TB-500 Dosage Chart: Vial Size to Syringe Units

A TB-500 dosage chart maps a vial's labeled mg amount and the bacteriostatic water added to it into the number that actually matters at injection time: syringe units. TB-500 is the common research name for a synthetic peptide corresponding to a fragment of Thymosin Beta-4 (Tβ4), supplied as lyophilized powder. The mg amount on the label is fixed, but concentration is not — it depends on how much water goes into the vial. Unlike some other research peptides, TB-500 doses are typically described in milligrams, not micrograms, which changes the arithmetic slightly. This chart shows that math for the two most common TB-500 reference setups. It is a reference for research and educational purposes only and is not medical advice.

Two reference concentrations

There is no single required water volume for TB-500. The two setups below are common because researchers frequently reference a 10 mg vial mixed with either 1 mL or 2 mL of bacteriostatic water:

Vial size	Water added	Concentration
10 mg	1 mL	10 mg/mL
10 mg	2 mL	5 mg/mL

Both come from the same formula — concentration equals vial mass divided by water volume — applied to the same 10 mg vial at two different water volumes. Neither concentration is more correct than the other; adding twice the water simply halves the concentration. For the full mixing procedure, see the TB-500 dosage calculator guide.

TB-500 dosage chart by target dose

Each row below shows a target dose converted to draw volume and units on a U-100 insulin syringe (100 units per mL) at both reference concentrations:

Target dose	mL at 10 mg/mL	Units at 10 mg/mL	mL at 5 mg/mL	Units at 5 mg/mL
1 mg	0.1 mL	10 units	0.2 mL	20 units
2 mg	0.2 mL	20 units	0.4 mL	40 units
3 mg	0.3 mL	30 units	0.6 mL	60 units
4 mg	0.4 mL	40 units	0.8 mL	80 units
5 mg	0.5 mL	50 units	1.0 mL	100 units

Every row above lands on a whole unit at both concentrations, because 10 and 5 both divide evenly into these particular dose sizes. Note the bottom row: a 5 mg dose at 5 mg/mL draws the syringe's entire 1 mL, 100-unit capacity, which is one reason a more concentrated mix is often the easier one to work with for larger doses.

Reading the chart against a specific vial

Worked example. Take a 10 mg vial mixed with 1 mL of bacteriostatic water. Concentration is 10 ÷ 1 = 10 mg/mL. For a 4 mg target dose: 4 ÷ 10 = 0.4 mL. Converted to units on a U-100 syringe, 0.4 mL × 100 = 40 units.

Compare that to the same 4 mg dose from the same 10 mg vial mixed with 2 mL of water instead, at 5 mg/mL: 4 ÷ 5 = 0.8 mL, or 80 units. The dose in mg is identical in both cases. The unit count differs only because the vial was reconstituted to a different concentration — which is exactly what this TB-500 dosage chart is showing at every row.

Vial size sets dose count, water volume sets draw size

Vial size and water volume do different jobs, and conflating them is the most common misread of a chart like this one. Vial size sets the total mg of TB-500 available across the whole vial. Water volume sets concentration, which is what determines the units for any single draw.

At a 1 mg dose, a 10 mg vial provides 10 ÷ 1 = 10 doses. A 5 mg vial at the same 1 mg dose provides 5 ÷ 1 = 5 doses — half the doses, because it holds half the TB-500, not because it was mixed differently. Water volume, by contrast, changes only the draw size per dose, not how many doses the vial holds.

When your vial doesn't match either setup

A vial mixed with a different water volume still follows the same formula — it just won't land on either column in the chart above. A 10 mg vial mixed with 0.45 mL of water, for example, gives a concentration of roughly 22.2 mg/mL. A 1 mg dose at that concentration is 1 mg × 0.45 mL ÷ 10 mg = 0.045 mL, or 4.5 units — a half-unit reading that only works cleanly on a syringe marked in half-unit increments. On a standard whole-unit barrel, that's a signal to change the water volume rather than round the draw up or down.

This is the case the peptide reconstitution calculator is built for: enter the vial size and water volume you actually used, rather than searching a chart for a close match. It runs the same concentration-to-units math for any combination, not just the two shown here.

Common mistakes

• Reading a unit count from this chart against the wrong vial. A number in the 10 mg/mL columns only applies if your vial was actually mixed to that concentration. Confirm which water volume you used before drawing.
• Assuming vial size sets the dose. It sets the total mg available across the vial. Concentration — set by water volume — is what determines units per dose.
• Confusing TB-500's mg-scale dosing with mcg-scale peptides. TB-500 vials and doses are generally described in milligrams, not micrograms, unlike some other research peptides. Confirm the unit before doing any conversion.
• Rounding mid-calculation. Carry the full decimal through the mL step and only round the final unit reading, and only if the syringe requires it.

Use the calculator

This chart covers two common TB-500 concentrations, but your vial and target dose may not match either row exactly. Enter your vial size, water volume, and target dose into the peptide calculator for an exact unit count, or run its reverse mode to find the water volume that lands a given dose on a whole unit mark. For the units-per-mL relationship in more depth, see the TB-500 units per mL calculator guide.