What is the recommended dose of selenium for patients with Hashimoto's (Hashimoto's thyroiditis)?

Recommended Selenium Dosage for Hashimoto's Thyroiditis

For patients with Hashimoto's thyroiditis, the recommended dose of selenium is 100-200 μg per day in the form of selenomethionine or sodium selenite. 1, 2, 3

Assessment Before Supplementation

Before starting selenium supplementation:

• Measure baseline plasma/serum selenium levels along with CRP and albumin to accurately assess selenium status 1
• Values <0.4 μmol/L (<32 μg/L) indicate definite deficiency requiring supplementation
• Values <0.75 μmol/L in patients without inflammation should trigger supplementation 4
• Consider testing thyroid antibodies (anti-TPO and anti-TG) to establish baseline levels 5, 3

Dosing Recommendations

Standard Dosing

• Initial dose: 100-200 μg per day 2, 3
• Selenomethionine appears to be more effective than sodium selenite for reducing anti-TPO antibodies 5
• Duration: Minimum 6 months to observe significant effects on antibody levels 2, 6

Monitoring and Adjustment

• Recheck selenium levels after 7-10 days if treating severe deficiency 4
• Measure anti-TPO antibodies every 3 months to assess response 6
• Continue supplementation for at least 6-12 months if beneficial effects are observed 6

Expected Benefits

• Reduction in anti-TPO antibody levels (5.6-9.9% reduction after 3-6 months, up to 21% after 12 months) 6
• Potential stabilization of thyroid function 2
• Possible improvement in subjective well-being 5
• May help prevent progression to overt hypothyroidism 2

Safety Considerations

• Upper limits for plasma selenium before toxicity: 6-12 μmol/L 4
• Adverse events are rare at recommended doses (reported in only 1-2% of patients in clinical trials) 5
• Avoid excessive supplementation as selenium overexposure has been associated with type 2 diabetes and high-grade prostate cancer 4

Special Populations

• Consider higher doses (up to 200 μg/day) for:

  • Patients with documented selenium deficiency
  • Those with higher inflammatory markers
  • Patients with more severe autoimmune activity (higher antibody titers) 4, 1

• Lower doses (100 μg/day) may be sufficient for:

  • Maintenance therapy after normalization of levels
  • Patients with adequate baseline selenium status 2

Important Caveats

• Selenium supplementation should not replace standard thyroid hormone replacement therapy when indicated
• The benefits of selenium supplementation appear most significant in areas with low selenium status 2, 7
• Dietary selenium intake is inversely associated with Hashimoto's thyroiditis risk and TPOAb levels 7
• Discontinuation of selenium supplementation may lead to rebound increases in antibody levels (4.8% increase observed after stopping) 6

Remember that selenium supplementation is an adjunctive therapy that may help reduce antibody levels and potentially improve outcomes in Hashimoto's thyroiditis, but it does not replace appropriate thyroid hormone replacement when indicated.