Evidence brief · Supplement
Iodine for Thyroid dysfunction (excess)
Evidence grade B — Too much also harms
- Overall grade
- Grade B
- Last revised
- 1
- graded outcome
- 0
- references listed
Assembled by the app from other entries in this library. It adds no evidence of its own — follow the links to the entries it draws on.
1 at grade B — 1 graded row
What is known
Each outcome with its grade (how strong the evidence is, A to D), the size of the effect where the entry records one, and how often studies agree.
- Thyroid dysfunction (excess)Evidence grade B
Too much also harms
Moderatehigh
The evidence in words
The verdict
For thyroid dysfunction (excess), Iodine earns evidence grade B (moderate effect, high consistency) — there is real evidence here. Too much also harms
How it might work
The thyroid concentrates iodine and attaches it to tyrosine residues to make T4 and T3, which set metabolic rate throughout the body. Both too little and too much disrupt hormone production.
How to use it
Iodized salt, dairy, and seafood cover most people. Pregnancy and lactation raise needs; prenatal vitamins typically include ~150 µg. Avoid high-dose kelp/iodine supplements.
Safety & cautions
High doses can induce thyroid dysfunction; kelp supplements deliver erratic, sometimes excessive amounts. Stay near requirements.
Bottom line
Use iodized salt or eat seafood/dairy; ensure adequacy in pregnancy. Don't megadose — the thyroid dislikes both extremes.
How it is used
As the entry records it, from the studies it summarises. Not a recommendation for you — doses that suit a trial population may not suit you.
- Adequacy
- Iodized salt / seafood; ~150 µg in pregnancy prenatals.
Goes with
- IodineRead the full Iodine monographEvidence grade B
Related reading
Entries that share this one's tags or conditions.
- Iodine for Deficiency disorders / fetal cognitionEvidence grade A — Especially pregnancyEvidence grade A
- Iodine: dosage and how to take itIodized salt / seafood; ~150 µg in pregnancy prenatals.Evidence grade B
- Iodine: side effects, safety & interactionsHigh doses can induce thyroid dysfunction; kelp supplements deliver erratic, sometimes excessive amounts. Stay near requEvidence grade B
- Choline for Cognition (replete adults)Evidence grade C — WeakEvidence grade C
Sources
This entry lists no references of its own — it is assembled from the entries it links to, whose sources are on their pages.
Last revised . A grade is this entry's reading of the evidence, not medical advice.