What role does Selen play in fertility?

Selenium is an essential trace element that acts as a cofactor for selenoproteins (e.g., glutathione peroxidases, thioredoxin reductases) involved in antioxidant defense and thyroid hormone metabolism. In fertility, selenium supports sperm maturation, motility, and protects oocytes from oxidative damage. Observational studies suggest low selenium levels may be associated with reduced fertility in both men and women, but evidence from large randomized controlled trials is lacking. The evidence level is moderate, based on mechanistic and epidemiological data. Selenium supplementation should be approached cautiously because excess intake can cause selenosis (toxic effects). The provided MyBody-X context does not directly address selenium and fertility; it focuses on DNA tests, microbiome, and general nutrition. Therefore, while selenium is biologically plausible for fertility support, consumers should not rely on direct-to-consumer tests alone and should consult a healthcare provider for personalized assessment.