Authored by Revere Health

Hyperthyroidism vs. Hypothyroidism

July 13, 2017 | Endocrinology

The thyroid is a vital gland in the body, responsible for producing a hormone called thyroxine. Thyroxine helps regulate metabolism and protein synthesis along with numerous other functions, including development.

When the thyroid produces too much thyroxine, this is referred to as hyperthyroidism or overactive thyroid. On the other hand, when too little thyroxine is produced, this is known as hypothyroidism or underactive thyroid. What are the differences between these thyroid disorders? Let’s take a look.


Hypothyroidism occurs if the thyroid gland can’t produce enough thyroid hormones. As the gland’s hormone production slows down, so does metabolism, which is directly controlled by thyroxine. In turn, this can lead to weight gain, fatigue, constipation, cold intolerance, period irregularities, and some negative side effects on the fetus if a person gets pregnant while diagnosed with hypothyroidism. Hypothyroidism is common, affecting about 4.6 percent of the United States population.

There is no cure for hypothyroidism, but there are some medications that can treat it by improving thyroid function and restoring hormone levels. Hypothyroidism is most commonly caused by a condition called Hashimoto’s thyroiditis, a condition where the body attacks its own immune system and causes the thyroid to stop producing hormones in the way it should. Hashimoto’s thyroiditis is more common in women than in men.


In patients with hyperthyroidism, the thyroid produces too much thyroxine. It will often accelerate metabolism, leading to sudden weight loss, a rapid or irregular heartbeat, sweating, and nervousness or irritability. Hyperthyroidism is commonly seen in one of three ways:

  • Thyroiditis, or inflammation of the thyroid: An inflamed thyroid causes too much thyroid hormone to enter the blood, leading to pain and discomfort that’s usually short term.
  • A thyroid nodule that produces too much thyroxine: This is common in both hyperthyroidism and hypothyroidism, and nodules are often benign.
  • An autoimmune condition called Graves’ disease: This condition causes the body to attack itself, making the thyroid gland produce too much thyroxine.


Hyperthyroidism can be treated using medications, radioactive iodine, or surgery. If left untreated, it can cause bone loss or an irregular heartbeat.

The Differences

There are a few distinct differences between the two:

  • Hypothyroidism leads to a decrease in hormones, while hyperthyroidism leads to an increase.
  • Hypothyroidism leads to slowed metabolism, tiredness and a general slowing of body functions. Alternatively, hyperthyroidism can lead to weight loss, instead of weight gain. You may feel anxious instead of depressed.
  • Hypothyroidism is more common in the United States than hyperthyroidism.


It’s not uncommon to have an overactive thyroid after an underactive thyroid, or vice versa. If you have symptoms of hyperthyroidism or hypothyroidism, speak to your doctor about treatment options.

At Revere Health Endocrinology, our specialists are uniquely trained to diagnose and treat diseases and disorders related to the glands.

Contact us


“Hypothyroidism vs. Hyperthyroidism: What’s the Difference?”

“Hypothyroidism (Underactive).” American Thyroid Association.

“Hyperthyroidism (overactive thyroid).” The Mayo Clinic.


The Live Better Team

Telehealth is not appropriate for every medical concern, so it’s important to ask your provider whether a virtual visit is suitable for your needs.

Learn more about Telehealth

This information is not intended to replace the advice of a medical professional. You should always consult your doctor before making decisions about your health.