A Primal Primer: Iodine

Yesterday I mentioned that sea vegetables are a great source of iodine. “But what is iodine?” many emailers asked. Well, dear friends, iodine is elemental. Let’s take a trip through the land of iodine to learn what it is, what it does for the human body and whether you should make an effort to get more iodine in your diet.

What is Iodine?

Iodine is a highly water-soluble trace element that’s rare in the earth’s crust, but fairly prevalent in its seas. Our bodies require it, for several reasons. Our thyroid glands use it to make thyroid hormones (T3 molecular weight is 59% iodine; T4 molecular weight, 65%), and a severe deficiency can manifest in the development of goiter, which is the thyroid gland swelling up in an attempt to keep up the pace of iodine uptake from the blood and thyroid hormone production. Lovely stuff, eh? Other common symptoms of iodine deficiency include hypothyroidism and hyperthyroidism. It can also increase the incidence of early mental retardation (iodine deficiency-related retardation is the most preventable kind, in fact), and even stunted infant brain development, provided the kid even makes it out alive: iodine deficient pregnant women are at a higher risk for miscarriages and stillbirths.

Today, most table salt has been iodized, and most processed food is in turn made with plenty of iodized salt. As Richard pointed out a few months back, an unintended benefit of the SAD may be the adequate intake of iodine! Ironically, hyper conscious eaters who eschew all processed foods and sprinkle shavings of the purest Himalayan salt blocks (reconstituted, perhaps, from the sweaty pits of organic Sherpas) on their meals may be missing out on iodine. Sea salt does contain trace amounts of iodine, being from the sea, but what’s there degrades pretty rapidly. Subsisting on sea salt alone is almost certainly inadequate for iodine intake. If you avoid processed food (as you should), be sure to eat sea vegetation from time to time.

Iodine Dosage

Iodine dosage is a tricky one to get a handle on. While the RDA of 150 micrograms is sufficient to prevent goiters (kinda like the RDA for vitamin D is enough to prevent rickets), it probably isn’t optimal, and humans can definitely handle larger intakes. After all, coastal-dwelling sorts, like the Japanese, have regularly been consuming iodine-rich sea vegetables for ages without wide-scale thyroid problems – some even suggest this level of intake is preventive against thyroid disorders and breast cancer. Most accounts put them at 5-12mg of iodine daily. The Japanese also consume a fair amount of soy, which has been shown to be antagonistic to iodine uptake, so perhaps they’ve found a balance between the two. At the same time, iodine supplementation can be overdone, leading to hyperthyroidism.

I lean toward the RDA being short sighted and rather inadequate, to be honest. The tolerable daily upper limit of 1 mg seems better. As they tend to do, the experts cast iodine in a single, solitary role – as the prime regulator of thyroid health and function – and ignore any possibility that it’s important in other realms, too. That’s madness, just like it’s madness to presume vitamin D is only about protecting rickets, even as evidence of its cardio-, immuno-, and carcino-protective effects mount. It’s often stated that the thyroid only needs around 100 micrograms of iodine per day to manufacture sufficient amounts of thyroid hormone and this is used as evidence of the RDA’s accuracy. But only 30% of the body’s total iodine content is concentrated in the thyroid. The rest of it is found in the mammary glands, eye, gastric mucosa, cervix, thymus gland, and salivary glands. If the body is doing something with any sort of consistency, if there’s a pattern to its processes, it’s probably playing an important – even if not entirely understood – role.

Let’s take a closer look at how iodine functions in the human body.

Fetal Development

The fetal thyroid gland begins to function at the 11 week mark of gestation, and at the 18th week, T4 is being produced by the fetus in order to develop its nervous system. The child’s neurological development also depends on proper functioning of the fetal thyroid glands. Sufficient iodine intake (by the mother, of course) is required for sufficient thyroid action in the fetus, just as it’s required in adult thyroids.


After birth, the child still depends on the mother for his or her iodine. Those little brains are experiencing their most rapid period of growth and development, and they need plenty of iodine to avoid impaired cognitive development. Nursing increases the dietary requirement for iodine.


Iodine has been effective in the therapeutic treatment of certain immune disorders, and researchers are beginning to understand how it works on the molecular level. Research (PDF) shows that iodine often gathers in damaged or diseased tissue, and it accumulates during phagocytosis, the process by which our immune systems attack, engulf, and consume foreign bodies or bacteria, suggesting a crucial role. During an acute infection, T4 hormone is actually subject to deiodination – the removal of iodine from thyroid hormone – and the resultant iodine is presumably mobilized for defensive aid.

