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PT-141 vs Melanotan II
Side-by-side comparison of evidence, mechanisms, dosing, safety, and regulatory status.
PT-141: AMelanotan II: F
| Attribute | PT-141 | Melanotan II |
|---|---|---|
| Category | Sexual Health | Melanocortin Agonist |
| Evidence Rating | A — FDA Approved | F — No Regulatory Activity |
| Clinical Status | FDA-approved (Vyleesi for HSDD in premenopausal women) | Research-only / Not approved. Multiple regulatory warnings issued worldwide. |
| Mechanism | PT-141 (MW ~1025 g/mol, C50H68N14O10, half-life 2-6 hours) is a synthetic analog of alpha-MSH targeting MC3R and MC4R. MC4R activation in the CNS enhances dopamine release in the nucleus accumbens and medial preoptic area, increasing sexual motivation. Subcutaneous bioavailability is approximately 1... | MT-II activates melanocortin receptors MC1R through MC5R non-selectively. MC1R activation stimulates melanogenesis (skin tanning) in melanocytes. MC3R/MC4R activation in the CNS increases sexual arousal and desire via dopamine release pathways. MC4R activation centrally suppresses appetite. The non-... |
| Half-Life | ~2.5 hours | ~36 minutes IV; longer SC due to depot effect |
| Bioavailability | ~25% SC | — |
| Molecular Weight | ~1025.2 g/mol | ~1024.2 g/mol |
| WADA Status | Not Listed | Prohibited |
| Dosing | 1.75 mg SC per dose (FDA-approved); max 1 dose per 24 hours, max 8 doses per month, As needed, at least 45 minutes before sexual activity (Subcutaneous) | Loading: 0.25–0.5 mg/day for 5–7 days; Maintenance: 0.5–1.0 mg 1–2x weekly, Daily during loading phase; 1–2x weekly maintenance (Subcutaneous) |
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| Regulatory (US) | FDA-approved (Vyleesi, 2019) for HSDD in premenopausal women. 1.75 mg SC on-demand, max 8 doses/month. | Not FDA-approved. FDA has issued warnings against use. Removed from Category 2 on April 15, 2026. PCAC review scheduled July 23-24, 2026 to determine compounding eligibility. |
Research Disclaimer: This comparison is provided for educational purposes only. All products are sold exclusively for in vitro research use. The information presented is based on published preclinical and clinical research and does not constitute medical advice. Consult a qualified healthcare professional before making any decisions regarding peptide use.
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