Thyroid conditions, including hypothyroidism, hyperthyroidism, and thyroid cancer, are common. For example, up to 7% of the U.S. population has hypothyroidism, a condition in which your thyroid doesn’t produce enough thyroid hormones (1).

Depending on the type of disease, thyroid conditions are typically treated with medications like thyroid hormone replacement, surgery, and other procedures, such as radiation therapy for thyroid cancer.

In addition to conventional treatments for thyroid conditions, research shows that dietary interventions, including supplements, may help treat certain thyroid diseases.

However, certain supplements may do more harm than good when it comes to thyroid health.

This article explains how supplements may help certain people with thyroid-related health conditions.

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Photography by Aya Brackett

If you walk down the supplement aisle of your favorite health food store, you’ll likely see a section dedicated to thyroid health.

Due to the prevalence of thyroid conditions, many supplement companies have started making supplements that are designed to “support thyroid health.”

Although some of these products are harmless, certain thyroid supplements may lead to negative side effects and can even harm your thyroid.

Before addressing why thyroid-specific supplements may not be the best choice for everyone, it’s important to explain what nutrients the thyroid needs for optimal functioning. Here are some of the most important nutrients for thyroid health:

  • Selenium. Selenium, a mineral needed for thyroid hormone production, helps protect the thyroid from damage caused by oxidative stress. The thyroid contains high amounts of selenium, and a deficiency can lead to thyroid dysfunction (2).
  • Iodine. Iodine is critical for thyroid function. In fact, currently, the only known role of iodine is to support thyroid hormone production. Triiodothyronine (T3) and thyroxine (T4) are thyroid hormones that contain iodine. Iodine deficiency causes thyroid disease (3, 4).
  • Zinc. The mineral zinc is required for thyroid hormone production. An optimal concentration of zinc is needed for healthy levels of T3, T4, and thyroid-stimulating hormone (TSH) (5).
  • Iron. The thyroid needs iron to convert T4 into T3, the active form of thyroid hormone. Iron deficiency is associated with thyroid dysfunction (6).

Other nutrients, including B vitamins and vitamins A and E, are also needed for optimal thyroid function. Being deficient in one or more nutrients can negatively affect thyroid health and increase your risk of thyroid disease (7, 8, 9, 10).

For most people, following a nutrient-dense diet rich in whole foods is enough to maintain optimal thyroid function.

However, certain populations may need to supplement their diet with vitamins, minerals, and other nutrients to maintain overall health, including the health of the thyroid.

These populations include people on restrictive diets, people who are pregnant or breastfeeding, and those who have a thyroid condition or other health issues.

Should you take thyroid-specific supplements?

There’s no doubt that a nutritious diet that provides optimal nutrient levels is important for maintaining thyroid health, nor that nutrient deficiencies can lead to thyroid issues.

Still, for people who don’t have thyroid issues and follow a well-balanced, nutrient-dense diet, there’s typically no need to take thyroid-specific supplements.

In fact, certain supplements marketed toward those looking to promote thyroid health may be dangerous to take.

For example, many thyroid supplements contain high amounts of iodine and may contain thyroid hormones. Taking these supplements can lead to dangerous side effects and create thyroid issues in people with healthy thyroid function (11).

One study that analyzed 10 thyroid supplements found that the majority of them contained detectable amounts of T3 and T4. Some of the products tested contained more T3 and T4 than healthcare providers typically prescribe to people with hypothyroidism (11).

Taking these supplements may lead to elevated thyroid hormone levels in the blood and cause symptoms of hyperthyroidism, which can lead to dangerous complications (12, 13, 14).

What’s more, excessive iodine intake from supplements may cause hypothyroidism in susceptible individuals (12, 13, 14).

Thyroid supplements may be unsafe for people who have thyroid conditions, too.

This is because people with thyroid issues have specific needs, and taking supplements marketed to enhance thyroid health may negatively affect thyroid function, causing their health and symptoms to worsen.

As such, people with and without thyroid conditions should avoid taking supplements marketed to promote thyroid health. Instead, work with a practitioner to come up with a healthy and safe plan that’s based on your specific needs and health status.

