Iodine is needed to make thyroid hormone — too little or too much can cause problems
🦋 ThyroidBy the Bloom Health Woman editorial team · Last updated October 2026 · Educational information, not medical advice. This page contains an affiliate link (see the product box). How we create content
The thyroid needs iodine to make thyroid hormone. Iodine deficiency can cause thyroid problems, and needs increase in pregnancy and breastfeeding. Most people in the U.S. get enough from iodized salt, dairy and seafood. More is not better: excess iodine can cause or worsen thyroid disease, so supplements should be used thoughtfully.
People with low iodine intake, and people who are pregnant or breastfeeding, as advised by their provider. Whether it suits you depends on your health, medicines and test results — ask a clinician.
Recommended intakes are about 150 mcg per day for adults, 220 mcg in pregnancy and 290 mcg when breastfeeding (NIH). The upper limit for adults is 1,100 mcg per day. Doses vary by product and person; this is not personal medical advice.
Deficiency can take weeks to months to correct.
Too much iodine can cause thyroid over- or under-activity, and stomach upset.
People with Hashimoto's thyroiditis or other thyroid disease should ask their endocrinologist before taking iodine, because excess iodine can worsen thyroid problems.
Evidence level (our editorial summary, not a formal grading): Established for deficiency; not a treatment for thyroid disease.
Pregnancy & breastfeeding: Needs are higher in pregnancy and breastfeeding; many prenatal vitamins contain iodine. Ask your provider.
Medication interactions: May interact with antithyroid medicines, thyroid medicines and some blood-pressure medicines.
Talk to a healthcare professional before use if you are pregnant, breastfeeding, planning pregnancy, have a medical condition, take any medicine, or are scheduled for surgery. Dietary supplements are not approved by the FDA for safety or effectiveness before they are sold, and quality varies between products.
Reliable sources to check: NIH Office of Dietary Supplements fact sheets · NCCIH Herbs at a Glance · MedlinePlus Herbs & Supplements · FDA — Dietary Supplements
Optional product link. We have not tested this product and its inclusion is not a medical recommendation or an endorsement of any brand.
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