How to Reconstitute Peptides — Step-by-Step Guide

What You Need Before You Start

The complete equipment list: your peptide vial (lyophilized powder), bacteriostatic water, a 1mL or 3mL drawing syringe for adding the BAC water, U-100 insulin syringes (28–31 gauge) for dosing, alcohol swabs, and a clean flat surface. That is the entire list. The most common substitution error is using sterile water instead of bacteriostatic water — sterile water has no preservative and is safe only for single-use reconstitution on the day of mixing.

Gather supplies and prepare a clean surface. Set everything out before opening anything. Minimize time between swabbing and injecting by preparing efficiently.
Swab both vial stoppers with a fresh alcohol swab. Allow 10–15 seconds to dry before inserting any needle. Do not touch the center of the stopper after swabbing.
Draw the calculated BAC water volume into your drawing syringe. Insert the needle at an angle into the BAC water stopper, pull slowly to avoid air bubbles. For 2mL additions, use two full 1mL pulls or a 3mL syringe.
Add BAC water slowly down the inside wall of the peptide vial. Tilt the vial, touch the needle tip to the glass, and release the water so it flows down the wall rather than blasting directly onto the powder. This prevents mechanical disruption of the lyophilized peptide.
Swirl gently until fully dissolved — do not shake. Rotate the vial slowly. Most peptides dissolve in 30–90 seconds. Shaking generates foam and can cause protein aggregation.
Label with date, BAC water volume, and concentration. Refrigerate. Reconstituted peptide in BAC water is stable for 28–30 days at 2–8°C. Never freeze a reconstituted vial.

The Calculator

The free peptide reconstitution calculator on this page handles the math: enter vial size, BAC water volume, and target dose to get concentration, draw units, and doses per vial. Custom Draw mode inverts the calculation — enter your target draw units and get the BAC water volume to use. Both are free with no account required at protocolapp.health/tools/peptide-calculator.

Frequently Asked Questions

What is the correct BAC water volume for a 5mg peptide?

2mL is the standard starting point for a 5mg vial. This gives a 2,500 mcg/mL concentration. For a 250mcg dose, that's 10 units on a U-100 syringe. If you prefer a larger draw (easier to measure), use 4mL BAC water — this gives 1,250 mcg/mL and doubles your draw to 20 units per 250mcg dose. Use the Custom Draw mode above to calculate any combination.

Why does it matter that I add BAC water down the glass wall?

Directing the water stream directly onto lyophilized peptide powder creates turbulence and mechanical pressure at the powder surface. For fragile or sensitive peptides, this can cause partial denaturation or aggregation. Running the water down the side wall creates a gentler hydration — the peptide dissolves as the liquid level rises around it rather than under direct impact. Not all peptides are sensitive to this, but the technique costs nothing and protects against vial-specific variation.

How long does reconstituted BPC-157 last?

Reconstituted BPC-157 in bacteriostatic water, stored refrigerated at 2–8°C, is stable for 28–30 days. After that window, potency may decline. Lyophilized BPC-157 (unreconstituted, dry powder) stored frozen at -20°C is stable for 12–24+ months. Always reconstitute only what you will use within 30 days, and label every vial with the reconstitution date.

How to Reconstitute
a Peptide

What You Need Before You Start

The Calculator

Frequently Asked Questions

Free Peptide Calculator

How to Reconstitutea Peptide

What You Need Before You Start

The Calculator

Frequently Asked Questions

Free Peptide Calculator

How to Reconstitute
a Peptide