Summary

It’s a smart idea to stay away from dietary supplements marketed to improve thyroid health. These products can cause health issues in people with and without thyroid disease.

Hashimoto’s disease is the most common cause of hypothyroidism in the United States. It’s an autoimmune disease in which the immune system produces antibodies that attack the thyroid, causing fibrosis or scarring of the thyroid tissue (15).

Hashimoto’s disease is associated with a variety of symptoms, including weight gain, fatigue, hair loss, anemia, constipation, cold intolerance, joint pain, dry skin, mood changes, difficulty concentrating, and more (15).

In addition to medication, diet and lifestyle modification can help reduce thyroid damage and improve symptoms and overall quality of life in people with Hashimoto’s.

Plus, people with Hashimoto’s disease are more likely to be deficient in certain nutrients, which can worsen Hashimoto’s-related symptoms.

Studies show that the following supplements can be beneficial for those with Hashimoto’s disease:

  • Selenium. Studies have shown that supplementing with 200 mcg of selenium per day may help decrease thyroid antibodies and improve mood in people with Hashimoto’s (16, 17).
  • Myo-Inositol. Inositol is a type of sugar that plays an important role in thyroid function. Some evidence suggests that daily treatment with 600 mg of Myo-Inositol and 83 mcg of selenium may help improve thyroid function in people with Hashimoto’s (18, 19).
  • Zinc. Zinc is needed for thyroid hormone production, and a deficiency can result in hypothyroidism. When used alone or in combination with selenium, 30 mg of zinc per day may help enhance thyroid function in people with Hashimoto’s disease (20, 21).
  • Vitamin B12. Vitamin B12 deficiency is common in people with Hashimoto’s disease. Taking a B12 or B complex supplement can help prevent and treat deficiency, as well as maintain optimal B12 levels (22, 23).
  • Magnesium. A magnesium deficiency may increase your risk of developing Hashimoto’s disease and is associated with elevated thyroid antibody levels. Correcting magnesium deficiency may improve Hashimoto’s symptoms (24, 25).
  • Iron. Many women with Hashimoto’s disease have low iron levels or iron deficiency anemia. Anemia negatively affects thyroid function. An iron supplement may be necessary to restore iron to optimal levels (26).
  • Vitamin D. People with Hashimoto’s disease are more likely to be deficient in vitamin D than the general population, and vitamin D deficiency can have an adverse effect on thyroid function (22, 27).
  • Curcumin. Curcumin may help protect your thyroid against oxidative damage. Plus, taking curcumin alongside other anti-inflammatory compounds may help reduce the size of thyroid nodules, which are common in Hashimoto’s disease (28, 29).
  • Vitamin C. Research suggests that taking a vitamin C supplement may help reduce thyroid antibodies in people with Hashimoto’s disease (30).

Other supplements may help people with Hashimoto’s as well. However, the supplements above have the most research to support their use in the management of Hashimoto’s disease.

Summary

Research suggests that certain supplements, including selenium, zinc, iron, and vitamins D and B12, may be beneficial for people with Hashimoto’s disease.

Graves’ disease is the most common cause of hyperthyroidism in the United States. Like Hashimoto’s disease, it’s considered an autoimmune condition.

In Graves’ disease, the immune system attacks your thyroid, causing it to overproduce thyroid hormones. Graves’ disease can also lead to thyromegaly or an enlarged thyroid (31).

Symptoms associated with Graves’ disease include weight loss, heart palpitations, shortness of breath, diarrhea, eye pain and irritation, fatigue, weakness, menstrual irregularities, insomnia, nervousness, and more (32).

Current treatment of Graves’ disease includes surgery, medication, and radioactive iodine therapy (RAI) (32).

Like Hashimoto’s disease, some research shows that dietary modifications may help improve symptoms and quality of life in people with Graves’ disease (33).

