Studies on Magnesium and Thyroid Health

Medically reviewed and written by Izabella Wentz, PharmD, FASCP


A few years ago, I started working with a new client who was taking twelve different supplements from an alternative medicine doctor. Some were antimicrobial agents used for killing gut pathogens; some were herbs and nutrients meant to support her liver and adrenals.

In theory, the protocol she was on was aligned with my teachings… supporting the gut, liver, and adrenals — but it did not consider her bio-individuality, nor her unique root causes. The practitioner she had seen gave her every protocol at once, without paying attention to how the different herbs could interact with one another in a body that was compromised. Her practitioner had given her everything but the kitchen sink — she had been spending thousands of dollars each month, and still couldn’t find relief from her symptoms!

Her top complaints were migraines, constipation, insomnia, sensitivity to loud noises, and anxiety. I went through my magnesium questionnaire with her, and she turned out to be at high risk for magnesium deficiency. I reviewed her list of supplements, had her stop all twelve of them, and recommended just one supplement, magnesium citrate, at bedtime.

Constipation is a red flag for magnesium deficiency, and is actually a contraindication for taking supplements for detoxes and/or for killing pathogens. When we are constipated, we don’t clear out toxins, they just get reabsorbed.

At our follow-up appointment, she reported that her migraines, constipation, and insomnia were gone! She no longer needed to take NSAIDs, laxatives, or sleep medications, and was able to tolerate her teenager’s music. 🙂

In this article, I’d like to dive a little deeper into the many benefits of magnesium for those with Hashimoto’s, including:

  • How the body uses magnesium

  • The magnesium and thyroid connection

  • Causes and symptoms of magnesium deficiency

  • Conventional and natural treatment options

How Does Magnesium Work In the Body?

Magnesium is a mineral that is essential for human function. It is required for more than 300 biochemical reactions in the body, including maintaining nerve and muscle function, supporting a healthy immune system, and keeping the heartbeat steady. Magnesium also helps create strong bones, steadies blood glucose levels, and aids in energy production. (1)

Magnesium is naturally present in a variety of foods, is often added to food products, is readily available as a dietary supplement, and is found in some medicines (such as antacids and laxatives).

The average adult body contains approximately 25 g of magnesium, with 50-60 percent in the bones, and most of the rest found in soft tissues.

About Magnesium Deficiency

Two types of magnesium deficiencies can occur with respect to nutrients. The first type, called overt deficiencies, can lead to low calcium or potassium levels due to a disturbed balance of minerals in the body. This is a serious condition that can present with numbness, muscle contractions/cramps, seizures, personality changes, abnormal heart rhythms, and other types of serious reactions. This is relatively rare, as, in times of low intake, the kidneys kick in to prevent the excretion of magnesium, holding onto its current magnesium stores to prevent this.

The second type, subclinical deficiencies, are not seen on standard blood tests but may, nonetheless, manifest with symptoms.

According to the Institute of Functional Medicine, the following symptoms, family history, and health conditions are reasons to suspect magnesium deficiency (aka hypomagnesemia): (2-4)

  • Depression or poor mood

  • Irritability or anxiety

  • Difficulty focusing

  • Family history of autism

  • Frequent headaches or migraines

  • Family or personal history of diabetes

  • Trouble swallowing

  • Acid reflux

  • Sensitivity to loud noises

  • Fatigue

  • Family history of asthma

  • Constipation (fewer than two bowel movements a day)

  • Excess stress

  • Trouble falling and/or staying asleep

  • Muscle twitching

  • Premenstrual syndrome

  • Hand cramps

  • Restless leg syndrome

  • Heart flutters, skipped beats, or palpitations

  • Family or personal history of kidney stones

  • Family or personal history of heart disease or heart failure

  • Family or personal history of mitral valve prolapse

  • Low intake of kelp, wheat bran or germ, almonds, cashews, buckwheat, or dark-green leafy vegetables

In my experience, joint pain, leg cramps, menstrual cramps, and thyroid disorders are always a reason to suspect magnesium deficiency. (5-7)

Magnesium deficiency can impact the body’s ability to metabolize important nutrients like vitamin D, potassium, and calcium — which is especially critical for those with Hashimoto’s, who may already have trouble with nutrient absorption.

Other health consequences of magnesium deficiency — and/or health issues that recent research suggests can be related — include: (8, 9)

  • Cardiovascular conditions

  • Chronic headaches

  • Tremors

  • Weak bones

  • Stroke symptoms (one case study)

  • Increased risk of preeclampsia

So all of the above may sound serious, but the good news is that newer research suggests that magnesium supplementation could be a simple solution when it comes to resolving some serious conditions. For instance, one study on rats showed that supplementation in magnesium deficient rats “almost completely restored cardiac and mitochondrial functions.” (10, 11)

Magnesium and Thyroid Health

Low magnesium levels are associated with thyroglobulin antibody (TGAb) positivity, Hashimoto’s thyroiditis, and hypothyroidism. A magnesium deficiency can put those with Hashimoto’s at a higher risk of developing symptoms.

