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Hyperthyroidism vs. Hypothyroidism: Spotting The Difference

Thyroid disorders affect over 20 million Americans. 12% of people will develop a thyroid-related problem at some point in their lives and surprisingly, up to 60% of people with a thyroid problem are not aware of their condition.

A senior citizen wearing a mask is seen having his thyroid glands inspected by a doctor

The thyroid is a small gland shaped like a butterfly, located in the front and bottom of the neck. The thyroid’s only function is to release two hormones called thyroxine (T4) and triiodothyronine (T3) which control the speed cells work throughout the body.

 Hyperthyroidism and hypothyroidism and two types of thyroid conditions  and cause changes in the amount of thyroid hormones released. Hyperthyroidism vs. hypothyroidism differences are listed below.


What is Hyperthyroidism?

The “hyper” in hyperthyroidism means the thyroid is overactive and releases too much thyroid hormone into the body.

What are the Symptoms of Hyperthyroidism?

A senior woman overheating tries to cool off with a fan

Hyperthyroidism symptoms occur because the cells in the body are working harder and faster than they should be. This creates extra heat, uses extra energy, and makes almost every body system faster. Hyperthyroidism symptoms include:

  • Feeling tired
  • Sensitivity to heat
  • Unhealthy weight loss
  • Sweatiness
  • Abnormal hunger
  • Diarrhea
  • Fast heart rate
  • Urinating more often
  • Feeling jittery or hyper
  • Tremors
  • Hair loss
  • Dry eyes

Many of these symptoms can be the same symptoms that occur when someone is anxious and can commonly be mistaken for anxiety or other mental health problems.

What Causes Hyperthyroidism?

Hyperthyroidism can occur by itself, but other factors can also cause it. The most common causes of hyperthyroidism include Grave’s disease and thyroid cancer, though cancer is not the most common cause. Graves disease is an autoimmune disease where the body’s immune system attacks the thyroid gland. This leads to an increased release of hormones by the thyroid. Thyroid cancer is caused by a tumor that grows on the thyroid. These tumors can lead to changes in how the thyroid produces or releases thyroid hormones. 

How is Hyperthyroidism Diagnosed?

A senior man is seen having his blood drawn by a phlebotomist

It is typically easy to diagnose hyperthyroidism. Often blood is drawn to test for a hormone called the thyroid stimulating hormone (TSH). TSH tells the thyroid how much hormone to make and is affected by the levels of thyroid hormones. Because TSH is the most accurate way to tell if the thyroid is working properly, doctors typically test TSH instead of thyroid hormones themselves. TSH levels decrease when thyroid hormones increase, so doctors use low TSH levels to diagnose hyperthyroidism.

Your doctor might order other tests once diagnosed with hyperthyroidism. These tests are more focused on determining the cause of hyperthyroidism.

How is Hyperthyroidism Treated?

Doctors treat hyperthyroidism by decreasing the activity of the thyroid through medicines or surgery. Treatment of hyperthyroidism may cause hypothyroidism, which is easier to treat.

Radioactive iodine is a common treatment for hyperthyroidism and uses a radioactive substance to deliberately damage the thyroid. This reduces the amount of thyroid hormone produced and can essentially cure hypothyroidism.

Doctors may treat hyperthyroidism using surgery. In surgery, part or all of the thyroid is removed, depending on the patient. This surgery is either a partial or a complete thyroidectomy. Removing only part of the thyroid can help to prevent hypothyroidism from occurring while removing the entire thyroid causes hypothyroidism for certain. 


What is Hypothyroidism?

Hypothyroidism is when the thyroid is underactive, making too little thyroid hormone.

What are the Symptoms of Hypothyroidism?

A senior man wearing a mask is having his weight measured by a medical assistant

In hypothyroidism, the body’s cells work too slowly and do not use as much energy or generate as much heat as they should. This leads to almost every body system running too slowly. Hypothyroidism symptoms include:

  • Feeling low on energy
  • Sensitivity to cold
  • Weight gain
  • Dry skin
  • Poor appetite
  • Constipation
  • Slow heart rate
  • Urinating less often
  • Feeling fatigued
  • Depression
  • Poor memory

Because hypothyroidism symptoms are similar to other conditions, it can be misdiagnosed as chronic fatigue or depression.

What Causes Hypothyroidism?

An Iora doctor talks o a senior male patient about his diabetes management

Hypothyroidism can occur without any obvious reason, or it can occur from medical conditions such as autoimmune diseases like Diabetes or Hashimoto’s disease. Hypothyroidism sometimes runs in families as well, so if your family has a history of hypothyroidism, you could be at risk. 

Hashimoto’s disease, like Grave’s disease, is an immune disorder. In both conditions the body’s immune system attacks the thyroid gland. Hashimoto’s disease however, causes a reduction in the thyroid’s ability to function and is one of the leading causes of hypothyroidism.

How is Hypothyroidism Diagnosed?

The main way doctors diagnose hypothyroidism is  by drawing blood to test  TSH levels. TSH levels are high when thyroid hormone levels are low, so doctors use a high TSH level to diagnose hypothyroidism. Additional tests may be required to examine the thyroid and better understand what is causing hypothyroidism.

How is Hypothyroidism Treated?

A prescription pill bottle for Levothyroxine

Treatment involves taking levothyroxine (T4) as a medicine. Your body naturally converts T4 into T3, so oftentimes replacing T3 with a supplement is not necessary. This hormone can be taken as a pill and can easily be adjusted depending on how much thyroid hormone is needed.

The expert providers at Iora are experienced in recognizing the differences between hyperthyroidism vs. hypothyroidism. We will listen to your concerns and take a personalized approach to your care. If you would like to learn more about our care and how to become a patient, contact us.

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