A practical reference on alpha-MSH: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-05-26 and is reviewed periodically as new material appears.
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.
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.
Melanotan-2 is a synthetic cyclic heptapeptide designed as a structural analogue of alpha-melanocyte-stimulating hormone, the endogenous tridecapeptide that regulates pigment production. Two modifications distinguish it from the natural hormone: norleucine replaces methionine at the N-terminus, which limits oxidation, and a D-phenylalanine substitution raises receptor affinity. The ring is closed through an aspartate-lysine lactam bridge, giving the molecule a constrained conformation. The free base has a molecular mass near 1024 daltons, and commercial material is usually supplied as an acetate salt. It appears in the literature as a research peptide rather than an approved therapeutic agent.
| 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 |
The compound emerged from research programs in the 1980s that examined analogues of alpha-melanocyte-stimulating hormone for pigmentation and photoprotection. Investigators modified the native sequence to extend activity duration and potency. A related analogue, afamelanotide, was developed within the same broad line of inquiry and eventually gained approval in certain jurisdictions for a rare light-sensitivity condition. Melanotan-2 itself did not progress through the same regulatory route and has no approved therapeutic indication.
Melanocortin receptors comprise five subtypes with distinct tissue distributions and functions. Melanotan-2 is described in the literature as a non-selective agonist that engages several of these subtypes, including MC1R, MC3R, MC4R, and MC5R. MC1R is the subtype most directly linked to melanin production in skin cells. Because the compound is not subtype-selective, its observed effects in experimental settings are generally attributed to activity across multiple receptor pathways rather than to a single target.
Melanotan-2 is a synthetic linear peptide built from seven amino acids arranged in a short chain. Its sequence is commonly written as Ac-Nle-Asp-His-D-Phe-Arg-Trp-Lys-NH2, which includes a modified N-terminus and an amidated C-terminus. The molecule belongs to the melanocortin family and acts as a receptor agonist. Structural features such as the D-phenylalanine residue and the Nle substitution are associated with increased stability against enzymatic degradation relative to the natural parent peptide.
Romanowsky was the first to realise the differences in the staining abilities of eosin and methylene blue. The individual stains (monochromatic staining) were good only for general colouring of tissue or cell, but not for contrasting the different components. By mixing specific amount of eosin and methylene blue, Romanowsky found that the mixture gave images of contrasting clarity that helped to visualise different parts and components of cells. This mixture method, polychromatic staining or polychromy, with various modifications became the most efficient way of staining cells for identifying cellular components. The chemical phenomenon by which a mixture of stains produces vibrant cell images is known as "Romanowsky effect". In December 1890, Romanowsky published his invention as a preliminary report of his major work for his doctoral thesis in the journal Vrach as "On the question of the structure of malaria parasites" (as translated in English). Incorrectly, it is more often recorded in books and journals that Romanowsky published his findings in 1891, which led to a controversy on priority that Ernst Malachowsky independently developed the technique as the latter published his research in August 1891.
24. Adv Gerontol. 2008;21(1):68-73. [Biological activity of regulatory peptides in model experiments in vitro]. [Article in Russian] Kozina LS, Arutiunian AV, Stvolinskiĭ SL, Khavinson VKh. Biological effects of short regulatory peptides, pinealon, vesugen, vilon and epitalon were studied in model experiments in vitro. These peptides were found not to demonstrate direct antioxidant activity but be able to restrict lipid peroxidation of human lipoproteins by modification of their structure. The short peptides increase stability of red blood cell membranes toward osmotic hemolysis. They also elevate the stationary level of intracellular reactive oxygen species and at the same time decrease (all excepting epitalon) percent of dead cells in neuronal population. The suggestion was made that under in vivo conditions, short peptides may participate in apoptosis/necrosis regulation.
=== Audio === The Index includes "a pair of ultra near-field, full-range, off-ear (extra-aural) headphones", which use Balanced Mode Radiator (BMR) drivers to produce accurate and low-frequency sounds. The headset also has a built-in microphone.
