Is Selen useful for longevity?

Selenium is an essential trace element that supports antioxidant enzymes like glutathione peroxidases and thioredoxin reductases. Observational studies link low selenium status to higher all-cause mortality and age-related diseases. However, evidence for selenium supplementation extending lifespan in well-nourished individuals is limited. Large RCTs (e.g., SELECT) showed no benefit for cancer or cardiovascular prevention, and excess selenium can be toxic (selenosis). Effects depend on baseline status, genetic variants (e.g., in SELENOP, GPX1), and selenium form (organic vs. inorganic). For longevity, maintaining an optimal – not excessive – selenium level is prudent, assessable via whole blood or toenail analysis. Direct-to-consumer DNA tests for selenium-related SNPs are not clinically actionable. Conclusion: Selenium is a necessary cofactor for antioxidant defense, but not a proven longevity intervention. Supplementation should only be considered if deficiency is confirmed.