How much bacteriostatic water do I add to a TB-500 vial?

A common research setup uses 1 mL of bacteriostatic water for every 10 mg of TB-500, which holds the concentration at 10 mg/mL across vial sizes. A 5 mg vial gets 0.5 mL, and a 10 mg vial gets 1 mL. Use the calculator to confirm the units for your exact vial and dose.

How many units is a 2 mg TB-500 dose?

At a 10 mg/mL concentration (1 mL water per 10 mg TB-500), a 2 mg dose is 20 units on a U-100 insulin syringe. A 5 mg dose at the same concentration is 50 units.

What concentration should I reconstitute TB-500 to?

There is no single required concentration. 10 mg/mL is a common reference point because it lands the typical 2-5 mg research dose range on clean, easy-to-read unit marks. Scaling the water to the vial size (1 mL per 10 mg) keeps that concentration constant across a 5 mg or 10 mg vial.

Can TB-500 and BPC-157 be drawn into the same syringe?

They are sometimes drawn together for a single injection in research settings, but they should not be reconstituted in the same vial. Compatibility and stability vary, so this is a per-protocol decision. See the BPC-157 dosage calculator for the BPC-157 side of that math.

TB-500 Dosage Calculator: Reconstitution & Syringe Units

By PeptCalc Research — Medically reviewed by David Mansour, MD — Last reviewed July 10, 2026

TB-500 is the common research name for a synthetic peptide corresponding to a fragment of Thymosin Beta-4 (Tβ4), supplied as lyophilized powder for research use. It has to be reconstituted with a liquid before it can be measured or drawn into a syringe. This reference explains how a TB-500 dosage calculator turns a vial size, water volume, and target dose into the exact number of units to draw on a U-100 insulin syringe. It is written for research purposes only and is not medical advice.

What the calculator does

The peptide reconstitution calculator handles the reconstitution math in two directions:

Forward mode — enter vial size, water volume, and target dose → it returns the syringe units to draw.
Reverse mode — enter vial size, target dose, and desired syringe units → it tells you how much water to add.

Both modes run on the same formula: concentration equals mass divided by volume, and dose in units equals dose in volume times 100 on a U-100 syringe.

Common TB-500 vial sizes

Research vials are typically supplied in:

5 mg
10 mg

The calculator supports any vial size. These two are the ones most often listed by research suppliers.

Typical research concentration

A common reconstitution setup for TB-500 scales the water to the vial size at 1 mL per 10 mg, which holds the concentration at a constant 10 mg/mL no matter which vial you're working from:

Vial size	Water added	Concentration
5 mg	0.5 mL	10 mg/mL
10 mg	1 mL	10 mg/mL

Because the ratio is fixed, the units for a given dose don't change with vial size — only the number of full doses the vial holds changes.

Target dose	Units at 10 mg/mL
2 mg	20 units
3 mg	30 units
4 mg	40 units
5 mg	50 units

A 2 mg dose landing on an exact 20-unit mark is a large part of why 10 mg/mL is a common reference concentration for TB-500 — it reads cleanly on any U-100 syringe.

The math

Step 1: Calculate concentration

Concentration = vial mass ÷ water volume

5 mg vial + 0.5 mL water = 10 mg/mL
10 mg vial + 1 mL water = 10 mg/mL
10 mg vial + 2 mL water = 5 mg/mL

Step 2: Convert dose to volume

Volume (mL) = dose (mg) ÷ concentration (mg/mL)

Example: 3 mg dose at 10 mg/mL concentration = 3 ÷ 10 = 0.3 mL

Step 3: Convert volume to syringe units

On a U-100 insulin syringe, 1 mL = 100 units, so:

Units = volume (mL) × 100

Example: 0.3 mL × 100 = 30 units

The calculator performs these three steps instantly for any vial, water, and dose combination you enter.

Reconstitution process

Gather supplies — the TB-500 vial, bacteriostatic water, U-100 insulin syringes, alcohol swabs.
Swab both vial stoppers with alcohol.
Draw the calculated water volume (e.g. 1 mL for a 10 mg vial at 10 mg/mL).
Inject slowly down the inside wall of the vial, not directly onto the powder.
Swirl gently — do not shake. Let it dissolve completely.
Verify the concentration matches what you entered in the calculator.

For a detailed walkthrough, see how to reconstitute peptides.

Storage

Reconstituted peptide vials are generally stored refrigerated and protected from light. Unreconstituted lyophilized powder is stable at room temperature until the expiration date on the vial. Track the reconstitution date so you know how long a given vial has been mixed.

Why the water volume matters

The same dose can be drawn at very different unit marks depending on how much water goes into the vial:

3 mg dose from a 10 mg vial:

Water added	Concentration	Draw volume	Units
1 mL	10 mg/mL	0.3 mL	30 units
2 mL	5 mg/mL	0.6 mL	60 units

Neither is "wrong" — the math is identical either way. The calculator shows the units for any water volume so you can choose the draw size that's easiest to read accurately on your syringe.

Common mistakes

Confusing mg and mcg. TB-500 vials and doses are generally described in milligrams (mg), not micrograms (mcg) — unlike some other repair peptides. Double-check your units before drawing.
Shaking the vial. Swirl gently instead — shaking can degrade the peptide.
Not scaling the water to the vial size. Using the same water volume across a 5 mg and a 10 mg vial produces different concentrations. Recalculate for each vial size rather than reusing a number from memory.
Using a non-U-100 syringe. The calculator assumes a standard U-100 insulin syringe (100 units = 1 mL). If your syringe is marked differently, the unit conversion will not match.

Use the TB-500 dosage calculator

Enter your TB-500 vial size, bacteriostatic water volume, and target dose into the free peptide calculator to see the exact syringe units. Reverse mode also works — enter your target dose and the units you want to draw, and it tells you how much water to add.

For related math, see the BPC-157 dosage calculator guide, the GHK-Cu reconstitution calculator guide, or the general how to reconstitute peptides walkthrough. The calculator handles the math. This guide explains what the numbers mean.