TB-500 Reconstitution Calculator

TB-500, supplied here as full-length thymosin beta-4 (43 amino acids, N-acetylated), comes as a lyophilized powder in 5 and 10 mg vials. The calculator uses its molecular weight (4,963.4 g/mol) to report molar concentration alongside mg/mL. Enter the vial size and the volume of bacteriostatic water added to get the concentration, the amount in any measured volume, and how many aliquots a vial yields. For other compounds, use the general peptide calculator.

TB-500 calculator

—Concentration

—per 0.1 mL (100 µL)

—molar concentration (MW 4,963.4 g/mol)

This tool does solution-concentration arithmetic for laboratory preparation records. It does not provide dosage guidance. TB-500 is sold for research use only. It is not for human consumption, self-administration or therapeutic use.

TB-500 vial concentration table

Worked math for each TB-500 vial size in the catalog (5 mg, 10 mg) with 1, 2 and 3 mL of diluent. The figures come straight from concentration = mass ÷ volume. They are reference arithmetic, not a recommended preparation.

Vial	Diluent	Concentration	Per 0.1 mL	Molarity
TB-500 5 mg	1 mL	5 mg/mL	500 mcg	1.01 mM	Load ↑
TB-500 5 mg	2 mL	2.5 mg/mL	250 mcg	504 µM	Load ↑
TB-500 5 mg	3 mL	1.667 mg/mL	166.7 mcg	336 µM	Load ↑
TB-500 10 mg	1 mL	10 mg/mL	1,000 mcg	2.01 mM	Load ↑
TB-500 10 mg	2 mL	5 mg/mL	500 mcg	1.01 mM	Load ↑
TB-500 10 mg	3 mL	3.333 mg/mL	333.3 mcg	672 µM	Load ↑

TB-500 compound data used in the math

Compound class	43-amino-acid acetylated polypeptide (thymosin beta-4)
Molecular weight	4,963.4 g/mol
Molecular formula	C₂₁₂H₃₅₀N₅₆O₇₈S
CAS number	77591-33-4
Appearance	White to off-white lyophilized powder; clear, colorless solution
Storage	Lyophilized: −20 °C, desiccated, protected from light. Reconstituted: aliquot and hold at −20 °C or below.
Vial sizes	5 mg, 10 mg

Molar concentration (mM) = concentration (mg/mL) ÷ molecular weight (g/mol) × 1000. Every product ships with a certificate of analysis. See the TB-500 product page or the COA portal.

TB-500 reconstitution handling notes

Thymosin beta-4 is highly water-soluble. Add the diluent slowly down the vial wall and swirl. Vigorous shaking can foam and shear the peptide.
A 5 mg vial in 2.5 mL gives a round 2 mg/mL, which is 200 mcg per 0.1 mL. This is a convenient reference point for checking hand calculations.
Divide the solution into single-use aliquots and freeze them if it will be used over several weeks, so the stock is not repeatedly freeze-thawed.

For the full bench procedure, including materials, technique, blend vials and storage before and after, see how to reconstitute peptides.

How to reconstitute TB-500

The worked example uses a 10 mg TB-500 vial and 2 mL of bacteriostatic water. The same steps apply to any vial size or volume; only the resulting concentration changes.

Equilibrate and sanitize. Let the TB-500 vial and the bacteriostatic water reach room temperature, then wipe both rubber stoppers with an alcohol swab.
Draw the diluent. With a sterile syringe, withdraw 2 mL of bacteriostatic water.
Add it slowly down the wall. Insert the needle through the TB-500 vial’s stopper and let the water run down the inside of the glass, not directly onto the powder.
Swirl, don’t shake. Rotate the vial gently until the solution is completely clear and colorless. Cloudiness or particles after gentle mixing are a reason to check the lot’s certificate of analysis.
Label and store. Write the concentration on the vial: 10 mg ÷ 2 mL = 5 mg/mL (1.01 mM), plus the date and lot number. Storage: Lyophilized: −20 °C, desiccated, protected from light. Reconstituted: aliquot and hold at −20 °C or below.

TB-500 reconstitution FAQ

What concentration does a 5 mg TB-500 vial make with 2 mL of bacteriostatic water?

5 mg divided by 2 mL is 2.5 mg/mL, which is 250 mcg in every 0.1 mL. Using TB-500’s molecular weight of 4,963.4 g/mol, that is a molar concentration of 504 µM.

How much TB-500 is in 0.1 mL after reconstitution?

It depends entirely on the concentration prepared. For example, a 10 mg vial reconstituted with 2 mL gives 5 mg/mL, so 0.1 mL contains 500 mcg. The same vial reconstituted with 1 mL would give twice that per 0.1 mL.

Does adding more bacteriostatic water change how much TB-500 is in the vial?

No. The diluent volume only sets the concentration. The total TB-500 in the vial is the same whatever volume is added. More diluent spreads it across a larger volume, so any given amount takes up more mL and is easier to measure accurately.

How should reconstituted TB-500 be stored?

Lyophilized: -20 °C, desiccated, protected from light. Reconstituted: aliquot and hold at -20 °C or below. Label the vial with the compound, lot number, date and the concentration calculated here.