Thymosin Beta-4

In this randomized, placebo-controlled, double-masked Phase III trial, a topical thymosin beta-4 ophthalmic solution (RGN-259) was evaluated in patients with neurotrophic keratopathy, a disease of impaired corneal epithelial healing. Treated subjects showed improvements in corneal epithelial defect healing and significant reductions in ocular discomfort, foreign body sensation, and dryness at multiple time points relative to placebo. No significant treatment-related adverse effects were reported. This represents one of the few controlled human datasets for Tb4, though it is a single small trial in a specific ocular-surface indication.

This human study tested Tb4 eye drops in people whose corneas do not heal properly (neurotrophic keratopathy). The drops helped close corneal wounds and eased discomfort and dryness compared with a placebo, without notable side effects. It is genuine human trial evidence, but limited to eye-surface disease rather than skin, muscle, or general body-wide use.

In embryonic and postnatal mouse cardiomyocytes, thymosin beta-4 promoted cell migration and formed a complex with PINCH and integrin-linked kinase (ILK), activating the survival kinase Akt/PKB. Following coronary artery ligation in mice, systemic and intracardiac Tb4 administration upregulated ILK and Akt activity, enhanced early myocyte survival, reduced scar volume, and improved cardiac function. The findings define a mechanistic pathway by which Tb4 acts as a cardioprotective and pro-migratory factor. This is an animal (mouse) study, not human evidence.

In mice with induced heart attacks, Tb4 helped heart muscle cells survive and migrate, activating protective cell-signaling pathways and improving heart function afterward. It is a widely cited foundational study explaining how the peptide might aid tissue repair. Importantly, these results are in mice and have not been confirmed to work the same way in humans.

Using a rat full-thickness skin wound model, topical or intraperitoneal thymosin beta-4 increased reepithelialization by 42% over saline controls at day 4 and up to 61% at day 7 post-wounding. Tb4 also stimulated keratinocyte migration 2-3-fold in Boyden chamber assays and increased wound angiogenesis and collagen deposition. The results support an actin-sequestering, pro-migratory mechanism driving faster dermal closure. This is a preclinical rodent and in vitro study.

In rats, applying Tb4 to skin wounds made them close noticeably faster, with more new blood vessels and better tissue rebuilding. Lab tests showed the peptide prompts skin cells to migrate into the wound. This is early animal and cell evidence; it does not by itself prove the same benefit in people.