Selenium is an essential trace element incorporated into selenoproteins — including glutathione peroxidases (master antioxidant enzymes) and thioredoxin reductases. It is critical for thyroid hormone metabolism: the thyroid gland has the highest selenium concentration of any organ. The selenoprotein P transports selenium in blood. Soil selenium content varies dramatically by region, making geographic deficiency common in parts of Europe, China, and New Zealand.

Key Benefits

Thyroid hormone conversion (T4 to T3)
Glutathione antioxidant system
Immune function
Male fertility & sperm motility
Hashimoto's thyroiditis management
Prostate health

Best Form

Selenomethionine (organic form; best absorbed); Se-methylselenocysteine for cancer prevention research

Dosage

55–200 mcg/day

⚠ Safety Notes

NARROW THERAPEUTIC WINDOW. Toxicity (selenosis) occurs at >400 mcg/day — symptoms include brittle nails, hair loss, garlic breath, and neurological effects. Do not exceed 400 mcg/day from all sources.

This page is for educational purposes only. Consult a healthcare professional before starting any supplement.