Thyroid Cancer

When the thyroid is starved of iodine, it takes whatever it can get. And if an influx of radioactive iodine is suddenly made available, say, after a nuclear disaster, our thyroids will lap it all up if there’s a deficit in the body. After the Chernobyl disaster, for example, residents living in areas which administered pharmacological doses of potassium iodide in response to the blast reported (PDF) far fewer incidences of thyroid cancer when compared to residents that did not receive iodine supplements. It makes sense, then, to keep your iodine levels topped off to prevent uptake of radioactive iodine.

To figure out if you’re deficient in iodine, consider taking an iodine loading test. Dr. Eades discusses this in his latest book, and here’s how it works: take a large, 50mg dose of iodine; over the course of the next 24 hours, monitor the iodine levels of your urinary output. If you excrete most of it – say, 90% of the 50mg – you already have adequate stores of iodine. If you excrete very little iodine, that’s an indication of an iodine deficiency that your body is trying to correct.  If you’re deficient, consider eating more sea vegetables (daily) or taking an iodine supplement. Lugol’s solution and Iodoral are both good choices that many in the Primal sphere have taken with great success. Besides the obvious example of sea vegetables and seafood, eggs, milk, yogurt, and strawberries all contain decent amounts of iodine – enough to satisfy the RDA, at least, but not to achieve higher, possibly more therapeutic levels.

Who Should Take Iodine?

Those who eat a lot of raw broccoli, cauliflower, cabbage, brussel sprouts, bok choy, collard greens, mustard greens, Chinese broccoli/cabbage, radishes, rutabagas, turnips, rapini, kale, millet, soy, cassava, spinach, pine nuts, pears, peaches, sweet potatoes, peanuts, or bamboo shoots should supplement with iodine or consider swapping in some sea vegetables. The aforementioned are all sources of goitrogens, which, when eaten raw, prevent iodine uptake by the thyroid gland. Cooking takes care of most of the problem, but variety is always good.

Those with poor intakes of selenium, vitamin A, and iron may be at a greater risk for iodine deficiency symptoms. Eat your salmon, liver, and eggs, folks!

Those with minor hypothyroid symptoms (weight gain, sluggishness, fatigue, fuzzy brain, cold extremities) may want to consider eating more sea vegetables or supplementing with iodine. Richard Nikoley apparently solved his hypothyroid problems with 12.5 mg of iodine a day, and his experiences were corroborated by several commenters. Note that folks suffering from chronic iodine deficiency may react poorly (hyperthyroidism) to a sudden bout of iodine supplementation, if the starved thyroid begins producing thyroid hormone in excess. At the same time, excessive amounts of supplementary iodine can actually prompt the thyroid gland to halt production of thyroid hormone. This is a protective measure, since unchecked amounts of thyroid hormone are dangerous, but it can lead to a chronically down-regulated thyroid hormone production if iodine intake is excessive.

Talk to your doctor or endocrinologist if you’ve got established thyroid issues, like Hashimoto’s thyroiditis, (which has a confusing relationship with iodine; iodine deficiency seems to be the cause of HT, but once you’ve got it, iodine can make things worse by further increasing the thyroid’s resistance to iodine uptake) before supplementing.

Thyroid issues are incredibly complex, and too much iodine can actually exacerbate existing thyroid disorders just as too little can create them, so concrete recommendations can’t really be established. As always, nutrition is incredibly individualistic. We may need the same basic nutrients, minerals, fats, and proteins, and we may react poorly to the same Neolithic foods, but it’s all a matter of scale and degree.

If you have any questions about hyper or hypothyroidism let me know in the comment board and I’ll attempt to answer your questions this coming week. And check back tomorrow for a delicious chicken liver recipe. Grok on!

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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93 thoughts on “A Primal Primer: Iodine”

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  1. Before I went primal, I had a problem with low energy levels. I would have to fight to stay awake at work and school on a daily basis. A friend suggested I might have hypothyroidism and suggested I take some iodine supplements. They did the trick! After a week of taking the pills I was no longer falling asleep, and I quit taking them altogether after a month and haven’t seen any problems.

  2. Ironically enough, I just looked at the ingredients in my prenatal vitamins, and there is no iodine. If iodine has been shown to be so important in pregnancy and breastfeeding, why the heck is it not in a prenatal vitamin?

