Peptide Reconstitution: A Practical Guide to BAC Water Math

Lyophilized (freeze-dried) research peptides are shipped as dry powder. Reconstitution — adding bacteriostatic water — turns the vial into a measured solution you can dose precisely with a U-100 insulin syringe. It is simple arithmetic, but small errors compound fast.

The three numbers that matter

1. Vial dose — the total peptide in the vial, e.g. 5 mg (5,000 µg) for BPC-157 or 10 mg (10,000 µg) for retatrutide.
2. Water volume — the mL of bacteriostatic water you inject into the vial.
3. Target dose — the µg (or IU, for HGH 191aa) you intend per draw.

The math

Concentration = vial dose ÷ water volume.

Example: 5 mg BPC-157 + 2 mL water → 5,000 µg ÷ 2 mL = 2,500 µg/mL.

Per syringe unit = concentration × 0.01 (1 unit = 0.01 mL on U-100).

Draw volume = target dose ÷ per-unit amount.

Example: 250 µg target ÷ 25 µg/unit = 10 units = 0.1 mL.

The peptide reconstitution calculator does all of this for every lyophilized compound in the catalog, with presets for the actual vial sizes.

Three common mistakes

• Forgetting the unit conversion — mg is 1,000× µg. A 5 mg vial is 5,000 µg, not 5.
• Using the wrong syringe scale — U-40 and U-500 syringes use different units-per-mL; the math above assumes U-100.
• Reconstituting with plain water — bacteriostatic water (0.9% benzyl alcohol) preserves multi-dose vials; sterile water without preservative does not.

Storage and aseptic handling

• Lyophilized: −20 °C, protected from moisture.
• Reconstituted: refrigerate at 2–8 °C and use within the documented window.
• Swab the vial septum before each draw; use a fresh syringe per draw; never reuse needles.

Full handling data is listed on each product page — see BPC-157, TB-500 or GHK-Cu.

For laboratory research use only. Not medical advice.