Update: Iodine

Can you get a blood test to determine if you have enough iodine in your system?

No, there is no common test to determine how much iodine you have in your body. The American Thyroid Association discusses this in their article Iodine Deficiency.

I added a link to that article from the Iodine page on

If you have no idea if you get enough iodine, please check out the links!

11 Responses to “ Update: Iodine”

  1. Betty Says:

    Glad to see this article. 2 things: Good that you mention that raw cabbage-family vegetables are goitrogens, and not the cooked versions. (I could live on cabbage soup.) Also, you said,

    “•For practical purposes, the terms iodide (one molecule) and iodine (two iodide molecules) can be used interchangeably.”

    I was wondering why all the articles I read on iodine supplementation tell us that both iodine and iodide are needed when supplementing (if we think we aren’t getting enough in our diet). Tk. you.

  2. Jack Norris RD Says:


    > I was wondering why all the articles I read on iodine supplementation tell us that both iodine and iodide are needed when supplementing

    I don’t think that’s the case. I’m not a chemistry expert, but here is my understanding. Elemental iodine comes in the form I2, in other words, as two atoms of iodine attached together. In solution, they will come apart and form two molecules of iodide. Iodine/iodide is only useful as part of other molecules and whether it starts out as iodine or iodide, it will end up as iodide. I’m not aware of the iodine form, I2, being used for anything in the human body, and don’t know if it could even exist in such a state.

  3. Betty Says:

    Thanks, Jack. But I meant that virtually every liquid Iodine supplement I found says on the label “contains both Iodine and Iodide”. The Iodide is usually in the form of potassium or ammonium. If the labels are correct, they somehow put plain I2 in there. Here’s the label for liquid Iosol:

    Ingredients: Glycerine (vegetarian); Iodine; Ammonium Iodide.

    The articles that I have read stress that we need to take iodine in both Iodine and Iodide forms. As to the usefulness of the Iodine form, maybe the act of conversion to Iodide does something good for us. That it ends up as Iodide may be irrelevant.

    “The “SS” in “SSKI” refers to “Saturated Solution Potassium Iodide”. Other medically useful forms of iodine include “Lugol’s solution”, invented by Dr. Lugol of Paris in the 1840s, which contains a mixture of types of iodine and iodide, and “di-atomic iodine”, which is another name for iodine, but usually prepared as a solid in a capsule instead of a liquid.” (Dr. Wright of Tahoma Clinic).

    “During the production of Iosol, iodine is extracted from kelp and made into pure iodine crystals. This is not potassium iodide, rather it is an unbound form of iodine.

    The second form of iodine used is ammonium iodide, a form that readily dissolves in water. These two forms of iodine are combined in a proprietary manner in a base of vegetable glycerin.” From the Iosol Company.

  4. Jack Norris RD Says:


    > As to the usefulness of the Iodine form, maybe the act of conversion to Iodide does something good for us.

    I seriously doubt this. Nothing of this sort has every been mentioned in any of the literature or in any of the textbooks I’ve read regarding iodine.

    > That it ends up as Iodide may be irrelevant.

    To be used by the thyroid hormones, it has to end up as iodide. I’m not sure if you meant that ending ups as iodide was “irrelevant” or if you just meant there may be other needs in addition to being part of they thyroid hormones.

  5. Betty Says:

    I can only pass on what I’ve read about iodine/iodide. To sum it all up, the doctors involved are saying that, where supplementation is concerned, the molecular form is necessary for breast health; and the iodide form essential for thyroid health.

    There have been debates between various doctors on the topic of iodine supplementation. One good one, if I recall right, on the Townsend Letter for Doctors.

    Me, I take Iosol or Iodoral sporadically. From what I hear, some people take 50 mg per day. That’s milligrams, not micrograms. Some claim to have had monumental improvements in their health with these large doses.

    Jes’ passin’ it along. When it comes to supplementation I never know who or what to believe any more. So I take herbs for good digestion, make the sign of the cross over any possibly unhealthful food, and wait.

  6. Jack Norris RD Says:


    I did a little searching and found this:

    Which, ever so slightly, confirms that idea that iodine might be more useful for treating fibrocystic breast disease than iodine, though that part of the research did not contain a control group from what I can see. This was the only study I found comparing iodine to iodide though there could be (many) more.

  7. Michal Nowak Says:

    Hi Jack,

    Here in the Czech Republic is produced mineral water called Vincentka (click to “Výtah analýzy zdroje” for label) which has: Jodid I- 6,36 mg/l It seems to me that one bottle which is 0.7 liter should (6360÷150×0.7=29.68) provide iodine for about a month.

    However I am not sure whether is safe to serve iodine in high doses but low frequencies. Any idea? Thanks!

  8. Jack Norris RD Says:


    It is not safe to take iodine in high doses but low frequencies. The Upper Tolerable Limit set by the Food and Medicine Board is 1.1 mg for adults. I would try not to take more than 300 micrograms per day.

    You should also be aware that iodine is not stored in the body with much efficiency, so you cannot build up your stores in order to rely on them in the future when you don’t have a high iodine intake. Iodine is something that needs to be eaten consistently, in small amounts.

  9. Jeannine Says:

    Please note that Iodine is actually very unsafe for people who already have Thyroid disease such as Hashimoto’s Thyroiditis (an autoimmune disease where the immune system attacks the thyroid). Iodine ads fuel to the fire for people with Hashi’s.

    I read this in a couple of books “Stop the Thyroid Madness” and “What your doctor may not have told you about Hashimoto’s”, as well as online.

  10. Daniel Says:

    There is no limit to how much iodine you can really have if it’s coming from food. In Japan, they have more than 10 mg (10,000 mcg) a day and have no problems. Why is there such a fear if iodine? If it’s coming naturally from food, the body can regulate it effectively. You can’t get too much vitamin c or iron or magnesium from food. Why would iodine be different? I’d be far more concerned about not getting enough. I think a minimum of 300 mcg should be consumed instead of maximum. I would be cautious about non food forms like potassium iodide and avoid that in lage amounts, but not from kelp or seawood.

  11. Jack Norris RD Says:


    I decided to look into what you are saying and there is evidence of harm from eating too much seaweed – thyroid cancer:

    Japanese women were followed for 14 years and an “increased risk was observed in postmenopausal women (papillary carcinoma HR for almost daily consumption compared with 2 days/week or less=3.81, 95% CI: 1.67-8.68; trend P<0.01)..."

    The Linus Pauling Institute says:

    “In iodine-sufficient populations (e.g., the U.S.), excess iodine intake is most commonly associated with elevated blood levels of thyroid stimulating hormone (TSH), hypothyroidism, and goiter. Although a slightly elevated TSH level does not necessarily indicate inadequate thyroid hormone production, it is the earliest sign of abnormal thyroid function when iodine intake is excessive. In iodine-sufficient adults, elevated TSH levels have been found at iodine intakes between 1,700 and 1,800 mcg/day.”

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