Is Iodine Safe for Hashimoto’s Patients?

Hashimoto’s thyroiditis is a condition whereby the immune system attacks enzymes within the thyroid gland, impairing their function and often damaging thyroid cells in the area. The result is low response from the thyroid gland to stimulation. Blood work shows high TSH and low T4, and a diagnosis of “hypothyroidism” is given. However, most doctors don’t know that autoimmunity is the cause, because they don’t test for the anti-TPO and anti-TG antibodies that would show this. However, the official figures show that 0.3-5 people per 1,000 develop this condition each year, with it 15-20 times more likely to occur in females. These figures may significantly underestimate the condition.

While many doctors simply ignore the cause and settle on a lifetime of thyroid drugs for their patients, there are plenty that do order these assessments and try hard to address the causes. Where Hashimoto’s is concerned, there are a number of factors that have a huge impact on dealing with the autoimmunity: gluten and food intolerances are a huge factor, as are chronic infections, Vitamin D deficiency and stress levels. There is little disagreement on this. However, there is fierce debate as to the role of iodine in the management of Hashimoto’s.

Epidemiological studies, ie. those that examine patterns across an entire population, found that increased intakes of iodine are correlated with increases incidences of autoimmune disease. This pattern could be seen in several studies that looked into the effect of adding iodine to water or food staples in populations that were previously suffering from iodine deficiency disorders, like goiter. But, whereas in some populations the addition of iodine appeared to simply swap goiters for autoimmune disease, this effect simply did not appear in other studies (Aghini-Lombardi et al, 1999; Strieder et al, 2008).

Dr Datis Kharrazian, Chris Kresser and Dr David Clark all firmly oppose the idea of providing iodine to Hashimoto’s patients and have described the addition of iodine to an individual undergoing an autoimmune attack to ‘adding gasoline to a fire’. However, Dr Guy Abraham, Dr Jorge Flechas and Dr David Derry all list iodine as the most valuable tool to use in Hashimoto’s. Patient advocate groups say that ‘some people do well on high-dose iodine, others do not’. How can there be such a difference opinion? Well, the question should be: why are the last four doctors getting good results from iodine when the others are not?

And the answer is quite obvious. The latter four all recommend selenium alongside the iodine. The addition of this mineral changes the picture altogether. But, first, let’s look at why some doctors suggest you avoid iodine if you are inclined towards hypothyroidism/autoimmunity. The idea goes that increased iodine leads to increased levels of Thyroid Peroxidase. This enzyme is already the target of the attack, so increased levels result in a further attack.

This theory makes sense but, as well as ignoring the role of selenium, it’s not actually what happens. When you provide iodine in large doses, the level of TPO actually decreases (Xu et al, 2010; Muller et al, 2011; Man et al, 2006). As is so often the case, the 1970s textbooks are wrong; in other words, iodine does not trigger flare-ups of Hashimoto’s through this mechanism and those that tell you this is the case need to go back to school and look at the evidence.

However, it is true that providing more iodine without additional selenium DOES reliably induce autoimmunity if the individual is genetically predisposed to it. How so? Chen et al (2007) demonstrated that, in the presence of selenium deficiency, iodine increased the levels of circulating lymphocytes, types of white blood cell that can enhance an immune attack (including autoimmune attacks). However, the scientists found that providing extra selenium (as well as the iodine) totally reversed this trend, and allowed the subjects to consume iodine at high levels without altering these immune parameters at all from controls. All the benefits of iodine, none of the problems.

They found a similar pattern when they looked at the Th1/Th2 balance in the different groups. Th1/Th2 balance refers to the two arms of the immune system that must cross-regulate one another; the former is responsible for cellular threats, such as viruses, bacteria, fungi and tumours. The latter works outside of cells, and produces antibodies. If Th2 becomes overactive, allergies tend to be the result. If Th1 becomes overactive, autoimmunity is likely to flare. The group who took iodine on it’s own exhibited Th1 dominance; this, in addition to the increased T-lymphocyte population, explains why iodine can and does cause flare-ups of Hashimoto’s when it is thrown into the mix in isolation.

The conclusion that can be made from the above measurements is that isolated iodine makes Hashimoto’s worse, and that iodine and selenium does not make it worse. However, the combination treatment actually makes a positive difference: the researchers went on to study the CD4+/CD8+ ratio in all the treatment groups. This is relevant because, the ratios of these lymphocytes is used to indicate the severity of an autoimmune attack; the lower the ratio, the worse the problem. High-dose iodine used in isolation lowered the ratio compared to controls. Iodine and selenium in combination increased the ratio compared to controls. Important distinction.

This explains why I have used high-dose iodine in my clinic since 2008 with countless of individuals (including Hashimoto’s patients) and never seen any autoimmune issues. I have always provided selenium and sea salt alongside the halogen element; in some cases, increased Vitamin C also. At levels closer to those of the mainland Japanese, iodine can enter the thyroid gland in sufficient concentrations to form iodo-lactones. These compounds control the level of oxidation, regulating it to the extent that thyroid peroxidase is no longer damaged (this is an important trigger in the cascade of events that results in autoimmune inflammation). Increased levels of iodine can also improve inflammation across the body, help clear chronic infections, improve cellular sensitivity, improve estrogen management and protect against cancer (Brownstein, 2008).

I commend all physicians that are going beyond the normal standard of care, which rarely improves patient well-being and consigns them to a lifetime of thyroid drugs. However, I do not agree with any conclusion against the use of iodine for Hashimoto’s, especially when the explanation given to justify this stance is physiologically incorrect. The scientific evidence for iodine use (with selenium) is strong; my clinical experience unequivocal. Iodine is safe, beneficial and often necessary to rebalance the thyroid function in Hashimoto’s.

