Silymarin as a promising antioxidant for sperm cryopreservation: a narrative review.

Background and objective: Sperm cryopreservation is a key technology in preserving male fertility, particularly for patients undergoing chemotherapy, radiotherapy, or those with compromised semen quality. However, the cryopreservation and thawing processes frequently lead to oxidative stress, resulting in significant deterioration of sperm motility, viability, morphology, and DNA integrity. This review explores the potential role of plant-derived antioxidants in mitigating cryodamage, focusing on silymarin-a polyphenolic flavonoid extracted from Silybum marianum. The objective is to evaluate the effect of silymarin on post-thaw sperm parameters in comparison to traditional antioxidants such as vitamin C and vitamin E.

Methods: This narrative review was conducted by systematically searching PubMed, Scopus, Web of Science, and ScienceDirect for publications between 2015 and 2025. Relevant studies examining the influence of silymarin and other antioxidants on sperm cryopreservation outcomes were identified and analyzed. Emphasis was placed on experimental models that assessed motility, viability, morphology, DNA fragmentation, and reactive oxygen species (ROS) levels.

Key content and findings: Findings suggest that all three antioxidants demonstrate potential in enhancing post-thaw sperm quality. However, silymarin consistently exhibited superior effects on sperm motility, membrane integrity, and antioxidant defense, particularly when used at optimized concentrations. Despite these promising results, clinical protocols for silymarin remain undeveloped.

Conclusions: Silymarin shows promise as a multifunctional antioxidant for improving post-cryopreservation sperm quality. Its incorporation into assisted reproductive technology (ART) protocols may enhance reproductive outcomes. Further clinical research is needed to validate its efficacy and determine optimal dosing for human applications.