Protocols › Iodine

Iodine for thinking skills in children

Goal: What trials gave children with low iodine, and what it changed in their thinking skills.

Each protocol describes what studies used, for one goal or for one group of people. It is not advice for you: talk to a doctor before you start a supplement.

Updated 10 Nov 2026
Dose

150 µg a day in children aged 10 to 13 with mild deficiency.[1] In areas with iodine deficiency, one dose of 400 to 490 mg by mouth for children aged 6 to 17.[2]

Form

A daily tablet, or iodized oil by mouth.[1][3]

How long

28 weeks of daily tablets.[1] Trials followed children for 3 to 22 months.[2]

What studies found

A 2026 Cochrane review of 8 trials with 2,528 children found a slight increase in cognitive function (high certainty) and little or no difference in weight (low certainty).[2] In the 28-week trial, the overall score was 0.19 standard deviations higher than with placebo.[1]

Ask a doctor first

The US upper limit is 300 µg a day at 4 to 8 years, 600 µg at 9 to 13 years and 900 µg at 14 to 18 years.[4] The single 400 mg dose was tested in children with moderate deficiency.[3] Doses above the upper limit should only be given under a doctor's care.[4]

Ask a doctor or pharmacist first if the child has a thyroid disease.[4]

References

  1. Iodine supplementation improves cognition in mildly iodine-deficient children. Gordon RC, Rose MC, Skeaff SA, Gray AR, Morgan KM, Ruffman T Am J Clin Nutr, 2009. PMID 19726593
  2. Iodine supplementation for preventing iodine deficiency disorders in children and adolescents. Velasco I, Rueda-Etxebarria M, Trak-Fellermeier MA, Taylor P, Rabassa Bonet M, Chi Y, et al. Cochrane Database Syst Rev, 2026. PMID 42720098
  3. Iodine supplementation improves cognition in iodine-deficient schoolchildren in Albania: a randomized, controlled, double-blind study. Zimmermann MB, Connolly K, Bozo M, Bridson J, Rohner F, Grimci L Am J Clin Nutr, 2006. PMID 16400058
  4. Iodine: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. ods.od.nih.gov