Peptide reference
TB-500
Last reviewed · Written by the PepCycle team
TB-500 is a synthetic peptide related to thymosin beta-4, a naturally occurring protein involved in cell migration and actin regulation. It is supplied as a lyophilised powder, commonly in 2 mg, 5 mg or 10 mg vials, and reconstituted with bacteriostatic water. It is not an approved human medicine and is sold for research use only.
What TB-500 is
Thymosin beta-4 (Tβ4) is a naturally occurring 43-amino-acid protein found in most human cells, best known for binding actin and playing a role in cell migration and wound repair. TB-500 is the name used commercially for a synthetic peptide based on a short, biologically active region of that sequence — frequently a fragment around the actin-binding motif rather than the complete protein.
This distinction matters when you keep records. Products labelled "TB-500" and products labelled "Thymosin Beta-4" are not automatically the same molecule, and different suppliers do not always mean the same thing by either term. Record the exact label wording and the supplier in your log rather than normalising both to one name.
- Lyophilised
- Freeze-dried under vacuum. The peptide is frozen and the water removed by sublimation, leaving a dry, stable pellet or film that can be shipped without a cold chain and dissolved later. Almost every research peptide arrives in this form.
How it is supplied and stored
Like most research peptides, TB-500 arrives as a small white pellet in a stoppered glass vial. Because the pellet is tiny relative to the vial, an apparently "empty" vial is normal — the powder is often a barely visible film on the glass.
| Vial label | Peptide mass | In mcg | If reconstituted with 2 mL |
|---|---|---|---|
2mg | 2 mg | 2,000 mcg | 1,000 mcg per mL |
5mg | 5 mg | 5,000 mcg | 2,500 mcg per mL |
10mg | 10 mg | 10,000 mcg | 5,000 mcg per mL |
- Sealed lyophilised vials are the stable storage form; suppliers typically specify refrigeration or freezing, protected from light.
- Once reconstituted, the vial is refrigerated and has a much shorter usable window.
- Bacteriostatic water (0.9% benzyl alcohol) is the standard diluent for a vial you will access more than once.
- Record the reconstitution date on the vial itself as well as in your log — the physical label and the digital record should agree.
Units and the arithmetic
TB-500 entries are frequently recorded in milligrams rather than micrograms, simply because a typical entry is a larger fraction of the vial than with BPC-157. Either unit is fine as long as your log is internally consistent — mixing them across entries is what produces unreadable history.
The conversion chain is unchanged: vial mass ÷ water volume gives concentration; amount ÷ concentration gives volume in mL; volume × 100 gives U-100 syringe units. Run the numbers in the reconstitution calculator or the unit converter rather than doing them in your head at the counter.
Research context and status
The underlying protein, thymosin beta-4, has a genuine research literature: it has been studied in animal models of cardiac injury, corneal and skin wound healing, and has been evaluated in early-phase human trials for certain ophthalmic and dermatological indications by pharmaceutical developers. None of that literature transfers automatically to a synthetic fragment sold as a research chemical.
TB-500 itself has no approved human indication. It is listed as prohibited by anti-doping authorities, and has been the subject of enforcement action in animal sport, particularly horse racing. As with any unapproved compound, human safety data is absent rather than reassuring.
What to record
- Vial mass in mg, supplier, lot number and reconstitution date.
- Exact bacteriostatic water volume added.
- Amount per entry, in a unit you use consistently across the whole cycle.
- Injection site, rotated deliberately — see injection site rotation.
- Whether this compound was logged alongside others; if so, log each one separately rather than as a combined entry, unless it genuinely arrived pre-blended in one vial.
PepCycle handles TB-500 alongside other compounds without forcing them into one entry, so a stack stays legible: each compound keeps its own vial, its own concentration and its own schedule, while the calendar shows them together.
Frequently asked questions
Is TB-500 the same as thymosin beta-4?
Not usually. Thymosin beta-4 is a naturally occurring 43-amino-acid protein; TB-500 as sold is generally a shorter synthetic fragment based on part of that sequence. Because suppliers use the names inconsistently, record the exact label text and supplier in your log rather than treating the two as interchangeable.
How do I convert a TB-500 vial into syringe units?
Divide the vial mass by the volume of bacteriostatic water you added to get the concentration, divide your intended amount by that concentration to get millilitres, then multiply by 100 for U-100 insulin syringe units. The reconstitution calculator performs this arithmetic on the numbers you enter.
Can I mix TB-500 and BPC-157 in one vial?
Some suppliers sell pre-blended vials, which are logged as a single blend compound with per-component amounts. Combining two separately purchased vials yourself is a different situation with its own sterility and stability considerations, and it makes your record ambiguous. If a vial arrived as a blend, log it as a blend; otherwise keep the compounds separate.
Why does my vial look empty?
Because a few milligrams of freeze-dried peptide occupies almost no volume, and it often dries as a thin film rather than a visible pellet. An apparently empty vial is normal; hold it to the light at an angle before assuming a problem.
Related pages
Track TB-500 without re-doing the maths
Enter the vial once — mass, diluent volume, lot, date — and every entry after that converts automatically between mcg, mL and syringe units, with the vial counting down as you log.
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