Evidence check: Selen in the context of skin aging

Selenium is an essential trace element that acts as a cofactor for selenoproteins such as glutathione peroxidases and thioredoxin reductases, which protect cells from oxidative stress – a key driver of skin aging caused by UV radiation and environmental pollutants. Mechanistic and animal studies suggest adequate selenium supports collagen synthesis and may preserve skin elasticity. However, human evidence is limited: observational studies link low selenium status to increased skin aging, but robust randomized controlled trials are lacking. Supplementation in well-nourished individuals shows no proven benefit, and excessive intake (>400 µg/day) can cause selenosis (toxicity). Consumer DNA or blood tests for selenium can indicate status but do not provide clinically actionable insights for skin aging. Evidence grade: mechanistic. Recommendation: obtain selenium from dietary sources (Brazil nuts, fish, eggs); supplement only if deficiency is confirmed under medical supervision.