Low Thyroid Hormones

Symptoms and Prevalence

Thyroid issues top the list of endocrine disorders, with around 20 million Americans being affected [1].

Levothyroxine (synthetic T4) for hypothyroidism is the second most prescribed drug in the US [2].

Low thyroid hormones (hypothyroidism) manifest with cold intolerance, fatigue, weight gain, goiter, and constipation. This condition is most common among young women [3].

Autoimmune Hypothyroidism

Autoimmune disorders are the leading cause of hypothyroidism in developed countries. Hashimoto’s disease is the main form of autoimmune hypothyroidism, in which antibodies attack and destroy thyroid tissue [4].

Lab markers that can help diagnose Hashimoto’s include [5]:

  • Elevated TSH
  • Low T3 and T4
  • Antibodies to thyroglobulin (Tg)
  • Antibodies to thyroid peroxidase (TPO)
  • Antibodies to TSH


Hypothyroidism manifests with fatigue, weight gain, and goiter; autoimmunity is the leading cause in the western world. It mostly affects women and causes high TSH and low T3 and T4.

Top Recommendations for Hashimoto’s


Heavy metals such as mercury and cadmium can increase thyroid antibodies. Removal of mercury-containing dental amalgams cut thyroid antibodies in half in 27 people with mercury allergies [6].

In a study of over 5,600 Chinese adults, women exposed to more cadmium had higher thyroglobulin antibody levels. Sources of cadmium exposure include cigarette smoke, processed and instant foods, and contaminated large ocean fish [7, 8].

Low-level laser therapy (LLLT) on the neck and upper chest reduced anti-TPO antibodies in two trials with 58 patients [9, 10].


Low-carb diets can decrease the levels of antibodies to thyroid peroxidase (TPO), a crucial enzyme for the production of thyroid hormones [11].

For those with celiac disease, a gluten-free diet may cut autoimmune thyroid antibodies and possibly thyroid inflammation [12, 13].

Although iodine is essential for thyroid health, high doses given at once (1.53 mg each week) can increase antibodies to TPO and thyroglobulin (Tg). For those at risk of deficiency, daily supplementation with up to 200 mcg is a much better idea [14].


You can reduce thyroid antibodies by cutting back on carbs, avoiding gluten if you are sensitive, and maintaining an optimal iodine intake.

Drugs and Supplements

Thyroid hormones are available by prescription for people with Hashimoto’s disease and some other forms of hypothyroidism. However, they come with a significant downside; see this post for more details.

If you believe you need to take synthetic thyroid hormones, we recommend discussing the possibility with your doctor.

For more reading, see this post.

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