PT-141 (Bremelanotide)

Structure: Synthetic cyclic heptapeptide. Melanocortin receptor agonist targeting MC3R and MC4R in the central nervous system. Derived from Melanotan II but with reduced melanocortin-1 receptor activity (less tanning).

Dosage:

• Standard (as-needed): 1-2mg SubQ, 45-60 min before anticipated sexual activity
• Conservative start: 500mcg to assess response and nausea tolerance
• Maximum: 1.75mg per dose; no more than 1 dose per 24 hours; max 8 doses per month

Administration:

• SubQ injection, abdomen
• 27-30g insulin syringe
• On-demand dosing only — not for daily use

Key Notes:

• Works centrally (brain) via dopamine release — fundamentally different mechanism from PDE5 inhibitors (Cialis/Viagra)
• FDA-approved (Vyleesi) for hypoactive sexual desire disorder in women — used off-label by men
• Enhances desire and arousal, not just erectile function — can work when PDE5 inhibitors alone are insufficient
• Nausea is very common (~40%) especially at first use — tends to diminish with subsequent doses
• Flushing is common (~20%) and temporary
• Transient blood pressure increase post-injection — monitor if hypertensive
• Can be combined with Tadalafil for both desire (PT-141) and mechanical function (PDE5)
• Mild skin darkening possible with repeated use (reduced vs Melanotan II but still present)
• Reconstitute with bacteriostatic water, store refrigerated