PT-141, also known as Bremelanotide, is a melanocortin receptor agonist. Its dosing differs from most other peptides in a few important ways: the dose range is relatively narrow, it is used on-demand rather than on a daily schedule, and the timing of administration matters more than with most compounds.
Dose Range
The typical PT-141 dose range in research protocols:
- Starting dose: 0.5mg (500mcg)
- Common dose: 1mg to 1.5mg (1,000-1,500mcg)
- Upper range: 2mg (2,000mcg)
Most protocols start at 0.5mg to assess individual response, then adjust upward if needed. The FDA-approved pharmaceutical version (Vyleesi) uses a fixed 1.75mg subcutaneous dose.
Reconstitution and Calculation
PT-141 is commonly available in 10mg vials. Here is the math for different water volumes:
10mg vial + 2mL bacteriostatic water
| Desired Dose | MCG | Syringe Units |
|---|---|---|
| 0.5mg | 500 | 10 units |
| 1.0mg | 1,000 | 20 units |
| 1.5mg | 1,500 | 30 units |
| 2.0mg | 2,000 | 40 units |
At 2mL of water, the concentration is 5,000mcg/mL (50mcg per syringe unit). A 10mg vial provides between 5 and 20 doses depending on your dose size.
10mg vial + 1mL bacteriostatic water
Concentration = 10,000mcg/mL (100mcg per unit). This is more concentrated:
- 0.5mg dose = 5 units
- 1.0mg dose = 10 units
- 1.5mg dose = 15 units
- 2.0mg dose = 20 units
Less water means smaller injection volume, but the doses land on tighter syringe markings. For beginners, 2mL of water is easier to measure accurately.
Timing Considerations
PT-141 is not a daily peptide. Key timing notes from research protocols:
- Onset: Effects typically begin 45 minutes to 2 hours after injection
- Duration: Can last 6-12 hours in some individuals, with peak effects at 2-4 hours
- Frequency: Not more than once in a 24-hour period
- Limit: Research protocols typically recommend no more than 8 doses per month
Side Effects to Note
PT-141 commonly causes nausea, particularly at higher doses. This is the main reason protocols start at 0.5mg — it allows you to find the minimum effective dose before encountering side effects. Flushing and mild headache are also reported.
Taking the dose on a partially empty stomach and staying hydrated may reduce nausea. Some protocols suggest taking an antiemetic 30 minutes beforehand when first determining dose tolerance.
Storage
Unreconstituted PT-141 can be stored at room temperature but lasts longer refrigerated. Once reconstituted with bacteriostatic water, store in the refrigerator and use within 3-4 weeks.
Get exact syringe units for your PT-141 vial with our PT-141 dosage calculator.