This is a post for you who maybe know, or suspect, you suffer from iodine deficiency. But at the same time, you may be scared of supplementing with iodine. In this post, I won’t be referring to heaps of studies, as I want to keep it easy and assessible.  But everything I write, I have read in books or studies. Except when I write “I believe” or “I think”.

Iodine deficiency

A lot of people suffer from iodine deficiency. And even more so us with thyroid disorders. Iodine deficiency is the number one reason for thyroid disorders. I am not saying it’s the only reason. You might not suffer from a thyroid disorder though. There is an almost phobia of iodine in the world, you can read more about that here

At the same time as we often get too little iodine, we have big issues with other halogens occupying the iodine receptors. Iodine is a halogen, and toxins like Fluoride, Bromide and Chloride can occupy the iodine receptors. This happens less if we have ample iodine in our bodies.

We get a lot of Fluoride in our tooth paste. Bromide from our furniture as flame retardant. In the US, they apparently even add Bromide to bread! Which is very difficult to understand. In some countries, Chloride is added to drinking water, and of course, it’s in our pools.

Deficiency symptoms

  • Tiredness
  • Freezing
  • Weight gain
  • Dry, scaly skin
  • Hair loss
  • Low stomach acid
  • Dry eyes
  • No sweating
  • Goiter
  • Thyroid nodules
  • Fibromes and cysts in breasts and uterus/ovaries
  • Brain fog
  • Low IQ and in worst case scenario, cretinisme in the fetus

Of course, many of these symptoms are symptoms of low thyroid, and will disappear as we become euthyroid, have good thyroid levels. You can read more about that here, For the thyroid newbie and here, Optimal thyroid levels. BUT far from all. Many with thyroid disease still have many of these symptoms DESPITE good thyroid levels. Many believe, even doctors, that the thyroid is the only organ in the body in need of iodine. This is not the case. ALL glands in the body need iodine to function. Breast glands, ovaries, the prostate, the little glands excreting stomach acid, tear film and so on.

So even if you now get thyroid hormones, if you are taking that, all these other glands in the body are not getting the Iodine they need.

Isn’t Iodine dangerous for people with Hashimotos?

This is the most common comment, that iodine is dangerous for those suffering from Hashimotos.  One of Norway’s better known endocrinologists, Ingrid Norheim, told me in 2007 that I should avoid ALL iodine , even the 150 mcg in multivitamins. I listened to her, unfortunately. I understand now, I was severely iodine deficient at that time, and had been for years. I believe she has become wiser.  I hope so at least.

There are two kinds of Hashimotos, the one that starts with goiter and the one without goiter. The latter is in reality Ord’s disease or Ord’s anthropic.  It was a doctor named Ord that diagnosed it, years before Hashimotos named the AIDT with goiter. Why do I mention this?

It’s because, with Ord’s, the gland atrophies. After some years, one has little or no gland. I belong to this group myself. While those with “real” Hashimotos can have a full size gland after years of disease. And it’s not the case either, as many say, that Anti-TPO “eats” our gland. One can have high levels of Anti-TPO for years without the gland decreasing in size. But it doesn’t function, it’s infiltrated by t- and b lymphocytes. And the TPO enzyme is damaged, you can read more about that here.

Why does this matter in terms of iodine  supplementation? It’s because all thyroid anti bodies are produced inside the thyroid itself. So if you have little or no thyroid, you don’t have to worry about increase in anti bodies when taking iodine.  There will be no anti body flares. You might have a little anti bodies even if you have an atrophied gland. I had a little Anti-TPO still. But it is all gone after I started on The Iodine protocol.

What about people WITH a gland

When you have a gland, it’s wise to be a bit more careful. It’s not so much increase in Anti-TPO one needs to worry about, but more Anti-TG and TRAb. Especially the first.  According to a scientist called Michael Zimmermann, we don’t know if the increase in Anti-TG is transitory or more chronic. I  recommend him as a serious investigator of Iodine. He realizes the importance of iodine.

What Zimmermann also writes, and which is important, is that one sees a sharp increase in Anti-TG especially when someone has been Iodine deficient for a long time, and then suddenly gets a lot of iodine.  One sees this when a country starts iodizing the salt. In the countries where they have started on a high addition from the get go, one has seen a big increase in Anti-TG. Whereas in the countries where one has added iodine a little at the time, there has been less increase in Anti-TG.

