Underactive thyroid


Underactive thyroid, also known as hypothyroidism, is a condition in which the thyroid gland does not produce enough of the hormones thyroxine (T4) and/or triiodothyronine (T3). This can lead to a variety of symptoms including dry skin, fatigue, constipation, depression, and weight gain. Treatment typically includes daily supplementation with synthetic thyroid hormones. It is important to maintain regular follow-up with your doctor and monitor the effectiveness of the treatment.


Symptoms of an underactive thyroid, or hypothyroidism, can vary but generally include fatigue, difficulty concentrating, depression, constipation, dry skin and hair, weight gain, irregular periods, and a slowed heart rate. Other common signs and symptoms of hypothyroidism include feeling cold, muscle pain, joint pain, and a hoarse voice.


The most common cause of an underactive thyroid is a condition known as primary hypothyroidism, which occurs when the thyroid gland does not produce enough of the hormones needed to regulate the body’s metabolic processes. Other known causes of an underactive thyroid include autoimmune diseases such as Hashimoto’s thyroiditis, certain medications and radiation treatments, iodine deficiency, and various physical conditions, such as cysts or tumors on the thyroid gland, congenital defects, and inflamed lymph nodes near the thyroid.

Risk factors

Risk factors for Underactive thyroid include:

  • Age – The prevalence of hypothyroidism increases with age.
  • Genetics – Individuals with a family history of hypothyroidism are at an increased risk.
  • Gender – Women are at a higher risk of hypothyroidism than men.
  • Pregnancy – Increased levels of hormone production during pregnancy can lead to hypothyroidism.
  • Stress – Chronic stress can cause hormonal imbalances which can lead to symptoms of hypothyroidism.
  • Medications – Certain medications or treatments like chemotherapy or radiation therapy can increase the risk of hypothyroidism.
  • Autoimmune Disorders – People with autoimmune diseases such as Hashimoto’s thyroiditis are at an increased risk of hypothyroidism.
  • Iodine Deficiency – Those with a lack of iodine in their diet may develop hypothyroidism.
  • Surgery – Surgery on the thyroid or goiter can increase the risk of developing hypothyroidism.


Underactive thyroid, or hypothyroidism, is typically diagnosed through a physical exam, a detailed medical history, and lab tests to measure thyroid hormones. The most common lab test used to diagnose hypothyroidism is a blood test that measures a hormone called thyroxine (T4). Other tests may include triiodothyronine (T3) or thyroid-stimulating hormone (TSH). The doctor may also order additional tests to help determine the cause of the hypothyroidism, such as an autoantibody test, iodide uptake test, or thyroid ultrasound.


The various subtypes of underactive thyroid include:

  1. Primary hypothyroidism: This is the most common type where the thyroid gland does not produce enough hormones due to a problem with the thyroid itself. Common causes of primary hypothyroidism include Hashimoto’s thyroiditis, iodine deficiency, surgical removal of the thyroid, and some medications.
  2. Central hypothyroidism: In this type, the thyroid does not produce enough hormones due to a problem with the hypothalamus or pituitary glands. This type can be caused by tumors, inflammation, head trauma, radiation, or certain medications.
  3. Secondary hypothyroidism: This type is caused due to a problem with the pituitary gland, which prevents the gland from releasing the hormones thyroid-stimulating hormone (TSH) and thyroxine. This can be caused by a tumor, head trauma, radiation, or certain medications.
  4. Tertiary hypothyroidism: This type is caused due to a problem with the hypothalamus, which prevents the gland from releasing the hormone thyrotropin-releasing hormone (TRH). This type can be caused by a tumor, inflammation, head trauma, radiation, or certain medications.
  5. Congenital hypothyroidism: This type is caused by an inherited problem, usually resulting from a gene mutation. This type can be present at birth or begin shortly after birth.


