Health Conditions A-Z Endocrine Conditions Thyroid What Is Hypothyroidism? Hypothyroidism affects about 5 in 100 people in the United States. The condition causes symptoms like weight gain, depression, muscle soreness, and fatigue. By Sarah Fielding Sarah Fielding Instagram Twitter Website Sarah Fielding is a freelance writer covering a range of topics with a focus on mental health and social issues. health's editorial guidelines Updated on January 20, 2023 Medically reviewed by Isabel Casimiro, MD Medically reviewed by Isabel Casimiro, MD Isabel Casimiro, MD, PhD, is an endocrinologist at the University of Chicago in Illinois. As a physician-scientist in molecular biology, she uses her research on diabetes, lipid disorders, cardiovascular function, and more to provide comprehensive care to her patients. Her research findings have been published in several scientific and medical journals, including Cell Metabolism and the Journal of the Endocrine Society. Dr. Casimiro also has extensive experience providing gender-affirming hormone therapy and improving education regarding transgender medicine for endocrinology fellows. Her work with transgender patients has been published in the Journal of the Endocrine Society and Transgender Health. Dr. Casimiro also serves on graduate and medical school program committees and is a clinical instructor at the University of Chicago. Dr. Casimiro received her PhD in biomedical research from the Albert Einstein College of Medicine and her medical degree from the University of Washington. She completed her internal medicine residency and endocrinology fellowship through the Physician Scientist Development Program at the University of Chicago. She is board-certified in internal medicine. learn more Share Tweet Pin Email Hypothyroidism occurs when the thyroid doesn't produce enough hormones. In contrast, hyperthyroidism occurs when the thyroid produces too many hormones. The thyroid, part of the endocrine system, is the butterfly-shaped gland at the base of the neck. The endocrine system uses hormones to regulate metabolism, energy levels, and body temperature. Hypothyroidism can cause many symptoms, ranging from brain fog to low libido. Like many thyroid disorders, hypothyroidism is often misdiagnosed or undiagnosed. In fact, about 5% of people with hypothyroidism are undiagnosed. Here's what you need to know about hypothyroidism, including common symptoms, causes, and potential treatment options. What Every Woman Should Know About Her Thyroid Gland Hypothyroidism Symptoms Hypothyroidism affects almost five in every 100 people in the United States. Symptoms vary widely based on sex, age, menstrual status, weight, and fat distribution. Typically, symptoms develop gradually over many years and include: FatigueConstipationDry, thinning hairInability to tolerate cold temperaturesTingling and numbness in hands and feetWeight gainSlow heart rateDepressionFace and eye puffinessBrain fogHeavy and irregular menstrual periodsMuscle soreness If you're experiencing any of those symptoms gradually worsening, consult a healthcare provider. An endocrinologist is a healthcare provider who diagnoses and treats endocrine system disorders. Thyroid Disease Symptoms You Should Be Aware Of Hypothyroidism Symptoms in Children and Infants Hypothyroidism usually occurs in adulthood. Still, children can also have the condition. Specifically, children may have the following symptoms: Stunted growthMental development delaysDelayed puberty Additionally, in infants, hypothyroidism cause symptoms like: Jaundice, or the yellowing of the skinHearing lossSwollen tongueDifficulty breathingPoor feedingUmbilical hernia What Causes Hypothyroidism? Hypothyroidism occurs when the thyroid doesn't produce enough of the hormones triiodothyronine (T3) and thyroxine (T4). Those hormones affect metabolism, body temperature, and heart rate. There are many reasons why the thyroid may be underactive, including: Hashimoto's thyroiditis: This autoimmune condition causes chronic inflammation of the thyroid. Hashimoto's thyroiditis is the leading cause of hypothyroidism in the United States.Thyroid surgery: A healthcare provider removes part of the thyroid with this type of surgery.Hyperthyroidism treatments: Some treatments for an overactive thyroid, like radioactive iodine, may overcorrect the issue.Medications: Lithium and bexarotene may contribute to an underactive thyroid.Thyroid nodules: These are abnormal growth of thyroid cells. While most thyroid nodules are noncancerous, they can disrupt thyroid function.A pituitary gland disorder: This occurs when something impacts the area of the brain responsible for regulating the thyroid.Iodine deficiency: Iodine helps produce thyroid hormones. So, a deficiency in the mineral may contribute to an underactive thyroid. Risk Factors Some people are more likely to develop hypothyroidism. The risk factors include: Being a woman Being 60 years or older Having a family history of thyroid disease Having an autoimmune disease Being pregnant or giving birth in the last six months Having a history of thyroid problems or recently undergoing thyroid surgery Having a history of radiation therapy to the neck, thyroid, or chest How Is Hypothyroidism Diagnosed? To diagnose hypothyroidism, a healthcare provider will likely do the following: Ask about your medical history, including symptoms you havePerform a physical examOrder a blood test to measure thyroid-stimulating hormone (TSH), T4, T3, and thyroid antibodiesOrder imaging tests, such as a thyroid scan, ultrasound, or radioactive iodine uptake test Your pituitary gland produces TSH, which regulates how much T3 and T4 your thyroid releases. If you have an underactive thyroid, your pituitary gland releases more TSH to boost thyroid hormone levels. High levels of TSH and low levels of T4 indicate an underactive thyroid, indicating hypothyroidism. The normal range for TSH and T4 for children varies depending on age. But high levels of TSH and low levels of T4 also inform diagnosis. If your TSH levels are high, but your T4 reading is relatively normal, you may have subclinical hypothyroidism. Subclinical hypothyroidism is an early form of the condition. In about 70% of cases, subclinical hypothyroidism is asymptomatic. Still, the condition increases the risk of later developing hypothyroidism. If You Have a Borderline Underactive Thyroid, Do You Need to Treat it? Treatments for Hypothyroidism There's no cure for hypothyroidism. However, medicine can manage symptoms. In most cases, prescription thyroid hormone, either in a tablet or liquid form, is the standard treatment. Most people feel better within six to eight weeks of starting medication. The synthetic hormones will lower TSH levels back to their normal range. Once you begin treatment, a healthcare provider will order another blood test in six to eight weeks to check your TSH levels. The healthcare provider will adjust your medication dose as necessary, depending on the results. The dose will continue to change until thyroid hormone levels are in the normal range. Consistently taking the medication is key to managing the condition. Still, you can also make small dietary changes to alleviate symptoms further. For example, the thyroid gland needs iodine to produce hormones. So, if you have low blood levels of the mineral, you may want to try eating more iodine-rich foods like: Fish, particularly codSeaweedDairy You'll also want to limit or avoid goitrogens, like soy and kale. Goitrogens cause an underactive thyroid to swell, which worsens symptoms. A Quick Review Hypothyroidism occurs when the thyroid doesn't make enough of the hormones that regulate metabolism, temperature, and heart rate. The symptoms can vary widely and usually develop gradually over several years. The condition is common among adults, but children may have symptoms. If you're experiencing symptoms, talk with a healthcare provider. In particular, an endocrinologist can run tests to determine if you have an underactive thyroid. Was this page helpful? Thanks for your feedback! Tell us why! 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