This is why I advice starting low and increasing over time if you have a thyroid. And especially if you have functioning thyroid. If you have had Hashimotos for years, your thyroid does not function anymore. Which is why you need thyroid hormones. The gland will be infiltrated, and it will never be healthy again, I don’t think. In that case, there is no danger of further damage to the gland by ingesting Iodine. The gland is already destroyed, more or less. After many years of thyroid disease, I think everybody deserves an ultra sound of their gland. It’s the only way of truly seeing the state of the gland.

If this is the case with you, you have to decide if an increase in anti bodies would worry you or not.

But if you are just in the beginning of thyroid disease, you have gotten some Anti-TPO or your FT4 is becoming too low, under 40% of range, then I think “low and slow” is the safe way to go.


Those with a functioning gland should start with 2 to 300 mcg. I see, Kris Kresser starts his patients up on 325 mcg. Test anti bodies BEFORE you start. then follow up with frequent thyroid testing including for anti bodies in the first months. Then you can’t go wrong. Increase dose when you feel safe about it. See under for safe max doses.

Those without a functioning gland can start on higher doses. You can do the Iodine protocol if you feel like it. If you feel safer supplementing lower doses, start with 3 to 500 mcg, and increase over time. I think one can safely take up to 2 mg without issues, see below. When one does the Iodine protocol, one can get detox symptoms. It can also be hard on the kidneys with all that iodine  And one needs to really study before starting on large doses. You can read more about the Protocol here.

What iodine to take?

Take a supplement where you can see the exact content. If you take a sea weed supplement, take one where the amount of iodine is listed. I see in American iodine groups, that many consider sea weed to be full of toxins. I believe this fear is exaggerated. We get so many toxins, I don’t think small amounts of sea weed is the biggest culprit. Some swear by nascent iodine. I take Lugol’s. But that is high dose iodine.


Selenium is the most important thing when taking iodine. Do not take iodine with poor selenium levels. Selenium protects the thyroid. All enzymes involved in the production of thyroid hormones and hormone conversion, are Selenium enzymes. I read an article in The journal of the Norwegian  physicians, written by 3 doctors, the current reference range for selenium is way too low. They argued, that we need to have as high as 3 ng/dl in serum.  reference often goes to 1.8 or 1.9 ng/dl today. And that it is levels over 3.5 ng/dl that can be toxic. They wrote, one needs to take 300 mcg/day to achieve such levels.

Many have been worried about overdosing on  selenium, but maybe we can stop worrying about that at least. I have increased my selenium intake after reading this.

Other supplements

On high dose iodine, we take several other supplements. We take large doses of niacin (B3) and riboflavin (B2). B3 can give temporary flushing. One needs to buy the no-flush kind. Even then one can get a flush if the dose is high. These two vitamins are important for the ATP function in the mitochondria. I think it’s good for all hypo thyroid to have good levels of these two, as we have a metabolism dysfunction. But I don’t really know how important it is when doing small dose iodine.

We also take magnesium and sea salt. Sea salt is important for detoxing bromide. When we take iodine, we can start detoxing the other, toxic halogens, fluoride and bromide. Which is a very good thing, but one can get detox symptoms. I don’t know to what extent this happens on low dose iodine. But just keep it in mind.

Testing your thyroid

Please take care to test your anti-bodies if you still have a thyroid. Anti-TPO, Anti-TG and TRAb.  You also need to keep an eye on your thyroid levels. they can both increase and decrease. Your thyroid can start producing again, and you can become hyper. In that case you will need to decrease your thyroid meds. And that is just great I have read some people saying, if you go hyper, that is a sign you take too much iodine. NO, it’s not. It’s a sign you take too much medicine. If you are not taking thyroid meds, then of course, you should not go hyper and need to have your TRAb tested asap. If you could have gotten Graves. And again, if you have a hot nodule, do not supplement idoine.

Elevated TSH

If your TSH should go up, but FT4 and FT3 stay normal, that is nothing to worry about. The TSH is not actually just a signal hormone. It is also involved in making new symporters, the channels whereby iodine is channeled into the cells. The TSH can rise for a few months in this process.

Your levels can also go down. My FT3 went down, I am sorry to say. I have to increase my dose. I have seen this also with a few other people in iodine groups. I was very puzzled by this, shocked even. But I read on Kris Kresser’s blog, that large doses of  iodine can inhibit all selenium enzymes, like TPO and all the conversion enzymes (deiodinases). That is, the enzymes converting T4 to T3. I am not 100% sure about this as yet, I need to investigate further. But it makes sense in my case. I don’t have much TPO enzyme, but I do hopefully have D1, D2 and D3 deiodinase. And these can have become inhibited.

