TB-500 Calculator — reconstitute a 2 mg, 5 mg or 10 mg vial and read mg per insulin unit.
A free TB-500 calculator built for the vial sizes research users actually reconstitute — 2 mg, 5 mg and 10 mg. Type the vial mass, pick a target concentration in mg/mL (or a target milligram dose per U-100 mark) and the calculator returns the volume of bacteriostatic water to add, the resulting mg/mL, the mg per insulin-syringe mark and the number of full doses per vial. Formula shown on every result.
Open the TB-500 calculator Use the general reconstitution calculator
Free TB-500 calculator
Solve for the bacteriostatic water volume, resulting concentration, milligrams per insulin-syringe mark and total doses in a TB-500 vial. Pick the 2 mg, 5 mg or 10 mg preset (or type your own mass), choose a target concentration in mg/mL or a target mg per U-100 mark, and read the result instantly with the formula on screen.
Result — TB-500 BAC water & dose per unit
What Is the TB-500 Calculator?
The TB-500 calculator on PeptideCalculatorTools.com is a small math tool built around the three vial sizes research users actually handle — 2 mg, 5 mg and 10 mg. It solves the four numbers every researcher has to check before drawing a dose: how much bacteriostatic water to add, the resulting concentration in mg/mL, the milligrams per insulin-syringe unit, and the total number of full doses the vial will yield.
It is a peptide-specific front end for our general peptide reconstitution calculator and BAC water calculator. The math is identical; the TB-500 page just presets the common vial sizes, dose range and unit (milligram, not microgram) so the typical workflow takes two clicks instead of five. If you need to mix TB-500 with another peptide in one vial — a routine "stack" with BPC-157, for example — the peptide mixing calculator covers that workflow.
How to Use the TB-500 Calculator
1. Pick the TB-500 vial mass
Click the 2 mg, 5 mg or 10 mg preset, or type any other vial mass in mg. The unit selector converts automatically between mg and µg. The default is 5 mg because that is the most commonly reconstituted TB-500 vial.
2. Choose a target concentration or a target milligram dose
Use By concentration when you know the mg/mL you want. The presets 1, 2, 2.5 and 5 mg/mL are listed because they cover the range that keeps the BAC volume inside a typical 5–10 mL vial and produces a readable mg/U number on a U-100 syringe. Use By units per dose when you already know the milligram per U-100 mark you want to draw — the calculator back-solves the concentration and the BAC volume. The presets in that mode are user-entered examples only, not recommended doses.
3. Read the TB-500 result
The result card lists BAC water volume in mL and µL, the resulting concentration, the milligrams per insulin-syringe mark, the dose volume per mark and the number of full doses the vial will yield. The animated pipette shows the BAC volume as a fraction of a 3 mL pipette. Use the action row to reset, copy a plain-text result, print a worksheet or copy a shareable URL with your inputs embedded.
How the TB-500 Math Works
Solving for BAC water by concentration
V = m ÷ c
V is the bacteriostatic water volume in mL. m is the TB-500 vial mass in mg (2, 5 or 10). c is the target concentration in mg/mL. Example: 5 mg ÷ 2 mg/mL = 2.5 mL BAC water. For µg and µg/mL inputs, the calculator converts to mg and mg/mL first.
Solving for BAC water by milligram per unit
Each U-100 insulin mark holds 0.01 mL; each U-50 mark 0.02 mL; each U-30 mark ≈ 0.033 mL. If you want d milligrams per mark, the required concentration in mg/mL is d ÷ vmark. Then BAC water = m ÷ c, exactly as above.
c = d ÷ vmark, then V = m ÷ c
Reading the mg/U on a U-100 syringe
With a resulting concentration of c mg/mL, each U-100 mark (0.01 mL) draws c × 0.01 mg. At 1 mg/mL you get 0.01 mg/U; at 2 mg/mL you get 0.02 mg/U; at 2.5 mg/mL you get 0.025 mg/U; at 5 mg/mL you get 0.05 mg/U. The same rule scales for U-50 (×2) and U-30 (×3.33).
Doses per vial
doses = floor(vial mass in mg ÷ dose per mark in mg). The floor comes from the fact that a partial last mark is not counted as a full dose. A 5 mg vial drawn at 0.05 mg/U on a U-100 syringe is 5 ÷ 0.05 = 100 full marks; a 10 mg vial at 0.25 mg/U is 10 ÷ 0.25 = 40 full marks.
TB-500 Vial Size vs BAC Water — Quick Reference
How much bacteriostatic water to add to a TB-500 vial at the most commonly cited research concentrations.
| TB-500 vial | 1 mg/mL | 2 mg/mL | 2.5 mg/mL | 5 mg/mL | 10 mg/mL |
|---|---|---|---|---|---|
| 2 mg | 2.0 mL | 1.0 mL | 0.8 mL | 0.4 mL | 0.2 mL |
| 5 mg | 5.0 mL | 2.5 mL | 2.0 mL | 1.0 mL | 0.5 mL |
| 10 mg | 10.0 mL | 5.0 mL | 4.0 mL | 2.0 mL | 1.0 mL |
Reconstitution volumes above 5 mL usually require a 10 mL vial. Reconstitution volumes below 0.5 mL are below the smallest accurate U-100 reading for many syringes, so a higher concentration may not be practical.
