Selenium

About Selenium

Essential component of selenoproteins including glutathione peroxidase (antioxidant defense) and deiodinases (thyroid hormone activation). Selenomethionine is the most bioavailable supplemental form, while sodium selenite is inorganic and less efficiently absorbed. Brazil nuts are the richest food source—just 1–2 nuts can meet the daily requirement. The therapeutic window is narrow: deficiency impairs immunity and thyroid function, while chronic excess (above 400 mcg/day) causes selenosis with hair loss and nail brittleness.

What Selenium supports

• 🛡️Protects cells as antioxidant
• ❤️Supports thyroid health
• 🧬May protect against chronic disease

How much Selenium to take

Clinical studies typically use 100–200 mcg of Selenium. Common supplement dose; UL is 400 mcg/day.

RDA

55 mcg

Upper limit (UL)

400 mcg

Effective range

100–200 mcg

Forms of Selenium compared

• SelenomethioninePremium
  Organic, well-retained form found in foods.
• Selenium yeastStandard
  Organically bound selenium; well-retained in tissues.
• Selenium chelateStandard
  Amino-acid bound; reasonable absorption.
• Sodium seleniteBudget
  Inorganic, lower retention
• Sodium selenateBudget
  Inorganic, lower retention

Clinical evidence

Strong clinical evidence. SELECT trial (35,000+ men) found no cancer prevention benefit; essential for thyroid via selenoproteins