Maybe this become a bit complicated for you. The point is, keep an eye on your levels.

Temperature and pulse

The best thing is always to follow pulse and temperature. There is a difference between morning- and evening temperature. Some say, our temperature is individual. I don’t believe that. I think our evening temperature needs to be 37 to 37,2 ° C/ 98,6-98,9 ° F. Taken inside the body, vaginal or rectal. Concerning pulse, so many hypothyroid live with too low pulse. I did myself for years. I personally am good when morning pulse is around 68, and daytime pulse around 78/80. Morning pulse at 60 or under is in my view hypo thyroid. Unless you are an athlete 😉

Iodine testing

Iodine needs to be tested in urine. In serum is no good. There are various ways to do it. The best test, is the 24 hours iodine loading test. In the US you can get it from a couple of labs, Hakala is one of them. It’s quite expensive. We can get the Hakala test here in  -Europe as well, from but it costs a lot. Many labs offer 24 hours test where you just collect the urine for 24 hours, and include the morning urine. then send off a sample. And there is urine spot tests, which is the morning urine. I think the 24 hours is better. Some say  no iodine testing is accurate. I am the kind who like to test things.

Here is a table of 24 hours testing from Zimmermann, link

Table 2Epidemiological criteria for assessment of iodine nutrition in populations based on median urinary iodine concentrations4,9

Iodine intake Iodine nutrition
School-aged children and adults
<20 μg/L Insufficient Severe iodine deficiency
20–49 μg/L Insufficient Moderate iodine deficiency
50–99 μg/L Insufficient Mild iodine deficiency
100–299 μg/L Adequate Optimal
≥300 μg/L Excessive Risk of iodine-induced hyperthyroidism and autoimmune thyroid disease
Pregnant women
<150 μg/L Insufficient ..
150–249 μg/L Adequate ..
250–499 μg/L More than adequate ..
≥500 μg/L Excessive ..
Lactating women
<100 μg/L Insufficient ..
≥100 μg/L Adequate

I believe that those without a thyroid can safely take at least 800 mcg. As you see from the table under, the highest recommended intake in the US is 1100 mcg. The European scientific committee says 600 mcg, whereas WHO says 40 mcg pr kg body weight for pregnant and lactating women. That means a pregnant woman weighing 70 kg can take 2800 mcg. They don’t say anything about other adults. But they give very high levels for babies and infants. In Japan the upper limit is set at 3000 mcg.

Table 1. Recommended upper intake levels for iodine
Age group IOM (μg/day) SCF (μg/day) WHO (μg/kg/day)
Premature infants ND ND 100
0−6 months ND ND 150
7−12 months ND ND 140
1−3 years 200 200 50
4−6 years 300 (4−8 years) 250
7−10 years 600 (9−13 years) 300 50 (7−12 years)
11−14 years 450 30 (>13 years)
15−17 years 900 (14−18 years) 500
Adult 1100 600
Pregnant and lactating women 1100 600 40
  • Sources: IOM, the United States Institute of Medicine;21 SCF, the European Union Scientific Committee on Foods;20 WHO, the World Health Organization.16
  • ND, not determined.

This table is from this study. It also says further down

The lowest observed adverse effect level (LOAEL) proposed for iodine intakes based on these studies is 1700−1800 μg/day, based on a mild increase in thyroid‐stimulating hormone (TSH) that was not associated with clinical adverse effects

And as you remember, one can have an increase in the TSH for the first few months of iodine supplementation. And that this is a positive thing.


Don’t be afraid of iodine. I take large doses at present, as I am trying to detox fluoride and bromide. As well as achieving a good iodine status. I have been iodine deficient for a very long time. And it has certainly contributed to my Hashimotos. It’s a long time since I stopped sweating.

But as I have said maybe too many times, high doses are not for everyone. Small doses ARE for  everyone, except those with hot nodules. It’s safer to take it low and slow. But don’t be so afraid of iodine that you don’t try supplementing. If you read this, you have a feeling that you need it.

I feel much better after taking iodine for about 11/2 years. More awake, improved memory, warmer, my back is straighter, my skin is less dry, my eyes are less dry, sweating better. I see many in a Norwegian thyroid group I am in, who also feel better for taking iodine.

We must have iodine! Good luck!