    Thanks for the good information Mark!

    1. Hahaha, and here I was just assuming that my pre-natals had everything required. Time to grab some seaweed snacks!

      1. Of course I eat enough iodized salt to feed a small army, so….

        1. Getting adequate iodine during pregnancy – eating plenty of gush and seafood, eggs, kelp etc., apparently can help produce very brainy babies….!

  3. I eat several of the produce items that you listed… sometimes cooked and sometimes raw. After yesterdays post and now todays it makes sense that I should start buying sea vegetables or supplement with iodine. I am very interested in trying new things so I will be on the lookout for sea veggies.

    I am sure harvest health has some. Unfortunately there is no trader joes or whole foods by me. I believe sunfood sells them too.

  4. Mark,
    6 months after having my son I developed hyper-thyroid. I am still nursing so have opted to not take the anti-thyroid medication and only take propranolol to control my heart rate. I have also been juicing in my vitamix a mixture of goitrogenic foods to help control my thyroid which has helped my thyroid levels have dropped significantly. My question is am I hurting myself in the long run by consuming the goitrogens and are there any supplements you would recommend?

    1. You might not be hurting yourself with the goitrogenic foods, but propranolol long term is not a good idea. You’re not controlling blood pressure; you’re controlling heart rate, and that typically doesn’t go well for long. I’d suggest talking to your endocrinologist and rethinking the medication.

    2. I had the same issue, I developed hyper-thyroid, AKA Thyroiditis brought on when I birth to my son. I didn’t have to do any anti thyroid medication or the radioactive iodine to kill my thyroid. I found out after seeing a competent endocrinologist, that the thyroid will not take iodine, which is unique to that condition. I was on a beta blocker to help with the symptoms and luckily within 6 months it corrected itself. My TSH level was almost non existent and now it is well into the normal range again. I was told most cases will correct itself within 6 mos, the occasional person will take up to 2 years. About 10% never correct itself. We also came to the conclusion that nursing my son may have delayed the onset because those hormones can effect your thyroid. In fact a lot of women see improvement in their thyroid when they get pregnant. I hope this information is helpful.

    3. It’s worth noting that propanolol is known among the other beta blockers to actually depress T4 to T3 conversion. This is great if you have hypERthyroidism, but not so great if you’re still on it for heart issues or anxiety once your hyperthyroidism treatment has left you hyper.

  5. I had a thyroidectemy at 16 due to cancer. Every year I have a scan that invovles a few weeks of no iodine. I’m amazed at how much iodine is in our food. I swear I mostly just ate watermelon during those times. I find it hard to believe that you would need to supplement. Is this due to the low salt intake with the primal diet?

  6. Great article! This is something I’ve believed to be true for some time especially if you’re not getting enough seafood/sea veggies in. As a competitive distance runner I find supplementing with Iodine at random (when I haven’t had seafood or sea veggies) keeps me up to par! Just wondering what sort of GENERAL recommendation for dosage you would think is reasonable for a very active athlete??

  7. Great article; It might be worth a follow-up detailing iodine vs iodide as different organs use the diffferent forms.

  8. I started taking iodine (12.5mg Lugol’s solution per day) about a month or so ago, and thus far it has almost completely cleared up all my fibrocystic breast tissue and cold/discolored hands and feet. I am amazed at how well it worked–I never thought my hands would EVER be normal-colored!! My fiancee is also taking the same dosage, but not for as long. I would like to get an iodine loading dose test done on us both, but $$ is an issue 🙁
    For now, I just figure that since we only eat seafood maybe 2x a month, and don’t really eat any seaweed at all, we are probably deficient. Plus we livein the midwest which, I believe, has soil very depleted in iodine? I think we’ll go back down to 6.25mg after a bit, and then once the bottle of Lugol’s is gone, we’ll change over to adding kelp flakes to food, and eating seaweed for iodine. What do you guys think? Does this sound like a reasonable plan?

  9. How can the iodine in sea salt “degrade”? Chemical elements can’t degrade, unless they undergo radioactive decay.

      1. You’re thinking of elemental iodine. Iodine in seawater is present as iodide or iodate ions, which do not sublimate.

        1. As it turns out iodides tend to be quite sensitive to air and oxigen. When left in opened container with enough free flowing air, iodized salt can loose almost all of it’s iodine content (via iodide reacting with air oxygen and producing free iodine that sublimes) within forthnight.

  10. Could you write more on hypothyroidism? I’ve stopped taking my medication in hopes that the pb lifestyle will auto correct it. Are my hopes too high?

    1. hypothyroidism can have up to 24 (!) different metabolic causes. it’s nearly impossible to properly address the problem just by guessing what it might be. often, however, an autoimmune disorder is part of the puzzle. because of this, it indeed can not harm to go completely 100% gluten and dairy free for a few month and see what happens. also, there is a ton of great resources about this topic available on the internet. apparently, only very few doctors are capable of diagnosing and treating this extremely complex problem properly.

      1. Thanks for the info. I’ve been working with a holistic doctor for a couple months it’s a long process. I definitely will cut out dairy.

  11. Good stuff. Dr. Davis seems to be adamant that we need more than we’re getting, and it’s probably true, but my problem is that it triggers acne in me. Ever since starting paleo I have been completely clear and my systemic inflammation is lower than ever, and yet just like wheat and dairy, kelp and sea veggies set me off so I have been mainly keeping to the current dietary recommendations. I wonder what the deal is, that’s not normal.

    1. when i first started Iodoral, i had a brief period of bad skin — i strongly suspect that it’s a detox symptom, because it went away soon and never returned. i understand that iodine receptors will take in bromine when not enough iodine is present, and releasing it may cause this….

  12. Very timely post. This is something I’ve been looking into a lot lately. I have symptoms of hypothyroidism and have started taking kelp in hopes that I can offset the symptoms without going through expensive testing. I do have a nodule on my thyroid that the iodine uptake scan says functions normally. It’s too soon to tell if there’s been any benefit. I would love to eat more sea veggies too. =)

    1. If you have early onset of hypothyroid symptoms, the last thing you want to do is increase your iodine intake!

      1. Why is it that increasing iodine is a bad idea if you have early onset of hypothyroid symptoms?

        Aren’t these symptoms a sign of a lack of iodine? I’m confused…

  13. I, too, would very much like to get your take on hypothyroidism. I was diagnosed with a low level a few years ago, and have been following a CW medication routine since then. Sometimes I feel better, and sometimes not. I would be very interested to find another approach that does not involve taking drugs for the rest of my life.

  14. I am hypothyroid, but as you said iodine is complicated. I would like to supplement because I have pretty much cut out iodized salt and think I may be deficient, but I just read a post https://tiny.cc/8iwi7 at the Healthy Skeptic about the dangers of iodine supplementation.

    It’s difficult to know how to proceed.

    1. I just found out that I have hyperpara thyroidism and was told that I need to have a surgery. I like to no if I can revers that? or what can i do.


  15. to all those peeps with hypothyroidism: there is currently a multi-part blog post series available on the following blog which you should read, starting with the folling post: https://thehealthyskeptic.org/the-most-important-thing-you-may-not-know-about-hypothyroidism

    also, i recently stumbled over the following videos about this topic (also check the other parts):

    there are many other great resources on this topic. don’t just rely on your doctor/medication alone – make yourself an expert!

  16. An easier (nearly foolproof) method of ascertaining whether you’re deficient in iodine, and no need to analyze your urine:

    go to the drug store and buy that little brown bottle of iodine. Then when you go home and you know you’re gonna be hanging around the house for awhile, preferably wearing a t-shirt or going sleeveless…then, using a q-tip, swab a little bit of iodine onto the inner elbow – about the size of a quarter. Let it sit. Don’t shower, don’t go rubbing it off on accident. If the iodine is there 15 hours later — you’re fine. If you sucked it all up in less time than that, you’re in need of some iodine.

  17. I would be careful with the iodine loading test.

    First, there are debates as to its effectiveness:

    Second, like Mark mentioned, suddenly upping the dosage can often cause problems for people with an already fragile thyroid.

    Iodine is also a very potent antifungal and is used to clean and disinfect wounds. Note that some people use iodine as an effective way to help with intestinal bacterial overgrowth. I wouldn’t take it at the same time as probiotics because the bacteria will get killed by the iodine as well.

    1. I have read that iodine will NOT kill good bacteria so probiotics taken daily should be fine. Iodine “knows” good from bad? I gave had serious watery “runs” – volumes are surprising… I began with iodine and Arthur Andrew probiotics at the same time. One month ago. I assumed this was from Candida kill off. No?

  18. we take our daily kelp supplements. we also try to steer clear of the raw veggies that were mentioned. i learned that a long time ago from sally fallon. nori is great toasted and used as chips. my girls love ’em!

  19. My PhD dissertation studies the induction of tolerance in patients and models with hypothyroid disease. Iodine will NOT benefit persons with HYPO-thyroid disease. Iodine increases the antigenicity of thyroglobulin, one of the hormones your body attacks in hypothyroidism. It is incredibly dangerous to play with iodine levels if you are diagnosed with hypothyroidism, especially if you are being treated with Synthroid or Levothyroxine. I typically enjoy your posts, Mark, but you’re off on this one!

    1. it may not be politically correct to contradict the medical community, but i have to say, i absolutely disagree with you! what happens in the lab is not necessarily what happens in the body. i’ve been living in this one more than half a century, and when my D.O. recommended Iodoral for my hypothyroidism, my physical condition improved immensely.

      1. You are correct that sometimes what we see in the lab does not translate directly to the human body. However, I have done extensive studies with this (and live with it myself) in the animal model, not just in vivo. I will tell you that my animals less than thrive over the long term when iodine is introduced. I can refer you to approximately 200 primary literature references that corroborate this if you like. Ultimately, however, your decisions should be between you and a specialized endocrinologist.

        1. like the specialized endocrinologist who put me on synthroid? 🙂 that ain’t gonna happen.

        2. Synthroid is the ONLY currently available synthetic thyroid hormone replacement. If you have thyroglobulin deficiencies, you can take either that or porcine thyroglobulin…both require a prescription. Handling a problem as complex as hypothyroid disease on your own is incredibly dangerous, but hey, its your life.

    2. Rebecca, is the mechanism you describe here — supplemental iodine increasing the antigenicity of thyroglobulin — similar to the mechanism involved in the original discovery of Hashimoto’s in Japanese who ate very large amounts of sea vegetables?

      1. Yes, this mechanism serves as an explanation for what was seen in the first studies of Hashimoto’s. Those first studies characterized the disease and made correlations, but only now (using molecular biological advances) can we explain what Hashimoto saw!

        1. Rebecca, If supplemental iodine worsens autoimmune thyroid disease, it seems obvious that eating sea vegetables is not a good idea. Is iodized salt also not a good idea?

    3. I read the abstract you posted earlier, but I would really like to learn more about this. Because I have difficulty shedding weight, and my family has a history of hypothyroid issues (and my cat no longer has one, either – it went hyper and partially blocked his trachea, so we had it removed) I would like to learn more about this from the research standpoint. I’ve been tested, but results “normal”. I don’t feel normal, though, I’m tired all the time.
      Anyways, if you could direct me to some more reading or research, I’d appreciate it.

      1. I tested negative also but my doctor sent me in for a ultersound and found that my thyroid was 3 times normal size.

  20. New to the site. Is there a place to introduce oneself? Seems rude to hyjack a post about iodine. 🙂

    I’ve read through the archives, quite a bunch and I’m greatful for the ability to learn from you guys.

    I look forward to sharing.

    1. There is a meet and greet section in the forums (link near the top of the page below the ever changing picture of Mark).

  21. “weight gain, sluggishness, fatigue, fuzzy brain, cold extremities”

    Wow that exactly describes my pre-primal life. I wonder if, in addition to poor diet, I might be borderline hypothyroid.

    1. Most people who are eventually diagnosed with hypothyroid disease do suffer from a period of “subclinical” disease. This means that you have the symptoms of the disease, but your doctor tells you that, based on testing, you are fine. Most likely, this is the stage you’re at!

  22. Greets, Mark & all:

    I should probably update what I’ve been doing. Weird thing is that I never really had symptoms of being hypo, just a high TSH (10-16, usually), but with T3 and T4 in the low part of the “normal” range.

    At any rate, a bit over a year ago I got on Armor, initially 90mg per day and then after another test with normal TSH but pretty much the same low-normal range T3,4, I upped to 120mg. Then that’s when I began getting the really cold hands & feet.

    So some months back I got the Iodoral and began with the one pill per day (12.5 mg iodine & iodide). Cold hands & feet resolved within days. So, after a while I cut the Iodoral in half and I’ve since cut the Armour in in half to 60mg.

    Still feeling fine, no symptoms. No recent labs so I probably should do that.

    It’s all very confusing. And then in Primal Body Primal Mind Nor Gedgaudas argues that lower T levels are actually better so long as you’re healthy and don’t have symptoms (which I didn’t, before).

