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Identity And Chemical Background — 2026 Update

By Editorial Desk · published 2026-03-15 · last reviewed 2026-04-24 · Data

The short version of alpha-MSH analog fits in a sentence. The long version — which is the one that helps — is below.

This page was last updated on 2026-04-24 and is reviewed periodically as new material appears.

Identity and Chemical Background

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.

Origins and Research Status

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.

Melanotan II is a synthetic peptide analog modeled on alpha-melanocyte-stimulating hormone, a naturally occurring signaling peptide involved in pigmentation. Its structure is a cyclic heptapeptide containing two non-natural substitutions, norleucine at position four and D-phenylalanine at position seven. These modifications resist enzymatic breakdown and extend the molecule's activity relative to the native hormone. The compound binds melanocortin receptors and is studied mainly as a pharmacological tool rather than a therapeutic product. It has never received approval as a medicine in any major jurisdiction.

Melanotan-2 at a glance

PropertyValueNotes
Molecular formulaC50H69N15O9Free base; salt forms differ
Molecular weightApproximately 1024 g/molCalculated for the free base
AppearanceWhite to off-white powderTypically supplied as a lyophilised solid
SolubilitySoluble in water and polar solventsPoorly soluble in non-polar solvents
Typical storage-20 degrees Celsius, dry, protected from lightRefers to the solid form

Melanotan-2 Identity and Receptor Pharmacology

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.

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Background and Mechanism of Melanotan-2

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.

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 Structure and Receptor Pharmacology

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.

Further detail

Type 1 diabetes, in which the immune system attacks the pancreas, is "extremely rare" in cats, unlike in dogs and humans. Type 2 diabetes is responsible for 80–95% of diabetic cases. They are generally severely insulin dependent by the time symptoms are diagnosed. Glipizide for T2DM are not known to be effective in cats, unlike in humans. Gestational diabetes, which occurs in humans and dogs, has never been found in cats. Insulin resistance and diabetes in cats can also have a component of hypersomatotropism (an excess of growth hormone, also leading to acromegaly) and hyperadrenocorticism. In some cats, cancer causes the loss of pancreatic islets.

=== Han dynasty === The Yellow Emperor's Inner Canon (Huangdi Neijing), the oldest received work of Chinese medical theory, was compiled during the Han dynasty around the first century BCE on the basis of shorter texts from different medical lineages. Written in the form of dialogues between the legendary Yellow Emperor and his ministers, it offers explanations on the relation between humans, their environment, and the cosmos, on the contents of the body, on human vitality and pathology, on the symptoms of illness, and on how to make diagnostic and therapeutic decisions in light of all these factors. Unlike earlier texts like Recipes for Fifty-Two Ailments, which was excavated in the 1970s from the Mawangdui tomb that had been sealed in 168 BCE, the Inner Canon rejected the influence of spirits and the use of magic. It was also one of the first books in which the cosmological doctrines of Yinyang and the Five Phases were brought to a mature synthesis. The Treatise on Cold Damage Disorders and Miscellaneous Illnesses (Shang Han Lun) was collated by Zhang Zhongjing sometime between 196 and 220 CE; at the end of the Han dynasty. Focusing on drug prescriptions rather than acupuncture, it was the first medical work to combine Yinyang and the Five Phases with drug therapy. This formulary was also the earliest public Chinese medical text to group symptoms into clinically useful "patterns" (zheng 證) that could serve as targets for therapy.

=== Myomesin 2 === Myomesin 2 (also known as M-protein) is located in the M1 line of the M-band. It is encoded by the MYOM2 gene. There is currently only one known variant of myomesin 2 and it can be found in fast skeletal muscles and adult cardiac muscles. Myomesin 2 has been shown to have an inverse relationship with the expression of EH-myomesin; as cardiac muscles mature, EH-myomesin is downregulated while myomesin 2 is upregulated.

There are also several passages with chains that begin with the six sense spheres (ayatana). They can be found in SN 12. 24, SA 343, SA 352-354, SN 12. 13-14 and SN 12. 71-81. Another one of these is found in SN 35.106, which is termed the "branched version" by Bucknell because it branches off into six classes of consciousness:Eye consciousness arises dependent on the eye and sights. The meeting of the three is contact. Contact is a condition for feeling. Feeling is a condition for craving. This is the origin of suffering … [the same formula is repeated with the other six sense bases and six consciousnesses, that is, ear, nose, tongue, body, and mind]Other depictions of the chain at SN 12.52 and its parallel at SA 286, begin with seeing the assada (taste; enjoyment; satisfaction) which leads to craving and the rest of the list of nidanas. Meanwhile, in SN 12.62 and SA 290, dependent origination is depicted with just two nidanas, contact (phassa) and feeling (vedana). SN 12.62 says that when one becomes disenchanted with contact and feeling, desire fades away.

Sources: en.wikipedia.org

Supporting material

=== Rehabituation to dairy products === Regular consumption of dairy foods containing lactose can promote a colonic bacteria adaptation, enhancing a favorable microbiome, which allows people with primary lactase deficiency to diminish their intolerance and to consume more dairy foods. The way to induce tolerance is based on progressive exposure, consuming smaller amounts frequently, distributed throughout the day. Lactose intolerance can also be managed by ingesting live yogurt cultures containing lactobacilli that are able to digest the lactose in other dairy products.

