, testing for the post-transfusion RBC survival in vivo is done on a sample of healthy volunteers, and then compliance is presumed for all RBC units based on universal (GMP) processing standards (RBC survival by itself does not guarantee efficacy, but it is a necessary prerequisite for cell function, and hence serves as a regulatory proxy). Opinions vary as to the "best" way to determine transfusion efficacy in a patient in vivo. In general, there are not yet any in vitro tests to assess quality or predict efficacy for specific units of RBC blood product prior to their transfusion, though there is exploration of potentially relevant tests based on RBC membrane properties such as erythrocyte deformability and erythrocyte fragility (mechanical). Physicians have adopted a so-called "restrictive protocol" – whereby transfusion is held to a minimum – in part because of the noted uncertainties surrounding storage lesion, in addition to the very high direct and indirect costs of transfusions.
cell compartmentalization The subdivision of the interior of a cell into distinct, usually membrane-bound compartments, including the nucleus and organelles (endoplasmic reticulum, mitochondria, chloroplasts, intracellular vesicles, etc.), a defining feature of the Eukarya.
molecular genetics - proving compound heterozygous or homozygous disease causing variants in the DDC gene CSF examination - low levels of 5-HIAA, HVA, and MHPG, increased levels of 3-OMD, L-DOPA and 5-HTP, and normal levels of pterins serum examination - decreased AADC enzyme activity To establish the diagnosis of AADCD, patient must have positive genetic testing (1st criterion) while also fulfilling either one of the other two criteria. Elevated 3-OMD levels in serum can be used as a simple and sensitive screening test, positive result of which must be confirmed by the diagnostic criteria above.
Sources: en.wikipedia.org
Since u needs to be finite at r = 0, c1 = 0. The no slip boundary condition at the pipe wall requires that u = 0 at r = R (radius of the pipe), which yields c2 = GR2/4μ. Thus we have finally the following parabolic velocity profile:
==== Difficulties with interpretation of TSH measurement ==== Heterophile antibodies (which include human anti-mouse antibodies (HAMA) and Rheumatoid Factor (RF)), which bind weakly to the test assay's animal antibodies, causing a higher (or less commonly lower) TSH result than the actual true TSH level. Although the standard lab assay panels are designed to remove moderate levels of heterophilic antibodies, these fail to remove higher antibody levels. "Dr. Baumann [from Mayo Clinic] and her colleagues found that 4.4 percent of the hundreds of samples she tested were affected by heterophile antibodies.........The hallmark of this condition is a discrepancy between TSH value and free T4 value, and most important between laboratory values and patient's conditions. Endocrinologists, in particular, should be on alert for this." Macro-TSH - endogenous antibodies bind to TSH reducing its activity, so the pituitary gland would need to produce more TSH to obtain the same overall level of TSH activity. TSH Isomers - natural variations of the TSH molecule, which have lower activity, so the pituitary gland would need to produce more TSH to obtain the same overall level of TSH activity. The same TSH concentration may have a different meaning whether it is used for diagnosis of thyroid dysfunction or for monitoring of substitution therapy with levothyroxine. Reasons for this lack of generalisation are Simpson's paradox and the fact that the TSH-T3 shunt is disrupted in treated hypothyroidism, so that the shape of the relation between free T4 and TSH concentration is distorted.
=== By mouth === If taken by mouth it is toxic. Side effects may include nausea, vomiting, and shortness of breath may occur. If a sufficiently large amount (about 10 grams) is eaten death may occur. Concentrated solutions when drunk have resulted in Acute Respiratory Distress Syndrome or swelling of the airway. Recommended measures for those who have ingested potassium permanganate include gastroscopy. Activated charcoal or medications to cause vomiting are not recommended. While medications like ranitidine and N-acetylcysteine may be used in toxicity, evidence for this use is poor.
== See also == Acquired immune deficiency syndrome (AIDS) Immune disorder Autoimmune disease, immune response to self-proteins Allergy, immune response to harmless non-self proteins Histamine Immunosenescence, age-associated immune deficiency Steroids, commonly administered drugs like prednisone that suppress the immune system Human genetic enhancement Immune system Immunology
Sources: en.wikipedia.org
Raw dry buckwheat is 10% water, 72% carbohydrates, 13% protein, and 3% fat (table). In a reference amount of 100 g (3.5 oz), dry buckwheat supplies 343 calories of food energy, and is a rich source (20% or more of the Daily Value, DV) of three B vitamins (riboflavin, niacin, pantothenic acid) and several dietary minerals (table).
In mid-2017, Wenger brought in two signings; Alexandre Lacazette for a fee of £45m, the club's most expensive signing, and Sead Kolašinac on a free transfer from Schalke 04. On 6 August, Wenger won his seventh FA Community Shield as manager as Arsenal beat Chelsea 4–1 on penalties following a 1–1 score at full time. However, in the 2017–18 FA Cup, Arsenal lost to Nottingham Forest in the third round of the FA Cup, and again stood well outside the top four in the Premier League. The club also dealt with player unrest in the form of Sánchez, who voiced his desire to depart, and Wenger sanctioned a transfer to Manchester United in January 2018, whereby Arsenal received Henrikh Mkhitaryan in a swap-deal. Later that month, he signed Pierre-Emerick Aubameyang for a club-record fee of £56 million. However, these additions did not aid Arsenal's performances as a team, and on 20 April, Wenger announced he would step down as Arsenal manager at the end of the 2017–18 season. His final home game was a 5–0 win against Burnley on 6 May, where he received a standing ovation before the game and was gifted the gold mini-replica Premier League trophy he won during the 2003–04 Invincibles season as a departing gift from Arsenal. He officially concluded his tenure with a 1–0 away win against Huddersfield Town. Wenger later revealed that he wanted to stay at the club until the expiration of his contract, but the club thought it better he leave, with the board informing him in January of their decision to end his contract at the end of the season.
Meanwhile, Pakistani officials said that they had put forward three core demands to Taliban representatives: that Afghanistan formally designate Tehreek-e-Taliban Pakistan (TTP) as a terrorist organisation, dismantle its infrastructure, and provide verifiable proof of these actions. Pakistani officials also said that military operations in Afghanistan would continue until militant safe havens there were eliminated. Five policemen were injured in an IED attack by TTP in Lakki Marwat District.
Sources: en.wikipedia.org
It is a synthetic cyclic heptapeptide and an analogue of alpha-melanocyte-stimulating hormone. The molecule is produced by chemical synthesis rather than extracted from a biological source.
It is shorter than the native hormone and carries a cyclic constraint that improves stability. These changes raise receptor potency and slow breakdown relative to the naturally occurring peptide.
Published accounts date its development to the 1980s, when researchers were generating analogues of melanocyte-stimulating hormone. That work aimed to produce more stable compounds for studying pigmentation biology.
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.