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Peptide profile · Musculoskeletal

TB-500

A synthetic fragment related to thymosin beta-4, marketed for tissue repair claims. Human clinical evidence is minimal, and it is prohibited in sport.

Research use only
GradeDPreclinical only
Last reviewed 2026-07-30Updated 2026-08-10

Quick facts

Classification
Synthetic peptide fragment of thymosin beta-4
Target / mechanism
Actin-binding and cell-migration pathways (proposed)
Development status
Preclinical; limited early-phase work on related full-length peptide
Regulatory status
Research use only
Evidence level
Preclinical only
Therapeutic area
Musculoskeletal / wound repair (proposed)
Route / formulation
Injectable preparations are marketed; none are approved

Also referred to as · Thymosin beta-4 fragment

What it is

TB-500 refers to a marketed synthetic fragment associated with thymosin beta-4, a naturally occurring actin-sequestering protein. TB-500 and thymosin beta-4 are not interchangeable in the evidence base.

How it works

Thymosin beta-4 is involved in actin regulation, cell migration, and angiogenesis in laboratory models. Whether the marketed fragment reproduces those effects at doses used outside research is not established.

What it has been studied for

  • Wound healing and corneal repair models (mostly the full-length peptide)
  • Cardiac and soft-tissue repair in animal models

Safety and side effects

No robust human safety data set exists for TB-500 as marketed. Product quality is a distinct and significant unknown.

Warnings and contraindications

Not approved for human use in any major jurisdiction.
Prohibited at all times in sport under WADA's growth-factor category.
Marketing claims about accelerated recovery are not supported by adequate human trials.

Compounded / research status

Almost exclusively sold as 'research use only'. This is a commercial category, not a safety assessment.

Investigational uses

Some clinical work exists on full-length thymosin beta-4 in ophthalmic and dermatologic indications; that literature should not be read as evidence for marketed TB-500 products.

Frequently asked questions

References

  • WADA Prohibited ListWorld Anti-Doping Agency
  • Thymosin beta-4 preclinical literaturePeer-reviewed scientific literature

Reference entries are editorial placeholders describing source type and origin. Primary documents are linked as each profile is expanded.

Editorial disclaimer

This site is educational and does not provide medical advice, dosing protocols, or treatment recommendations. Regulatory status and evidence strength differ sharply between compounds. A “research use only” label does not indicate that a product is appropriate for human use. Decisions about medicines belong with a qualified clinician.
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