The clean number to start from: a 10 mg PDA vial plus 2 mL of bacteriostatic water gives 5 mg/mL. Because PDA (Pentadeca Arginate) is the arginate-salt form of BPC-157 — the same peptide — it is mixed exactly the same way, and community-reported doses are small (often 250-500 mcg), so at 5 mg/mL a typical dose is just 5-10 syringe units. That makes dilution choice the real decision here.
Research-context information only. PDA (pentadeca arginate) is an unapproved research compound not evaluated by the FDA. There is no PDA-specific reconstitution or stability study; the math below follows standard peptide-handling convention, BPC-157 practice, and community sources, not validated protocols. This article reports how reconstitution is documented, not what should be done. Consult a licensed physician for personal medical decisions.
This guide covers supplies, the step-by-step mixing process, and dilution charts for PDA. For dose context and why no PDA-specific trial dose exists, see the PDA dosing guide.
New to bacteriostatic water? Start with what it is, how much to use per vial, and how long it lasts — or see the full Bacteriostatic Water Guide.
What You Need
- A vial of lyophilized (freeze-dried) PDA — commonly 10 mg
- Bacteriostatic water (0.9% benzyl alcohol)
- Insulin syringes (100-unit / U-100, 29-31 gauge)
- Alcohol swabs
- A clean, flat surface
Step-by-Step Reconstitution
Documented community and BPC-157-practice protocols describe the following mixing steps:
- Let both vials reach room temperature. Cold peptide and cold water are documented to cause condensation.
- Swab both stoppers — the PDA vial and the bacteriostatic water vial — with an alcohol swab, per standard sterile practice.
- Draw the bacteriostatic water. For 5 mg/mL on a 10 mg vial, protocols describe drawing 2 mL. For more concentrated, smaller-volume dosing, sources describe drawing 1 mL (10 mg/mL).
- Add water slowly down the side wall. Standard practice is to angle the needle so the water runs down the inside wall — not directly onto the powder.
- Swirl, do not shake. Documented protocols describe swirling gently until the powder fully dissolves; shaking can shear the peptide.
- Inspect. A properly reconstituted solution is reported to be clear and free of particles.
Dilution Chart
10 mg vial + 2 mL bacteriostatic water = 5 mg/mL (standard, easy-to-read draws):
| Dose | Volume (mL) | Units (100-unit syringe) |
|---|---|---|
| 250 mcg | 0.05 mL | 5 units |
| 500 mcg | 0.10 mL | 10 units |
| 750 mcg | 0.15 mL | 15 units |
| 1 mg | 0.20 mL | 20 units |
10 mg vial + 1 mL bacteriostatic water = 10 mg/mL (more concentrated; smaller volumes, less liquid per shot):
| Dose | Volume (mL) | Units (100-unit syringe) |
|---|---|---|
| 250 mcg | 0.025 mL | 2.5 units |
| 500 mcg | 0.05 mL | 5 units |
| 750 mcg | 0.075 mL | 7.5 units |
| 1 mg | 0.10 mL | 10 units |
Syringe Math
The conversion is deterministic. On a U-100 insulin syringe, 1 unit = 0.01 mL.
- Concentration = vial mg ÷ bacteriostatic water mL. For 10 mg + 2 mL: 5 mg/mL.
- Volume for a dose = dose mg ÷ concentration. For a 250 mcg (0.25 mg) dose at 5 mg/mL: 0.25 ÷ 5 = 0.05 mL.
- Units = volume mL × 100. For 0.05 mL: 5 units.
Why dilution matters for PDA: community-reported doses are small (250-500 mcg), so a higher concentration like 10 mg/mL can put a 250 mcg dose at just 2.5 units — hard to draw accurately. Diluting to 5 mg/mL doubles the unit count for the same dose and improves accuracy.