Most people with Hashimoto’s have numerous nutrient deficiencies, which can occur as a result of eating nutrient-poor foods, having inflammation from infections or food sensitivities, taking certain medications, or having an imbalance of gut bacteria. (12-14)

Factors like low stomach acid, fat malabsorption, and a deficiency in digestive enzymes, which are common in those with Hashimoto’s, will result in many people not being able to break down and absorb the nutrients from the food they eat. A lack of sufficient thyroid hormones can also lead to nutrient deficiencies, as it makes nutrient extraction from food more difficult and less efficient.

Magnesium is crucial for liver health, and I include it as part of my liver detox protocol that I recommend as a key first step toward healing for those with Hashimoto’s. Furthermore, magnesium helps support adrenal function — another area that is often compromised for those with thyroid dysfunction.

Research has shown that magnesium deficiency can have a direct impact on thyroid function.

Australian researchers Roy and Helga Moncayo have been working with people with autoimmune thyroid disease since 2007. In their initial interventions, they noticed that thyroid patients had low selenium and began to address this with supplementation. But since supplementing with only selenium did not lead to lasting results, they continued to dig deeper. They then found that magnesium deficiency correlated to many thyroid symptoms.

They reported that physical and psychological stress led to the depletion of magnesium, which is needed for iodine utilization by the thyroid gland.

In one study, 11 patients with an elevated TSH (range of 2.3 – 21 mIU/L, average of 7.67 mIU/L), received magnesium citrate for six weeks. Every patient had a drop in TSH (the resulting range was 1.6 – 4 mIU/L). The average drop was by five points, resulting in an average TSH of 2.67 mIU/L after treatment. The highest drop was from a TSH of 21 mIU/L to a TSH of four mIU/L! (15)

In addition to the magnesium citrate, these clinicians used selenium and Coenzyme Q10 with their patients, as well as managed their psychological stress and physical alignment.

Patients reported feeling better and having more energy, as well as better sleep, less anxiety, and less constipation, after starting magnesium supplementation.

Additionally, these researchers reported a normalization on some of the patients’ thyroid ultrasounds (the patients with Hashimoto’s initially presented an increased appearance of veins and damage to the thyroid on their initial ultrasound). They cautioned that not everyone’s thyroid tissue will normalize, and that at least eight months of supplementation with magnesium is needed to see improvement on the thyroid gland. (However, I think it’s worth a try, especially since magnesium can help many symptoms that are common in Hashimoto’s.) (16-18)

Testing for Magnesium Deficiency

I generally don’t test people for magnesium deficiency, as not all tests are reliable and my experience has shown that most people with Hashimoto’s are deficient in magnesium. Additionally, it is generally safe to take without testing. If any of the symptoms above apply to you, supplementing with magnesium is usually recommended.

However, If you wish to assess your magnesium levels with blood testing, I recommend the Spectracell Micronutrient Test Panel or Magnesium, RBC.

The recommended daily value of magnesium is 400 mg per day, and most adults eating the Standard American Diet are getting less than 300 mg per day.

Populations at increased risk for deficiency include: (19)

  • People with type 2 diabetes

  • People with a history of alcoholism – among other mechanisms, alcohol can double, or even quadruple, our excretion of magnesium

  • People with diarrhea

  • People with gut conditions such as celiac disease, IBS, and Crohn’s

  • Older adults (their ability to absorb magnesium in the gut, is reduced as they age, and their excretion of magnesium through the kidney increases)

  • People taking certain medications that can result in a magnesium depletion, the most common ones being proton pump inhibitors (Nexium, Prilosec, Omeprazole, Protonix), female hormones (oral contraceptives and hormone replacement therapy), and antibiotics

  • People with hypothyroidism – a lack of thyroid hormones can lead to low magnesium levels

  • Americans (in 2009, the World Health Organization released a report stating that up to 75 percent of Americans were not receiving adequate amounts of magnesium!)

  • People on certain diets, such as Paleo (or Autoimmune Paleo) diets, that eliminate food sources of magnesium (grains, processed foods, nuts, seeds, beans, and legumes)

Additionally, caffeine, stress, and common toxins like fluoride and alcohol, can further deplete us of magnesium.

Food Sources of Magnesium

Food sources of magnesium include green leafy veggies (like spinach and kale), whole grains, nuts, beans, legumes, and seeds. Some processed foods like breakfast cereals may also be fortified with magnesium.

Ideally, we would obtain all of the magnesium we need from our diet. However, this might not be realistic for most people. Not only are many of our food sources deficient in nutrients, due to modern farming practices, but many people with Hashimoto’s may exclude a number of these foods if they are following a Paleo diet (or other types of elimination diets).

Of course, green leafy vegetables are an appropriate option for most people with Hashimoto’s. (If you are concerned about goitrogens, please read my Thyroid Food Myths post.) However, we’d need to eat a lot of green veggies to really get enough magnesium — a half cup of boiled spinach provides us with just 20 percent of the recommended daily allowance of magnesium! (20)

For this reason, I recommend that most people supplement with magnesium.

