5 Best Iodine Supplements for Thyroid Support: Nutritionist’s Pick

Fact checkedFact Checked

This article is reviewed by a team of registered dietitians and medical doctors with extensive, practical clinical and public health experience.

 

Advertiser Disclosure

All products picked below are evaluated by our objective standards of quality and scored accordingly. Health Canal is part of an affiliate program of brands where we earn a small commission from your purchase choice.

Learn more about how we earn revenue by reading our advertise disclaimer.

Blanca Garcia

Updated on - Written by
Medically reviewed by Dr G. Michael DiLeo, MD

Peak Performance Raw Whole Food Iodine from Organic Kelp

Peak Performance Raw Whole Food Iodine from Organic Kelp

  • Vegan-friendly 
  • Good Manufacturing Practices certified (GMP)
  • Third-Party Tested

Life Extension Sea-Iodine Capsules

Life Extension Sea-Iodine Capsules

  • Iodine sourced from kelp and bladderwrack
  • Affordable
  • 12-month return policy

$10 off $75 Order + Free Shipping Code: AFFNEW10

Mary Ruth's Nascent Iodine Liquid Drops

Mary Ruth’s Nascent Iodine Liquid Drops

  • Liquid form
  • Third-Party tested
  • Organic and Vegan-friendly

Ever wonder why your salt is iodized? Having an iodine deficiency can affect the body significantly. Therefore, many countries have programs that add iodine to salt. Iodized salt increases iodine in the diet and prevents health conditions related to not having enough iodine in the body. Having a healthy thyroid function can help solve some problems associated with hypothyroidism (low-functioning) or hyperthyroidism (over-functioning). Symptoms associated with imbalanced iodine levels, whether the dysfunction is hypo- or hyper-, can be weight gain, tiredness, brittle hair, hair loss, or nervousness.

Food sources of iodine can be foods like seaweed, fish, other seafood, eggs, some dairy products, and iodine supplements. Not having enough iodine can be most common among people who don’t consume iodized salt, pregnant women, vegans, people who eat few or no dairy products, seafood, eggs, or people who live in areas with iodine-deficient soils[1].

Finding the iodine supplement that fits your lifestyle is now doable, and it can accommodate many preferences. First, many iodine supplements already come with 100% of the daily value; other options are liquid iodine supplements, vegan iodine supplements, prenatal supplements, and organic supplements.

Best Iodine Supplements for Thyroid Support in (July. 2022)

What Is Iodine?

Iodine is an essential mineral and important for thyroid health[2]. Iodine also helps with immune function, the development of the skeleton, and the central nervous system. Being labeled “essential” is why iodine is given its place of importance. 

Iodine comes in several forms; the most common are sodium iodide and potassium iodide, known as iodide salts. Its use in health helps establish proper thyroid function to control the making of thyroid hormone and its secretion for normal metabolism. This protects the body from an underactive thyroid, resulting in hypothyroidism, or from iodine levels that are so high in an overactive thyroid that they can cause hyperthyroidism. Iodine also functions as a blocker of iodine-131 exposure, a type of radioactive iodine[3]; therefore, the solution for such radioactive exposure is a non-radioactive potassium iodide tablet. 

To find the five best iodine supplements for thyroid support, read on.

The Line Up At A Glance

Peak Performance Raw Whole Food Iodine from Organic Kelp

Editor’s Choice

Peak Performance Raw Whole Food Iodine from Organic Kelp

  • Vegan-friendly 
  • Good Manufacturing Practices certified (GMP)
  • Third-Party Tested

Life Extension Sea-Iodine Capsules

Best Value

Life Extension Sea-Iodine Capsules

  • Iodine sourced from kelp and bladderwrack
  • Affordable
  • 12-month return policy

$10 off $75 Order + Free Shipping Code: AFFNEW10

Mary Ruth's Nascent Iodine Liquid Drops

Best in liquid form

Mary Ruth’s Nascent Iodine Liquid Drops

  • Liquid form
  • Third-Party tested
  • Organic and Vegan-friendly

Thorne Iodine and Tyrosine

Most Potency

Thorne Iodine and Tyrosine

  • Includes Tyrosine for adrenal support
  • Derived from natural flavors and colors
  • Gluten, dairy, and soy-free

NOW Supplement, Kelp 150 mcg of Natural Iodine

Best Natural Ingredients

NOW Supplement, Kelp 150 mcg of Natural Iodine

  • GMP certified
  • Iodine sourced from kelp
  • Vegan-friendly, halal, kosher, non-GMO

How Does Iodine Work?

