Informational use only — not medical advice. For adults 21 and over. Talk to a qualified healthcare professional before making decisions about medications or supplements.

How to reconstitute peptides

Bacteriostatic water in, a readable syringe number out. The steps, the syringes, and the arithmetic — with worked examples from the Dosify Me database.

Informational use only. Not medical advice. Follow the instructions that came with your product.

Step by step

Check the vial. Read the milligrams (or IU) on the label. Powder should be a compact puck or fine powder; refrigerate until use unless the product says otherwise.
Decide the water. Pick the bacteriostatic water amount that gives a concentration you can read on the syringe. Dosify Me gives each compound a standard mix — e.g. BPC-157 at 3.33 mg/mL — so the units stay the same across vial sizes. A vial that would need more water than it holds (usually over 3 mL) is mixed more concentrated instead.
Draw the water. Wipe both stoppers with alcohol. Draw the bacteriostatic water into a 3 mL reconstitution syringe.
Add it slowly. Insert the needle at an angle and let the water run down the inside of the glass rather than onto the powder. Do not shake; roll or swirl gently until clear.
Label and store. Write the date and concentration on the vial. Most reconstituted peptides keep in the fridge for weeks; the app tracks a discard date per vial.
Draw the dose. Use an insulin syringe (U-100 or U-50). Units = dose ÷ (mcg per unit), where mcg per unit = mg/mL × 10.

The math, once

Units and millilitres both measure liquid. 100 units (U-100) = 1 mL, so 50 units = 0.5 mL and 10 units = 0.1 mL.

Micrograms and milligrams measure the compound itself. 1000 mcg = 1 mg, so 250 mcg = 0.25 mg.

mL and cc are the same volume.

Concentration = vial mg ÷ water mL. mcg per unit = concentration × 10. Units to draw = dose mcg ÷ mcg per unit.

Vial	Water	Concentration	Per unit	200 mcg
10 mg	3 mL	3.33 mg/mL	33.3 mcg	6 units
5 mg	1.5 mL	3.33 mg/mL	33.3 mcg	6 units
10 mg	1 mL	10 mg/mL	100 mcg	2 units

Open the reconstitution calculator How much BAC water to add

Which syringe

U-50 (0.5 mL): markings every 5 units with minor lines every unit — small doses are easy to see and measure.
U-100 (1 mL): markings every 10 units, minor lines every 2 — better for larger doses, harder to read small ones.
3 mL reconstitution syringe: peptide vials are generally 3 mL, so a 3 mL syringe draws the water in one pull.

Frequently asked

How much bacteriostatic water do I add to a peptide vial?

Vial mg ÷ target mg/mL. A 10 mg vial to 3.33 mg/mL needs 3 mL; a 5 mg vial needs 1.5 mL. The per-compound pages and the calculator do this for you.

What is the difference between a U-50 and U-100 syringe?

Both are insulin syringes marked in units where 100 units = 1 mL. The U-100 holds 1 mL (100 units); the U-50 holds 0.5 mL with the scale spread out, so small doses are easier to read. The units are the same size on both.

How many units is 250 mcg?

It depends on the concentration. At 33.3 mcg per unit (3.33 mg/mL) it is 7.5 units; at 100 mcg per unit (10 mg/mL) it is 2.5 units. Use the calculator for your exact mix.

Can I use sterile water instead of bacteriostatic water?

Bacteriostatic water contains 0.9% benzyl alcohol so a multi-dose vial stays usable for weeks; plain sterile water has no preservative and is only suitable for single, immediate use.

Dosify Me does this math for you. Pick the compound, your vial size and dose, and the app draws the exact syringe reading, keeps your schedule and reminders, and logs every dose — privately, on your phone.

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Go deeper

BAC water calculator · Per-compound dosing reference · Dosing chart · Schedules and cycles