    Then there’s a recent series at The Healthy Skeptic, 4 or 5 posts beginning here:


    Frankly, I’m not confident I know what to think, anymore and am considering dumping both the Armour and the Iodine, get some sea veggies now and then, and see if any symptoms return.

  23. I was diagnosed with Hashimoto’s thyroiditis in 1998. After years of taking Thyroxin I’ve now switched to dessicated porcine hormone and never felt better. Mark, I am also interested in the link between HYPOthyroidism and iodine…would love to supplement but am not sure if it’s the right thing to do in this situation. My endocrinologist, who has Hashi’s herself and is alternative in her views, seems to think not. Thanks and all the best from Sydney.

  24. I became hypothyroid following Lyme Disease.
    15mg of iodine a day has dramatically reduced the amount of thyroxin I require.
    If only I could cure the Lyme’s too, but altering my diet has helped a lot.

    1. Hi,

      I also have hypothyroidism and lyme. I’ve just started in iodine so too early to say if this will help.

      what diet has helped the symptoms of lyme?

      thank you

  25. My 3 year old son has had hypothyroidism since birth. He takes Levoxyl daily, what can or should I do to help get him off of his medication? I refuse to believe that taking a pill is better than eating the right natural foods. Thanks

    1. Justen,

      I know its tempting to think we can resolve all of our issues with the proper diet and exercise. You have to remember, though, that there are all kinds of environmental factors that we face and “Grok” didn’t! Levoxyl is simply a synthetic hormone to replace what your son’s body destroys. There is a lot of research being done with tolerance mechanisms to reverse and/or abrogate the progression of this disease, but its in the early stages. I recommend staying with the medication and waiting for science to give you a better answer….we’re almost there!!!!

  26. hi justen. i’d recommend checking out weston a price foundation if you’re interested in natural foods. mark’s site is great too. so sorry to hear this. research your butt off. the answer is out there. good luck.

  27. Just curious, if iodine is so important and hard to come by, where was non-seashore Grok getting it?

    1. Central europe has several places that contain high amounts of Salt = Salzburg being one of the examples.

      Also the native european brown trout has iodine, too.

      1. But does salt automatically have iodine?
        It is my understanding that iodine is added to table salt in an attempt to address the issue of deficiencies.

        1. Okay, I’ve done some research and from my understanding ALL unrefined Salts (sea or rock) have iodine.

          It is the refined salts (table salt) that has every single element stripped out of it and is turned into something that’s actualy quite toxic to humans. They then add iodine because inland foods have very little iodine and it would not be enough for humans.

          Don’t ever consume table salts supplemented with iodine…get natural sea or rock salt with all 84 trace elements in it.
          My mother consumed and fed us refined white table salt with iodine as kids and her thyroid went so out of control she had to have it cut out. My thyroid as a teenager always looked kind of swollen but nobody knew why.
          Now my neck is slender and normal, ever since I started using natural salts.

          I used to buy sea salt but then found out some of it could be contaminated with mercury so I switched to himalayan salt. It’s delicious on steak!

  28. Just a heads-up – the Japanese do NOT eat a lot of soy.

    I’ve travelled all over Asia and you see much the same thing there: “Americans eat lots of soy!”

    It’s marketing.

    In truth soy is primarily used as a condiment, not a main course. Tibet monks eat tofu because it reduces their libido (it mimics eostrogren or however you spell it) Raw soy beans are considered poisonous; it’s only really safe to eat (if you wish to keep your libido) once fermented, such as natto.


  29. Thanks! I have been prescribed Levothyroxin for hypothyroidism for several years now. Part of a diabetes-based metabolic syndrome? Our area, Alamogordo, New Mexico, famous for being near the first atomic bomb test, and other tests at White Sands Missle Test Range. I also understand rocket or missle exhaust chemicals can cause thyroid problems. Cancer is also found in an unusually high rate here. I did start taking Potassium Iodide (over the counter)with good results, but doctors won’t engage the subject. Any suggestions?

  30. I absolutely love everything I’ve read on this site, and I’ve never posted before but.. I was seeing a doctor a few years ago who put me on 12.5mg/day of Iodoral. He was monitoring my thyroid to make sure it was normal following a fairly recent diagnosis of celiac disease. One month went by, I felt absolutely no changes from the Iodoral.. “try it for another month” – still, no changes, then “try taking two a day” – and my body’s reaction was to turn hypothyroid. I stopped taking it and everything returned to normal.

