Joel Fuhrman, MD, who practices so-called functional medicine and integrative medicine, sells an at-home urine iodine test on his website for $131. He claims the test can assess if one is deficient in iodine. The test requires two urine samples (morning and evening) dried on filter paper and submitted by mail.

Dr. Fuhrman recommends avoiding salt and supplementing with iodine. He says:

If the iodine results are low, please note it still is NOT recommended to consume high and potentially harmful amounts of iodine. Recommended levels of supplementation would be between 150 and 300 mcg/day. For someone with high iodine results, the recommendation would be to reduce or eliminate high iodine seaweed and seafood, all iodinated salt, and not consume more than the 150 mcg/day RDA for iodine.

There is at least one other brand of direct-to-consumer iodine test that sells for much less: $84.99. Even at the lower price, these tests are a waste of money. No test can reliably diagnose iodine deficiency in individual patients.

No test can reliably diagnose iodine deficiency in individual patients.

Single urine tests are not accurate because the level fluctuates due to factors like variation in iodine intake and the amount of water consumed. Iodine excretion can vary from day to day even if the iodine intake is the same. The most accurate test measures the total amount of iodine excreted in the urine in 24 hours. More than one 24-hour urine collection should be used to get more reliable results. For population screening, less precision is needed if a large number of people are tested, so single urine tests suffice.

Several respected medical organizations have spoken out against individual iodine testing. The World Health Organization says “Urinary iodine concentrations are, therefore, not useful for the diagnosis and treatment of individuals.” The American Association of Clinical Endocrinologists says “urinary iodine concentrations cannot be used to determine the iodine status of individuals.” The Centers for Disease Control and Prevention says the tests are “useful for classifying population risk but are not categories to define individual risk for adverse health outcomes.” The American Thyroid Association and the Endocrine Society concur.


Iodine deficiency causes goiter, hypothyroxinemia, neurodevelopmental disorders, cretinism, stillbirth, and increased perinatal mortality. Worldwide, it is the leading cause of intellectual and developmental disabilities. Deficiency is bad, but excess is bad, too. Chronic iodine toxicity (intake of over 1.1 mg/day) is associated with increased risk of Hashimoto’s thyroiditis, hypothyroidism, and goiter.

People who live in coastal areas tend to get adequate iodine from their food; those who live in the interior are more likely to develop iodine deficiency. Iodine deficiency is a worldwide health problem, but there is an effective and inexpensive way to combat it: adding iodine to table salt. 120 countries have passed laws requiring salt to be iodized. In the US, goiter was once common, especially in the Great Lakes and parts of the Pacific Northwest. In 1924, the Morton Salt Company made iodized salt available nationally. The incidence of goiter dropped. The IQ of the quarter of the population most deficient in iodine rose by one standard deviation. Iodized salt protects the population as a whole, but some people forgo its protection by choosing specialty salts (kosher, sea salt, etc.) that don’t contain iodine.

Dr. Fuhrman turns back the clock

Dr. Fuhrman doesn’t want us to take advantage of this important public health measure. He recommends avoiding salt and supplementing with iodine at 150-300 mcg (0.15 to 0.3 mg) a day. The RDA is 0.15 mg a day. So he is recommending up to twice the RDA from a supplement, without counting the iodine obtained from foods.

This celebrity doctor is selling an invalid test at an elevated price, telling patients to trust those invalid test results, and making recommendations that go against an accepted public health measure. In my opinion, that is unethical.

Questionable iodine supplements

An email correspondent wrote to ask me about Survival Shield X-2, an iodine supplement touted on the InfoWars website. They claim that “proper iodine levels may provide support for normal response to environmental and dietary toxins to keep your body clean and moving,” that it “supports thyroid health to regulate hormone production and vitality,” and that it “may support breast milk production and quality for new mothers.”

My correspondent asked whether iodine is as critical to good health as claimed, and whether this particular product is worth the money, and if not, what other iodine supplement would I recommend.

I answered,

Iodine deficiency is rare in Western nations. Iodine was added to our salt to prevent deficiency. Even without iodized salt, most people get enough iodine from food. This article covers the subject well: It warns “additional iodine should only be taken with a doctor’s supervision… The amount in the Survival Shield supplement exceeds the maximum recommended daily intake and would be more likely to cause harm than benefit. The health information on the InfoWars website is pseudoscientific bullshit designed to sell overpriced products to naïve customers.

