Cyclic seven-amino acid melanocortin agonist (broader receptor profile than PT-141). Stimulates melanin production and central libido pathways.
Evidence is experimental. Most claims trace to limited human studies or animal models. Treat as a research direction, not a protocol.
Originally researched at University of Arizona for sun-protection. Tanning effect comes from MC1R activation (peripheral); libido from MC4R (central). Australia's TGA and the UK MHRA have warned consumers about safety. Multiple case reports of new melanomas under MT-II use.
Multiple case reports linking MT-II to new melanomas and atypical mole changes. Regulators in AU/UK have issued explicit warnings. Strongly favor PT-141 (FDA-approved, narrower mechanism) over MT-II for any libido-only use.
Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂. Same core as PT-141, amidated C-terminus.
Per-claim grading. Each claim is graded independently — same peptide, different claims can carry different grades.
External links to PubMed searches, ClinicalTrials.gov, and FDA materials. We do not host papers — we point at canonical sources.
Pre-filled with this compound's published dose range: 0.25-1 mg · varies, subcutaneous
Calculator is a discussion tool. Verify reconstitution + dosing with a qualified provider. Stack is not a prescription source. Use sterile technique and inspect every vial.
Public-source attribution across the production + distribution chain. Stack does not endorse vendors — this is who is in the chain, not which one is best.
Long-established US vendor (7+ years). Broad catalog including GHRPs, GHRHs, and cognitive peptides. Third-party HPLC and mass-spec COA per batch. Active Finnrick Analytics coverage.
For laboratory use only / not for human consumption. Stack may earn affiliate commissions.
Established vendor with multi-year community track record. Offers peptide blends (Wolverine Stack, etc.) alongside singles. Third-party COA available on request.
For laboratory use only / not for human consumption. Stack may earn affiliate commissions.
FDA Cat. 2 removed Apr 2026 — PCAC review Feb 2027. AU/UK still warn consumers.
FDA's Pharmacy Compounding Advisory Committee scheduled to review the second cohort of peptides removed from Category 2 in April 2026. Panel votes whether to add each to the official 503A bulks list.
FDA published a Federal Register notice on April 15 2026 removing 12 peptides from the Category 2 ('significant safety concerns') compounding list, paving the way for PCAC review for inclusion on the 503A bulks list. Peptides removed: BPC-157, TB-500, Epitalon, GHK-Cu (injectable), MOTS-c, DSIP, Dihexa Acetate, MK-677, Melanotan II, KPV, Semax, LL-37.
FDA's Pharmacy Compounding Advisory Committee categorized a wide list of peptides as Category 2 ('significant safety concerns'), effectively banning their compounding at 503A and 503B pharmacies. Affected: BPC-157, TB-500, Epitalon, GHK-Cu, MOTS-c, DSIP, Dihexa, MK-677, Melanotan II, KPV, Semax, Selank, LL-37 and others.