Record league victory: 9–0 v Loughborough, Second Division, 28 January 1899 v Accrington Stanley (away), Third Division North, 3 February 1934 Record cup victory: 6–0 v Blackpool, FA Cup first round, 20 January 1910 Record league defeat: 9–0 v Notts County, Second Division, 19 January 1927 Record cup defeat: 8–1 v Derby County, FA Cup first round, 30 January 1897 7–0 v Manchester United, EFL Cup third round, 17 September 2024 Most appearances: Barry Murphy, 569 Most goals scored for the club: Ernie Hine, 131 Most league goals scored in a season: Cecil McCormack, 33, 1950–51 Second Division Most international caps: Gerry Taggart, 35, Northern Ireland Record transfer fee received: £5,000,000 from Swansea City for Alfie Mawson (2017) Record transfer fee paid: £1,500,000 to Partizan Belgrade for Georgi Hristov (1997) and £1,500,000 to QPR for Mike Sheron (1999) Record attendance: 40,255 v Stoke City, FA Cup fifth round, 15 February 1936 Youngest ever Football League player: Reuben Noble-Lazarus, 15 years and 45 days Oldest player: Mike Pollitt, 41 years, 5 months and 30 days Most goals scored in a single game: 5; Frank Eaton v South Shields, 1927 Peter Cunningham v Darlington, 1933 Beaumont Asquith v Darlington, 1938 Cecil McCormack v Luton Town, 1950 Barnsley have spent more seasons and played more games at the second level of English football than any other team.

In 2017, the U.S. Food and Drug Administration (FDA) approved L-glutamine oral powder, marketed as Endari, to reduce severe complications of sickle cell disease in people aged five years and older with the disorder. The safety and efficacy of L-glutamine oral powder were studied in a randomized trial of subjects ages five to 58 years old with sickle cell disease who had two or more painful crises within the 12 months prior to enrollment in the trial. Subjects were assigned randomly to treatment with L-glutamine oral powder or placebo, and the effect of treatment was evaluated over 48 weeks. Subjects who were treated with L-glutamine oral powder experienced fewer hospital visits for pain treated with a parenterally administered narcotic or ketorolac (sickle cell crises), on average, compared to subjects who received a placebo (median 3 vs. median 4), fewer hospitalizations for sickle cell pain (median 2 vs. median 3), and fewer days in the hospital (median 6.5 days vs. median 11 days). Subjects who received L-glutamine oral powder also had fewer occurrences of acute chest syndrome (a life-threatening complication of sickle cell disease) compared with patients who received a placebo (8.6 percent vs. 23.1 percent). Common side effects of L-glutamine oral powder include constipation, nausea, headache, abdominal pain, cough, pain in the extremities, back pain and chest pain. L-glutamine oral powder received orphan drug designation. The FDA granted the approval of Endari to Emmaus Medical Inc.

==== El Salvador ==== "Triple saldo" is a Salvadorean cuisine bull penis and testicles soup. The soup is simmered for eight hours, with crema and eggs of free-range chickens added at the end. Triple saldo is eaten as an aphrodisiac. Bull penis and testicle tacos (tacos de viril) are becoming popular in Ahuachapán.

Land mobile radio system – short-range mobile or portable half-duplex radio transceivers operating in the VHF or UHF band that can be used without a license. They are often installed in vehicles, with the mobile units communicating with a dispatcher at a fixed base station. Special systems with reserved frequencies are used by first responder services; police, fire, ambulance, and emergency services, and other government services. Other systems are made for use by commercial firms such as taxi and delivery services. VHF systems use channels in the range 30–50 MHz and 150–172 MHz. UHF systems use the 450–470 MHz band and in some areas the 470–512 MHz range. In general, VHF systems have a longer range than UHF but require longer antennas. AM or FM modulation is mainly used, but digital systems such as DMR are being introduced. The radiated power is typically limited to 4 watts. These systems have a fairly limited range, usually 3 to 20 miles (4.8 to 32 km) depending on terrain. Repeaters installed on tall buildings, hills, or mountain peaks are often used to increase the range when it is desired to cover a larger area than line-of-sight. Examples of land mobile systems are CB, FRS, GMRS, and MURS. Modern digital systems, called trunked radio systems, have a digital channel management system using a control channel that automatically assigns frequency channels to user groups. Walkie-talkie – a battery-powered portable handheld half-duplex two-way radio, used in land mobile radio systems.

Sources: en.wikipedia.org

Frequently asked questions

Is melanotan-2 a naturally occurring substance?

No. Melanotan-2 is manufactured synthetically. The naturally occurring peptide in the same family is alpha-melanocyte-stimulating hormone, which the body produces as part of normal endocrine and neural signalling.

How is melanotan-2 distinguished from afamelanotide?

Both are synthetic analogues derived from the same parent hormone. Reference descriptions usually characterise afamelanotide as more selective for the MC1R subtype, whereas melanotan-2 is reported to interact with a wider range of melanocortin receptors.

Why does the compound appear in tanning-related discussion?

Early studies explored melanocortin signalling and pigmentation, which later led to informal use of the label tanning peptide. That label is not a regulatory category and does not imply approved status for any purpose.

What is melanotan II?

It is a synthetic cyclic peptide designed as an analog of alpha-melanocyte-stimulating hormone. It acts on melanocortin receptors and is best known from research into pigmentation. It is not an approved pharmaceutical product.

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