The critical role of oxidative stress in male infertility: causes, diagnostic biomarkers, and the efficacy of antioxidant therapy.

Male infertility is a significant global health concern, impacting approximately 15% of couples attempting to conceive, with male-related factors accounting for nearly 50% of these cases. A key underlying mechanism increasingly recognized by researchers is oxidative stress—the disruption between reactive oxygen species (ROS) and the body’s ability to neutralize them with antioxidants. While low levels of ROS are necessary for normal sperm functions such as maturation and fertilization, excessive ROS accumulation—driven by conditions like varicoceles, infections, or exposure to tobacco, alcohol, radiation, and environmental toxins—can lead to significant sperm damage. This includes fragmented DNA, reduced motility, and impaired mitochondrial function, all of which hinder fertility potential. This comprehensive analysis, drawing on research published between 2000 and 2025, identifies key oxidative stress biomarkers, including malondialdehyde (MDA), 8-hydroxy-2’-deoxyguanosine (8-OHdG), and total antioxidant capacity (TAC), as valuable tools for assessing sperm health and diagnosing oxidative imbalance. These indicators offer essential insights into the biological mechanisms behind male infertility and hold significant promise for clinical application. Various antioxidant supplements—such as vitamins C and E, selenium, zinc, carnitine, coenzyme Q10, lycopene, and folic acid—have shown potential in improving semen parameters by counteracting oxidative damage. However, clinical outcomes remain inconsistent, largely due to variability in dosing strategies, treatment length, and individual patient responsiveness. Additionally, the absence of standardized testing methods for measuring oxidative stress in clinical settings hinders early diagnosis and the development of customized treatment plans. To advance the field, there is an urgent need to establish clearer biomarker reference ranges, implement consistent diagnostic criteria, and develop antioxidant treatment protocols grounded in robust clinical evidence. Integrating these advancements into routine medical practice could transform the approach to male infertility, enabling earlier identification of at-risk men and more personalized therapeutic interventions. By aligning scientific discoveries with real-world healthcare delivery, clinicians may offer renewed hope to couples facing fertility struggles. Ongoing, rigorous research remains essential to convert current knowledge into practical, effective treatments that improve reproductive outcomes.