Hyperthyroidism is a condition where the thyroid produces or secretes excessive amounts of thyroid hormone. If left untreated, hyperthyroidism is associated with an increased risk of osteoporosis, atrial fibrillation, and stroke. In rare cases, hyperthyroidism can progress to a life-threatening condition called thyroid storm, characterized by a sudden and severe worsening of hyperthyroid symptoms, including fever, rapid heartbeat, chest pain, and confusion.^[1][2][3]

Common signs and symptoms include:

• Palpitations
• High blood pressure
• Tremors
• Sweating
• Weight loss
• Anxiety
• Heat intolerance (feeling warm/flushed or “running hot”)
• Exophthalmos (bulging of the eyes)

To diagnose hyperthyroidism, a healthcare professional may order blood tests to gauge the levels of thyroid hormones in the body, such as thyroid-stimulating hormone (TSH), and perform a thorough clinical assessment. Other tests that may be performed include thyroid ultrasound, thyroid radioactive iodine uptake, and additional thyroid hormone levels like triiodothyronine (T3), thyroxine (T4), or free T4 (FT4).

Treatment can vary depending on the cause of hyperthyroidism. Common treatments include antithyroid drugs, radioactive iodine ablation of the thyroid, or surgical removal of the thyroid (known as a thyroidectomy). Beta-blockers — drugs that reduce blood pressure and heart rate — may also be prescribed to help treat cardiovascular symptoms associated with hyperthyroidism.^[1]

Calcium and calcitriol (a form of vitamin D) may be supplemented if a person is experiencing hypocalcemia (low blood calcium levels) after a thyroidectomy. Other supplements that have been studied are L-carnitine and selenium. In some cases, biotin supplementation can falsely elevate thyroid hormone levels, so it's recommended to stop biotin supplementation for two days before testing.^[4][1]

Iodine is a mineral necessary for the production of thyroid hormones, and excess consumption of iodine-rich foods such as seaweed and kelp can cause or worsen hyperthyroidism.^[5] One study found that the autoimmune protocol diet reduced inflammation and symptoms associated with Hashimoto’s thyroiditis, an autoimmune disease causing hypothyroidism. Although Graves’ disease, another autoimmune thyroid disorder, is the most common cause of hyperthyroidism in countries with adequate iodine intake, not all hyperthyroidism occurs via autoimmune mechanisms. More research is needed to see if this benefit extends to people experiencing hyperthyroidism.^[6]

Studies have explored the potential of using herbal medicines commonly found in traditional Chinese medicine to treat hyperthyroidism, but there is insufficient high-quality evidence regarding their efficacy.^[7]

The most common cause of hyperthyroidism is Graves’ disease, an autoimmune condition in which the immune system produces antibodies that stimulate the thyroid gland to produce too much thyroid hormone. Other causes of hyperthyroidism include toxic multinodular goiter, toxic adenomas, and thyroid cancer. Some medications, such as amiodarone, lithium, and tyrosine-kinase inhibitors, may also cause hyperthyroidism.^[3] In some instances, people with hypothyroid who are being treated with thyroid hormone replacement medication may also develop hyperthyroidism.