TB-500
Also known as Thymosin Beta-4 fragment
A synthetic peptide related to thymosin beta-4, studied for cell migration and tissue repair.
Medically reviewed by Dr. Jonathan Snipes, MD
Reviewed for clinical accuracy · Last reviewed September 23, 2026 · Review policy
Quick answer
TB-500 is a synthetic peptide related to thymosin beta-4, a naturally occurring protein involved in cell migration and tissue repair. The full-length parent protein reached early human trials for wound and cardiac repair, but FDA found no human studies of TB-500 itself. TB-500 is not FDA-approved and is prohibited in sport; in July 2026 an FDA advisory committee recommended it for the 503A compounding list, but the FDA decision is pending.
- Type
- Synthetic thymosin beta-4 fragment
- FDA status
- Not approved; PCAC recommended for 503A list (FDA decision pending)
- Human evidence
- None for TB-500 itself; early trials of parent protein (TB4)
- Evidence grade
- D (Preclinical Only)
- Banned in sport
- Yes (WADA)
Key takeaways
- →TB-500 is marketed as a research version of thymosin beta-4 (TB4), a natural peptide central to cell migration and wound healing.
- →TB4 (the full-length, 43-amino-acid parent protein) reached early-phase human trials for wound, cardiac and corneal repair, but those results do not transfer to the 7-amino-acid TB-500 fragment. FDA found no human studies and no animal wound-healing studies of TB-500 itself, so we grade it D (Preclinical Only).
- →TB-500 the fragment is less directly studied in humans than TB4, and it is not FDA-approved.
- →It is prohibited in sport under WADA. FDA staff recommended against listing it, but at the July 23, 2026 PCAC meeting the committee voted to recommend TB-500 for wound healing, in a vote reported as 8-6 with 1 abstention. The vote is advisory and FDA has not yet acted.
- →As with BPC-157, the biggest practical risk is the unregulated research-chemical supply, where purity and dosing are unverified.
TB-500 is usually discussed alongside BPC-157 as a recovery peptide, but its evidence story is slightly different and worth separating carefully. TB-500 is a synthetic peptide related to thymosin beta-4 (TB4), a naturally occurring protein that plays a real, well-documented role in cell migration and tissue repair. The nuance is that most of the human research applies to TB4, not to the specific TB-500 fragment sold in the peptide market.
How TB-500 works
Thymosin beta-4 regulates actin, a protein essential to cell movement, which lets cells migrate to sites of injury and supports angiogenesis and tissue remodeling. TB-500 is a 7-amino-acid acetylated fragment of TB4 (residues 17 to 23) intended to reproduce its active region. In the one published lab test FDA found, TB-500 did not speed wound closure in cultured cells. The underlying biology is legitimate and studied; the open question is how faithfully the synthetic fragment reproduces it in humans, and at what dose and safety profile.
What the evidence shows, by use
Each use is graded on the same A-E scale, based on human-trial quality rather than popularity.
Wound and tissue healing
DPreclinical OnlyFull-length thymosin beta-4, a different and larger molecule, reached early-phase human trials for wound healing. Those results do not transfer to TB-500: FDA found no human studies and no animal wound-healing studies of TB-500 itself, and one lab study in which it had no effect on wound closure.
Cardiac and corneal repair
DPreclinical OnlyTB4 has been investigated in early human and animal studies for cardiac and corneal repair; results are preliminary and apply to the full-length protein, not the TB-500 fragment.
Athletic injury recovery
EAnecdotalPopular for this use based on user reports, but there is no controlled human trial supporting TB-500 for sports injury recovery.
Dosing
There is no FDA-approved TB-500 product and no validated human dosing. Protocols in circulation are derived from animal work and community practice. Given that most market supply is research-grade material of unverified purity, any use should be through a licensed clinician and legitimate pharmacy rather than research-chemical vendors.
Side effects
- •Injection-site reactions · Reported
- •Fatigue or lethargy · Reported
- •Head-rush or lightheadedness · Reported
- •Temporary flu-like feelings · Reported
Legal & regulatory status
TB-500 is not FDA-approved and is prohibited in sport. FDA staff recommended against listing it, but the PCAC voted on July 23, 2026 to recommend TB-500 for wound healing (reported as 8-6-1). The vote is advisory and FDA has not yet acted.
Is TB-500legal? Full regulatory status →Where to get it: TeleRanked independently ranks the telehealth providers that offer clinician-prescribed peptides. See our Peptide Therapy rankings. We rank providers, we do not sell compounds, and rankings are never for sale.
Frequently asked questions
Is TB-500 the same as thymosin beta-4?+
No. TB-500 is a synthetic 7-amino-acid fragment meant to reproduce the active region of thymosin beta-4 (TB4), a 43-amino-acid protein. The human research applies to TB4; FDA found no human studies of TB-500 itself.
Is TB-500 FDA-approved?+
No. TB-500 is not FDA-approved. In July 2026 an FDA advisory committee recommended it for the 503A compounding list, but the vote is advisory and the FDA decision is pending.
Is TB-500 banned in sport?+
Yes. TB-500 is prohibited under the WADA framework.
How we grade evidence
Grade D: Preclinical Only. Evidence is largely limited to animal or laboratory studies; human data is minimal or absent. Our A-E scale reflects the strength of human evidence, not how popular a compound is.
Sources
- 1.July 23-24, 2026: Meeting of the Pharmacy Compounding Advisory Committee · U.S. Food & Drug Administration
- 2.FDA briefing document: TB-500, Pharmacy Compounding Advisory Committee (July 2026) · U.S. Food & Drug Administration
- 3.WADA Prohibited List · World Anti-Doping Agency
- 4.Compounding and the FDA: Questions and Answers · U.S. Food & Drug Administration