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Mineral

Selenium

Also known as: Selenium glycinate

A
Evidence

Essential trace mineral for glutathione peroxidase activity, thyroid function, and optimal immune response to viral infections.

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Daily target & upper limit

55 mcg / day · UL 400 mcg

Selenium has an established daily reference intake. See best forms, label synonyms, upper-limit warnings, and top-scoring supplements:

Selenium dosage reference →

Primary uses

  • Antioxidant enzyme support
  • Thyroid function
  • Viral immunity
  • Selenoprotein production
  • T4 to T3 conversion
  • Thyroid protection
  • Autoimmune thyroid (Hashimoto's)
  • Prostate health
  • Antioxidant
  • Prostate cancer (controversial)

How it works

  • Required for deiodinase enzymes
  • Converts T4 to active T3
  • Protects thyroid from oxidative damage
  • May reduce thyroid antibodies

Dosage

Typical range
100-200mcg daily
Timing
With meals
With food
Yes
Duration
Ongoing for thyroid support
Special populations
Hashimoto's, hypothyroid, those on iodine

Forms

  • Selenomethionine
  • Selenium yeast
  • Sodium selenite
  • Brazil nuts

Safety

Common side effects

  • Garlic breath (high dose)
  • GI upset

Contraindications

  • Excessive supplementation

Products containing Selenium

Top-scoring supplements in our catalog that list Selenium on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.

Thorne
Selenium
98
Thorne
MediClear-SGS™ - Vanilla
95
Thorne
Thyroid Health Complex (formerly Thyrocsin)
94
Thorne
Basic Nutrients 2/Day
93
See all products →

Known interactions

Evidence notes

Well-established for thyroid function and protection

Grade A: Multiple well-designed human trials support the main claims.

Cited research for Selenium

Clinical studies referenced across Formulate guides that mention selenium. Each links to the full study page with PubMed source + the guides that cite it.

Related in Mineral

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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider.