Myths vs facts: Selen and Müdigkeit

Selenium is an essential trace element that, as part of selenoproteins (e.g., glutathione peroxidases, thioredoxin reductases), plays a key role in antioxidant defense, thyroid metabolism, and immune function. Deficiency can indeed cause fatigue, muscle weakness, and cognitive impairment – this is supported by studies in populations with low selenium intake (e.g., certain regions of China, parts of Europe). However, clinically relevant selenium deficiency is rare in Western countries with a balanced diet. The myth often claims that selenium supplements generally relieve fatigue – this is not supported by randomized controlled trials (RCTs) in healthy individuals with normal selenium status. In fact, overdosing (selenosis) can itself cause fatigue, hair loss, and neurological symptoms. The evidence for benefit of selenium supplementation for fatigue without proven deficiency is weak and relies mostly on mechanistic reasoning or observational studies. Anyone with persistent fatigue should have other causes (iron deficiency, thyroid function, sleep quality) medically evaluated before taking selenium. A blood test for selenium or selenoprotein P can clarify if deficiency is present.