Hypothyroidism vs. Hyperthyroidism

The thyroid gland is a small, butterfly-shaped gland located in the neck. It makes thyroid hormones called thyroxine (T4) and triiodothyronine (T3). These hormones affect nearly every organ function in the body and control many critical body processes, such as heart rate, breathing, digestion, weight, and mood.

An estimated 20 million Americans suffer from some form of thyroid disease. Up to 6 out of 10 people with thyroid disease are unaware they have a problem with their thyroid gland. Women are up 5-8 times more likely than men to have thyroid disorders.

The two main types of conditions that affect the thyroid gland are hypothyroidism (underactive thyroid) and hyperthyroidism (overactive thyroid). Please continue reading to learn more about hyperthyroidism vs hypothyroidism and how these thyroid conditions are different from each other.

What is hypothyroidism?

Hypothyroidism is an underactive thyroid gland that cannot make enough thyroid hormones. This condition affects about 1 in 300 people in the United States or roughly 4.5% of the population. Low thyroid hormone levels lead to a variety of symptoms of hypothyroidism, including a slowing of metabolism, weight gain, and fatigue. Other hypothyroidism symptoms include constipation, dry skin, thinning hair, sensitivity to cold, muscle weakness, joint pain and stiffness, high blood pressure, puffiness, hoarseness, irregularities in the menstrual cycle, and infertility. Hypothyroidism symptoms can also include psychological symptoms like depression and memory problems.

The most common cause that can trigger hypothyroidism is Hashimoto’s thyroiditis. It is an autoimmune disease in which the immune system mistakenly attacks the thyroid cells. Over time, this causes the thyroid gland to stop producing enough thyroid hormones, which causes the person to develop hypothyroidism. Rarely, a person can have congenital hypothyroidism due to a missing thyroid gland (the thyroid gland fails to develop or function properly).

Doctors can diagnose hypothyroidism (underactive thyroid) with thyroid function tests. These are blood tests to evaluate thyroid levels. A blood test can be done to measure thyroid stimulating hormone (TSH) as well as T4 and T3 thyroid hormone levels. A high TSH level and low T4 level indicates hypothyroidism.

There is no cure for hypothyroidism, but medications are available to treat this thyroid disease. If you have had hypothyroidism diagnosed, treatment with synthetic thyroid hormones is a simple, safe, and effective way to restore thyroid hormone levels and improve thyroid function. With the proper treatment, people with thyroid disorders can live normal lives.

What is hyperthyroidism?

Hyperthyroidism (overactive thyroid) is a condition in which the thyroid gland makes too many thyroid hormones. It is less common than hypothyroidism in the United States and affects about 1% of the population.

Some common hyperthyroidism symptoms include a racing, pounding, or irregular heartbeat, heart palpitations, abnormal heart rhythm, increased appetite, sudden or unintentional weight loss, thin skin, fine and brittle hair, heat sensitivity, fatigue, weakness, sleeping difficulties, frequent bowel movements, nervousness, shakiness, anxiety, sweating, and irregular menstrual periods.

The three most common causes of hyperthyroidism are thyroiditis (inflammation of the thyroid gland), thyroid nodules (a thyroid nodule can produce too much T4 hormone), and Graves’ disease (an autoimmune disorder that results in an enlarged thyroid gland which makes too much thyroid hormone).

Less commonly, hyperthyroidism occurs in pregnant women or women who have recently given birth (postpartum thyroiditis). Occasionally, a problem with the pituitary gland in the brain can cause secondary hyperthyroidism.

A low TSH level and elevated T4 and T3 thyroid hormone levels indicate an overactive thyroid gland that is producing too much thyroid hormone.

Hyperthyroidism treatments include anti-thyroid medications and radioactive iodine to decrease the production of thyroid hormones. In some patients, hyperthyroidism treatment options involve thyroid surgery (surgical removal of a part or all of the thyroid gland).

What is the difference between hypothyroidism and hyperthyroidism?

As mentioned, hypothyroidism is an underactive thyroid while hyperthyroidism is an overactive thyroid. The most important difference between hypothyroidism and hyperthyroidism is in the hormone production. In hypothyroidism, the thyroid gland produces hormones at a slower rate, leading to lower levels of thyroid hormones. People with hyperthyroidism produce hormones at an increased rate, leading to too much hormone.

What is TSH level in hypothyroidism and hyperthyroidism?

The normal range for TSH in most laboratories is 0.4 to 4 mU/L (milliunits per liter). A low TSH level (under 0.5 mU/L) indicates an overactive thyroid or hyperthyroidism. A high TSH level over 4.0 mU/L indicates underactive thyroid or hypothyroidism. Doctors may also order T4 and T3 thyroid hormone tests before making a diagnosis of hypothyroidism and hyperthyroidism.

Which is worse: hypothyroidism or hyperthyroidism?

Between hypothyroidism and hyperthyroidism, one condition is not necessarily worse or more dangerous than the other. However, hypothyroidism is more common than hyperthyroidism. Also, hypothyroidism tends to be easier to treat and causes fewer long-term health problems compared to hyperthyroidism.

Can you be hypothyroid but have hyperthyroid symptoms?

It is not uncommon to have an overactive thyroid and then an underactive thyroid or the other way around. For example, radioactive iodine therapy is used to treat hyperthyroidism caused by autoimmune diseases. It slowly destroys the thyroid cells that produce thyroid hormones. Over time, people who receive this treatment can develop hypothyroidism because the thyroid cells have been destroyed.

An endocrinologist is a doctor who specializes in treating disorders of the endocrine system, including thyroid disorders. They can provide professional medical advice for thyroid conditions and develop a safe and effective treatment plan for your thyroid problems.

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