A short fragment of thymosin beta-4 promoted for recovery. FDA has found no human exposure data for compounded use.
Key takeaway
TB-500 is a seven-amino-acid fragment of thymosin beta-4, a protein involved in cell movement and tissue repair. It is often sold in blends with BPC-157.
At a glance
| FDA status | Not FDA-approved |
|---|---|
| 503A compounding | No 503A pathway: nomination withdrawn after FDA safety review |
| Body areas | Muscle, joints & recovery, Skin & hair |
| Through ScriptMates | Information only |
| Open questions | None noted |
What is TB-500?
TB-500 is a seven-amino-acid fragment of thymosin beta-4, a protein involved in cell movement and tissue repair. It is often sold in blends with BPC-157.
FDA reports it has not identified human exposure data for the proposed routes and has concerns about aggregation and impurities.
Dosage forms
No FDA-approved dosage form. A standardized dosage form for human use was not confirmed from the sources below.
Is TB-500 FDA-approved?
Not FDA-approved. Thymosin beta-4 fragment (TB-500) was nominated for the 503A bulks list and placed in Category 2 over safety concerns; the nomination was later withdrawn. FDA notes it has no, or only limited, safety information for the proposed uses.
Can it be prescribed through ScriptMates?
No 503A pathway: nomination withdrawn after FDA safety review. A partner pharmacy lists it, but it has no lawful 503A pathway today (nomination withdrawn after FDA safety review).
Sources
- FDA: Bulk substances that may present significant safety risks (Category 2 and withdrawn nominations)
- FDA: Bulk drug substances nominated under 503A, Categories 1–3 (May 14, 2026)
Checked October 27, 2026. FDA updates these pages, so confirm before relying on them.