TB-500 Worked Examples
Example 1 — 5 mg vial at 2 mg/mL (Mathematical Example)
V = 5 ÷ 2 = 2.500 mL BAC water. Resulting concentration: 2.000 mg/mL. On a U-100 syringe, each mark draws 0.02 mg. Doses per vial at 0.5 mg per dose: 10. Doses per vial at 0.25 mg per dose: 20.
Example 2 — 10 mg vial at 2.5 mg/mL
V = 10 ÷ 2.5 = 4.000 mL BAC water. Resulting concentration: 2.5 mg/mL. Each U-100 mark draws 0.025 mg. Doses per vial at 0.25 mg per dose: 40.
Example 3 — 5 mg vial at 5 mg/mL
V = 5 ÷ 5 = 1.000 mL BAC water. Resulting concentration: 5 mg/mL. Each U-100 mark draws 0.05 mg. Doses per vial at 0.25 mg per dose: 20.
Example 4 — 10 mg vial at 1 mg/mL
V = 10 ÷ 1 = 10.000 mL BAC water. The required BAC volume exceeds a 5 mL vial — a 10 mL vial is needed. Resulting concentration: 1 mg/mL. Each U-100 mark draws 0.01 mg.
Example 5 — 10 mg vial targeting 0.05 mg/U on a U-100 syringe
Required concentration = 0.05 mg ÷ 0.01 mL = 5 mg/mL. V = 10 ÷ 5 = 2.000 mL BAC water. Each U-100 mark draws 0.05 mg. Doses per vial: 200.
Common TB-500 Reconstitution Mistakes
TB-500 (Thymosin Beta-4) is typically handled in milligram units, not microgram. Switching to µg by accident will give a result that is 1 000 × smaller than the mass printed on the vial. Read the unit selector on every calculation.
The calculator uses the value you enter. If the certificate of analysis states 10.4 mg with a stated overfill, type 10.4 — do not subtract the overfill yourself.
V = 10 ÷ 10 = 1 mL BAC water. The math is correct, but 1 mL is hard to handle accurately with a standard 3 mL syringe and the resulting solution is dense enough to be slow to draw.
A U-100 mark is 0.01 mL; a U-50 mark is 0.02 mL. The same 2 mg/mL solution gives 0.02 mg/U on U-100 but 0.04 mg/U on U-50. Pick the syringe in the calculator to match the physical syringe you are using.
TB-500 Calculator FAQ
What does the TB-500 calculator do?
It solves the reconstitution math for a TB-500 vial. You enter the vial mass (2 mg, 5 mg or 10 mg), pick a target concentration in mg/mL or a target milligram dose per U-100 mark, and it returns the BAC water volume, the resulting mg/mL, the mg per insulin mark and the number of doses per vial.
How much BAC water do I add to a 5 mg TB-500 vial?
5 mg ÷ 1 mg/mL = 5 mL; 5 mg ÷ 2 mg/mL = 2.5 mL; 5 mg ÷ 2.5 mg/mL = 2 mL; 5 mg ÷ 5 mg/mL = 1 mL.
How much BAC water do I add to a 10 mg TB-500 vial?
10 mg ÷ 1 mg/mL = 10 mL; 10 mg ÷ 2 mg/mL = 5 mL; 10 mg ÷ 2.5 mg/mL = 4 mL; 10 mg ÷ 5 mg/mL = 2 mL; 10 mg ÷ 10 mg/mL = 1 mL.
How is the BAC water volume calculated?
V = m ÷ c, where V is the BAC water volume in mL, m is the TB-500 vial mass in mg, and c is the target concentration in mg/mL.
How is the milligram dose per U-100 mark calculated?
Each U-100 mark is 0.01 mL. With a resulting concentration of c mg/mL, each mark draws c × 0.01 mg. At 2 mg/mL you get 0.02 mg/U; at 5 mg/mL you get 0.05 mg/U.
Why does the calculator default to 2 mg/mL?
2 mg/mL is one of the most commonly cited TB-500 research concentrations — it produces a small, manageable BAC volume and an easy-to-read 0.02 mg/U number on a U-100 syringe. The default is a math example, not a recommended dose.
Can I switch from mg/mL to mg/U on the same calculator?
Yes. The mode toggle switches between By concentration (mg/mL) and By units per dose (mg per U-100 mark). Both modes use the same formula.
How many doses per vial will I get?
It depends on the dose per mark and the vial mass. The calculator divides the vial mass by the dose per mark. For example, a 5 mg vial drawn at 0.05 mg/U on U-100 yields 100 full marks.
Is this calculator medical advice?
No. The TB-500 calculator is a math tool. It does not provide medical advice, recommend a dose for any person, or model pharmacokinetics. The presets are user-input examples, not recommended doses.
Can I share my TB-500 inputs with someone else?
Yes. Click Copy share link. The button copies a URL with your vial mass, target concentration and syringe scale embedded; opening that URL restores the same values.
Related Peptide Calculators
The TB-500 calculator on this page performs mathematical conversions only. It does not give medical advice, recommend a dose for any person, or model pharmacokinetics. TB-500 (Thymosin Beta-4) is treated as a research peptide on this site. The preset values shown in the By units per dose mode are user-input examples only, not recommended doses. Read the full medical disclaimer and the site disclaimer.