What Does an Iodine Supplement Do?

Medically Reviewed on 8/11/2021
iodine supplement for iodine deficiencies
Iodine supplements can effectively prevent and treat iodine deficiencies, which such deficiencies can cause low thyroid levels, infertility and certain types of cancer.

Iodine supplements help prevent issues related to iodine deficiency in the body, which is a mineral required by the body for optimal growth and survival. Iodine is important because it is a prime constituent of thyroid hormones produced in the body.

  • Thyroid hormones are essential for energy expenditure, growth and other metabolic functions in the body.
  • They are essential for a developing baby in the mother’s womb and help in the physical and neurological development of unborn babies, infants and children.
  • Low iodine levels can, thus, cause low thyroid hormone levels.
  • Iodine deficiency in adults can cause low thyroid hormone levels that present as goiter (an enlarged thyroid gland that presents as neck swelling), sluggish metabolism, weight gain, mood problems including depression and infertility.
  • Iodine deficiency is also associated with fibrocystic breast disease (painful breast lumps) and thyroid cancer.
  • Thyroid cancer may especially be seen in people with iodine deficiency who are exposed to radioactive iodine.
    • Potassium iodide is a type of iodine supplement approved by the US Food and Drug Administration (FDA) to reduce the risk of thyroid cancer in such individuals.

Various iodine supplements are available on the market in the form of potassium iodide or sodium iodide and iodine-containing kelp (a seaweed). Several multivitamin and multimineral supplements also contain iodine.

Ask your doctor whether you should take iodine supplements because they can be harmful when taken in excess. These supplements may also react with certain medications, such as anti-thyroid medications, blood pressure medications and water pills (diuretics), causing undesirable effects.

How much iodine do you need every day?

The amount of iodine needed may vary depending on your age or current situation, such as pregnancy and lactation. The average daily recommended amounts of iodine are given in the table below.

Age group Recommended amount (micrograms)
Birth to six months 110
7 to 12 months 130
One to eight years 90
9 to 13 years 120
14 to 18 years 150
Adults including nonpregnant and nonlactating women 150
Special situations Recommended amount (micrograms)
Pregnant teens and women 220
Breastfeeding teens and women 290
Ref: The United States Institute of Medicine (IOM, now called the National Academy of Medicine)

How is iodine deficiency diagnosed?

Your doctor may diagnose iodine deficiency based on several factors, such as your medical history, physical examination and certain investigations. This deficiency is generally assessed by measuring iodine concentration in the urine.

Iodine deficiency is diagnosed across populations and not for a particular individual. About 90 percent of the iodine consumed by a person (through diet or supplements) is eliminated in the urine. Thus, knowing the urinary iodine concentration can help understand whether a population is deficient in iodine (iodine deficiency) or has enough iodine in the body (iodine sufficiency). Measurements are done across a large population to measure the amounts of iodine in urine samples.

Population group Median urinary iodine concentration Interpretation
Children and nonpregnant adults 100 to 299 mcg/L# Iodine sufficiency
Pregnant women 150 to 249 mcg/L Iodine sufficiency
Nonpregnant individuals Less than 100 mcg/L Iodine deficiency
Pregnant teens and women Less than 150 mcg/L Iodine deficiency
#micrograms per liter

Iodine deficiency may further be classified as mild, moderate or severe.

Classification of iodine deficiency
Median urinary concentration of iodine Interpretation
50 to 99 mcg/L Mild iodine deficiency
20 to 49 mcg/L Moderate deficiency
<20 mcg/L Severe deficiency


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Medically Reviewed on 8/11/2021