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.

This is a unit converter. It converts an amount you already have into volume and syringe units. It does not tell you what to take, and it is educational only — not medical advice. Confirm every amount with your clinician and your product label.

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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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Reviewed by the DoseRoutine editorial team. Last reviewed 2026-08-03.

Who maintains this page

The DoseRoutine Editorial Team maintains the compound library and the interaction rule set behind DoseRoutine. We summarize published trials, regulatory documents (FDA, EMA) and company announcements into plain-English updates. Every factual claim on a post is tied to a linked source below.

Posts are written and reviewed by the editorial team, not by a licensed clinician. This is educational reference content — it never recommends an amount for you to take.

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