    Bad idea. I’ve worked in health food stores for years and always heard the benefits of iodine supplementation – but I would *never* recommend it! Particularly in the outrageously high doses you’ll find with Iodoral.

    If you google “townsend letter for doctors and patients” with “Iodoral” – you’ll see a few articles – one suggesting it, one arguing it, and a rebuttal from the original author. It might help you to decide what to do with Iodine. Good luck! 🙂

    I’ll not be taking it again though! 😉

    1. Everything is synergistic. Nothing works in isolation. Taking isolated supplementation will always be risky because everything needs other elements or co-factors in order to work properly in the body.

      Taking iodine in food form such as in fish, eggs, seaweed, strawberries etc., will always be a preferable option due to the benefit of the support of the other elements within the food. Even overdoing individual foods can be problematic, so balance is the key.

      Isolated ingredients can never work as effectively as naturally buffered ones and that is why isolated salicylic acid (Aspirin) can make the stomach bleed, but in its natural form as White Willow Bark it is unlikely to (I can take WWB, but cannot touch Aspirin with a bargepole….). Isolating the ‘active ingredient’ and discarding the other buffer and support elements is like throwing the baby out with the bathwater…….

  31. So you folks have tried the Logols? i read reviews at swansons.com and they are all GREAT.
    I am a complete and total athlete person. sweating, running, biking, yogaizing, and i think i am salt, sodium, and iodine (besides other things) deficient, even though i take a great multi and a bilion other supps.
    Are there others out there who are “sweating hard” every day too who suffer from fatigue, sleeplessness, irritability etc.?
    just checking. think i will try this iodine approach. one i have not tried yet:)

  32. Can anyone help. I have an underactive thyroid. Have been on Medication for years. When I have blood tests to check my thyroid fuction my T4 is always normal but my T3 is always low. What does this mean and how does it effect my health and why dont the Doctors seem to worry about that,

  33. I haven’t read through all the comments here but I do remember learning that in cases of hypothyroid,esp when due to Hashimoto’s, it’s probably NOT a good idea to supplement with iodine. Check out Dr. Kharrazian’s blog http://www.drknews.com – there’s actually a tab at the top – iodine and hashimoto’s and site http://www.thyroidbook.com

  34. I have thyroid and am also on antidepressants and the doctor is reluctant to let me off them. Can I decrease the anti’s and take St johns wort to reduce the dose. Also do anti depressants pile on the weight as well as the thryoid.

  35. Mark, I can’t thank you enough for this post. I had some of the hypo-thyroid symptoms, mainly feeling tired all the time. I ordered Iosol, which seeemed like a better supplement choice than Lugol’s based on web research. After 4 days on this, I don’t think I have ever had such a dramatic improvement in overall well being and energy. I just realized I haven’t had coffee in 36+ hours, which would normally be inconceivable. And I have had more energy than I can remember in a long time, despite staying up late every night working on a deadline.

    In reading some of the above comments, it seems like I need to be careful with dosage and maybe just use this periodically when I feel a need.

  36. This is super late to the game (1 year later), but this youtube video by Dr. Bryan P Walsh is a great explanation of all the different ways someone could be suffering from Hypothyroidism symptoms. Which is why different people have different results from different supplements or medications. Depending on where the problem is, different actions need to be taken to help. https://www.youtube.com/watch?v=ehXGaX8lccw

  37. I had a colon resection in November 2010 and have not felt well since then with excessive hot sweats, fatigue etc. Last week I started taking 150 mcg (3 drops) of iodine and iodide. By last Friday the sweats stopped and I started to feel better. From 2010 to now I have had every test imagineable for other cancers etc and everything has been negative. Is 150mcg per day enough? I want to get it right and not over or under do it. I can honestly say that I have never felt more ill in my life from December 2010 to one week ago and do not want to go back there!!!

  38. Hey Mark,

    I was wondering if you have done any research on nascent iodine and if you see any larger benefit from it compared to other sources of iodine supplements, like Lugol’s or iodoral?

