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Melanotan II: Why It Is a Peptide-Blend Boundary Case illustration
Vermarktete Mischung
B 0162026-08-06

Melanotan II: Why It Is a Peptide-Blend Boundary Case

Alle MischungenMelanotan II (single peptide)
Idealisierte Strukturdarstellung für Melanotan II: Why It Is a Peptide-Blend Boundary Case
B 016Melanotan II (single peptide)

Aus der Sequenz aufgebautes idealisiertes Konformer; keine experimentell bestimmte oder vorhergesagte Struktur.

BOUNDARY CASE: SINGLE SUBSTANCE

Der Beweisinhalt wird in englischer Sprache gepflegt.

Bottom line

A boundary-case entry: Melanotan II is a single synthetic peptide (a cyclic alpha-MSH analog), not a blend. It is included here because it is frequently discussed in "stack" contexts alongside other peptides (PT-141/Bremelanotide, GH secretagogues) and illustrates the blurred line between single-compound and combination marketing in the research-peptide space.

No established or recommended human dose.

Name and formulation variability

Observed market contextSubstance(s) claimedStandardized?Verification limit
Single-substance listings observed in 2026Melanotan IINo standardized market productSeller-declared identity and amount are not independent verification
Combination-market claimsMelanotan II with PT-141, GHRP-6, or other substancesNo standardized combinationNo combination efficacy or compatibility evidence identified

Melanotan II is a synthetic cyclic heptapeptide (Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂) developed as a non-selective melanocortin receptor agonist (MC1R, MC3R, MC4R, MC5R). It was originally investigated for skin tanning and sexual dysfunction but never received FDA approval.

Why it appears in a blend atlas

Melanotan II is frequently promoted in combination "stacks": with PT-141 (bremelanotide, a related metabolite) for tanning/libido claims, or with GH secretagogues for body-composition claims. However, there is no standardized pre-formulated "Melanotan II blend" product and no basis for treating these marketing combinations as studied regimens.

This illustrates a broader pattern: many blends in the research-peptide market are not manufacturer-pre-formulated combinations but user-defined stacks that vendors encourage by selling multiple peptides from the same catalogue.

Single substance versus market associations
Melanotan II is one peptide surrounded by market associations, not a standardized blendA solid center node for Melanotan II is surrounded by dotted PT-141, GHRP-6, and other market nodes. A barred ring states that no standard blend or combination evidence was identified.PT-141market association onlyGHRP-6market association onlyother market pairingsmarket association onlyMELANOTAN IIsingle peptideNO STANDARD BLEND / NO COMBINATION EVIDENCEhuman-development recordsafety signalsregulatory / sport checksIDENTITYHYPOTHESIZED / SHARED DOMAINMARKET ASSOCIATIONEVIDENCE GAP
Evidence, safety, regulatory, and sport checks attach only to Melanotan II. Legend: solid outlines identify the substances described on the page; dashed lines show hypothesized or shared biological domains; dotted lines show market association only; barred lines mark missing combination or compatibility evidence.
Textalternative

Melanotan II is a single peptide. PT-141, GHRP-6, and other pairings are market associations only. No standard blend or combination evidence was identified. Its human-development record, safety signals, and regulatory and sport checks must be assessed independently.

Evidence for Melanotan II alone

DomainEvidence for the single substance
MechanismNon-selective melanocortin receptor agonist; MC1R relates to melanogenesis and MC4R to erectile and appetite effects
Human developmentPhase 1/2 tanning studies were reported; development was discontinued after safety concerns
Medicine approvalMelanotan II was never FDA-approved; FDA Import Alert 66-41 includes it in scope, which is an enforcement-screening record rather than approval
Safety signalsMelanocytic-nevus changes, nausea, flushing, spontaneous erections, and melanoma case reports
Sport statusNot explicitly named in the 2026 index; class language and the catch-all require a case-specific determination rather than inference from the market name

Regulatory and product-quality notes

  • FDA Import Alert 66-41 identifies Melanotan I and II in its scope; an import alert is an enforcement screening mechanism, not a marketing approval or a clinical safety determination

  • Multiple adverse event reports including melanocytic nevi changes and melanoma case reports

  • Sold as "research use only" with no pharmaceutical regulatory oversight

  • PT-141 (Bremelanotide) is FDA-approved as Vyleesi for hypoactive sexual desire disorder — a separate regulatory path from Melanotan II

Compare the separate Melanotan II monograph and bremelanotide monograph. The WADA and sport page explains why sport status is an independent axis, and the blend index documents market-name instability.

Sources

  1. FDA. Import Alert 66-41, "Unapproved New Drugs Promoted in the U.S." Product scope includes Melanotan I and II. https://www.accessdata.fda.gov/CMS_IA/importalert_190.html

  2. PubChem. Melanotan II (CID 92432). https://pubchem.ncbi.nlm.nih.gov/compound/92432 accessed 2026-08-06.

  3. Habbema L, et al. Melanotan II safety and side effects. Ned Tijdschr Geneeskd. 2012;156(40):A5134.

  4. ClinicalTrials.gov. Melanotan II studies (various). Accessed 2026-08-06.

  5. World Anti-Doping Agency. 2026 Prohibited List. https://www.wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf

Expertenstimmen

Was Experten sagen

Kommentare sind Meinungen und nicht Teil der Evidenzprüfung; eine Aufnahme bedeutet keine Befürwortung.

Für diese Verbindung wurde kein verifizierter Expertenkommentar in den Quellen gefunden, die dieser Atlas akzeptiert — peer-reviewte Literatur, Mitteilungen von Universitäten, Krankenhäusern und medizinischen Fachgesellschaften, Behörden sowie wissenschaftlicher Journalismus mit namentlicher Autorenschaft.

Das Fehlen von Kommentaren ist kein Beleg für oder gegen die Verbindung.

Aussagen von Anbietern, Kliniken und aus sozialen Medien sind grundsätzlich ausgeschlossen und werden nicht als Kommentare gezählt.

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Fragen

What is Melanotan II?

Melanotan II is a single synthetic cyclic peptide, not a standardized blend. It is included here because market discussions often associate it with unrelated substances.

Do market pairings containing Melanotan II have combined evidence?

No standardized combination or combination-specific efficacy and compatibility evidence was identified. Dotted market associations do not turn separate substances into a studied mixture.

What safety and regulatory uncertainties apply to Melanotan II?

The page records human-development and safety signals, no FDA approval, and an import-alert record that is an enforcement-screening tool rather than a clinical determination. Market material is not independently verified.

Why is a single peptide included in the blend atlas?

Melanotan II illustrates classification ambiguity created by market pairings. Its inclusion documents that context without redefining one peptide as a blend.

Is there a standardized Melanotan II combination?

No. The page identifies market associations with PT-141, GHRP-6, and other substances, but no standard composition or combination evidence.

Can sport status be inferred only from whether a substance is named?

No. The WADA page explains that class language and catch-all provisions can matter, so an athlete needs a current case-specific determination rather than an inference from name presence alone.