Short Facts Sheet:

What is Hypothyroidism?

Hypothyroidism is a condition in which the thyroid gland does not produce enough thyroid hormones, leading to a slowdown in metabolism and various bodily functions. I

Types of Hypothyroidism

1.      Primary Hypothyroidism – Caused by issues within the thyroid gland itself, such as autoimmune disease or iodine deficiency.

2.      Secondary Hypothyroidism – Due to dysfunction in the pituitary gland, which fails to produce enough TSH.

Causes of Hypothyroidism

• Autoimmune (Hashimoto’s thyroiditis) – The most common cause.

• Iodine deficiency or excess – Iodine is essential for thyroid hormone production.

• Post-thyroid surgery or radioactive iodine treatment – May lead to permanent hypothyroidism.

• Congenital hypothyroidism – A condition present at birth.

• Pituitary gland dysfunction – A rare cause where TSH production is impaired.

• Medications – Certain drugs like lithium or amiodarone can affect thyroid function.

What Causes Autoimmune Hypothyroidism?

Autoimmune hypothyroidism occurs when the immune system mistakenly attacks the thyroid gland. This can be triggered by:

• Genetic predisposition

• Environmental factors (e.g., exposure to radiation or certain chemicals)

• Chronic stress

• Viral infections

• Gut health imbalances and intestinal permeability

• Injury or physical stress

• Pregnancy

Why is the Term "Hashimoto’s" Used?

Hashimoto’s thyroiditis is the most common cause of hypothyroidism and is an autoimmune condition where the immune system mistakenly attacks the thyroid gland, leading to chronic inflammation and reduced hormone production. It is named after Dr. Hakaru Hashimoto, who first described the condition in 1912.

How is Thyroid Health Measured?

Thyroid function is assessed using various tests:

• TSH (Thyroid-Stimulating Hormone):

• High TSH levels usually indicate an underactive thyroid because the pituitary is trying to stimulate more hormone production.

• Low TSH levels may suggest an overactive thyroid or excessive thyroid hormone replacement.

• T4 (Thyroxine): The main hormone produced by the thyroid, converted into T3 in the body.

• T3 (Triiodothyronine): The active form of thyroid hormone, directly influencing metabolism and energy levels.

• Thyroid Antibodies (TPO & TgAb): Their presence may indicate autoimmune thyroid disease.

Signs and Symptoms of Hypothyroidism

• Fatigue

• Weight gain

• Cold intolerance

• Dry skin

• Hair thinning

• Depression or brain fog

• Slow heart rate

• Constipation

• Puffy face or swelling

• Joint and muscle pain

• Menstrual irregularities

Thyroid Damage and When Replacement Therapy is Necessary

In cases where the thyroid gland is significantly damaged or removed (such as in a thyroidectomy, or after radioactive iodine treatment), thyroid hormone replacement therapy is necessary to maintain normal metabolism and bodily functions.

Thyroid Hormone Replacement: Synthetic vs. Desiccated Hormones

• Levothyroxine (T4): The gold standard treatment, as it is stable, consistent, and well-researched. The body converts T4 into T3 as needed. This treatment in regulated.

• Desiccated Thyroid Hormone (NDT, such as Armour or NP Thyroid): Contains both T4 and T3. Some individuals who struggle with T4-to-T3 conversion feel better on this form of treatment however, levels can be difficult to manage as desiccated thyroid hormone is not regulated and you can’t be certain of how much T3 or T4 is in the treatment.

If you would like to learn more or listen to Dr. Ur’s most recent Podcast on Hypothyroidism: CLICK HERE to listen on Spotify or CLICK HERE to listen on Apple Podcasts