Zinc for Thyroid Disorders
Zinc supplementation improves thyroid hormone parameters in people who are zinc-deficient, with no demonstrated benefit in replete individuals.
Overview
Verdict
How It Works
Dosing & Protocol
Typical dose
- Recommended dose
- 15-30mg elemental zinc daily with food
- Expected timeframe
- 3-6 months if deficient
Protocol
- form
- Zinc gluconate or sulfate with food
- duration
- 3-6 months, then reassess
- co factor
- Take with food and at least four hours away from levothyroxine. Evidence is mixed. Zinc is a genuine cofactor for the deiodinase enzymes that convert T4 to active T3, and for thyroid hormone receptor function, and small studies in zinc-deficient people report improved T3 and lower TSH after repletion. Hypothyroidism can itself cause zinc deficiency by reducing absorption, so the relationship runs both ways. But no trial shows supplementation improves thyroid function or reduces medication requirement in people with adequate zinc, and it does nothing for nodules, goitre or thyroid cancer.
- titration
- Do not exceed 40 mg/day. Recheck thyroid function 6-8 weeks after any change in supplement routine, since absorption interactions can shift levothyroxine levels
- starting dose
- 15-30 mg elemental zinc daily with an evening meal, after checking zinc status
Evidence
What the studies say
No studies are yet linked to both Zinc and Thyroid Disorders.
Safety
Caveats
Critical interaction: zinc reduces levothyroxine absorption and must be separated by at least four hours - levothyroxine on an empty stomach 30-60 minutes before food, zinc with an evening meal - and thyroid function should be rechecked 6-8 weeks after starting, because inconsistent timing produces erratic control. Never adjust thyroid medication yourself; untreated hypothyroidism has cardiac consequences and, in pregnancy, affects fetal brain development, so levels need checking early and often in pregnancy. A thyroid lump, hoarseness, difficulty swallowing or a rapidly enlarging goitre needs urgent assessment. Safety ceiling: the tolerable upper intake level is 40 mg elemental zinc per day; chronic excess causes copper deficiency with anaemia and irreversible neurological damage. Zinc also reduces absorption of tetracyclines, quinolones, bisphosphonates and iron. In pregnancy do not exceed 40 mg/day.
Less likely to help if
Medical Disclaimer
The information provided on this website is for educational and informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any supplement regimen.
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.