Thymosin Beta-4

Also known as: TÎ²4, Thymosin Î²4, RGN-259

Evidence Tier B-Cmed-high riskintermediateinvestigational

Actin-sequestering peptide with clinical data in ophthalmic wound healing and preclinical tissue repair.

WADA S2

This substance falls under WADA S2 (Peptide Hormones, Growth Factors, Related Substances and Mimetics). If you are subject to anti-doping rules, this category of substances is prohibited at all times.

FDA Safety Flag

The FDA has identified this substance as one that may present significant safety risks when used in compounding, including concerns about immunogenicity, impurity characterization, and/or insufficient safety information.

Overview

Thymosin beta-4 is a 43-amino-acid peptide involved in cell migration, angiogenesis, and tissue repair. Clinical ophthalmic studies using topical 0.1% formulations (RGN-259) report safety and improved epithelial healing in corneal disorders. Systemic claims have weaker clinical grounding. WADA classifies thymosin-Î²4 derivatives under growth factor modulators.

Research Details

Mechanism of Action

Actin-sequestering protein with roles in cell migration, angiogenesis, and tissue repair across multiple active domains.

Study Dose Range

Clinical ophthalmic: topical 0.1% formulation. Systemic dosing not well established in humans.

Administration Routes

topical, subcutaneous

Onset / Timeline

Corneal healing studies: days to weeks; systemic repair claims are less well-timed.

Expected Effects

Ophthalmic: improved corneal epithelial healing. Systemic: wound healing signals in preclinical models.

Adverse Effects

Human ophthalmic safety reported as acceptable in trials; systemic safety requires caution.

Contraindications

Limited formal contraindication data.

Interaction Notes

Limited formal interaction studies; treat as unknown outside studied settings.

Related Goals

Tissue Repair & RecoveryImmune Support

Known Interactions

caution with TB-500

TB-500 is often described as a thymosin beta-4 fragment/region; must confirm exact sequence and avoid mixing fragment vs full-length assumptions.

caution with BPC-157

Commonly co-marketed; limited interaction evidence; treat as uncertain.

Available From

No vendors currently listed for this peptide.

Frequently Compared

BPC-157

Preclinical cytoprotective peptide studied for tissue repair and GI protection in animal models.

Tier C

TB-500

Marketed thymosin beta-4 fragment (LKKTETQ actin-binding motif) studied for soft-tissue repair in preclinical models.

Tier C

MGF E-domain

IGF-1 splice variant peptide studied preclinically for muscle repair signaling.

Tier C

Thymosin Alpha-1

Immunomodulatory peptide approved in various countries with broader clinical literature than most RUO peptides.

Tier B

Information provided for educational and research reference only. Not medical advice. Not for diagnosing, treating, curing, or preventing disease. Products referenced are labeled Research Use Only (RUO) by vendors; not for human or veterinary use.