Molecular hydrogen is a colorless, tasteless, biologically active small-molecule gas with reducing properties, demonstrating therapeutic and preventive effects across various human systems. Its mechanisms of action include selective antioxidation, anti-inflammatory effects, apoptosis inhibition, and the regulation of gene expression and signaling pathways. In the skin, molecular hydrogen reduces oxidative damage by scavenging free radicals and inhibiting oxidative stress, leading to improvements in texture and tone. It also regulates the inflammatory response, alleviating redness, itching, and discomfort, while promoting skin repair and regeneration. Moreover, hydrogen activates antioxidant enzymes in skin cells, boosting their antioxidant capacity and delaying aging. Clinical trials show that molecular hydrogen significantly improves conditions like acne, chloasma, and skin sensitivity. However, research in skin cosmetology remains in its early stages, with unanswered questions regarding mechanisms of action, optimal dosage, and long-term safety. Further investigation through clinical trials is essential for expanding its applications in this field. Molecular hydrogen holds significant promise in skin cosmetology, and as research and technology evolve, it is expected to drive innovations and breakthroughs in skin care. This review examines the therapeutic potential, mechanisms, and clinical applications of molecular hydrogen in skin cosmetology, addressing challenges and proposing pathways for future advancements in this field.