Enter the vial size and the bacteriostatic water you added to get the concentration and the micrograms carried by each unit on a U-100 syringe. TB-500 has no established dose, and its compound page declines to recommend one, so this page does the arithmetic, not the recommendation. The compound itself is covered in the TB-500 guide.
A 10 mg vial of TB-500 reconstituted with 2 mL of bacteriostatic water gives a concentration of 5.0 mg/mL, or 50 mcg per unit on a U-100 syringe.
Defaults: 10 mg is the most common labelled vial among the TB-500 tests on file, 21 Sep 2026 (284 of 417); 2 mL was chosen for simple arithmetic and is not a sourced volume. Peptigrity publishes no TB-500 dose, so the dose field starts empty.
Draw the syringe up to
Enter your own amount to see the draw. Add 2 mL of water to your 10 mg vial first.
TB-500 has 417 independent lab tests on file at Peptigrity, averaging 99.40% HPLC purity across the tests that report one. Purity is not net content: a clean certificate confirms what is in a vial, not how much. See the TB-500 lab-test records.
TB-500 is a short synthetic fragment of thymosin β4 — the seven-residue Ac-LKKTETQ actin-binding motif — researched for tissue repair, wound healing and cardiac tissue recovery. The animal evidence is extensive; the human evidence for the fragment is not. No human trial has studied TB-500 itself, and a 2026 scoping review cited on the compound page found direct TB-500 evidence limited to a single included study. The TB-500 compound page declines to recommend a dose, and a calculator that printed one would be inventing the number the evidence does not supply.
The table sets out what the TB-500 compound page states (last updated August 2026) on the questions a calculator depends on.
| Question | What the compound page states | Evidence level |
|---|---|---|
| What is it? | A synthetic fragment of thymosin β4: the seven-residue Ac-LKKTETQ actin-binding motif (residues 17–23), about 889 Da | Chemical identity |
| Is it thymosin beta-4? | No. Thymosin β4 is the full 43-amino-acid parent protein, about 4,963 Da; most published efficacy research used the full protein | Chemical identity |
| Human studies? | None of the TB-500 fragment itself; full-length thymosin β4 (RGN-352) has Phase 2 data | Preclinical extensive |
| A route? | Not stated | Not stated |
| An approved dose? | Not approved for any medical indication anywhere in the world (as of August 2026) | None |
| A research dose? | None stated; the page declines to recommend one | None — declined |
The identity point has an arithmetic consequence. The compound page notes that some vendors sell one molecule mislabelled as the other, and that the roughly 4,000 Da mass gap between them is the cleanest identity check. A milligram is a milligram to this calculator, but a milligram of the ~4,963 Da protein holds fewer than a fifth as many molecules as a milligram of the ~889 Da fragment (889 ÷ 4,963 ≈ 0.18). The units below cannot tell you which one is in a vial; only a mass-spectrometry result on its certificate can.
The table converts reference quantities to syringe units at the default of 5.0 mg/mL (10 mg of TB-500 in 2 mL), and counts how many draws of each a vial holds. Every row is arithmetic, not a dose: read the units for the amount you already intend to measure.
| Quantity | Draw at 5.0 mg/mL | Volume | Draws from a 5 mg vial | Draws from a 10 mg vial |
|---|---|---|---|---|
| 250 mcg | 5.0 units | 0.05 mL | 20 | 40 |
| 500 mcg | 10.0 units | 0.10 mL | 10 | 20 |
| 1 mg | 20.0 units | 0.20 mL | 5 | 10 |
| 2.5 mg | 50.0 units | 0.50 mL | 2 | 4 |
| 5 mg | 100.0 units | 1.00 mL | 1 | 2 |
The same TB-500 quantity lands on a different mark depending on how much water went into the vial. Read down the column for the concentration you actually mixed; a units figure carried across from another column is simply wrong.
| Quantity | At 10 mg/mL (10 mg + 1 mL) | At 5.0 mg/mL (10 mg + 2 mL) | At 2.0 mg/mL (10 mg + 5 mL) |
|---|---|---|---|
| 250 mcg | 2.5 units | 5.0 units | 12.5 units |
| 500 mcg | 5.0 units | 10.0 units | 25.0 units |
| 1 mg | 10.0 units | 20.0 units | 50.0 units |
| 2.5 mg | 25.0 units | 50.0 units | — over a 1 mL barrel (125 units) |
| 5 mg | 50.0 units | 100.0 units | — over a 1 mL barrel (250 units) |
Every cell is the same arithmetic: units = (quantity in mg ÷ concentration in mg/mL) × 100 on a U-100 syringe. More water spreads the same mass over more units, which is the fix when a small quantity would otherwise sit at two or three units, where a one-unit misread is a large error.