How to Supplement with Magnesium

I always recommend starting with the Root Cause approach — figuring out the main reason your body is out of balance and leading you to experience symptoms. Ask yourself:

  • Why is your magnesium deficient in the first place?

  • Do you lead a life that is too stressful?

  • Are you taking on too many responsibilities?

  • Do you not eat enough leafy greens?

However, I am also a fan of orthomolecular medicine — using nutritional supplementation to maintain health. I was first exposed to orthomolecular medicine during the clinical rotations of my fourth year in pharmacy school. I was an intern at the Pfeiffer Treatment Center led by Dr. William Walsh. The center often used high doses of vitamins and minerals to address symptoms of biochemical imbalances that manifested as mood disorders.

This was a fascinating experience for me, and I learned so much, getting to see how the right nutrients could help people feel better. While I’m always looking for root causes, I love to utilize orthomolecular principles in combination with other interventions, to help people meet their health goals and feel better fast!

For this reason, magnesium is one of the tools in my toolbox to address my client’s symptoms:

  • For constipation: Constipation is a red flag for magnesium deficiency. I recommend taking 1-2 capsules of magnesium citrate at bedtime to help. The magnesium citrate salt works like a gentle laxative. If you are still constipated, increase your dose gradually by one capsule per evening. If your bowel movements become too loose, cut back on your dose. You may also want to explore gut issues that may be a trigger, including SIBO, parasites, and food sensitivities. (21)

  • For insomnia: I like to recommend Epsom salt baths (one cup of salts per tub – follow package instructions, and don’t overdo it!), and either magnesium citrate or magnesium glycinate at bedtime. Please watch how the magnesium makes you feel. Some people report much better sleep with both versions of magnesium, while others report worse sleep. You may need to try a few different kinds to see which works best for sleep, but generally, I would recommend starting with the citrate version.

  • For period cramps: Magnesium deficiency can increase prostaglandin production, which is associated with painful menstrual cramps. (22) Prevention is key for period cramps, so if this is an issue for you, I recommend starting a magnesium supplement immediately. Either magnesium citrate or magnesium glycinate can work to relieve your cramps right away! For acute cramps, you can also take magnesium as needed (one to four times per day), which should help relieve pain as quickly as ibuprofen, without the side effects. In my clinical experience, I’ve seen women who take magnesium for one month say that their cramps are reduced by 80-90 percent the first period after starting magnesium, and they are almost completely gone within two months. If you find that your periods are still painful, that may be a sign that you will need more time with magnesium to replete your stores, and that you should work on your adrenals, which can lead to menstrual issues when impaired. In such cases, you can combine magnesium with ibuprofen for period cramps. However, your ultimate goal, of course, is to get off the ibuprofen and save it for emergencies only.

  • For body cramps: Increasing your magnesium stores will prevent body cramps, so if you have intermittent cramps now, you should start taking magnesium preventatively. You can take either magnesium citrate or magnesium glycinate. Again, if you are having acute cramps, you can also take magnesium as needed, one to four times per day (magnesium glycinate is less likely to cause diarrhea), as well as soak in Epsom salt baths – they are so soothing and are a wonderful tool for your self-care routine. If you find that you are still cramping, that may be a sign that you will need more time on magnesium to replete your stores, or that you have other nutrient deficiencies or food sensitivities. You can combine magnesium with pain medications as you work your way off them, though I do recommend checking with your pharmacist first, as magnesium can prevent the absorption of some medications.

  • For anxiety: Magnesium deficiency can contribute to anxiety, and I recommend replenishing your magnesium stores to reduce symptoms. (23) The citrate salt of magnesium (magnesium citrate) is the most common ingredient in formulations of “calming” supplements – though, for acute bouts of anxiety, a faster-acting magnesium supplement in liquid form may work best. Other reasons for anxiety that should be explored include blood sugar imbalances, selenium deficiency, adrenal dysfunction, and gut issues.

  • For headaches: Prevention is key for migraines and headaches as well, so I recommend starting magnesium immediately if you suffer from either. You can take either magnesium citrate or magnesium glycinate. If you are having acute headaches, you can also take magnesium as needed, one to four times per day. If you find that you are still getting headaches/migraines, it may be a sign that you need more time on magnesium to replete your stores, or that you are reacting to foods. You may also have infections, like H. pylori, that can contribute to such food sensitivities. You can combine magnesium with pain medications in most cases, though I’d recommend checking with your pharmacist first, as magnesium can prevent the absorption of some medications.

  • Eye twitches: Research has shown that eye twitches (blepharospasms) can be one of the ways magnesium deficiency manifests in the body. When the cellular levels of magnesium are low, the cells within the eyes are more easily “excitable”, resulting in them firing off even weaker signals from the brain. While this effect may happen all over the body with magnesium deficiency, it is especially felt in the eyes, as the skin is very thin there. (24)

It’s important to note that if you are currently using other medications, such as those used to regulate blood pressure, you should check with your pharmacist before supplementing with magnesium, as it can interfere with the absorption of some medications.

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