melanotan-2 is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2025-08-29. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Analytical confirmation of identity relies on mass spectrometry, most often coupled to liquid chromatography. Reversed-phase high-performance liquid chromatography separates the peptide from related impurities and provides a purity estimate based on peak area. Electrospray ionization mass spectrometry then confirms the expected molecular mass, while tandem mass spectrometry can map the fragment sequence. For research-grade material, these two techniques together form the standard minimum. Purity figures reported by vendors are frequently not traceable to an independent laboratory.
Independent verification is central to quality control because the compound is not produced under pharmaceutical manufacturing standards. Third-party laboratories can measure purity, identity, residual solvents, and microbial contamination, though the scope of testing varies between services. Reported analyses of vendor samples have shown batch-to-batch variation in peptide content and the presence of truncated or oxidized species. How much of this variation reflects synthesis conditions versus storage and shipping is not well characterized. No harmonized reference standard exists for the material as sold.
Handling guidance for melanotan II follows general practice for small synthetic peptides rather than a product-specific monograph. Lyophilized powder is typically kept at minus twenty degrees Celsius or colder, protected from light and moisture, because warmth and humidity accelerate degradation. Once reconstituted, solutions are usually refrigerated and used within a short window, as hydrolysis and microbial growth both become concerns. Repeated freeze-thaw cycles are generally avoided. These conventions come from laboratory peptide chemistry and not from formal stability studies on this specific compound.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic cyclic heptapeptide | Analog of alpha-MSH with an internal lactam bridge |
| Molecular weight | Approximately 1024 daltons | Free base value; salt forms differ |
| Appearance | White to off-white powder | Usually supplied as a lyophilized solid |
| Solubility | Freely soluble in water | Poorly soluble in nonpolar solvents |
| Typical storage | −20 °C, dry, protected from light | Repeated freeze-thaw cycles degrade peptides |
Early published reports described melanotan-2 as a tanning agent without sun protection, which means darkening is not the same as protection against ultraviolet radiation. Later studies explored the peptide in erectile dysfunction, hemorrhagic shock, and some skin conditions. No regulator in the United States or Europe has approved it for clinical use. Many products labelled melanotan-2 are sold without approval and their identity and purity are unverified. Its long-term safety in humans remains an open question.
Melanotan-2, also written Melanotan II, is a synthetic cyclic heptapeptide designed as an analogue of alpha-melanocyte-stimulating hormone. Its sequence is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, and the lactam bridge between the aspartate and lysine side chains constrains the peptide into a ring. This structural change increases receptor affinity and metabolic stability relative to the native hormone. The compound was created in the 1980s as a research tool for studying pigmentation biology.
Melanocytes are the pigment-producing cells of the skin, and they carry melanocortin-1 receptors on their surface. When the receptor is activated, cyclic adenosine monophosphate rises inside the cell and raises the activity of enzymes such as tyrosinase, which increases melanin output. Melanotan-2 binds melanocortin-1 receptors in vitro and in animal models, and this binding is generally described as the basis for the tanning effect. Other receptors account for different effects: melanocortin-4 receptors contribute to appetite and erectile signalling, while melanocortin-3 and melanocortin-5 receptors contribute to energy balance and exocrine function.
Verification of a purchased sample requires documentation linking a batch to a certificate of analysis, and that document should be read for the methods used rather than the headline purity figure. A single chromatographic percentage does not establish identity. Independent laboratories can perform identity and content assays, but no such test establishes that a product is suitable for human use. Claims about efficacy rest largely on small, early studies rather than on replicated controlled trials, and that gap remains open.
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.
== External links == Boston University School of Medicine: Michael F. Holick Harvard Catalyst Profiles: Michael Holick Search Results for author Holick MF on PubMed. Last capture of VitaminDhealth.org Dr. Holick’s current webpage
Poppy tea is a herbal tea infusion brewed from poppy straw or seeds of several species of poppy. The species most commonly used for this purpose is Papaver somniferum, which produces opium as a natural defense against predators. In the live flower, opium is released when the surface of the bulb, called the seed pod, is pierced or scraped. For the purpose of the tea, dried pods are more commonly used than the pods of the live flower. The walls of the dried pods contain opiate alkaloids, primarily consisting of morphine and codeine. The tea is consumed for its narcotic effect, and in small amounts for analgesic, anti-diarrheal, and sedative effects. It has also been known to be used as a method of relieving withdrawal symptoms. Use of such preparations originated in parts of Central and Eastern Europe, the Levant and Near East, and Central and South Central Asia millennia ago. The flowers of the poppy plant have long been used as a painkiller for soothing mild aches and pains (e.g. toothache, earache and sore throat), a mild sedative/relaxant, an expectorant for treating catarrh and coughs, as a digestive, and even for reducing the appearance of wrinkles and in lipsticks. This tea is depicted both in Asian literature, Western literature, and is depicted as being available in opium dens.
