What TB-500 is
TB-500 is the synthetic active fragment (LKKTETQ) of thymosin beta-4, a protein involved in actin regulation and cell migration. Animal studies point at systemic effects on soft-tissue repair, which is why the community treats it as the whole-body counterpart to BPC-157's more local reputation. It is unapproved everywhere and banned in tested sport.
What we do not know
- Human trials exist for full-length thymosin beta-4, not for the TB-500 fragment. The two are routinely treated as interchangeable and have not been shown to be.
- No published human pharmacokinetics for the fragment.
- Banned in sport by WADA, which constrains the human data that would otherwise have been generated in athletes.
Reconstitution math
Concentration is everything: the same 5 mg vial gives a different draw for every amount of bacteriostatic water you add. The table uses the common 2 mL setup for each vial size, which puts every unit on a U-100 insulin syringe at 25 mcg for the default vial. Dashes mark draws too small to measure or larger than the syringe.
| Vial | BAC water | Concentration | 2 mg | 2.5 mg | 5 mg |
|---|---|---|---|---|---|
| 2 mg | 2 mL | 1 mg/mL | - | - | - |
| 5 mg | 2 mL | 2.5 mg/mL | 80 u | 100 u | - |
| 10 mg | 2 mL | 5 mg/mL | 40 u | 50 u | 100 u |
Dosing and protocol
Community loading: about 2 to 5 mg twice weekly for 4 to 6 weeks, then maintenance every 1 to 2 weeks.
Community protocols load with roughly 2 to 5 mg per week, usually split into two injections, for four to six weeks, then drop to a maintenance dose every one to two weeks. These are milligram doses with comfortable draw volumes; the default 5 mg vial with 2 mL of water puts 2.5 mg at 100 units (a full 1 mL syringe), so many users add less water or split the draw.
Pharmacokinetics
No curve is shown, on purpose.
Human pharmacokinetics have never been formally characterized for TB-500. Rodent subcutaneous data suggest a half-life of roughly 1.5 to 3 hours. As with BPC-157, tissue-repair effects persist long after the peptide clears, so no concentration curve is shown.
How it is thought to work
A synthetic fragment of thymosin beta-4, the actin-binding region. Thymosin beta-4 itself regulates actin polymerization, cell migration and angiogenesis, and has been trialed in humans; TB-500 is the fragment, not the full protein.
What the evidence supports
This table grades how well each outcome has been studied in humans, not how well TB-500 works. A strong grade means the question was asked properly, and the answer may still have been negative. Nothing here is inherited from a drug class, a close analog, or the parent molecule of a fragment.
| Outcome | Strongest published evidence |
|---|---|
| Tissue repair (full-length thymosin beta-4) | Human, observational |
| Tissue repair (TB-500 fragment) | Animal only |
| Any outcome in humans from the fragment | No data |
Storage and handling
Lyophilized vials keep best cold, dark, and dry; refrigeration is the community default and freezing lyophilized powder is common for long holds. After reconstitution, refrigerate at 2 to 8 C, do not freeze the solution, and date the vial. Bacteriostatic water's preservative keeps multi-dose use practical for about 28 days by USP convention, though our 120-day stability study found the preservative itself outlasts that window.
Got a certificate of analysis with your vial? Run it through our COA Reader: it reads the report in plain English, checks purity and mass against the label claim, and links the testing lab’s own verification page. Our guide to reading a COA explains what the numbers do and do not tell you.
Sources
- Goldstein et al., Thymosin beta-4 in tissue repair, Ann N Y Acad Sci 2012
- Kwok et al., Doping control analysis of TB-500, J Chromatography B 2013