A vital Saudi oil facility was protected by one battery, and a natural gas facility in Qatar was protected by the other. U.S. military planners pointed out that obtaining Saudi Arabia's consent to use its airspace was dependent on making sure its energy facilities were sufficiently protected. The strategic deployment was intended to reassure the Gulf allies as Trump prepared for the possibility of resuming major combat operations against Iran. The US military started sending about 9,000 soldiers to the Middle East on naval ships, such as the USS Makin Island amphibious readiness group and the USS Theodore Roosevelt carrier strike group, on 1 October.
OSB's mechanical properties make it suitable for load-bearing applications in construction. In North America, it is more popular than plywood, commanding 66% of the structural panel market in 2016. The most common uses are as sheathing in walls, flooring, and roof decking. For exterior walls, panels are available with a radiant-barrier layer laminated to one side; this eases installation and increases energy performance of the building envelope. OSB is also used in furniture production.
Sources: en.wikipedia.org
The activities of progesterone besides those mediated by the PRs and mPRs are also of significance. Progesterone lowers blood pressure and reduces water and salt retention among other effects via its antimineralocorticoid activity. In addition, progesterone can produce sedative, hypnotic, anxiolytic, euphoric, amnestic, cognitive-impairing, motor-impairing, anticonvulsant, and even anesthetic effects via formation of sufficiently high concentrations of its neurosteroid metabolites and consequent GABAA receptor potentiation in the brain. There are differences between progesterones and progestins, such as medroxyprogesterone acetate and norethisterone, with implications for pharmacodynamics and pharmacokinetics, as well as for efficacy, tolerability, and safety.
Other media in Moscow include the Echo of Moscow (Russian: Эхо Москвы), the first Soviet and Russian private news radio and information agency, and NTV, one of the first privately owned Russian television stations. The number of FM radio stations in Moscow totals about 50. Moscow television networks:
Mild glutathione synthetase deficiency usually results in the destruction of red blood cells (hemolytic anemia). Rarely, affected people also excrete large amounts of a compound called 5-oxoproline (also called pyroglutamic acid, or pyroglutamate) in their urine (5-oxoprolinuria). This compound builds up when glutathione is not processed correctly in cells. Individuals with moderate glutathione synthetase deficiency may experience symptoms beginning shortly after birth including hemolytic anemia, 5-oxoprolinuria, and elevated acidity in the blood and tissues (metabolic acidosis). In addition to the features present in moderate glutathione synthetase deficiency, individuals affected by the severe form of this disorder may experience neurological symptoms. These problems may include seizures; a generalized slowing down of physical reactions, movements, and speech (psychomotor retardation); intellectual disability; and a loss of coordination (ataxia). Some people with severe glutathione synthetase deficiency also develop recurrent bacterial infections.
However, bicalutamide does not increase sex hormone levels if combined with adequate doses of an antigonadotropin such as a GnRH modulator, estrogen, or progestogen, due to the negative feedback effects of these medications on sex-hormone production. Because bicalutamide does not lower androgen levels, it may be a particularly favorable antiandrogen for transgender women who wish to help preserve sex drive, sexual function, and/or fertility, as antiandrogens that strongly suppress levels of testosterone and its metabolites, such as CPA and GnRH modulators, can greatly disrupt these functions. Although bicalutamide has the potential to increase testosterone levels, there is no effect of this testosterone due to the blockade of the AR by bicalutamide. Neyman and colleagues in 2019 published a study on bicalutamide as a puberty blocker in adolescent transgender girls. It was employed both alone (n=17) and in combination with estrogen (n=6) at a dose of 50 mg/day in 23 transgender girls (mean age of 16 years, range 12 to 18.4 years) between 2013 and 2018. Of the girls who were treated exclusively with bicalutamide alone, 13 returned for follow-up and were analyzed. In addition to apparently showing effectiveness as an antiandrogen and puberty blocker, bicalutamide alone increased estradiol levels and promoted feminization as a secondary effect. This included breast development to Tanner stages 2 to 5 in 85% of the patients at the first follow-up visit at 6.3 months of treatment.
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.
No regulatory agency has authorised melanotan-2 as a medicine for any indication. It circulates mainly as a research chemical or through unregulated channels. As a result, identity, purity and content are not independently guaranteed.