Thyroid Function and Magnesium

Dr. John A. Robinson, NMD -

For those of you who have been diligently exploring the best nutrient strategies for your thyroid health, your research has likely brought you to things like iodine, selenium, tyrosine, and zinc. Iodine tops the list as one of the most important nutrients for the thyroid, as do the others, but there are two other nutrients that are not that often properly lauded with the accolades they deserve. These nutrients are also massively misunderstood in respect to their role in health and thyroid function but also highly misdiagnosed as being deficient in the first place. But misunderstood and misdiagnosed are two phenomena that spark me to dig deeper, which is why I am a thyroid disease advocate and why I am going to shed some much needed light on these nutrients for you right now.


Now this really isn’t earth-shattering (or thyroid-shattering) news for some of you, but magnesium isn’t always at the top of the list for thyroid health. It’s often viewed as an after-thought and if it is prescribed, then the dose is often more of a maintenance dose that does not really improve body magnesium stores. Let’s dig into this now and see how magnesium not only helps your thyroid, but countless other mechanisms in your body.

The thyroid cannot function without magnesium. Here is a list of very important functions of magnesium and how it relates to your thyroid gland health.[i]

  • Magnesium is responsible for converting the inactive T4 thyroid hormone into the active form of T3. This is extremely important because the metabolism of your body cells are enhanced by T3, not inactive T4.
  • Magnesium deficiency is related to goiter, or an enlarged thyroid gland. Another important nutrient in preventing goiter is iodine, but magnesium is right there helping too.
  • Magnesium helps you to make more T4 in the thyroid gland. Without magnesium, many of the thyroid enzymes that make thyroid hormone simply could not function.
Where is all the Magnesium?

We live in a calcium dominant and magnesium deficient society. Simply, we ingest many foods that have plenty of calcium but not a lot of magnesium. We tend to hear more about the importance of calcium supplementation than we ever do about magnesium supplementation, although that is starting to change. High amounts of calcium not only compete with your magnesium stores in your body, the excess intake of calcium has been associated with kidney stones and atherosclerosis.[ii] [iii] One of the reasons we are seeing the excess accumulation of calcium deposits is that we are not properly absorbing calcium due to being deficient in magnesium and even vitamin K2.

Where Do I Get Magnesium? How Much Do I Need?

Be sure to focus on magnesium-rich foods which include almonds, pumpkin seeds, chard, spinach, avocado, figs, and even dark chocolate. Unfortunately, the quality of most foods, even organic, do not contain consistently adequate amounts of minerals including magnesium. So supplementation is key to getting your magnesium stores up for your thyroid health.

For supplementation for your thyroid and general health, I suggest two different categories of magnesium, depending on whether you have constipation or not.

If you have constipation, then I recommend Magnesium Citrate at a dose of 400 mg to 1000 mg to relieve the constipation and start to increase magnesium stores.

Vitamin A is the second nutrient that is not only deficient in most patients with low thyroid, but is often avoided because of a huge misconception about what it is and how it can help you.

Learn more…


[i] Hsu JM, Root AW, Duckett GE, Smith JC Jr, Yunice AA, Kepford G. The effect of magnesium depletion on thyroid function in rats. J Nutr. 1984 Aug;114(8):1510-7. PubMed PMID: 6747732.

[ii] Li K, Kaaks R, Linseisen J, Rohrmann S. Associations of dietary calcium intake and calcium supplementation with myocardial infarction and stroke risk and overall cardiovascular mortality in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition study. Heart. 2012 Jun;98(12):920-5.

[iii] Chakraborti S, Chakraborti T, Mandal M, Mandal A, Das S, Ghosh S. Protective role of magnesium in cardiovascular diseases: a review. Mol Cell Biochem. 2002 Sep;238(1-2):163-79.


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