Iodine explained: what it is and its food sources
The NIH says your body needs iodine to make thyroid hormones, and seaweeds such as kelp are among the best food sources. Adults 19 and older need 150 mcg a day, with higher needs during pregnancy and breastfeeding. Three products we reviewed list iodine, and all three labels print amounts of 50 to 275 mcg per serving.
- What it is
- Mineral
- What adults need a day (ages 19 and older)
- 150 mcg
- Upper limit
- 1,100 mcg
- In the products we reviewed
- 3, every label prints the amount
What iodine is
- Seaweeds such as kelp, nori, kombu, and wakame are among the best food sources of iodine.2
- Your body needs iodine to make thyroid hormones.1
- Thyroid hormones control your body's metabolism and many other important functions.1
- Thyroid hormones are needed for proper bone and brain development during pregnancy and infancy.1
- Iodine supplements usually contain potassium iodide or sodium iodide.1
- Many multivitamin and mineral supplements contain iodine, and iodine-containing kelp supplements are also available.1
- Iodide is absorbed quickly and almost completely in the stomach and the first part of the small intestine.2
Foods that have it1
- Cod
- Tuna
- Seaweed
- Shrimp
- Other seafood
- Milk
- Yogurt
- Cheese
- Eggs
- Iodized salt
How much iodine each product gives
Adults need 150 mcg a day
Before you take it
If you take medicines
- Antithyroid medications such as methimazole (Tapazole)
- High doses of iodine with antithyroid medications could cause your body to produce too little thyroid hormone.1
- ACE inhibitors including benazepril (Lotensin), lisinopril (Prinivil and Zestril), and fosinopril (Monopril)
- Potassium iodide with ACE inhibitors could raise blood potassium to an unsafe level.1
- Potassium-sparing diuretics such as spironolactone (Aldactone) and amiloride (Midamor)
- Potassium iodide with potassium-sparing diuretics can make blood potassium too high.1
Foods and drinks
- Soy, cabbage, broccoli, cauliflower, and brussels sprouts
- These foods contain substances that interfere with iodine use, but reasonable amounts are not a concern for most people who get enough iodine.1
Side effects
- High iodine intake can cause an enlarged thyroid gland.1
Ask a doctor first
- The adult daily upper limit is 1,100 mcg of iodine.1
- Excessive iodine intake near the end of pregnancy or during breastfeeding can increase breastmilk iodine and temporarily impair a breastfed infant's thyroid function.3
These statements have not been evaluated by the FDA. A supplement is not a medicine.
The 3 products we reviewed that list iodine
| Product | Form and serving | Iodine per serving | Our score | Price a bottle | Buy |
|---|---|---|---|---|---|
 ViriFlow#1 in prostate health support | Liquid drops2 ml | 275 mcg183% of daily need | 9.4 | $49 | Check price |
 DentiCore#4 in oral health support | Soft tablets1 tablet | 50 mcg33% of daily need | 8.9 | $49 | Check price |
 Prostadine#7 in prostate health support | Liquid drops2 droppers (2 ml) | 275 mcg183% of daily need | 8.3 | $49 | Check price |
Questions people ask
How much iodine do adults need per day?
150 mcg a day is the recommended iodine intake for adults 19 and older. Daily needs are 220 mcg during pregnancy and 290 mcg while breastfeeding. Ask a clinician before starting an iodine supplement during pregnancy or breastfeeding.
What foods are high in iodine?
Seaweeds such as kelp, nori, kombu and wakame are among the best food sources of iodine. Other sources include cod, tuna, shrimp, milk, yogurt, cheese, eggs and iodized salt.
What side effects can too much iodine cause?
High iodine intake can cause an enlarged thyroid gland. The adult daily upper limit is 1,100 mcg of iodine. Ask a clinician before starting an iodine supplement.
What do iodine supplements contain?
Iodine supplements usually contain potassium iodide or sodium iodide, according to the NIH. Many multivitamin and mineral supplements contain iodine, and iodine-containing kelp supplements are also available.
Which products we reviewed contain iodine?
ViriFlow, DentiCore and Prostadine all list iodine. DentiCore prints 50 mcg per serving, while ViriFlow and Prostadine each print 275 mcg per serving.
Also in these products
Sources
The products, amounts and prices come from each product's label and checkout, as its review shows them. AI drafts our pages from listed sources, figures are checked against them, and we have not tried the products.
- 1NIH Office of Dietary Supplements, Iodine, Fact Sheet for Consumersods.od.nih.gov/factsheetschecked
- 2NIH Office of Dietary Supplements, Iodine, Fact Sheet for Health Professionalsods.od.nih.gov/factsheetschecked
- 3NIH LactMed, Iodinencbi.nlm.nih.gov/bookschecked