Molecular hydrogen (H2) has emerged as a promising therapeutic agent with potential applications across a wide range of conditions, including neurological, cardiovascular, oncologic, and respiratory diseases. Substantial preclinical studies attribute its benefits to selective antioxidant, anti-inflammatory, and cytoprotective properties. Published clinical findings are encouraging, although data are limited by small sample sizes, methodological variability, and the absence of standardized and validated commercially available delivery systems. This narrative review summarizes the current clinical experience with inhaled H2 therapy, discusses key challenges and limitations in the existing literature, and identifies areas of interest for future research, including the development of a validated delivery system to enable broader clinical investigation and application of H2 therapy.
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