Melanotan II vs PT-141: Melanocortin Peptides Compared

Melanotan II and PT-141 (bremelanotide) are both synthetic melanocortin receptor agonists, but they differ in receptor selectivity and primary research applications. Melanotan II is a non-selective agonist that activates MC1R (melanogenesis/tanning), MC3R, MC4R (sexual function), and MC5R. PT-141 is a cyclic metabolite of Melanotan II that selectively targets MC3R and MC4R in the central nervous system for sexual function research without significant tanning effects. PT-141 was essentially developed from Melanotan II by isolating the sexual function pathway in test subjects. For research purposes only.

Melanotan II: • Loading dose: 250-500 mcg daily for 2-3 weeks • Maintenance dose: 250 mcg 1-2x per week • Vial: 10mg • Reconstitution: 10mg + 2mL BAC water = 5mg/mL (50 mcg/unit) • 250 mcg = 5 units | 500 mcg = 10 units • Use: Continuous (loading then maintenance) PT-141: • Dose: 1-2 mg per use • Frequency: As needed (not daily), max 2-3x per week • Vial: 10mg • Reconstitution: 10mg + 2mL BAC water = 5mg/mL (50 mcg/unit) • 1 mg = 20 units | 2 mg = 40 units • Use: On-demand (45-60 minutes before desired effect)

Receptor targets: Melanotan II = MC1R, MC3R, MC4R, MC5R | PT-141 = MC3R, MC4R Tanning effect: Melanotan II = Strong | PT-141 = None/minimal Sexual function: Melanotan II = Yes (secondary) | PT-141 = Yes (primary) Appetite suppression: Melanotan II = Mild | PT-141 = Minimal Dosing pattern: Melanotan II = Daily loading + maintenance | PT-141 = As-needed Onset: Melanotan II = Days-weeks (tanning) | PT-141 = 45-60 minutes Nausea risk: Melanotan II = Moderate (especially early) | PT-141 = Mild Mole darkening: Melanotan II = Yes (monitor) | PT-141 = No Research approval: Melanotan II = Research only | PT-141 = FDA-approved (as Vyleesi)

Choose Melanotan II when: The research investigates melanogenesis (tanning response), the protocol examines broad melanocortin receptor activation, or both tanning and sexual function effects are relevant to the study in test subjects. Choose PT-141 when: The research specifically targets sexual function through CNS melanocortin pathways, tanning effects are undesired confounders, or the protocol requires on-demand acute dosing rather than chronic administration in test subjects. PT-141 is the more targeted compound for sexual function research, while Melanotan II remains the standard for melanogenesis studies. For research purposes only.