Vitamin D for Hashimoto's Thyroiditis
Vitamin D deficiency is common in Hashimotos, and correcting it lowers TPO antibody titres in several trials - but antibody reduction has not been shown to change clinical outcomes.
Overview
Verdict
How It Works
Dosing & Protocol
Typical dose
- Recommended dose
- 2000-5000 IU daily (target 50-80 ng/mL)
- Expected timeframe
- 3-6 months
Protocol
- form
- Vitamin D3 (cholecalciferol)
- duration
- 3-6 months with thyroid peroxidase antibodies and TSH at baseline and end
- co factor
- Take with the largest meal, and separate from levothyroxine, which must be taken on an empty stomach. Evidence is mixed: vitamin D deficiency is more common in Hashimoto thyroiditis, and several small trials report falling TPO antibody titres after supplementation, but the trials are small and short, and no trial has shown preserved thyroid function or reduced levothyroxine requirement.
- titration
- Target 75-125 nmol/L; some Hashimoto trials used higher weekly loading under supervision
- starting dose
- 1000-2000 IU (25-50 mcg) vitamin D3 daily with a fat-containing meal, after checking 25-hydroxyvitamin D
Evidence
What the studies say
Effects of different supplements on Hashimoto's thyroiditis: a systematic review and network meta-analysis
Selenium reduced TPOAb and TgAb; myo-inositol, vitamin D alone and Se+myo-inositol did not significantly reduce antibodies over 6 months.
Effects of vitamin D supplementation on autoantibodies and thyroid function in patients with Hashimoto's thyroiditis: A systematic review and meta-analysis
Vitamin D supplementation may have beneficial effects on HT patients by modulating immune responses and improving thyroid function.
Safety
Caveats
Do not adjust or stop levothyroxine - untreated hypothyroidism has cardiac consequences and, in pregnancy, affects fetal brain development, so thyroid function must be checked early and often in pregnancy. Antibody titres are not the treatment target; TSH is. Safety ceiling: the tolerable upper intake level is 4000 IU (100 mcg) per day; excess causes hypercalcaemia, kidney stones and kidney injury. Avoid unsupervised use in sarcoidosis, granulomatous disease and primary hyperparathyroidism. Interacts with thiazide diuretics and digoxin. Take levothyroxine 30-60 minutes before food and separate it from calcium and iron by four hours. Safe in pregnancy at 400-1000 IU/day.
Less likely to help if
Medical Disclaimer
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Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.