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Peptide Reconstitution Calculator

Enter your peptide amount, bacteriostatic water volume, and desired dose — see exactly how many units to draw on a standard insulin syringe. No sign-up, no ads, bookmarkable.

mg
ml
mcg
Draw to
10.0 units
on a 1 mL, 100-unit syringe
Valid draw
10 u
Volume 0.10ml
Concentration 2.50mg/ml
Doses / vial 20

How to reconstitute a peptide — step by step

  1. Sanitise the vial stoppers. Wipe both the peptide vial and bacteriostatic water vial tops with a fresh alcohol swab. Let them air-dry for a few seconds.
  2. Draw your BAC water. Pull back the syringe plunger to the desired ml amount, insert the needle into the BAC water vial, and draw the liquid. Expel any air bubbles.
  3. Add water to the peptide vial slowly. Insert the needle at an angle and let the water run down the inside wall of the vial — not directly onto the peptide powder. Sharp streams can denature delicate peptides.
  4. Do not shake. Gently swirl or roll the vial between your palms until the powder fully dissolves. Shaking introduces air and can damage some peptides.
  5. Store reconstituted peptide in the fridge (2–8 °C / 36–46 °F). Use within roughly 28 days unless the specific peptide has a shorter stability window.
  6. Draw each dose using the calculator above. Invert the vial, insert the insulin syringe, and draw to the unit mark shown for your syringe size.

How the math works

The calculation is a straightforward ratio: your peptide mg is dissolved uniformly in the BAC water you added, so the concentration is mg ÷ ml. Each dose is the fraction of that total volume that contains your desired mcg amount.

Formula: units = (desired_mcg ÷ (peptide_mg × 1000)) × bac_ml × 100

Insulin syringes are marked in "units" where 100 units = 1 ml on a U-100 syringe. The calculator always gives you the same volume — what changes between 100u, 50u, and 30u syringes is precision: on smaller syringes the tick marks are further apart, so small doses are easier to read.

Common reconstitution ratios

These are typical starting points, not recommendations — adjust to your own protocol and preferred dose size.

BPC-157 (5 mg vial)

Common: 2 ml BAC water → concentration 2.5 mg/ml. A 250 mcg dose = 10 units on a 100u syringe.

TB-500 / TB4-Frag (5 mg or 10 mg vial)

Common: 2–3 ml BAC water. With 10 mg in 2 ml → concentration 5 mg/ml. A 2 mg dose = 40 units.

Semaglutide (5 mg vial)

Common: 2 ml BAC water → 2.5 mg/ml. A 0.25 mg (250 mcg) starter dose = 10 units.

Tirzepatide (10 mg or 15 mg vial)

Common: 2 ml BAC water. With 10 mg in 2 ml → 5 mg/ml. A 2.5 mg starter dose = 50 units.

Tired of running this math every time?

Peptide Protocol does the reconstitution math for you, tracks every dose, logs side effects, and keeps your whole protocol on one calm iPhone screen.

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Frequently asked questions

What is peptide reconstitution?

Reconstitution is the process of adding a sterile liquid — typically bacteriostatic water — to a lyophilized (freeze-dried) peptide powder to produce an injectable solution. The final concentration depends on the peptide mg and the water volume added.

What does 1 unit on an insulin syringe mean?

A standard 100-unit (U-100) insulin syringe holds 1 ml at its maximum. One unit equals 0.01 ml. A 50u syringe holds 0.5 ml; a 30u holds 0.3 ml. Smaller syringes show tick marks further apart, which makes fine dosing easier to measure.

Is bacteriostatic water the same as sterile water?

No. Bacteriostatic water contains 0.9% benzyl alcohol, which inhibits bacterial growth and allows a multi-dose vial to be used for up to 28 days. Sterile water has no preservative and is intended for single use only.

How long does reconstituted peptide last?

Once reconstituted with bacteriostatic water, most peptides remain stable refrigerated (2–8 °C / 36–46 °F) for 28 days. Stability varies by peptide — always check specific guidance for the compound you are using.

Why does the calculator show different numbers for 100u, 50u, and 30u syringes?

Each syringe has a different total volume but the same number of marked units. A dose of 0.1 ml is 10 units on a 100u syringe, 10 units on a 50u syringe, and 10 units on a 30u syringe — the math is the same. What changes is how far apart the tick marks are, which affects measurement precision.

My dose exceeds the syringe capacity — what do I do?

Either split the dose across two injections, or reconstitute with less bacteriostatic water so the same dose fits in a smaller volume. The calculator warns you when your dose exceeds a given syringe's capacity.

Related tools & guides

Educational use only. Peptide Protocol and this calculator are informational tools. Nothing on this page constitutes medical advice. Peptides may be prescription-only or restricted in your jurisdiction. Always consult a licensed healthcare professional before injecting any compound.