TB-500 (Thymosin Beta-4)

Summary

TB-500 is a synthetic fragment of thymosin beta-4, an endogenous actin-binding protein involved in cell migration and wound repair. The published human trials are for topical eye use (dry eye, corneal healing); systemic use for sports injuries has no human trial support.

Mechanism

Thymosin beta-4 is a 43-amino-acid actin-binding protein found in nearly all cells. It sequesters G-actin monomers, regulating cytoskeletal dynamics, and thereby promotes cell migration, angiogenesis, and tissue remodeling. It also downregulates inflammatory mediators including pro-inflammatory cytokines and matrix metalloproteinases. 'TB-500' refers to a synthetic fragment marketed as a version of thymosin beta-4.

Reported effects

Ratings are relative to peers in the same category, not absolute claims.

Corneal wound healing★★★★☆Phase 3 trial of topical 0.1% solution showed improved healing in neurotrophic keratopathy.

Dry eye signs and symptoms★★★☆☆Phase 2 trials of topical drops showed significant improvements in corneal staining and symptoms.

Systemic musculoskeletal repair★☆☆☆☆Animal data only; no human trials of systemic use for injuries.

Studied dosing — research context

Published human trials used topical ophthalmic 0.1% thymosin beta-4 solution for eye indications. No published human trial has studied systemic injectable dosing for injury or recovery. This describes the state of the literature, not guidance.

Research context only. This is not a recommendation.

Safety

Topical thymosin beta-4 was well tolerated in eye trials with no serious adverse events attributed to treatment. There are no published human safety data for systemic (injectable) use, so its systemic risk profile is unknown. As an angiogenic modulator, theoretical concerns about effects on abnormal tissue growth have been raised but not tested in humans.

Limitations