Iodide controls thyroid function, specifically decreasing the thyroid response to the thyroid-stimulating hormone. Intake is essential in making the thyroid hormones thyroxine (T4) and triiodothyronine (T3) [4]. It’s so important that it’s on the World Health Organization’s List of Essential Medicines [5]

The entire metabolism of the human body is managed by thyroid function in what’s called a “negative-feedback loop”[6]. Metabolism, when it needs adjustment, i.e., speeding up or slowing down, will act on the production of thyroid-stimulating hormone (TSH). When TSH is low, the thyroid is less stimulated, as in cases when the metabolism is too fast and needs slowing down; alternatively, when the metabolism is too slow, TSH is elevated, and thyroid function increases, i.e., to crank out more T3 and T4 to boost metabolism.

The “negative feedback” part acts like this: when T3 and T4 get high, the brain senses this and makes less TSH slow their production. The opposite is true, too–when T3 and T4 get too low, more TSH is made to counteract this. T3 is the active thyroid hormone, so T4 can be thought of as a storage hormone: T4 is then converted into T3 on demand. In a sense, the whole thing works like a thermostat[7].

As a medicine, it has many uses; for example, it’s used as an antiseptic in operating rooms[8]; it enters microorganisms by penetrating their cells and attacking a specific amino acid that results in cell death. 

Pregnant women with a severe iodine deficiency increase the risk of fetal neurodevelopmental problems and delayed maturation in the fetus[1]. After birth, there is an increased risk of childhood cognitive dysfunction, deaf-mutism, and stunted growth (“cretinism[9]”). A prenatal supplement may be the most appropriate therapeutic intervention when the dosage is specifically indicated for this population. 

When you don’t get enough iodine, it cannot produce thyroid hormones. T3 and T4 dwindle, which cranks up TSH secretion to try (in vain) to compensate. The body can enlarge thyroid tissue in its attempt to correct this dysfunction, leading to goiter, a swelling of the thyroid gland. In small children, less severe iodine deficiencies can lower than average intelligence.

Lastly, iodine needs a healthy balance, and your body is already at work to do this with the negative feedback loop. A chronic reduced intake of iodine can lead to thyroid cancer; on the other hand, an excess of iodine can cause thyroiditis and thyroid papillary cancer[10].

5 Best Iodine Supplements for Thyroid Support in 2022

Peak Performance Raw Whole Food Iodine from Organic Kelp

Peak Performance Raw Whole Food Iodine provides iodine sourced from the actual kelp plant for the most natural way to obtain iodine.

  • Vegan-friendly 
  • Good Manufacturing Practices certified (GMP)
  • Third-Party Tested
  • Discounts only available with a subscription

The Peak Performance vegan iodine supplements are the editor’s choice because they offer raw organic kelp, an ingredient with vegan-friendly capsules processed in a GMP facility and third-party tested. It provides its iodine from the whole plant of organic kelp plant at a dosage that meets 100% of the recommended daily value. 

This iodine supplement is ideal for people who may not get iodine through their regular diet[1]. It helps maintain optimal energy levels; its contents are whole food organic kelp, boosting immunity and supporting a healthy thyroid gland. You can take one capsule per day; the manufacturer cautions to consult with a physician if you are pregnant, nursing, taking medication, or have medical conditions. 

Peak Performance products are manufactured and tested in the US and are non-GMO and gluten-free. You can purchase this product at a discount with a subscription or if you buy in bulk. You get a 30-day money-back guarantee that promises no hassles.

Life Extension Sea-Iodine Capsules

Life Extension Sea-Iodine Capsules

$10 off $75 Order + Free Shipping Code: AFFNEW10

See Life Extension Reviews

A unique blend of two different marine plants for iodine supplementation helps you reach your goals. To help provide a healthy thyroid function, you get organic kelp and bladderwrack extracts.

  • Iodine sourced from kelp and bladderwrack
  • Affordable
  • 12-month return policy
  • Exceeds Daily Value at 667%

Life Extension Sea-Iodine Capsules provide natural sources of iodine through kelp and bladderwrack marine plants. These plants are great sources of iodine and can easily satisfy the nutritional needs of iodine. You will also get potassium iodide included in this supplement. 

