PT-141 / Bremelanotide (10 mg Vial) Dosage Protocol
PT-141 (bremelanotide) is a melanocortin receptor agonist (MC3R and MC4R) studied for sexual arousal and erectile function. It is FDA-approved as Vyleesi for hypoactive sexual desire disorder (HSDD) in premenopausal women. Unlike PDE5 inhibitors, it acts through the central nervous system rather than vascular mechanisms.
⚡ Quickstart Highlights
Dosing & Reconstitution Guide
Route: Subcutaneous | Frequency: As needed (PRN), minimum 45 min before activity
| Dose | U-100 Units | Volume (mL) | Notes |
|---|---|---|---|
| 1.0 mg | 20 units | 0.20 mL | Starting dose; assess response |
| 1.75 mg | 35 units | 0.35 mL | FDA-approved Vyleesi dose |
| 2.0 mg | 40 units | 0.40 mL | Maximum research dose |
Reconstitution Steps
- Draw 2.0 mL bacteriostatic water.
- Inject slowly down the vial wall.
- Gently swirl until dissolved.
- Refrigerate at 2–8°C; use within 28 days.
Supplies Planning
| Item | 10 Doses | 20 Doses |
|---|---|---|
| PT-141 vials (10 mg each) | 2 vials | 4 vials |
| Insulin syringes (U-100) | 10 | 20 |
| Bacteriostatic water (10 mL) | 1 × 10 mL | 1 × 10 mL |
| Alcohol swabs | shared | shared |
Mechanism of Action
PT-141 is a cyclic heptapeptide analog of alpha-melanocyte-stimulating hormone (α-MSH). It acts as an agonist at melanocortin-3 (MC3R) and melanocortin-4 (MC4R) receptors in the central nervous system — specifically in the hypothalamus and limbic system — to enhance sexual motivation and arousal.
This CNS mechanism distinguishes PT-141 from PDE5 inhibitors (sildenafil, tadalafil) which work peripherally through vascular smooth muscle relaxation. PT-141 can produce desire and arousal even in the absence of physical stimulation, and may work in cases where vascular mechanisms are intact but desire is impaired.
The FDA approved bremelanotide (Vyleesi) at 1.75 mg subcutaneous injection PRN for hypoactive sexual desire disorder in premenopausal women. Studies in males have shown improvements in erectile function via the same central mechanism.
Research Findings & Safety Profile
- FDA-approved (Vyleesi) at 1.75 mg SC for HSDD in premenopausal women — one of few peptide compounds with regulatory approval.
- Phase 2/3 trials in males with erectile dysfunction showed dose-dependent improvements in erectile responses.
- CNS mechanism: acts through MC3R and MC4R, distinct from vascular PDE5 inhibition.
- Common adverse effects: nausea (40% in trials — most common), flushing, headache, transient hypotension.
- Nausea can be mitigated with antiemetic pre-treatment (ondansetron 4 mg oral, 30 min prior) per clinical practice.
- Transient blood pressure increase in early Phase trials led to initial hold; resolved with protocol modifications.
Storage
| State | Temperature | Duration | Notes |
|---|---|---|---|
| Lyophilized | −20°C (−4°F) | Up to 24 months | Dry, dark conditions |
| Reconstituted | 2–8°C (35–46°F) | Up to 28 days | Avoid freeze-thaw |