In the three and a half years since writing this article, I have worked with two individuals who have seen their antibody count increase after using high-dose iodine (2/38 = 5%). In both cases, testing showed issues with oxalates. Resolving issues with oxalates yielded a lot of benefits and also saw both tolerate the iodine in a positive fashion.


Aghini-Lombardi et al (1999). The spectrum of thyroid disorders in an iodine-deficient community: the Pescopagano Survey. J. Clin. Endocrinol. Metab. 84, 561-566

Brownstein (2008). Iodine: Why You Need It and Why You Can’t Live Without It. Medical Alternative Press.

Chen X et al (2007). Effect of excessive iodine on immune function of lymphocytes and intervention with selenium. J Huazhong Univ Sci Technolog Med Sci. Aug;27(4):422-5.

Muller K et al (2011). Effect of iodine on early stage thyroid autonomy. Genomics. Feb;97(2):94-100.

Man N et al (2006). Long-term effects of high iodine intake: inhibition of thyroid iodine uptake and organification in Wistar rats. Zhonghua Yi Xue Za Zhi. Dec 26;86(48):3420-4.

Strieder TG et al (2008). Prediction of progression to overt hypothyroidism or hyperthyroidism in female relatives of patients with autoimmune thyroid disease using the Thyroid Events Amsterdam (THEA) score. Arch Intern Med. Aug 11;168(15):1657-63

Xu J et al (2010). Supplemental Selenium Alleviates the Toxic Effects of Excessive Iodine on Thyroid. Biol Trace Elem Res. Jun 2.


  1. says

    This is a good posting, I was wondering if I could use this write-up on my website, I will link it back to your website though. If this is a problem please let me know and I will take it down right away

  2. says

    Superb read, I just passed this onto a colleague who was doing a little analysis on that. And he really bought me lunch because I located it for him smile So let me rephrase that: Thanks for lunch!

  3. Sasha says

    Wonderful!!! Superb read. Thank you so much. Those who don’t recommend iodine don’t know how it should be taken. Thank you!!!!

  4. khali says

    hi, can you tell me how much Selenium should i take, i have been taking 200mcg for around a year and now supplementing with Celtic Salt and Lypospheric Vit C, 3,000 mg daily and ATP factors pill twice a day.

    • Marek Doyle says

      It’s difficult to give you a specific answer, as this is normally something I would tailor after a Red Blood Cell Mineral screen. However, 200mcg is a dosage that normally works out to be effective while not disturbing mineral balance.

  5. Tyrker says

    OK, so selenium should be ~200mcg, give or take. What would be a reasonable dose of iodine though? 100mcg, or much more?

    • Marek Doyle says

      The absolute minimum required for healthy thyroid function appears to be around 150-200mcg. However, it seems that this is insufficient to meet the full needs of the body. Most of the research indicates around 12.5mg (12,500mcg) is optimal, and this does appear to work well in most, However, from my observations, many people can get all the benefits with half this amount.

  6. Nathalie says


    I seem to have a mild case of hashi Endo did palpate a bit of inflammation in thyroid but if TSH is 1.3 / 1.7 and ANTI-TPO never above 39 (0-34) would the use of iodine still be indicated? I don’t know my Ft3 Ft4 level yet (checking for low T3 syndrome). Trying to find out where my symptoms come from (fibro diagnosis – hyperlaxity and endometriosis then total hysto in 2013 and all got worse). Thanks for this great article!!

    • Marek Doyle says

      It’s difficult to come to any conclusions without a full blood panel, although it does not sound like you have had anti-TG measured (some doctors try to save £16 by not testing both types of antibodies, anti-TPO and anti-TG). Without testing both, a negative test like yours means nothing. If there is palpable inflammation, then a complete thyroid panel is a necessity.

      • Dan says

        Could I have induced Hashimoto’s Disease by taking 12.5 mg of iThroid? I took i-Throid for approximately 12 weeks without any previous testing for aTPO or FrT4. On a routine physical my TSH, which was previously normal (2.44), went high (14), Free T4 Low (.49), aTPO high (201) and Thyroglobulin was normal (<20). I was asymptomatic at the time, but got scared and discontinued the iodine supplement. Five weeks later I started having brain fog issues which increased in intensity over the next five weeks. I had my thyroid levels retested and everything was within range except aTPO which was elevated at 161. Could the iodine supplement caused this problem and how do I address the brain fog issue considering all my other thyroid levels are okay except aTPO.

        • Marek Doyle says

          I’ve been keeping an eye on these things for the last 8 years and, in every case, it has been a case that, for individuals with low selenium stores, high-dose iodine has triggered/unmasked the autoimmunity. But not caused it… It’s difficult to make any conclusions from these two tests because the very nature of autoimmunity is that it ebbs and flows. Could the iodine have increased your anti-TPO? It’s very feasible, especially if you are short on selenium (which we do not know at this point). So I would be keen to test/correct your selenium levels first and then reconsider the iodine. Meanwhile, the brain fog could relate to the withdrawal of iodine but there are so many other areas than can cause brain fog (adrenal issues, dysbiosis, low B12, acute infections, poor sleep) so these should all be investigated.

  7. Susan says

    I have Hashimoto’s and very high count of antibodies (above 1300). I am taking selenium but my doctor told me to avoid any iodine.
    What should I do?

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