In this supplementation, you get quite a high amount of iodine at 1000 mcg, not surpassing the established UL of iodine[11] of 1,100 mcg but getting quite close. When considering this supplementation, consider what other supplements are being consumed. Also, if the diet already provides a good amount of iodine, this supplement may not be appropriate. You don’t want to overshoot–remember the balance cited above.

You should always consult with your physician if you plan on iodine supplementation; the risks of overconsuming can create symptoms similar–yet opposite–to iodine deficiency[12]

Life Extension provides an affordable supplement, and you can get an additional discount if you purchase in bulk. The dosage is one capsule per day, with no advantage or disadvantage in taking it with water or food. You get a 12-month money-back guarantee.

Mary Ruth’s Nascent Iodine Liquid Drops

A liquid iodine supplement to help with thyroid health, a role in metabolism function, and maintain normal immune and central nervous system function. 

  • Liquid iodine
  • Third-Party tested
  • Organic and Vegan-friendly
  • Discounts only available with a subscription

If you don’t like taking capsules; Mary Ruth’s offers this liquid potassium iodide supplement. According to its supplement facts label, you will get the daily value for pregnant and lactating women at 86%. Beware that this does not mean that this supplement is appropriate for pregnant or lactating women; always consult with your physician before taking any supplements[1]

However, it does provide 167% of the daily value for a non-pregnant person to support thyroid health, support the immune system and central nervous system, and generally improve iodine levels. 

You can get this product discounted if you subscribe. It’s recommended to shake well when using it. Adults take 1-2 drops or, as recommended by a physician, use a spoon to avoid contamination of the dropper–or add to water or juice. It has a no-hassle 90-day money-back guarantee with no need to return the product. 

Thorne Iodine and Tyrosine

You can get this iodine supplement that includes tyrosine for the optimum thyroid gland and adrenal function.

  • Includes Tyrosine for adrenal support
  • Derived from natural flavors and colors
  • Gluten, dairy, and soy-free
  • Tyrosine may not be tolerated

Thorne provides a unique iodine supplement that includes the amino acid tyrosine for adrenal support, making adrenaline, but also dopamine and other neurotransmitters, thyroid hormones, and melanin[13]. Of course, included is also the iodine as potassium iodide. The daily value for the iodine is 150%, and the tyrosine does not have an established daily value. 

With this supplement, you can get even more help with thyroid hormone production. If you are already on thyroid medication or your levels of the two thyroid hormones, T3 or T4, are too high or too low, this extra amino acid can affect the levels[12], requiring medical supervision.

You can take two capsules a day or as recommended by a health professional. It is not recommended for pregnant women. You can purchase the product at a discount if you subscribe. With a 60-day money-back guarantee, you can return the product for a full refund or credit toward a future purchase. 

NOW Supplement, Kelp 150 mcg of Natural Iodine

NOW Kelp supplement sources its iodine content from kelp, brown algae found in forests in the colder parts of the ocean. 

  • GMP certified
  • Iodine sourced from kelp
  • Vegan-friendly, halal, kosher, non-GMO
  • Strict return policy

NOW supplement kelp provides 100% of the recommended daily value of iodine through the natural source of kelp. This product helps support healthy thyroid function, is GMP certified, vegan-friendly, halal, kosher, and non-GMO. 

With NOW supplements, you will get 200 capsules equivalent to about a six-and-a-half-month supply. The recommended dose is one capsule per day with a meal and is recommended for adults only. 

The manufacturer cautions to consult with a physician if you are pregnant, breastfeeding, are on thyroid medication, or have thyroid disease. The 30-day money-back guarantee is conditioned on the product being unused and unopened, and the guarantee only applies if the product is purchased from the manufacturer’s website.

How to Choose An Iodine Supplement?

When choosing an iodine supplement, some factors are important to consider. The most important is the dosage, followed by ingredient content, quality, and price.

The dosage of iodine can vary among iodine supplements. Dietary supplements are not regulated by the Food and Drug Administration (FDA); therefore, there aren’t any government restrictions on the dosage required in the iodine supplements. Some can have too much iodine that, can exceed the Upper Limits (UL), and affect thyroid health.

