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Iodine is a mineral that may help thyroid function. The human body does not naturally produce it, but it is found in some foods. A doctor may suggest an iodine supplement if they feel it will benefit a person’s health.

Iodine deficiency is common, especially among people who follow a vegan diet and pregnant people.

Although iodine supplements are easy to find, it is important for people to speak with a doctor before taking them, as too much iodine can cause side effects and complications.

This article looks at what iodine does, its benefits, risks, and side effects. It also lists some iodine supplement products.

A quick look at the best iodine supplements in 2022

Iodine is a mineral that the human body does not naturally produce. It is found in some foods, such as:

  • iodized salt
  • fish, including cod and tuna
  • dairy products, such as milk, cheese, and yogurt
  • eggs

Iodine is essential for creating and maintaining thyroid hormones. Thyroid function is important for metabolism.

During pregnancy and in infants, iodine is essential for bone and brain development.

Additionally, a 2020 research review found that people following a vegan diet are at risk of having a low iodine level, so they may benefit from taking supplements under a doctor’s care.

Find out more about iodine here.

People may wish to consider the following when looking for an iodine supplement:

  • Brand: Supplements do not have to have Food and Drug Administration (FDA) approval before being sold. This means a person should purchase from a reputable brand that has positive customer reviews. Companies that use third-party testing are the safest option.
  • Dosage: A person should ensure their chosen supplement dosage does not exceed the upper limit for iodine mentioned in this article. Some people may be able to tolerate higher levels, but they should always consult a qualified medical professional.
  • Ingredients: Some supplements may contain ingredients such as sugar, preservatives, artificial sweeteners, and animal products. These ingredients may not suit everyone.
  • Type: Some people may consider taking capsules or tablets, while others may require a chewable form, such as a gummy.

Medical News Today chooses products that meet the following criteria:

  • Ingredients: MNT chooses products containing safe and high quality ingredients that are clearly labeled. The labels should also confirm the products are free from pesticides, heavy metals, and mold.
  • Dosage: MNT chooses products that must clearly state the supplement dosage.
  • Serving size: MNT selects products in which manufacturers recommend a safe dosage.
  • Third-party testing: MNT chooses products that must undergo third-party testing for contaminants by an ISO 17025-compliant laboratory.
  • Available certificate of analysis: MNT chooses companies that demonstrate transparency and share a product’s certificate of analysis (COA) following receipt of its third-party lab results.

Below is a list of iodine supplements that a person may consider.

Please note that the writer of this article has not tried these products. All information presented is purely research-based and correct at the time of publication.

Medical News Today follows a strict product selection and vetting process. Learn more here.

Best overall: Pure Encapsulations

  • Cost: $17.70 for 120 capsules
  • Type: capsules
  • Iodine dose: 225 micrograms (mcg) per capsule

These capsules are vegan-friendly and gluten-free, according to the company. As well as iodine, ingredients include hypoallergenic plant fiber. The manufacturer’s recommended serving size is 1 capsule taken once or twice per day with a meal.

Pros

  • The product contains no genetically modified organisms (GMOs).
  • They are third-party tested.

Cons

  • The capsules are expensive.

Best complex: Swanson Vitamins Triple Iodine Complex

  • Cost: $14.99 for 60 capsules
  • Type: capsules
  • Iodine dose: 12,500 mcg per capsule

According to the company, these capsules are vegetarian. They contain three forms of iodine: molecular iodine, sodium iodide, and potassium iodide. Ingredients also include plant fiber and silica.

Pros

  • They are third-party tested.
  • The company has a high average rating on Trustpilot.

Cons

  • The high dose may not suit everyone.

Best for kids: SmartyPants Organic Kids Multivitamin

  • Cost: around $30 for 120 gummies
  • Type: gummies
  • Iodine dosage: 90 mcg per 4 gummies

Although this product is a multivitamin, it contains a dose of iodine for kids. It also includes a range of other vitamins and minerals, including vitamins A, C, D, B12, and E as well as folate, biotin, and zinc.

The gummies contain sugar. They are suitable for people following a vegan diet, according to the company.

Pros

  • They are certified organic.
  • They do not contain gluten, dairy, milk, soy, peanuts, or tree nuts.

Cons

  • These gummies contain sugar.
  • Since the dosage is 4 gummies daily, one bottle provides a 1-month supply, which may not be the most cost-effective option.

Best pregnancy formulation: Glow Prenatal

  • Cost: around $30 for 60 mini capsules
  • Type: mini capsules
  • Iodine dose: 290 mcg per 2-capsule serving

As well as iodine, these capsules contain 25 nutrients necessary for a healthy pregnancy. Ingredients include various vitamins, folate, iron, magnesium, and zinc. According to the company, the mini capsules are vegetarian.

Pros

  • The company operates in an FDA-registered facility.
  • These are third-party tested.

Cons

  • The manufacturer produces and markets the capsules solely for pregnant people, so may not suit everyone.
  • A 60-capsule bottle is a 1-month supply, so more cost-effective options may be available.