He replied, “but this NON-commercial source NOT SELLING iodine is thought-provoking:”

From that website:

Are there any easy answers? Not really. It appears that both insufficient and excessive amounts of iodine can be problematic. Dr. Christianson believes that a safe daily intake is 150mcg, and that occasionally 1,000mcg (1mg) is tolerable. I, along with others, believe that short-term, high levels of iodine, for specific therapeutic purposes, can be of value, but should only be done briefly, and ideally with the help of a health professional. I believe that we can still safely consume near the Japanese level of intake (1 to 2 mg daily) if it is in a complex form (i.e. seaweed), or if it is the mix of iodine and iodide (e.g. Lugol’s solution). And, as always, I recommend not taking any supplement daily, so skip a few days every week, and give the body a chance to use up any iodine that is in excess of its needs.

It also says,

Because of the extra radiation currently in the environment from the Fukushima power plant meltdown, now is a good time to keep our levels of iodine relatively high.

I answered:

They may not be selling it on their website, but they are a company selling supplements and they tell you where you can buy them. The link you provided is a blog post by an anonymous author and contains information I do not consider reliable (“We need more iodine because of Fukushima” is nonsense.) Please note that he says “I believe” without providing evidence to support his beliefs. And he cautions that supplementation should be done with the help of a health professional. Yes, you can find websites telling you you need iodine supplements, but you can also find websites telling you the Earth is flat. …searching the Internet is full of pitfalls and will lead you to false claims that may be harmful. You are only alarming yourself needlessly.

I went to the website of the Dr. Christianson they referred to. He is a naturopath. He advises against iodine testing, but gives this advice:

  • If you’re on thyroid medication, use non-iodized salt, and avoid iodine in supplements and sea vegetables like kelp.
  • If you’re not on thyroid medication, iodine supplementation is not necessary.
  • If you’re not on thyroid meds and you’re a raw food vegan, use iodized salt and eat at least 3 servings of moderate iodine sea veggies

The so-called Great Iodine Debate is summarized on the unreliable Weston Price Foundation’s website. They cite studies showing that high doses of iodine can prevent and treat a variety of diseases including breast cancer and fibrocystic breast disease. They suggest that iodine may be helpful in treating other cancers because it induces apoptosis, it can detox heavy metals, and it can protect against the harmful effects of fluoridated water (!?). They recommend iodine supplementation in doses considerably higher than the generally accepted upper limits of intake.

Orthomolecular doses

An orthomolecular website makes claims that are not accepted by mainstream medicine. They provide a long list of conditions they say are related to iodine deficiency, including various cancers, reduced alertness, autism, ADHD, fatigue, depression, insomnia, dry skin, muscle pain, fibromyalgia, erectile dysfunction, infertility, miscarriages, overweight, high blood pressure, and an elevated risk of heart attacks and strokes. They speak of “iodophobia,” the idea that mainstream medicine has been unduly biased by faulty research and fears using the high doses of iodine that are required for health. They say that the doses needed to prevent cancer are 100 times the RDA. And they claim that adults need 2-5 mg of iodide daily for optimum health and 15-50 mg a day in illnesses like thyroid disease, fibrocystic breast disease, or cancer. The references they cite are mainly studies by one author, Guy E. Abraham.

Guy E. Abraham

Abraham’s research is cited on the website of the Optimox supplement company. His research studies are not listed on PubMed; he published them in a non-listed alternative medicine publication called The Original Internist, dedicated to promoting natural health care as a primary treatment. The publishing organization also provides marketing and administrative support for the 300-hour Chiropractic Family Practice Diplomate Program.

In a paper titled “ Orthoidodosupplementation: Iodine sufficiency of the whole human body” he starts with a rant about “iodophobia and misinformation about iodine” and goes on to claim that the optimal daily requirement for iodine is 6 mg for the thyroid and 5 mg for the mammary glands. In an “Epilogue” that is decidedly out of place in a scientific publication, he says evolution does not account for our need for extra iodine, but the Biblical account does. The original planet contained a topsoil rich in iodine, but this was washed away by the Flood. He says, “The post-deluvian [sic] worldwide I [iodine] deficiency may be a reminder to mankind of the flood, their fallen state and their need for a Redeemer.”

