GW788388 is primarily utilized in biomedical research due to its role as a potent and selective inhibitor of the TGF-β type I receptor kinase, also known as ALK5. This compound is extensively used in studies aimed at understanding the TGF-β signaling pathway, which plays a critical role in various cellular processes, including cell proliferation, differentiation, apoptosis, and extracellular matrix production. Researchers employ GW788388 to investigate its effects on fibrosis, cancer progression, and immune responses, as aberrant TGF-β signaling is implicated in these conditions. Additionally, it serves as a valuable tool in preclinical studies to explore potential therapeutic strategies targeting TGF-β-related diseases. Its specificity and efficacy make it a key compound in advancing the understanding of TGF-β biology and its implications in human health and disease.