Reconstitution guide
How to Reconstitute Peptides: Step-by-Step Reference Guide
By Baris Bingor · Last updated
What are the steps to reconstitute a peptide?
Peptide reconstitution has seven steps: read the vial label, pick a BAC water volume that lands your dose at a readable unit count, disinfect the stopper with isopropyl, slowly add BAC water down the inside wall, swirl gently until dissolved (never shake), work out the draw volume (the free calculator on this site does it), and write the date and water on the label. Math: vial mass ÷ BAC water = concentration.
What you need
- Lyophilized peptide vial
- Bacteriostatic water for injection (BWFI)
- U-100 insulin syringe
- Isopropyl alcohol swabs
- A calculator for the math — the free one on this site runs in your browser
Step-by-step
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Read the vial label. Confirm the peptide name and the total mass in mg. Note the lot number and the manufacturer recommendations for reconstitution if present.
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Pick a BAC water volume. Choose a bacteriostatic water volume so that your typical dose lands at a readable unit count on a U-100 syringe — usually 10–50 units. The free calculator on this site shows the unit count as you change the water volume.
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Disinfect the rubber stopper. Wipe the vial stopper with an isopropyl alcohol swab and let it dry for ~30 seconds before piercing.
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Add BAC water slowly. Draw the chosen BAC water volume into a syringe and inject it into the vial slowly, angling the needle so the stream runs down the inside wall of the vial rather than hitting the powder directly.
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Swirl gently. Roll the vial between your palms or swirl gently until the powder is fully dissolved. Do not shake. Most peptides dissolve in seconds; a few take longer.
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Work out the draw volume. Divide the vial mass by the BAC water you just added to get the concentration, divide your amount by it, and multiply by 100 for U-100 units. The free calculator on this site does it for the numbers you type and draws the line on a syringe.
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Write it down. Note the date, the water you added and the concentration on the vial label, so later draws do not need the math again.
Common mistakes
- Shaking the vial. Swirl gently; do not shake.
- Adding too little or too much BAC water. Pick the volume so your dose lands at 10–50 units on a U-100 syringe.
- Mixing up mcg and mg. 1 mg = 1,000 mcg.
- Confusing U-100 and U-40. 10 units on U-100 is 0.1 ml; 10 units on U-40 is 0.25 ml.
- Re-deriving the math every dose. Work it out once and write it on the label.
See also
- Reconstitution mistakes (and how to avoid them)
- Peptide calculator
- BAC water calculator
- Insulin syringe units explained — U-100 vs U-40
- Reconstitution math reference
- Peptide dosage reference
Frequently asked questions
Should I shake the vial after adding BAC water? +
Most research protocols recommend gentle swirling or rolling rather than shaking. Vigorous shaking can damage some peptides. Swirl until the powder is fully dissolved.
What if the powder does not fully dissolve? +
Most peptides dissolve in seconds; some take longer. If powder remains after several minutes of gentle swirling, let the vial sit at room temperature for 5–10 minutes and swirl again. Do not heat.
Can I reuse a syringe between draws? +
No. Use a new sterile syringe for each draw. This is a standard injection hygiene rule, not a Peptly recommendation.
Where should reconstituted peptide be stored? +
Most research protocols refrigerate at 2–8 °C. Stability varies by peptide — most are typically used within 2–4 weeks. Consult primary sources or a licensed clinician.
Does the Peptly app do the reconstitution math? +
No. The Peptly app is a log and tracker: it keeps the entries you type, exactly as you typed them, with reminders and injection-site rotation, and never calculates or suggests an amount. The free calculator on this site does the math: vial mass ÷ BAC water = concentration, and target dose ÷ concentration = draw volume (× 100 for units on a U-100 syringe).