Over-the-Counter Drug-Induced Thyroid Disorders

Over-the-Counter Drug-Induced Thyroid Disorders

We see a lot of people asking about taking iodine in various forms. Sometimes the iodine content of thyroid support products is not obvious.

The following paper (more available by following the link) is of interest.

Some of the authors also wrote the Walter Reed Hospital study on Armour which was so interesting. Desiccated thyroid extract compared with levothyroxine in the treatment of hypothyroidism: a randomized, double-blind, crossover study.


Over-the-Counter Drug-Induced Thyroid Disorders

Thanh D. Hoang, DO, Vinh Q. Mai, DO, Patrick W. Clyde, MD, FACE, Mohamed K.M. Shakir, MD


Objective: Excessive iodine ingestion may cause thyroid dysfunction. In this case series, we report four patients who developed significant thyroid dysfunction after ingesting over-the-counter (OTC) drugs containing large concentrations of iodine.

Methods: Four patients from a tertiary medical center are reported.

Results: Case 1 involved acute exacerbation of thyrotoxicosis induced by taking OTC Tri-iodine TM in a 35-year-old woman while still on methimazole therapy. Case 2 involved thyroid-extract-induced thyrotoxicosis following ingestion of Thyromine TM, and was confirmed by laboratory studies and 131I thyroid uptake. Cases 3 and 4 involved severe, symptomatic hypothyroidism induced in 2 patients with underlying autoimmune thyroiditis (Hashimoto's disease) following ingestion of Iodoral TM. In all cases, thyroid dysfunction resolved with appropriate management and discontinuation of the OTC drugs.

Conclusion: These case reports demonstrate the significant risks associated with OTC preparations containing iodine in patients predisposed to thyroid dysfunction. There is no valid reason for taking high-dose OTC iodine supplements, which have been shown to cause harm and have no known benefit.



Picture is of kelp on a beach in Scotland.

7 Replies

  • Must say Rod I have never been convinced that going down the iodine route was a good one.

    Moggie x

  • I find myself being convinced that general iodine levels in the UK might be teetering on the brink of inadequacy (especially during pregnancy). But any supplementing of iodine in people with a background of thyroid disorder seems to absolutely require testing and deep thought.


  • Couldn't agree more Rod but then I think our views on testing before supplementing run along similar lines (and I dont just mean iodine).

    Moggie x

  • My husband would tell them that 16 weeks is by no means an adequate time to evaluate armour versus levo or t3

    it took well over a year on armour for full effects to be felt andcfor all the damaged tissues to heal

    the authors also did not bother to state what the ferritin , folate, b12 etc status of the patients was therefore the study is ineffectual and a ninsense

  • They are eminently available for contact - for example, I had an email interchange with one of the authors of the Armour study.

    You could put your point of view directly to them.

    However, I am very pleased that they even bothered to look at doing the study. I believe that a further study involving at least some of the same people is under way. Considering the typical views of many endos, their openness to the possibility that there really is something to desiccated thyroid is to be commended.


  • Can you pm me the email addy please cos i did not find it came up when i tried

  • See Clinical Trials page here:


You may also like...