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Melanotan-2 Structure And Receptor Pharmacology — Beginner to Advanced

By Editorial Desk · published 2026-02-14 · last reviewed 2026-03-28 · Topic

melanotan-2 comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.

Last reviewed on 2026-03-28. Where a claim depends on a specific study, the study is described rather than over-claimed.

Melanotan-2 Structure and Receptor Pharmacology

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.

Identity and Chemical Background

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.

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.

Melanotan-2 at a glance

PropertyValueNotes
Molecular formulaC50H69N15O9Free base; salt forms add to total mass
Molecular massAbout 1024 daltonsCalculated for the free base
Structural classCyclic heptapeptideContains D-phenylalanine and norleucine
Parent hormoneAlpha-melanocyte-stimulating hormoneEndogenous tridecapeptide of 13 residues
Receptor profileNon-selective melanocortin agonistInteracts with MC1R, MC3R, MC4R and MC5R

Melanotan-2 Identity and Receptor Pharmacology

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.

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.

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Reference notes

== Development in humans == Newborn humans are not developed enough yet to chew and thus cannot handle eating solids, and survive solely on drinking liquid breast milk or infant formula. As infant development proceeds, small amounts of puréed baby foods are sometimes fed to babies as young as two or three months old, but most infants do not eat anything solid until they are between six and eight months old. Premastication, in which adults chew up food and then "kiss-feed" a softened food bolus into the infant's mouth, can also be seen in many undeveloped countries as a form of improvised puréed food. The practices of feeding only liquid or semi-liquid food to young infants is because they still have few teeth and an immature digestive system. Between 8 and 12 months of age, the digestive system improves and deciduous teeth progressively emerge (i.e. "teething"), and many babies can begin weaning and eating finger foods. Their diet is still limited, however, because most babies lack molars or canines at this age, and often have a limited number of incisors. By 18 months, babies often have enough teeth and a sufficiently mature digestive system to eat the same foods as adults. Learning to eat food is a messy process for children, and they often do not master neatness or eating etiquette until five or six years old.

=== Advancing women in academia === Masur aims to advance and increase the visibility of women in STEMM. She uses her voice to create opportunities for women in science and fights for more equitable academic space. During her tenure at Mount Sinai, Masur was the first Dean of Faculty Developmencreating mentorship opportunities for women and men . She is a member of the Office of Gender Equity as Director of the Office for Women's Careers, which evolved from the Women Faculty Group at Mount Sinai (established in 1986). As the Director of the Office of Women's Careers, she advocates for women at ISMMS. Targeted programs and monthly events are hosted for women to discuss juggling career with family and to provides them with mentorship and leadership opportunities. Masur has published works describing the development of Women in Cell Biology (WICB) as well as anticipations of the future of women in STEMM. Masur held leadership roles including Chair of Diversity Issues Committee on Women and Minorities for the Association for Research in Vision and Ophthalmology from 1997 to 1999, co-director of the National Eye Institute's "Fundamental Issues in Vision Research" at the Marine Biological Laboratory from 2001 to 2010, and Chair of Women in Cell Biology for the American Society of Cell Biology from 2010 to 2016. In 2015 the American Society for Cell Biology honored Masur by naming one of their leadership awards the "Sandra K. Masur Senior Leadership Award" for efforts in scientific leadership and her long history of creating opportunities for women.

CNMamide (CNMa) is a cyclic neuropeptide identified by computational analysis of Drosophila melanogaster protein sequences and named after its C-terminal ending motif. A gene encoding CNMa was found in most arthropods and comparison among the precursor sequences of several representative species revealed high conservation, particularly in the region of the predicted mature peptide. Two conserved cysteine residues enveloping four amino acids form a disulfide bond and were shown to be important for binding of the peptide to its receptor. Expression of CNMa was confirmed in the larval and adult brain of D. melanogaster but the function of the peptide has not been elucidated yet.

Sources: en.wikipedia.org

Notes from published material

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=== PTFE filter === Polytetrafluoroethylene (PTFE) filter has wide operating temperature (−120 °C ~ 260 °C) with high air permeability. The resistance to high temperature makes PTFE filter paper suitable for use in autoclaves. It is often used to filter hot oils, strong solvents and collecting airborne particulates.

Sources: en.wikipedia.org

Frequently asked questions

Is melanotan-2 approved for medical use?

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.

How does melanotan-2 differ from melanotan-1?

Melanotan-1, also called afamelanotide, is a linear analogue with greater selectivity for MC1R and has received approval in some jurisdictions for a specific photosensitivity disorder. Melanotan-2 is cyclic, less selective, and reaches central receptors more readily. The two are often confused in online discussion despite different pharmacology and regulatory status.

What is the connection to alpha-MSH?

Alpha-MSH is an endogenous tridecapeptide derived from pro-opiomelanocortin. Melanotan-2 reproduces its core receptor-binding sequence inside a shortened, stabilised ring. The result is a molecule with a longer effective half-life and higher potency than the parent hormone.

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.

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