Bicalutamide monotherapy has been found to decrease circulating levels of prostate-specific antigen (PSA), a marker of prostate cancer growth, by 57% at 10 mg/day, 73% at 30 mg/day, 90% at 50 mg/day, 97% at 100 mg/day, and 97% at 150 mg/day, while a 97% reduction in PSA is observed with 50 mg/day bicalutamide as a part of CAB. It has also been reported that bicalutamide monotherapy decreases median circulating levels of PSA at 3 months by 86.7% at 100 mg/day, 91.1% at 150 mg/day, and 93.8% at 200 mg/day (relative to 94–97% for castration). Above a bicalutamide monotherapy dosage of 200 mg/day, up to 600 mg/day, decreases in PSA levels reach a plateau. In a study of very-high-dose bicalutamide monotherapy, decreases in PSA levels after 12 weeks were approximately 93% with 300 mg/day, 96% with 450 mg/day, 96% with 600 mg/day, and 96% with castration. Earlier studies with bicalutamide instead assessed changes in prostatic acid phosphatase (PAP) levels; proportions of patients with decreases of PAP of greater than or equal to 50% were 33% with 10 mg/day, 53% with 30 mg/day, and 83% with 50 mg/day bicalutamide. PSA is a more sensitive and specific prostate cancer tumor marker than PAP and subsequent studies employed PSA. Despite the high medication levels that are achieved, due to their relatively low affinities for the AR, it has been suggested that 5 to 10% of DHT may remain unblocked in the prostate gland with CAB using standard doses of first-generation NSAAs.
HCO−3 + OH− ⇌ CO2−3 + H2O Carbonic acid equilibria are important for acid–base homeostasis in the human body. An amino acid is also amphoteric with the added complication that the neutral molecule is subject to an internal acid–base equilibrium in which the basic amino group attracts and binds the proton from the acidic carboxyl group, forming a zwitterion.
Sources: en.wikipedia.org
To increase the theoretical storage capacity of the material, and To bring the operating conditions closer to ambient temperature and pressure. Rowsell and Yaghi have identified several directions to these ends in some of the early papers.
The first President of Cuba, Tomás Estrada Palma, was a Freemason. After his election in April 1902, he returned from exile to Cuba and went on a tour of the island's Masonic Lodges. On May 20, 1902, the Cuban flag was raised for the first time on its own, without the American Flag flying next to it. The next day, on May 21, General Máximo Gómez placed that same exact flag in a wooden chest and handed the chest to Grand Master José Fernández Pellón Castellanos, to ceremonially honor the sacrifices that Cuban Freemasons had made, and the efforts that Cuban Freemasonry had contributed to the creation of an independent Cuba. Freemasonry steadily grew across Cuba. New Masonic Temples were erected across the island, and a Masonic Band was created. Freemasons largely returned to the normal work of charity; schools were built, shoes were dispensed to children in need, an ambulance was given to a hospital, hurricane relief funds were gathered for Puerto Rico and other islands, medical procedures were funded, and a dental dispensary was created. Four entirely English-speaking Lodges were established in communities that had been established by American colonists to the island; Island Lodge in Havana, Landmark Lodge in Camagüey, Kane Lodge in Banes, and Santa Fe Lodge on the Isle of Pines. By 1953, there were 400 English-speaking members across these English language Lodges.
=== Canada === In Canada, Canadian medical graduates (CMGs), which includes final-year medical students and unmatched previous-year medical graduates, apply for residency positions via the Canadian Resident Matching Service (CaRMS). The first year of residency training is known as "Postgraduate Year 1" (PGY1). CMGs can apply to many post-graduate medical training programs including family medicine, emergency medicine, internal medicine, pediatrics, general surgery, obstetrics-gynecology, neurology, and psychiatry, amongst others. Some residency programs are direct-entry (family medicine, dermatology, neurology, general surgery, etc.), meaning that CMGs applying to these specialties do so directly from medical school. Other residencies have sub-specialty matches (internal medicine and pediatrics) where residents complete their first 2–3 years before completing a secondary match (Medicine subspecialty match (MSM) or Pediatric subspecialty match (PSM)). After this secondary match has been completed, residents are referred to as fellows. Some areas of subspecialty matches include cardiology, nephrology, gastroenterology, immunology, respirology, infectious diseases, rheumatology, endocrinology and more. Direct-entry specialties also have fellowships, but they are completed at the end of residency (typically 5 years).
=== 2. Two-Phase Synthesis === A systematic approach to the synthesis of terpenes was developed and executed in the context of numerous natural products, paralleling natural product formation. By rapidly building up a carbon skeleton followed by oxygenation, shorter synthesis routes are achieved, as exemplified with several Baran syntheses (including 14-Step Synthesis of (+)-Ingenolfrom (+)-3-Carene, Two-Phase Synthesis of (−)-Taxuyunnanine, Two-Phase Synthesis of Taxol, Development of a Concise Synthesis of (-)-Ingenol, among others)
==== UK ==== Classified as a controlled drug, listed under Schedule IV, Part I (CD Benz POM) of the Misuse of Drugs Regulations 2001, allowing possession with a valid prescription. The Misuse of Drugs Act 1971 makes it illegal to possess the drug without a prescription, and for such purposes, it is classified as a Class C drug.
Sources: en.wikipedia.org
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.
Melanotan-1, also called afamelanotide, is a shorter linear analog with a different amino acid sequence and no lactam ring. It has been evaluated in formal clinical programs, while melanotan-2 has not. The two are distinct molecules and are not interchangeable.
No. Bremelanotide is a related but distinct cyclic peptide that reached approved status for one specific clinical indication. Melanotan-2 is a separate molecule with its own sequence and properties. Shared ancestry in the melanocortin family does not make them the same substance.
The lyophilized powder is generally held at minus twenty degrees Celsius or below, away from light and moisture. Reconstituted solutions are typically refrigerated and used quickly. These practices derive from general peptide handling rather than a formal stability study.