TB-500 Reconstitution Calculator: BAC Water, mL and Units

Pick your TB-500 vial size and enter how much water you add to see the concentration and how much is in each unit on a U-100 syringe. Enter an amount and it also gives the units to draw. Quick picks are shortcuts for vial sizes; always use the amount printed on your own vial.

TB-500 reconstitution table

What different amounts of water give you, for each quick-pick vial size. This is arithmetic, not a recommendation: the right amount of water is whatever makes your measurements easy and matches any instructions you were given.

TB-500 concentration by vial size and water added, on a U-100 syringe
Vial	Water	Concentration	Per unit (0.01 mL)	Per 10 units (0.1 mL)
5 mg	1 mL	5 mg/mL	50 mcg	500 mcg
5 mg	2 mL	2.5 mg/mL	25 mcg	250 mcg
5 mg	3 mL	1.67 mg/mL	16.67 mcg	167 mcg
10 mg	1 mL	10 mg/mL	100 mcg	1 mg
10 mg	2 mL	5 mg/mL	50 mcg	500 mcg
10 mg	3 mL	3.33 mg/mL	33.33 mcg	333 mcg

How the math works for TB-500

A 10 mg TB-500 vial holds 10,000 mcg. Mixed with 2 mL of water, that's 10,000 ÷ 2 = 5,000 mcg per mL. One unit on a U-100 syringe is 0.01 mL, so each unit holds 50 mcg. More water spreads the same 10 mg across more units; less water packs it into fewer.

Concentration (mcg per mL) = vial (mg) × 1,000 ÷ water (mL)
mcg per unit = concentration ÷ 100
Units to draw = amount (mcg) ÷ mcg per unit

A peptide vial label with the vial size circled. The mg number is the total amount in the vial, and 1 mg equals 1,000 mcg — Use the mg number printed on your own TB-500 vial, not the quick-pick size, if they differ.

What is TB-500?

TB-500 is a synthetic fragment of thymosin beta-4, a protein the body makes naturally. The FDA's 2026 notice lists it as "Thymosin Beta-4, Fragment (LKKTETQ)".

Frequently asked questions

How much water do I add to a 10 mg TB-500 vial?

There's no single right amount. Less water makes each unit stronger and harder to measure; more water makes each unit weaker and easier to measure. For a 10 mg vial, 1 mL gives 100 mcg per unit, 2 mL gives 50 mcg, and 3 mL gives 33.33 mcg. If your TB-500 was prescribed, use the amount in your prescription instructions.

How many mcg of TB-500 are in one unit?

It depends on the vial size and how much water you add: mcg per unit = (mg in the vial × 1,000) ÷ (mL of water × 100). With a 10 mg vial and 2 mL of water, that's 50 mcg per unit on a U-100 syringe.

Is TB-500 FDA approved?

No. TB-500 isn't an FDA-approved drug. Removed from Category 2 in April 2026. Recommended for the 503A bulks list on July 23, 2026, against FDA staff's recommendation.

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General reconstitution calculator · Peptide FDA status tracker