DoseRoutine

Peptide reconstitution guide

Peptide Reconstitution Calculator

Enter vial size and BAC water volume to get exact mg/mL concentration, syringe units per dose, and doses remaining. Works with BPC-157, TB-500, semaglutide, tirzepatide, ipamorelin, CJC-1295 and any research peptide.

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1. Vial size

Enter total mg in the vial (e.g. 5 mg or 10 mg BPC-157).

2. BAC water

Enter mL of bacteriostatic water you'll add (usually 2 mL).

3. Dose

Enter target dose in mg or mcg. Get exact units for U-100 / U-40.

The reconstitution formula

Three equations do all the work:

Concentration (mg/mL) = vial mg ÷ BAC water mL
Volume per dose (mL) = dose mg ÷ concentration
Syringe units (U-100) = volume mL × 100

Example: 5 mg BPC-157 + 2 mL BAC water = 2.5 mg/mL. A 0.25 mg dose = 0.1 mL = 10 units on U-100.

Skip the math — use the calculator

Common peptide presets

BPC-157 — 5 mg vial / 2 mL BAC / 0.25 mg dose

TB-500 — 5 mg vial / 2 mL BAC / 2.5 mg dose

Semaglutide — 5 mg vial / 2.5 mL BAC / 0.25 mg dose

Tirzepatide — 10 mg vial / 2 mL BAC / 2.5 mg dose

Ipamorelin — 5 mg vial / 2 mL BAC / 0.2 mg dose

CJC-1295 — 2 mg vial / 2 mL BAC / 0.1 mg dose

Frequently asked questions

What is peptide reconstitution?

Reconstitution is the process of dissolving a lyophilized (freeze-dried) peptide with bacteriostatic water so it becomes an injectable solution. The math tells you exactly how many syringe units equal your target dose.

How much bacteriostatic water should I add to a 5 mg peptide vial?

A common starting point is 2 mL of BAC water for a 5 mg vial. That gives a 2.5 mg/mL solution. Adding 1 mL doubles the concentration (5 mg/mL) and halves the syringe units per dose. More water = easier to measure small doses.

How do I convert milligrams to insulin syringe units?

Concentration (mg/mL) = vial mg ÷ BAC water mL. Volume (mL) = dose mg ÷ concentration. On a U-100 insulin syringe, 1 mL = 100 units, so multiply mL by 100. Example: 0.25 mg from a 2.5 mg/mL solution = 0.1 mL = 10 units on U-100.

What syringe should I use for peptides?

Most subcutaneous peptides use a U-100 insulin syringe with a 29–31 gauge, 5/16 inch (8 mm) needle. U-40 syringes exist but are less common in peptide use — the calculator supports both.

How many doses are in one vial?

Divide total mg by your dose. A 10 mg BPC-157 vial dosed at 0.25 mg per injection gives 40 doses. A 5 mg semaglutide vial dosed at 0.25 mg gives 20 weekly doses.

Peptide dosage glossary

Quick definitions for the terms used across peptide reconstitution, syringe unit conversion, and TRT dosing.

Reconstitution: Dissolving a lyophilized (freeze-dried) peptide with bacteriostatic water to make an injectable solution.
Bacteriostatic water (BAC water): Sterile water with 0.9% benzyl alcohol that inhibits bacterial growth, extending a mixed vial's usable life to ~28 days refrigerated.
Concentration (mg/mL): Peptide milligrams divided by BAC water milliliters. Drives how many syringe units equal your target dose.
U-100 insulin syringe: Holds 100 units per 1 mL. 1 unit = 0.01 mL. The standard syringe for peptide and TRT subcutaneous dosing.
U-40 insulin syringe: Holds 40 units per 1 mL. 1 unit = 0.025 mL. Less common; using it in place of U-100 changes dose by ~60%.
Subcutaneous (SC): Injection into the fatty layer under the skin (abdomen, flank, thigh) using a 29–31 gauge, 8 mm insulin needle.
Intramuscular (IM): Injection into muscle tissue (glute, delt, quad) with a 23–25 gauge, 1 inch needle. Common for TRT esters.
Half-life: Time for blood levels to fall by half. Drives injection frequency — short half-life = more frequent shots.
Ester: Chemical tail attached to testosterone (cypionate, enanthate, propionate) that controls release speed and half-life.
mcg vs mg: 1 mg = 1,000 mcg. Peptide doses are often written in mcg; always confirm units before drawing.

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