Treatment for an underactive thyroid, or hypothyroidism, typically consists of taking a daily thyroid hormone replacement in pill form. This pill typically contains synthetic versions of the hormones thyroxine (T4) and triiodothyronine (T3). Other treatment options include radioactive iodine therapy and thyroid surgery, but these are usually only recommended in very specific cases. Furthermore, lifestyle modifications such as an improved diet high in iodine, selenium, and zinc, as well as stress reduction, can help manage symptoms of an underactive thyroid. Additionally, some evidence suggests taking dietary supplements such as vitamin D, Omega-3 fatty acids, and probiotics can help improve thyroid function.


  1. Take an iodine supplement that contains the recommended daily values.
  2. Increase dietary intake of foods that are rich in iodine, such as seafood, dairy products, and iodized salt.
  3. Avoid stress and get adequate rest.
  4. Exercise regularly to help keep hormones balanced.
  5. Manage underlying health conditions, such as diabetes and obesity.
  6. Avoid exposure to potential risk factors, such as radiation.
  7. Avoid saturated fat, processed foods, and refined carbohydrates.
  8. Maintain healthy levels of Vitamin D, which helps the body regulate thyroid hormones.
  9. Get screened for thyroid disorders, especially if you have a family history of thyroid disease.
  10. 0. Follow treatment plans prescribed by your doctor, including medications and lifestyle modifications.

Gender differences?

Yes, there are gender-specific differences in the presentation and management of underactive thyroid. Women tend to be more likely to develop hypothyroidism than men, and they are more likely to report symptoms such as fatigue, constipation, weight gain, dry skin, and thinning hair. Women may also experience heavy, irregular periods and infertility, which are not usually seen in men with hypothyroidism. Women’s hypothyroidism is also more likely to be associated with autoimmune disorders such as Hashimoto’s thyroiditis.

The management of hypothyroidism in women may also be different than for men. Women may require a lower starting dose of thyroid hormone replacement medication due to their smaller body size than men and because hormonal fluctuations related to the menstrual cycle can affect thyroid function. Additionally, due to the association between hypothyroidism and other autoimmune disorders, women with hypothyroidism may need to be monitored for other autoimmune diseases such as rheumatoid arthritis or celiac disease.


Nutrition plays an important role in the management of an underactive thyroid because certain nutrients are necessary for the production of thyroid hormones. These essential nutrients include iodine, selenium, zinc and omega-3 fatty acids. A diet rich in these nutrients and low in saturated fats and processed foods can help support thyroid health and improve symptoms of hypothyroidism. Additionally, eating a balanced and nutritious diet can improve overall health and well-being, which is important for people with an underactive thyroid.

Physical Activity

Physical activity can have a positive effect on people with an underactive thyroid, also known as hypothyroidism. Regular exercise can help to increase one’s metabolism, which can help to boost energy levels and aid in weight loss. Exercising also helps to reduce stress and anxiety levels, both of which can be exacerbated by an underactive thyroid. Additionally, regular physical activity has been shown to have a positive effect on hormone regulation. Exercise can help increase T3 and T4 hormone levels in the body, which can aid in increased metabolic rate, a decrease in fatigue, and even aid in balancing out the body’s thyroid hormones. However, it is important to note that physical activity should not be done too strenuously for those with an underactive thyroid, as it can put too much strain on the body and can leave one feeling exhausted. It is recommended to talk with a doctor before beginning any exercise program.

Further Reading

  1. https://www.niddk.nih.gov/health-information/endocrine-diseases/hypothyroidism
  2. https://www.uptodate.com/contents/hypothyroidism-underactive-thyroid-beyond-the-basics/print
  3. https://www.mayoclinic.org/diseases-conditions/hypothyroidism/symptoms-causes/syc-20350284
  4. https://medlineplus.gov/hypothyroidism.html
  5. https://www.pennmedicine.org/for-patients-and-visitors/patient-information/conditions-treated-a-to-z/hypothyroidism-underactive-thyroid
  6. https://www.btf-thyroid.org/hypothyroidism-leaflet
  7. https://www.thyroid.org/wp-content/uploads/patients/brochures/Hypothyroidism_web_booklet.pdf

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