TB-500
No human trials of TB-500. Limited human studies exist only for the full parent protein, in other forms.
At a glance. A fragment of a natural repair protein, widely used for recovery, with almost no direct evidence of its own. Sold by AVERON as TB-5.
Written and maintained by the AVERON Research Desk · Last reviewed September 2026
What it is
Thymosin beta-4 is a natural protein of 43 amino acids found in almost every cell. Its main role is regulating actin, the structural filament cells use to move and change shape, which is why it is involved in cell migration and tissue repair.
TB-500 is a synthetic fragment of thymosin beta-4, based on the short region of the protein thought to be responsible for its actin-binding activity. The name is used inconsistently in the market: some products sold as TB-500 are the short fragment, others are the full 43-amino-acid protein. They are different molecules.
Where BPC-157 is usually discussed for local effects, TB-500 is discussed for effects throughout the body.
What researchers study it for
Soft-tissue and muscle repair, wound healing, inflammation, and recovery of heart tissue after injury.
What the research shows
Most of the research concerns the full thymosin beta-4 protein, not the TB-500 fragment. In animal studies, thymosin beta-4 has been reported to support wound healing, the formation of new blood vessels and the repair of heart tissue after injury.
In people, the full protein has been tested mainly as eye drops for dry eye and corneal conditions, and as a topical gel for wounds, with mixed results. An injectable form entered early clinical development for heart attack patients but did not progress to approval.
A scoping review published in Applied Sciences in 2026 found that the evidence is weighted toward laboratory and animal studies and toward the full protein rather than TB-500 itself.
No controlled human trial of the TB-500 fragment has been published.
What it does not do, and what is not known
- There is no human trial of TB-500 for any use.
- Results for the full thymosin beta-4 protein cannot simply be applied to the fragment. They are different molecules.
- It does not work quickly, and it does not replace rehabilitation.
- Its long-term safety is unknown. Like BPC-157, it is associated with new blood vessel growth, which raises the same theoretical concern about existing tumours.
- Because the name is used for two different molecules, what a given product actually contains depends on testing.
Adverse effects reported in research
There is no systematic human safety data for the TB-500 fragment.
Regulatory and anti-doping status
Regulatory: Not approved as a medicine anywhere.
Anti-doping: Named explicitly on WADA's Prohibited List under category S2, which lists "thymosin-β4 and its derivatives, e.g. TB-500". Prohibited at all times in tested sport. It has also been detected in horse-racing doping cases.
At AVERON
Supplied as research-grade material under the name TB-5, 5 mg. A 10 mg vial is due in the next shipment.
Our independent testing distinguishes the full 43-amino-acid protein from a fragment, so the report shows which one the vial contains.
Independent lab report (5 mg): 99290_R39CVCUAH4CE. The 10 mg report will be published before it is sold.
Frequently asked questions
Doses mentioned on this page are the arms of published studies, given to describe their results. They are not guidance.