Advances in hydrogen therapy and hydrogen administration biomaterials for respiratory diseases

Molecular hydrogen has emerged as a promising therapeutic agent in respiratory medicine owing to its antioxidative, anti-inflammatory and immunomodulatory properties. Its visibility during the SARS-CoV-2 outbreak demonstrated its potential, but the significance of hydrogen therapy extends far beyond a single infection. This review examines pathological features shared across respiratory diseases, with emphasis on viral infections exemplified by SARS-CoV-2, and summarizes advances in hydrogen administration, its biological effects and therapeutic mechanisms. Particular consideration is given to biomaterial-assisted delivery strategies that enable sustained and targeted release in the lung. Clinical studies, including examples from COVID-19, provide evidence for the therapeutic potential of molecular hydrogen and its capacity to support recovery in respiratory diseases. Established administration routes such as inhalation, hydrogen-rich water and hydrogen-enriched saline have been evaluated in both preclinical and clinical settings, while emerging biomaterials provide platforms for controlled release and pulmonary targeting. Future development of hydrogen therapy in respiratory medicine is discussed, with particular focus on optimizing delivery strategies, establishing dose-effect relationships and strengthening long-term clinical evaluation.