Requirements in pregnancy and lactation

Iodine requirements are greater during pregnancy and lactation. The World Health Organization and UNICEF recommend iodine supplementation during pregnancy and lactation for women in countries where less than 20% of households have access to iodized salt. This does not apply to the US. The American College of Obstetricians and Gynecologists does not even mention iodine in its webpage on nutrition during pregnancy. On the other hand, the American Thyroid Association and other groups have called for adding small amounts of iodine to all prenatal vitamins.

Conclusion: No need for testing

In my opinion, it is unethical for Dr. Fuhrman to sell those iodine tests without giving customers the information about validity that they need to make an informed decision. There may be cases where iodine supplementation is indicated (pregnancy, lactation, a diet deficient in iodine and iodized salt) but in those cases supplementation (at low doses) should be recommended by a doctor and there is no need for prior testing. High dose “orthomolecular” supplementation is not supported by good evidence. I see iodine testing and supplementation as just another example of alternative medicine creating something for people to worry unnecessarily about and profiting from that worry.

ADDENDUM: Dr Fuhrman wrote to us on May 17, 2018 with this request:

Dear Dr. Gorski and Dr. Hall.

I was hoping you could remove the article criticizing me for selling a urine test for iodine on my website; since I no longer do so.
I had removed that test due to concerns about the misuse and inaccuracy of the test. before I saw this article criticizing me about it.

I do not want a disagreement about this controversial issue to distract from my overall mission of encouraging the consumption of more green vegetables, beans, nuts and seeds in the diet.

Since reviewing the literature on this subject, I agree that these tests are not needed for the general public and I had taken it off our website. However, I do feel there is some value in this test for those who are not using any iodinated salt, seaweed, animal products, or iodine supplements to assure adequacy. The reason urinary iodine testing is often considered inaccurate for individuals is because of day to day variations in dietary iodine intake.1, 2 Consistent intake improves accuracy. Individuals interested in this test will most likely be those who are not taking supplements and not eating any iodized salt or iodine-rich foods. In these individuals, day-to day variation in intake would be small. The other interested group would be those who are potentially eating too much iodine rich foods (such as seaweeds) and are concerned about getting too much iodine.

Although a single fasting urinary iodine test is not considered to be as good as the more accurate 24 hour collection method, performing a urinary iodine test using the ratio of urinary iodine to creatinine from two different urine samples – first thing in morning and last before bed (the method the ZRT test uses) – are similar to 24 hour urine collection results.2 We had encourage users to follow their usual diet and supplemental regimen consistently for days before the test to limit day-to-day variation. Even if iodine results are low, I do not recommend anyone consume high and potentially harmful amounts of iodine. Recommended levels of supplementation would be between 100 and 200 mcg/day. You may be aware there are some advocating very high intake of over 1000 mcg/day and testing was used to convince them to reduce that to safer levels.

  1. Pearce EN, Caldwell KL. Urinary iodine, thyroid function, and thyroglobulin as biomarkers of iodine status. Am J Clin Nutr 2016, 104 Suppl 3:898S-901S.
  2. Soldin OP. Controversies in urinary iodine determinations. Clin Biochem 2002, 35:575-579.

Thank you for your consideration of this request.

Joel Fuhrman, M.D.

Because this post was accurate at the time it was published we declined Dr. Fuhrman’s request to remove it. We did, however, in the interests of accuracy, agree to post his e-mail response.


Posted by Harriet Hall

Harriet Hall, MD also known as The SkepDoc, is a retired family physician who writes about pseudoscience and questionable medical practices. She received her BA and MD from the University of Washington, did her internship in the Air Force (the second female ever to do so),  and was the first female graduate of the Air Force family practice residency at Eglin Air Force Base. During a long career as an Air Force physician, she held various positions from flight surgeon to DBMS (Director of Base Medical Services) and did everything from delivering babies to taking the controls of a B-52. She retired with the rank of Colonel.  In 2008 she published her memoirs, Women Aren't Supposed to Fly.