  39. Thanks for this article. I nearly fell off my chair laughing when reading about those people who eschew table salt and processed food, as that pretty much describes myself. I don’t eat much salt to begin with, and ofcourse I’ve been using Italian sea salt for years. Over the past month I have been consuming daily smoothies with pear and arugula/watercress, which are both greens from the brassicae family. Recently I have been feeling more tired and sluggish and losing hair. Every article I read says that it is very rare in the Western world to have a iodide deficiency as most people consume table salt or bread with salt in it. I’m fairly certain I have a deficiency as I don’t eat either. I noticed that you recommend eating sea vegetables, however if one were to start using iodized salt, what would the recommended amount be daily? 1 to 2 teaspoons of the iodized Morton salt? Ofcourse, I will go ahead initially and eat seaweed to get my levels to normal, but for future reference, approximately how much table salt does a person need on average daily without fear of over doing it. Thanks again for this terrific article; I feel that it will be ever more useful to many people in future, as the trend of eating less processed food will be more prevalent.

  40. Hi

    I had a overactive thyroid and had radioactive iodine now I’m underactive. my Dr told me not to take anything with iodine in it. its been 7 years now and he still tells me not to take iodine. its making it very hard for a lot of things now have it in there ingredients. can you please tell me why I cant still have it after all these years. and I would like to say that the only side effect I had from the radioactive iodine was the top of my hands on the skin have gone very dry and have never gone back to normal. Thank you

  41. A few years back I lost a great deal of weight (about 10 kilograms & my weight went down to 41 kilograms) … I was diagnosed with Graves disease / HyPERthyroidism / over active thyroid. After medication for approximately one year my weight stabilised and I have not had any issues since. I think the birth of my child / breastfeeding / being really active may have led to the Graves disease popping it’s head up. I understand I will always have Graves disease (what a dreadful name hey! Named after the founder). Just wondering whether there have been any studies re: being wary of ketogenic diets speeding up my metabolism & leading to resurrection of Graves.

  42. If I have a test result from the iodine 24 hour test, of 90% excretion can I still be deficient? I still have symptoms , I am hypothyroid patient with all other levels under control?

  43. Hi Mark,
    Picked up this article (quite late admittedly) to learn a little more about iodine. It seems like it’s a great supplement to take for overall health; I was wondering if there were any benefits to megadosing or going beyond the 1mg a day?

    All the best,

  44. The term “mental retardation” is extremely outdated. No respectable medical professional uses it unless they’re very old. It’s also pretty socially unaccceptable to use that term. I know this article is old, but you link it in your recent articles, so you better change it if you care about credibility.

  45. I picked up the the link after reading the article from 29/03/17. As someone with Hashimoto, I’ve doing a lot of research lately and learned that optimal iodine dosage should be 225mcg, but not before establishing normal levels of selenium, based on 200mcg per day for one month; after that once a week will suffice. It’s best to build up iodine levels slowly, starting with around 50mcg (one nori sheet) or via pure iodine supplement as potassium iodide (no other additives). Some sea vegetables are OK but not Kelp. Based on my readings, those with Hashimoto saw their antibodies levels go down without ill effects (and stabilization of thyroid hormones) and I’m going to give it a try. By the way and contrary to common believe, Japanese don’t consume that much soy. Their high consumption of sea vegetables is also problematic, due to high levels of contaminates and high Bromine which disrupts Thyroid function and Iodine absorption.

    1. Why not kelp? Lots describe great benefits from it on the net. Surely it is far better to take iodine in food form with all the other minerals and co-factors, than as an isolate….?

      1. I am certainly not an expert. But I would say that mainly due to naturally produced compounds – in Asia for instance (bromine, arsenic and mercury) that are known to interfere with thyroid function, and, being that most are above the recommended dosage and include additives. I agree that we should strive to get all our requirements from real foods (nori is preferable to kelp since you can actually use it to warp other foods), except when other compounds are attached to those food. There’s plenty of info (some of it confusing) on the web and I suggest doing your own research (try perfecthealthdiet) and not take my word for it. By the way, who are those describe great benefits? Shoppers at online supplement outlets or otherwise? It also depends if one has Thyroid issues or not. I would also like to make a correction and put the maximum dose at 150mcg. Also, when there’s an issue with Iodine deficiencies and other medical problem or emergency (nuclear contamination), what’s being used is Potassium iodide not kelp and for a good reason.

        * I have kelp supplement with 360 mcg iodine that is sitting in my cupboard; you are welcome to it 🙂

  46. I had my thyroid out 15 years ago. Can I take
    iodine? I feel that I must need it. I take cytomel for having no thyroid. I had a goiter and they took the
    whole thyroid out even though it was not causing
    me trouble. Cytomel would have cured it on its own but i didnt know back then. Is it ok to take Iodine when you have no thyroid? Thanks