Each TB-500 vial holds as many draws as its labelled mass divided by the quantity per draw; the water volume changes nothing about it. The grid counts draws, not weeks — this page states no frequency.
| Vial size | At 250 mcg | At 500 mcg | At 1 mg | At 2.5 mg | At 5 mg |
|---|---|---|---|---|---|
| 5 mg | 20 | 10 | 5 | 2 | 1 |
| 10 mg | 40 | 20 | 10 | 4 | 2 |
| 20 mg | 80 | 40 | 20 | 8 | 4 |
The labelled mass is not a guarantee of the mass in your vial: net content is a separate measurement from purity, and certificates on file often measure a few percent above or below the label.
No label sets a diluent volume for research-grade TB-500, and the compound page states none, so the volume is a choice. The decision with real consequences is range: at the default of 5 mg/mL a full 100-unit barrel holds 5 mg, and a small quantity drawn from a strong solution sits at a few units, where a one-unit misread is a large error. More water fixes the second problem and makes the first one worse. The technique is covered once, elsewhere: reconstituting peptides step by step and the bacteriostatic water guide. Storage and in-use guidance there is general peptide guidance, not a TB-500-specific finding.
The compound page lists TB-500 in four blends: BPC-157 + TB-500 + KPV, GLOW, KLOW and Wolverine. A blend vial carries a fixed ratio, so one draw measures every component at once and this single-compound converter is the wrong tool for it. Use the BPC-157 + TB-500 calculator for a two-compound vial, or the GLOW and KLOW calculators for those blends.
TB-500 is not approved for any medical indication anywhere in the world as of August 2026. On April 22, 2026 the FDA removed TB-500 from its Category 2 bulk drug substances list because the nomination had been withdrawn by the nominators; removal did not add it to the 503A bulks list or to Category 1, and does not by itself authorize compounding. At its July 23–24, 2026 meeting the FDA's Pharmacy Compounding Advisory Committee voted 8–6–1 to recommend TB-500 for the 503A compounding bulks list — an advisory recommendation only, which FDA scientific staff opposed and the agency has not finalized. Compounding stays unlawful under 503A pending formal rulemaking, not expected before 2027. The dated sequence is in the FDA peptide regulation timeline.
For tested athletes, TB-500 and thymosin β4 are prohibited by WADA at all times under S2.3 (Growth Factors and Growth Factor Modulators), in and out of competition, as of August 2026.
Independent test records: TB-500 lab tests. Tracked prices: TB-500 price per milligram.
It depends on the concentration. At the page default of 5 mg/mL (a 10 mg vial with 2 mL of water), 1 mg (1,000 mcg) is 20 units on a U-100 syringe, or 0.20 mL, and the vial holds 10 draws of that size. With 5 mL in the same vial (2 mg/mL) it is 50 units. A units figure quoted without a concentration cannot be used.
There isn't one. TB-500 is not approved for any medical indication, no human trial has studied the fragment itself, and the TB-500 compound page declines to recommend a dose; Peptigrity is an independent review platform, not a medical authority. This calculator converts a quantity you already have in mind into syringe units; it does not supply the quantity.
No. TB-500 is the seven-residue Ac-LKKTETQ actin-binding fragment (about 889 Da); thymosin beta-4 is the full 43-amino-acid parent protein (about 4,963 Da). They are different molecules, and most published efficacy research used the full-length protein. Only mass spectrometry on a certificate can confirm which one a vial holds.
It is sold as a research chemical for laboratory use in most jurisdictions but is not approved for human consumption. The FDA removed it from Category 2 on April 22, 2026 because the nomination was withdrawn, and in July 2026 the Pharmacy Compounding Advisory Committee voted 8-6-1 to recommend it for the 503A bulks list. That vote is advisory and has not been finalized, so compounding stays unlawful under 503A pending rulemaking (as of August 2026).
Yes. TB-500 and thymosin beta-4 are prohibited by WADA at all times under S2.3 (Growth Factors and Growth Factor Modulators), in and out of competition, as of August 2026.