Best liquid option: Mary Ruth’s Nascent Iodine Liquid Drops

  • Cost: $19.95 for 1 ounce (oz)
  • Type: liquid drops
  • Iodine dose: 250 mcg per 2-drop serving

The serving size of this product is 1–2 drops daily, which a person can drop on their tongue. The drops are unflavored, so a person can add them to their choice of beverage.

As well as iodine, these drops contain organic vegetable glycerin and purified water. According to the manufacturer, they are also free from dairy, nuts, and gluten.

The company states this product is vegan-friendly and USDA-certified organic.

Pros

  • The drops are free from eight major allergens.
  • They are made in a certified good manufacturing practice (GMP) facility.
  • They are third-party tested.

Cons

  • There are no sample products available to check suitability.

Best powder: Now Kelp Powder

  • Cost: $12.99 for 8 oz
  • Type: powder
  • Iodine dose: 450 mcg per scoop

Kelp is a type of iodine-rich seaweed and is the only ingredient in this product. It is sold by weight rather than volume.

The dosage is 1 level scoop daily. The manufacturer recommends taking it with a meal.

According to the company, this product is kosher, vegan-friendly, and USDA-certified organic. It is also free from gluten, corn, dairy, egg, soy, and nut.

Pros

  • The product is third-party tested.
  • The powder is free from many allergens.

Cons

  • The powder may have an unpleasant taste.

Best high potency: Optimox Iodoral

  • Cost: around $39 for 90 tablets
  • Type: tablets
  • Iodine dose: 12,500 mcg per tablet

These high potency tablets contain a blend of:

  • potassium hydroxide
  • silicon dioxide
  • magnesium sulfate heptahydrate
  • polysorbate 80
  • citric acid

The company does not state whether the product is vegan-friendly.

Pros

  • The tablets have a thin coating to prevent bad taste.
  • The product is third-party tested.

Cons

  • The high dose may not suit people new to iodine supplements.
  • It is unclear whether the product is suitable for vegans and vegetarians.

Best raw food supplement: Peak Performance Raw Whole Food Iodine

  • Cost: $19.95 for 60 capsules
  • Type: capsules
  • Iodine dose: 150 mcg per capsule

According to the company, these capsules are vegan. They contain cellulose and water. The iodine is from organic, whole plant kelp.

A person can choose a one-time purchase or choose a money-saving subscription.

Pros

  • The company uses third-party testing.
  • The company uses a GMP-certified facility for manufacturing.

Cons

  • This product has a lower iodine dosage than some other products.

Best for fatigue: Thorne Iodine and Tyrosine

  • Cost: $19 for 60 capsules
  • Type: capsules
  • Iodine dose: 225 mcg per capsule

These capsules contain tyrosine as well as iodine. The company claims tyrosine may reduce fatigue and support the thyroid and adrenal glands.

According to the manufacturer, the product is suitable for vegans and is free from gluten, soy, and dairy.

Pros

  • The company uses third-party testing.
  • The product does not contain artificial colors or flavors.

Cons

  • The company advises pregnant people not to use this product.
  • The company also advises not using the product with some antidepressant medications due to drug interactions.

To avoid side effects, people can ensure they follow the manufacturer’s serving suggestions or medical advice from their doctor when taking iodine supplements.

Increasing iodine levels above the recommended amount may cause unwanted side effects, such as:

  • diarrhea
  • burning mouth or throat
  • nausea
  • vomiting
  • stomach cramps
  • fever

Iodine is most useful in thyroid function and the prevention of thyroid-related health conditions. It is also essential for brain and bone development in infants and during pregnancy.

However, too much iodine over time can cause enlarged thyroid glands, inflammation of the thyroid, and thyroid cancer. Therefore, anybody taking iodine supplements must adhere to the appropriate dosage.

The upper limit for iodine differs by age. The table below details the upper limits for iodine per each age group, according to the National Institutes of Health (NIH):

AgeDaily upper limit
Children 1–3 years200 mcg
Children 4–8 years300 mcg
Children 9–3 years600 mcg
Teens 14–18 years900 mcg
Adults aged 19 and over1,100 mcg

The NIH notes these levels reflect total iodine intake from all sources, including food and supplements. They do not apply to people taking iodine under a doctor’s care.

Below are some common questions about iodine supplements.

What are the symptoms of low iodine?

Symptoms of an iodine deficiency include:

  • weight gain
  • lethargy
  • weakness
  • cold intolerance
  • dry skin
  • hair loss
  • menstruation changes
  • slow heart rate

Find out more about the symptoms of iodine deficiency here.

What are iodine supplements good for?

Iodine supplements may provide the most benefit to pregnant people and people who do not get enough iodine from the food they eat, such as those following a vegan diet.

How long does it take for iodine supplements to work?

It may take a few weeks for iodine supplements to begin having positive effects, but it is difficult to say exactly how long it will take. It depends on many factors, such as the dosage and the severity of a person’s iodine deficiency.

Iodine is an essential mineral that promotes thyroid function. It is not naturally produced by the body but is contained in many foods. Supplements may help people who need to increase their iodine levels, such as pregnant people.

People should always seek medical advice before considering iodine supplements. When purchasing a supplement, they should ensure the manufacturer they choose uses third-party testing.

To avoid side effects, people can follow manufacturer dosage instructions and take care not to exceed the upper iodine intake levels.