Expert Guidance From Louise O’Connor - The Thyroid Naturopath { Discover More! }

Are Iodine Supplements For Thyroid Health Really Safe?

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iodine supplementsWhile it’s true iodine keeps the thyroid working properly. There’s an ongoing debate about iodine supplements being good, or bad when you have a thyroid disorder.

It’s not easy to know if taking iodine is safe when there are thyroid experts advocating HIGH doses of iodine…while others claim you should AVOID this nutrient at all cost.

Are you left wondering who’s giving the right advice?

As a Naturopath I think there’s one guiding rule when it comes to taking iodine. It’s about BALANCED INTAKE. So that means, not too much and not too little.

Iodine Supports Optimal Thyroid Function

You’re probably aware nutrient deficiencies are commonly associated with hypothyroidism. And iodine is one nutrient you don’t want to get low in. Studies show an iodine deficiency can lead to iodine induced hypothyroidism, enlargement of the thyroid, and a reduced ability of the thyroid to produce thyroid hormones.

Are Iodine Supplements For Thyroid Safe?

Iodine supplements are effective for preventing, and treating an iodine deficiency. Furthermore, they are considered an important extension of healthy eating when taken according to established reference values.

It’s not wise to take more than what’s safely recommended.

This is WHY iodine supplements usually supply trace, or microgram quantities. Generally speaking, getting around 150-300 micrograms per day of iodine from a nutritional supplement is considered a safe amount.

Here’s two useful facts I want you to know…

A microgram measurement can be abbreviated as ‘mcg’ or ‘µg’ on a label. AND 1000 micrograms equals 1 milligram. If you see milligram, not microgram doses recommended you need to be cautious!

For Most People HIGH DOSE Iodine Is Risky

  • High dose iodine is likely to cause adverse health effects.
  • Taking mega milligram doses saturates the thyroid with iodine which can cause irritation, and inflammation. Furthermore, the risk is greater if selenium concentrations are low within the thyroid.
  • Excessive iodine intake can cause similar symptoms to an iodine deficiency, including goiter which is the term for an enlarged thyroid.
  • Population studies show excessive iodine intake may trigger autoimmune thyroid disorders. If you have a diagnosed autoimmune thyroid disorder and are wondering how much iodine is safe you can read more here: Is iodine safe to take when you have Hashimoto’s thyroiditis?

The Safe Upper Level of Iodine Intake

As a point of reference, the Australian National Health and Medical Research Council (NHMRC), and the US National Institutes of Health have set the recommended safe upper level of intake at 1,100 micrograms per day.

Note: The upper level of intake does not apply to those taking iodine for medical reasons. For example, high doses of potassium iodide is an approved remedy to reduce thyroid cancer risk when there is a radiation emergency.

Are Iodine Supplements Safe To Buy Online

Even a quick search of iodine supplements online reveals there is a wide variety of products available. Iodine in dietary supplements is most often available in the form of potassium iodide. You will also see Bladderwrack supplements, and thyroid health formulas that contain iodine.

When purchasing a supplement it’s a good idea to carefully check exactly what the product contains, and most importantly how much iodine it supplies per serve. Doing this will ensure you are making informed choices about how much is safe.

Of course, if you have any concerns about taking iodine you should speak to your healthcare practitioner. Your healthcare practitioner can make recommendations based on your personal health needs. If you have an OVERactive thyroid you may be told to avoid iodine supplements as they are contraindicated in hyperthyroidism.


Australian National Health and Medical Research Council (NHMRC) and the New Zealand Ministry of Health (MoH). Nutrient Reference Values for Australia and New Zealand. Iodine.

Braun L, Cohen M. Herbs and natural supplements: an evidence-based guide, 3rd ed. Iodine Monograph. Page 614-622. Churchill Livingstone. 2007.

National Institutes of Health. Medline Plus. Herbs and Supplements. Iodine monograph. National Library of Medicine. National Institutes of Health (NIH), USA. Updated January 29, 2020.

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  1. Penny Boyle says:

    Hi Louise,

    Thank you for your ebook, I have read it with great interest but I do have one question.

    I am currently on Eutroxsig medication (after having it reduced to 75mg a day) my latest tests are good and the Dr is happy. Problem is my fatigue and constant low body temperature. My Dr (there have been a few) assures me everything Is ok and my medication should not be increased.

    My question is how safe is it for me to take kelp tables as well as Eutroxsig, as I feel this will support my thyroid on a natural level and hopefully correct my low temps and fatigue.

    I look forward to your reply and thank you for blog and newsletter.


    Pen B

  2. Louise O'Connor says:

    Hi Penny – when it comes to taking a kelp product it is best to look for a product that lists the botanical name Bladderwrack. In addition, a good quality Bladderwrack supplement has a guaranteed amount of iodine per capsule. Some kelp supplements, and even kelp food sources can have variable amounts of iodine. When you take a specially formulated thyroid product you will also get the supporting nutrients such as zinc, selenium, and B group vitamins. Zinc and selenium team up to support activation of T4 to T3 which is an important consideration if your T3 is low. As you may already know T3 is the more potent thyroid hormone and helps rev up your metabolic rate. This has far reaching effects on all organs and body systems. Best wishes, Louise O’Connor

  3. Kerry Harper says:

    Dear Louise.
    Do you recommend taking bladderwrack with eutroxsig? Or is it unnecessary ??
    Thank you. Kerry

    • Louise O'Connor says:

      Hi Kerry, this is a good question to discuss with your prescribing Dr. Eutroxsig (T4-only medication) is standard treatment for hypothyroidism. This medication supplies the synthetic form of thyroxine (T4). In contrast, Bladderwrack is a traditional thyroid remedy that also supplies iodine. A good quality Bladderwrack supplement supplies a standardised amount of iodine so you know exactly how much iodine you are getting. This should be stated on the label. In summary, Bladderwrack plays a different role in the body when compared to T4 medication. Your Dr can advise if the combination is suitable for you. Best wishes, Louise O’Connor

  4. Rhonda Petrie says:

    Hi Louise
    I have Graves Disease as well as multiple sclerosis (which go hand in hand apparently).
    My thyroid is only slightly overactive and I’m not on any medication. My GP consulted with the endocrine specialist about my TSH results and he said to just keep monitoring them.
    I have a goiter which had shrunk but I’ve noticed that it is getting larger. I have a shocking cough that I can’t put down to anything other than maybe the thyroid issue. There are nodules on my thyroid but they are monitored regularly.
    Would taking an iodine supplement help me or would it make me worse?
    Thank you

    • Louise O'Connor says:

      Hi Rhonda, for anyone with nodules they should be monitoring their thyroid antibodies. This can be done as part of a complete thyroid panel that also checks TSH, free T4, free T3, and reverse T3 (RT3). Testing free T4 and free T3 can provide clear picture if thyroid is under or overactive. Goiter and thyroid nodules can cause irritation to the throat especially if the goiter and nodules are becoming enlarged to the point they are affecting the airway. You may already know Grave’s and MS are both autoimmune disorders. Very important to uncover and treat underlying root causes. Have you you looked at the Wahls MS protocol? Dr Terry Wahls is a clinical professor of medicine. She has written extensively on diet, nutrients, etc for MS. Best wishes, Louise O’Connor

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