Mineral
Selenium (as Sodium Selenite)
Also known as: sodium selenite, selenium oxide, inorganic selenium
Selenium (as sodium selenite) is an inorganic form of selenium with moderate bioavailability, essential for glutathione peroxidase and thyroid hormone metabolism. Selenomethionine (organic form) is better absorbed.
Last reviewed June 2026 · Evidence graded from peer-reviewed research, not editorial opinion. Educational only — not medical advice.
Primary uses
- antioxidant defense
- thyroid function
- reproductive health
- immune support
How it works
- component of selenoproteins (glutathione peroxidase, thioredoxin reductase)
- supports thyroid hormone conversion
- reduces oxidative stress
Dosage
- Typical range
- 55–200 µg daily
- Timing
- can be taken anytime; consistent daily intake recommended
- With food
- May be taken with or without food
- Duration
- Safe long-term; avoid exceeding UL of 400 µg daily to prevent selenosis
- Special populations
- Brazil nuts naturally very high in selenium; adjust supplemental intake accordingly
Forms
- sodium selenite· 70/100
Safety
Common side effects
- garlic-like body odor (at higher doses)
- brittle nails
- hair loss (at excessive doses)
Contraindications
- history of selenosis
Products containing Selenium (as Sodium Selenite)
Top-scoring supplements in our catalog that list Selenium (as Sodium Selenite) on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.
Evidence notes
Selenium has good evidence for thyroid and antioxidant support; inorganic selenite form has lower bioavailability than organic selenomethionine.
Grade B: Some human trials support key claims; further confirmation needed.
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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Individual needs and risks vary — consult a professional before starting, stopping, or combining supplements, especially if you are pregnant or nursing, taking medication, or managing a health condition.