Lithium is a mood-stabilizing medication commonly used to treat mood disorders like bipolar disorder. However, it has several known side effects, including nausea, diarrhea, dry mouth, fatigue, and hand tremors.
Additionally, there is a known link between lithium and the thyroid. Research has shown that taking this medication can increase the risk of:
- enlarged thyroid, known as goiter
- hypothyroidism, a condition in which your thyroid gland doesn’t produce enough thyroid hormone
- hyperthyroidism (in rare cases), a condition in which the thyroid produces too much thyroid hormone
While lithium is considered an important medication for the treatment of mood disorders, it has several effects on the thyroid gland, a small, butterfly shaped gland at the front of the neck, just below the voice box.
The thyroid breaks down proteins and processes carbohydrates and vitamins. It also produces hormones that are essential for heart rate, mood, digestion, and other crucial functions. If there is a hormone imbalance, it can cause various health problems.
According to a 2022 review of studies, taking lithium is known to:
- Increase iodine content within the thyroid gland. While the body needs iodine to produce hormones, too much
can cause thyroid inflammation, goiter, and thyroid cancer. It can also lead to hypothyroidism or hyperthyroidism. - Reduce your thyroid gland’s ability to produce thyroxine (T4) and triiodothyronine (T3), two important hormones.
- Block your thyroid gland, preventing the release of thyroid hormones.
- Change the structure of a protein called thyroglobulin, which is involved in making thyroid hormones.
Goiter is the most common side effect of lithium usage, affecting about 40% of people taking the medication, according to
A 2023 study of people with bipolar disorder who took lithium showed that 32% developed a thyroid disorder. Of those, 79% developed hypothyroidism, which was treated with thyroid hormone replacement therapy.
According to a 2015 study, women younger than 60 and people who took higher concentrations of lithium were at the
Lithium-associated hypothyroidism is often considered reversible once lithium treatment has been stopped.
Medical research documents reports of lithium usage linked to new cases of hyperthyroidism, though this is rare. Doctors and researchers have not come to a consensus about why this could be so, and more research is needed.
The symptoms of lithium-induced hypothyroidism are the same as those in people with the primary instances of the disorder. They include:
- fatigue
- trouble thinking quickly
- depression
- weight gain
- dry skin
- extreme discomfort to cold environments
Lithium, a common and effective medication for mood disorders, is known to cause hypothyroidism and other thyroid issues. If you experience the symptoms of hypothyroidism or other disorders while taking lithium, speak with your doctor.