The following supplements may help people with Graves’ disease:

  • Selenium. Selenium deficiency can raise your risk of Graves’ disease. A review found selenium supplements in daily dosages of 100–300 mcg led to improved thyroid function at 6 months in people with Graves’ disease, but this effect was lost at 9 months (34).
  • Vitamin D. Research shows that people with Graves’ disease are more likely to be deficient in vitamin D than the general population. Correcting deficiency by taking a supplement may improve thyroid function (35, 36, 37).
  • L-carnitine. Research has found that hyperthyroidism depletes your body’s stores of carnitine, which plays a critical role in energy production. Taking L-carnitine may help reduce symptoms and improve quality of life in people with hyperthyroidism (38, 39).
  • Vitamin B12. People with Graves’ disease are at a greater risk of developing a vitamin B12 deficiency. Taking a high quality B12 or B complex supplement can help maintain healthy B12 levels (40, 41, 42).

Other supplements may help people with Graves’ disease. Work with a knowledgeable healthcare practitioner to develop a supplement regimen that’s right for you.

Summary

According to research, vitamin D, selenium, L-carnitine, and vitamin B12 may help people with Graves’ disease.

Thyroid cancer is considered a rare type of cancer, accounting for just 1–4% of all cancers in the United States. Cancers that stem from follicular cells in the thyroid account for up to 95% of all thyroid cancers (43).

Treatment for thyroid cancer includes surgical resection, radiation therapy, thyroid-stimulating hormone (TSH) suppression, radioactive iodine (RAI) therapy, total thyroidectomy, and palliative care management for untreatable thyroid cancer.

In addition to traditional treatment, diet, supplements, and lifestyle modifications may enhance treatment outcomes and improve quality of life in people with thyroid cancer.

Some animal and test-tube research suggests that omega-3 fats, curcumin, L-carnitine, quercetin, melatonin, resveratrol, selenium, inositol, zinc, and vitamins C, E, A, and D may benefit those with thyroid cancer (44, 45, 46).

Additionally, low iodine intake is linked to an increased risk of thyroid cancer, and research suggests that correcting iodine deficiency can help protect against the development of more aggressive forms of thyroid cancer (47).

However, although many of these nutrients, including vitamin D and selenium, are known to have anticancer effects, there’s currently a lack of human studies investigating the effects of these dietary supplements in people with thyroid cancer (47, 48).

Therefore, more studies are needed before these supplements can be routinely recommended for people with thyroid cancer (47, 49).

The best way to determine the best supplement regimen for your specific needs is to consult your healthcare provider.

Oftentimes, either your healthcare provider or a registered dietitian that specializes in oncology nutrition will recommend supplements depending on your diet, overall health, and what treatments you’re currently undergoing for thyroid cancer.

Summary

Although research suggests that some supplements may benefit people with thyroid cancer, human research is lacking. To ensure your safety, it’s best to check with your medical provider before taking any supplements.

As mentioned above, it’s best to avoid thyroid-specific supplement blends unless they’re specifically recommended by your healthcare provider.

Taking these supplements can harm your thyroid and lead to a thyroid condition (11, 12, 13, 14).

Still, there are many vitamins, minerals, and other dietary supplements that have been shown to improve thyroid function, reduce disease symptoms, and improve overall quality of life in people with thyroid disease.

For people who have Hashimoto’s disease, Graves’ disease, thyroid cancer, or other condition that affects the thyroid gland, it’s best to work with a qualified healthcare provider who specializes in thyroid conditions.

This is especially important if you’re currently taking medications. Many supplements, especially herbal products, have the potential to interact with commonly prescribed medications and may lead to dangerous side effects.

Lastly, it’s important to always purchase supplements from trusted brands that independently test their products for quality and purity using organizations like USP and NSF International.

Summary

If you’re interested in taking supplements to treat a thyroid condition, it’s important to work with a qualified healthcare provider. They can help you choose supplements based on your specific needs and health status.

Research shows that some vitamins, minerals, and other nutrients may benefit people with certain thyroid conditions.

However, it’s important to develop a supplement regimen based on your specific needs and health issues.

If you’re interested in treating a thyroid condition with supplements, it’s important to work with a qualified healthcare provider to ensure safety and effectiveness.

Useful supplement shopping guides

Check out these two articles to help make supplement shopping a breeze:

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