What reconstitution ratio is commonly used for TB-500?

A common reference ratio is 1 mL of bacteriostatic water per 10 mg of TB-500, which holds the concentration at 10 mg/mL whether the vial is 5 mg or 10 mg. It is a reference point, not a required ratio — the calculator works for any ratio you choose.

How do I turn a reconstitution ratio into syringe units?

First divide the vial's mg by the water volume to get mg/mL concentration. Then divide your target dose by that concentration to get a draw volume in mL. Multiply by 100 to get units on a U-100 insulin syringe. The calculator does all three steps at once.

Does a higher reconstitution ratio mean a stronger dose?

No. The ratio changes the concentration and therefore the draw volume, not the total amount of TB-500 in the vial or the dose you're targeting. A 2 mg dose is 2 mg regardless of whether the vial was mixed at 5 mg/mL or 10 mg/mL — only the number of units it takes to draw that 2 mg changes.

Can I change the reconstitution ratio after a vial is already mixed?

No. The ratio is set the moment water is added and can't be adjusted afterward without adding more water, which most protocols don't call for. Decide the ratio before reconstituting, using the calculator to check that your typical dose lands on a syringe reading you can measure accurately.

TB-500 Reconstitution Ratio Calculator

By PeptCalc — Medically reviewed by David Mansour, MD — Last reviewed July 15, 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. Before the powder can be measured into a dose, it has to be dissolved at a chosen reconstitution ratio — a set amount of water per mg of peptide. This reference explains what that ratio means, how a TB-500 reconstitution ratio calculator converts it into syringe units, and how to pick a ratio that reads cleanly on your syringe. It is written for research purposes only and is not medical advice.

What a reconstitution ratio is

A reconstitution ratio is the amount of liquid added per unit of peptide mass — for example, "1 mL of water per 10 mg of TB-500." The ratio sets the concentration in mg/mL, and concentration is what turns a target dose into a specific syringe reading. Two vials holding the same total mg of TB-500 can require very different draw volumes if they were mixed at different ratios.

What the calculator does

The peptide reconstitution calculator runs the ratio math in two directions:

Forward mode — enter vial size and water volume (which together define your ratio), plus a target dose → it returns the syringe units to draw.
Reverse mode — enter vial size, target dose, and the syringe units you want to land on → it tells you the water volume, and therefore the ratio, that gets you there.

Both modes reduce to the same two equations: concentration equals mass divided by volume, and units on a U-100 syringe equal draw volume in mL times 100.

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.

Common TB-500 reconstitution ratios

There is no single required ratio. The table below shows how different water volumes change the concentration for a 10 mg vial:

Ratio (water per 10 mg)	Concentration
0.5 mL	20 mg/mL
1 mL	10 mg/mL
2 mL	5 mg/mL

A commonly used reference point scales the water to the vial size at 1 mL per 10 mg, holding concentration at a constant 10 mg/mL across vial sizes:

Vial size	Water at a 1 mL-per-10 mg ratio	Concentration
5 mg	0.5 mL	10 mg/mL
10 mg	1 mL	10 mg/mL

Because that ratio is fixed, the units for a given dose stay the same whether the vial is 5 mg or 10 mg — only the number of full doses the vial holds changes.

The math

Step 1: Turn the ratio into a concentration

Concentration = vial mass ÷ water volume

10 mg vial + 1 mL water (a 1:10 mg-per-mL ratio) = 10 mg/mL
10 mg vial + 2 mL water (a 1:5 mg-per-mL ratio) = 5 mg/mL
10 mg vial + 0.5 mL water (a 1:20 mg-per-mL ratio) = 20 mg/mL

Step 2: Convert dose to volume

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

Example: 2 mg dose at 10 mg/mL concentration = 2 ÷ 10 = 0.2 mL

Step 3: Convert volume to syringe units

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

Units = volume (mL) × 100

Example: 0.2 mL × 100 = 20 units

The calculator performs these three steps instantly for any ratio you enter.

Choosing a ratio for your syringe

The same 2 mg dose reads very differently depending on the ratio used to mix the vial:

Ratio	Concentration	Draw volume for 2 mg	Units
1 mL per 10 mg	10 mg/mL	0.2 mL	20 units
2 mL per 10 mg	5 mg/mL	0.4 mL	40 units
0.5 mL per 10 mg	20 mg/mL	0.1 mL	10 units

None of these ratios is wrong — the total dose is identical at 2 mg in every row. What changes is how many units it takes to draw it, and how sensitive that reading is to a small measurement error. A ratio that lands your usual dose on a round, mid-barrel number (10 or 20 units rather than 3 or 47) is generally easier to draw accurately and easier to double-check by eye.

Reconstitution process

Gather supplies — the TB-500 vial, bacteriostatic water, U-100 insulin syringes, alcohol swabs.
Swab both vial stoppers with alcohol.
Draw the water volume your chosen ratio calls for (e.g. 1 mL for a 10 mg vial at a 1 mL-per-10 mg ratio).
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 into the calculator.

For the general reconstitution steps that apply to any peptide vial, 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.

The step where the actual error happens

Our position is that dosing errors trace to the reconstitution math, not the injection itself. A U-100 syringe's scale — 100 units per mL — never changes; what changes is the concentration created by the ratio you choose, and that arithmetic is fixed regardless of which peptide is in the vial. Picking a ratio and then not recalculating when the vial size or water volume changes is where a correct dose turns into an incorrect syringe reading.

Common mistakes

Reusing a ratio across different vial sizes without recalculating. A ratio expressed as "1 mL per 10 mg" scales — 0.5 mL for a 5 mg vial, 1 mL for a 10 mg vial. Adding a flat 1 mL to both changes the concentration on one of them.
Confusing the ratio with the dose. The ratio sets concentration; it does not change how much TB-500 is in the vial or how much the target dose delivers.
Shaking the vial. Swirl gently instead — shaking can degrade the peptide.
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 calculator

Enter your TB-500 vial size and water volume into the peptide reconstitution calculator to see the resulting ratio, concentration, and syringe units for any target dose. Reverse mode works the other way — enter your target dose and the units you want to draw, and it returns the water volume and ratio that produce that reading.

For related math, see the TB-500 dosage calculator, the BPC-157 dosage calculator, the bacteriostatic water calculator, or the reverse peptide calculator for BAC water guide. The calculator handles the math. This guide explains what the ratio means.