Some dietary supplements come with iodine included, so before choosing an iodine supplement, check that all other dietary supplements you take don’t exceed the recommended intake. You may also want to know which type of iodine; you can find supplemental iodine as sodium iodide, potassium iodide, or iodate. The one that seems to be absorbed almost completely is the potassium iodide at 96.4%[14]

Quality is hard to check, and often people rely on name brands for trust. The best way to determine quality is the manufacturer’s voluntary third-party testing. 

Price can vary significantly, but more expensive does not mean better quality, so beware of paying too much for a supplement that may not be the best quality.

How Much Iodine Should I Take Daily?

Recommended Dietary Intake (RDA) for daily iodine in men and women ages 18 and above is 150 mcg of iodine. For pregnant or lactating women under a doctor’s supervision, the RDA increases to 220 mcg of iodine, increasing even more for lactating women to 290 mcg of iodine[1]

There are also recommendations for iodine intake for children, but it’s best to consult with a pediatrician before providing a child with iodine supplementation. 

Safety Precautions

Just because iodine is essential does not mean you need to take a supplement for it. A high intake of iodine can give just as concerning symptoms as iodine deficiency. With high intake, you can experience feelings of jitteriness, nervousness, anxiety, rapid pulse, weight loss, bulging eyes, risk of developing goiter, high levels of TSH, iodine-induced hyperthyroidism, thyroiditis, or thyroid papillary cancer.  Cosmetically, you risk protruding eyes (thyroid eye disease called “exophthalmos”).

Final Thought

Choosing to take supplements is often a personal decision. Although iodine is an essential mineral, a physician consult is warranted, if not necessary, in the case of iodine supplements. Specifically, if a person has medical conditions related to the thyroid, manipulating the intake of iodine with supplements can cause iodine-induced medical complications. 

Most iodine supplements include high doses of iodine that can place it above the recommended amounts when combined with dietary iodine. You might have to do the simple arithmetic to add up what you get naturally with what you take with supplements so as not to exceed the RDA. 

If you search for additional iodine because you fall in the category of those at risk for not having enough iodine, you should first attempt to supplement with the top food sources. You can add iodine-rich foods through a balanced diet like whole-wheat bread baked with potassium iodate dough conditioner, baked cod, seaweed, kelp, oysters, greek yogurt, and iodized table salt. 

If at this point, those are foods that you either may not like or don’t fall into your desired style of eating, then iodine supplements can be beneficial.

Frequently Asked Questions

What is the best form of iodine to take?

It’s best to consume iodine through whole food sources.

Which iodine is best absorbed?

Several forms are available, yet a small study indicates that potassium iodide is almost completely absorbed at 96.4%[14].

Who should not take iodine?

Everyone needs some form of iodine, but children should not take iodine when it comes to supplementation unless diagnosed with a deficiency and managed accordingly by a pediatrician. Likewise, other groups like pregnant, breastfeeding, and people with thyroid conditions should only do so under medical supervision.

How many mcg of iodine should I take daily?

For a person, male or female over 18, the Recommended Dietary Allowance is 150 mcg of iodine. It increases to 220 mcg of iodine for pregnant women and 290 mcg of iodine for breastfeeding women.

Can I take an iodine supplement if I’m allergic to shellfish?

With an allergy to shellfish, it’s not the seafood iodine you’re allergic to but proteins specific to the shellfish. Therefore, you should be able to take iodine supplements if first cleared by your doctor. People allergic to actual iodine have reactions when iodine is used in diagnostic testing; if so, that could be a deal-breaker–again, check with your doctor.


+ 14 sources

Health Canal avoids using tertiary references. We have strict sourcing guidelines and rely on peer-reviewed studies, academic researches from medical associations and institutions. To ensure the accuracy of articles in Health Canal, you can read more about the editorial process here

