Hypothyroidism
Hypothyroidism is a condition in which the thyroid gland does not produce enough thyroid hormone, slowing the body's metabolism and affecting nearly every organ system. Symptoms often develop gradually and include fatigue, weight gain, cold intolerance, depression, dry skin, and cognitive difficulties. Prevalence in the U.S. has been rising, growing from 9.6% of the population in 2012 to 11.7% in 2019, with women 5 to 9 times more likely than men to be affected. The most common cause — responsible for more than 70% of cases — is Hashimoto's thyroiditis, an autoimmune condition in which the immune system attacks the thyroid gland. Subclinical hypothyroidism, where TSH levels are elevated but symptoms may be mild or absent, adds significantly to the overall burden. Levothyroxine, the primary treatment for hypothyroidism, was the single most prescribed medication in the United States in 2023, underscoring just how widespread the condition has become. While hypothyroidism is highly manageable with consistent treatment, it requires lifelong medication and monitoring, with undertreated or undiagnosed cases carrying elevated risk for cardiovascular disease, infertility, and complications in pregnancy.
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