Iodine is a trace element that is vital to the health of the thyroid gland. It also provides the building blocks for the hormones secreted by the thyroid. The availability of iodized salt has made iodine deficiency and its accompanying disorder, goiter, very rare in the United States and the developed world.

Iodized salt is the most common source of iodine in the United States. Iodine-rich foods include seafood, sea vegetables (seaweed), kelp and vegetables grown in iodine-rich soils.

Dosage Info

Dosage Range

Dosages typically used range from 50-250mcg daily. Occasionally doses as high as 0.08mg/kg (5.6mg for 70kg adult) have been used for fibrocystic breast disease. (1)

Most Common Dosage

150mcg daily.

Dosage Forms

Tablets, capsules, and liquid.

Reported Uses

Iodine’s only known function is the role it plays in the thyroid gland. (2) Without it, however, the thyroid cannot function properly, which leads to abnormal metabolism, oxygen consumption and energy production. The iodine-dependent hormones produced by the thyroid control such functions as body temperature, physical growth, reproduction and the growth of skin and hair.

Researchers have also found that iodine deficiency may be related to fibrocystic breast disease. Studies suggest that supplementation may treat the disease. (3) Iodine also effectively treats the disorder with which it is most commonly associated - goiter. When iodine deficiency is severe enough, the thyroid can become enlarged. Treatment by way of iodine supplementation usually decreases the size of these goiters. (4)

Iodine deficiency may occur during pregnancy and this could impair thyroid function. (5) Researchers found there was a deficit in thyroid function due to iodine deficiency, which worsened as the pregnancy advanced. (6)

Toxicities & Precautions


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This dietary supplement is considered safe when used in accordance with proper dosing guidelines.

Side Effects

Occasional side effects reported with the use of large doses of this dietary supplement include an enlargement of the thyroid gland resembling goiter. (7) The condition is called “iodine goiter." It may be necessary to reduce the dose of this dietary supplement. Tell your doctor if these side effects become severe or do not go away.

Pregnancy / Breast Feeding

To date, the medical literature has not reported any adverse effects related to fetal development during pregnancy or to infants who are breast-fed. Proper nutrition is essential during pregnancy for the healthy development of the fetus. Numerous vitamins and minerals are a vital part of proper nutrition. If you are pregnant, think you might be pregnant, trying to get pregnant, or breast-feeding an infant, talk to your healthcare professional about supplementing your diet with appropriate vitamins and minerals.

Age Limitations

To date, the medical literature has not reported any adverse effects specifically related to the use of this dietary supplement in children. Vitamins and minerals are an essential part of proper growth and development. Talk to your healthcare professional about the appropriate use of vitamins and minerals in children. Do not use any vitamin or mineral in children under 2 years of age unless first discussed with your healthcare professional.


  1. View Abstract: Ghent WR, Eskin BA, Low DA, Hill LP. Iodine replacement in fibrocystic disease of the breast. Can J Surg. Oct1993;36(5):453-460.
  2. View Abstract: De Vijlder JJ. Primary congenital hypothyroidism: defects in iodine pathways. Eur J Endocrinol. Oct2003;149(4):247-56.
  3. View Abstract: Ghent WR, et al. Iodine Replacement in Fibrocystic Disease of the Breast. Can J Surg. Oct1993;36(5):453-60.
  4. View Abstract: Feldkamp J, et al. Therapy of Endemic Goiter with Iodide or l-thyroxine in Older Patients. Dtsch Med Wochenschr. Dec1996;121(51-52):1587-91.
  5. View Abstract: Glinoer D. The regulation of thyroid function during normal pregnancy: importance of the iodine nutrition status. Best Pract Res Clin Endocrinol Metab. Jun2004;18(2):133-52.
  6. View Abstract: Dominguez I, Reviriego S, Rojo-Martinez G, et al. Iodine deficiency and thyroid function in healthy pregnant women. Med Clin (Barc). Apr2004;122(12):449-53.
  7. View Abstract: Kanno J, Onodera H, Furuta K. Tumor-promoting effects of both iodine deficiency and iodine excess in the rat thyroid. Toxicol Pathol. 1992;20(2):226-35.