  1. NIH, .(n.d). Iodine – Health Professional Fact Sheet. Available at: https://ods.od.nih.gov/factsheets/Iodine-HealthProfessional/
  2. Institute of Medicine and National Research Council. 1999. Exposure of the American People to Iodine-131 from Nevada Nuclear-Bomb Tests: Review of the National Cancer Institute Report and Public Health Implications. Washington, DC: The National Academies Press. DOI: 10.17226/6283.
  3. NECH. (2018). Radioisotope Brief: Iodine-131 (I-131). Available at: https://www.cdc.gov/nceh/radiation/emergencies/isotopes/iodine.htm.
  4. Cleveland Clinic. (2022). Thyroid Hormone: What It Is & Function. Available at: https://my.clevelandclinic.org/health/articles/22391-thyroid-hormone.
  5. Essential Medicines (2021). WHO model list of essential medicines – 22nd list, 2021. [online] Who.int. Available at: https://www.who.int/publications/i/item/WHO-MHP-HPS-EML-2021.02 ‌
  6. UCLA Health, (n.d). Normal Thyroid Hormone Levels: What Are Normal Thyroid Hormone Levels? Normal Thyroid Hormone Level Symptoms, Treatment, Diagnosis – UCLA. Available at: https://www.uclahealth.org/endocrine-center/normal-thyroid-hormone-levels.
  7. American Thyroid Association. 2015. Thyroid Function Tests | American Thyroid Association. Available at: https://www.thyroid.org/thyroid-function-tests/.
  8. Rabih O. Darouiche, M.D., Matthew J. Wall, Jr., M.D., Kamal M.F. Itani, M.D., Mary F. Otterson, M.D., Alexandra L. Webb, M.D., Matthew M. Carrick, M.D., Harold J. Miller, M.D., Samir S. Awad, M.D., Cynthia T. Crosby, B.S., Michael C. Mosier, Ph.D., Atef AlSharif, M.D., and David H. Berger, M.D. (2010). Chlorhexidine–Alcohol versus Povidone-Iodine for Surgical-Site Antisepsis. N Engl J Med 2010; 362:18-26. DOI: 10.1056/NEJMoa0810988
  9. Salisbury S. (2003). Cretinism: The past, present, and future of diagnosis and cure. Paediatrics & child health, 8(2), 105–106. https://doi.org/10.1093/pch/8.2.105
  10. Zimmermann, M. B., & Galetti, V. (2015). Iodine intake as a risk factor for thyroid cancer: a comprehensive review of animal and human studies. Thyroid Research, 8, 8. https://doi.org/10.1186/s13044-015-0020-8
  11. Institute of Medicine. (2001). Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: The National Academies Press. DOI: 10.17226/10026.
  12. Aakre, I., Solli, D. D., Markhus, M. W., Mæhre, H. K., Dahl, L., Henjum, S., Alexander, J., Korneliussen, P. A., Madsen, L., & Kjellevold, M. (2021). Commercially available kelp and seaweed products – valuable iodine source or risk of excess intake?. Food & nutrition research, 65, 10.29219/fnr.v65.7584. https://doi.org/10.29219/fnr.v65.7584
  13. Mullur, R., Liu, Y. Y., & Brent, G. A. (2014). Thyroid hormone regulation of metabolism. Physiological Reviews, 94(2), 355–382. https://doi.org/10.1152/physrev.00030.2013
  14. Aquaron, R., Delange, F., Marchal, P., Lognoné, V., & Ninane, L. (2002). Bioavailability of seaweed iodine in human beings. Cellular and molecular biology (Noisy-le-Grand, France), 48(5), 563–569.
Blanca Garcia

Written by:

Blanca Garcia, RDN

Medically reviewed by:

Blanca is a Registered Dietitian Nutritionist and freelance nutrition writer from Los Angeles, CA. She has more than 8 year’s experience in nutrition and dietetics. She is a Latina and enjoys traditional Mexican and Salvadoran cooking, eating flavorful meals and sharing her knowledge about food and nutrition with others through her writing.

Medically reviewed by:

Harvard Health Publishing

Database from Health Information and Medical Information

Harvard Medical School
Go to source

Trusted Source

Database From Cleveland Clinic Foundation

Go to source

Trusted Source

Database From U.S. Department of Health & Human Services

Governmental Authority
Go to source

WHO

Database from World Health Organization

Go to source

Neurology Journals

American Academy of Neurology Journals

American Academy of Neurology
Go to source

MDPI

United Nations Global Compact
Go to source

Trusted Source

Database From National Institute for Occupational Safety & Health

U.S. Department of Health & Human Services
Go to source

Trusted Source

Database from U.S. National Library of Medicine

U.S. Federal Government
Go to source

Trusted Source

Database From Department of Health and Human Services

Governmental Authority
Go to source

PubMed Central

Database From National Institute Of Health

U.S National Library of Medicine
Go to source