Home Articles Articles Causes of Hypertension Hypothyroidism (Underactive Thyroid): Symptoms, Causes & Treatment

Hypothyroidism (Underactive Thyroid): Symptoms, Causes & Treatment


What is Hypothyroidism (Underactive Thyroid)?

Hypothyroidism, also known as underactive thyroid, is a medical condition characterised by insufficient production of thyroid hormones by the thyroid gland. The thyroid gland, located at the base of the neck, plays a crucial role in regulating various bodily functions by releasing hormones into the bloodstream. These hormones are responsible for controlling metabolism, growth, development, and energy consumption throughout the body.

In hypothyroidism, the thyroid gland fails to produce enough thyroid hormones, primarily thyroxine (T4) and triiodothyronine (T3). This deficiency of thyroid hormones can lead to a slowdown in the body’s metabolic rate and disruption in its normal functioning.

Symptoms of Hypothyroidism

Hypothyroidism symptoms, or underactive thyroid, can vary from person to person and may develop gradually over time. Here are some common symptoms associated with hypothyroidism:

  • Fatigue and Weakness: Feeling tired, sluggish, and lacking energy is a common symptom of hypothyroidism. Even with enough sleep, individuals with hypothyroidism may still experience persistent fatigue.
  • Weight Gain: Unexplained weight gain or difficulty losing weight despite maintaining a healthy diet and exercise routine is often observed in individuals with hypothyroidism. The slower metabolism caused by the condition can contribute to weight gain.
  • Cold Intolerance: Hypothyroidism can make individuals more sensitive to cold temperatures. They may feel excessively cold or have a decreased tolerance for cold environments.
  • Constipation: Slowed digestion is a common symptom of hypothyroidism, leading to infrequent bowel movements and constipation.
  • Dry Skin and Hair: Reduced production of thyroid hormones can cause dry skin, which may appear pale or rough. Hair may become brittle, thin, and dry, with increased hair loss.
  • Muscle and Joint Aches: Muscle and joint pain, stiffness, or swelling can occur in individuals with hypothyroidism. These symptoms may be more noticeable in the morning or after physical activity.
  • Mood Changes and Depression: Hypothyroidism can affect mood, leading to feelings of depression, irritability, or anxiety. Cognitive difficulties, such as memory problems and difficulty concentrating, may also be present.
  • Menstrual Irregularities: Women with hypothyroidism may experience changes in their menstrual cycle, such as heavier or prolonged periods, or irregular menstrual cycles.
  • Hoarseness and Throat Discomfort: Swelling of the thyroid gland (goitre) can cause hoarseness, a raspy voice, or discomfort in the throat.
  • High blood pressure: High blood pressure, also known as hypertension, is not a typical symptom of hypothyroidism. In some cases, untreated or poorly controlled hypothyroidism, particularly in individuals with genetics and hypertension issues, can potentially contribute to an increase in blood pressure.
  • Elevated Cholesterol Levels: Hypothyroidism can lead to increased levels of cholesterol in the blood, which may contribute to the development of heart disease or even heart failure.

Causes of Hypothyroidism

The causes of hypothyroidism can vary depending on the individual. Here are some common causes and risk factors associated with hypothyroidism:

  • Autoimmune Disease (Hashimoto’s thyroiditis): The most common cause of hypothyroidism is an autoimmune disorder called Hashimoto’s thyroiditis. In this condition, the immune system mistakenly attacks the thyroid gland, leading to inflammation and impaired thyroid function.
  • Thyroid Surgery or Radiation Therapy: Surgical removal of the thyroid gland (thyroidectomy) or radiation therapy targeting the thyroid can result in reduced hormone production, leading to hypothyroidism.
  • Radioactive Iodine Treatment: Radioactive iodine treatment, commonly used for the treatment of hyperthyroidism (overactive thyroid), can sometimes lead to an underactive thyroid as a side effect.
  • Iodine Deficiency: In areas where iodine intake is insufficient, the thyroid gland may not be able to produce enough thyroid hormones, resulting in hypothyroidism. 
  • Medications: Certain medications, such as lithium (used for bipolar disorder) and amiodarone (used for heart rhythm problems), can interfere with thyroid hormone production and contribute to hypothyroidism.
  • Congenital Factors: Some individuals are born with an underactive thyroid due to genetic abnormalities or a missing thyroid gland.
  • Pituitary Gland or Hypothalamic Disorders: Problems with the pituitary gland or hypothalamus, which are involved in the regulation of thyroid hormone production, can disrupt the normal functioning of the thyroid gland and lead to hypothyroidism.
  • Ageing: As individuals age, the risk of developing hypothyroidism increases. This is primarily due to the natural ageing process and the cumulative effects of other risk factors.

Diagnosis & Treatment for Hypothyroidism

Diagnosis and treatment of underactive thyroid, involve a comprehensive approach to evaluate symptoms, determine the underlying cause, and provide appropriate management. Here is an overview of the diagnosis and treatment process:


  • Medical History and Physical Examination: Your healthcare provider will begin by discussing your symptoms, medical history, and family history. They will also perform a physical examination to check for signs of hypothyroidism, such as dry skin, hair changes, and an enlarged thyroid gland (goitre).
  • Blood Tests: Blood tests are essential for diagnosing hypothyroidism. The primary test measures the levels of thyroid-stimulating hormone (TSH) in the blood. Elevated TSH levels typically indicate an underactive thyroid. Additionally, levels of thyroid hormones, such as thyroxine (T4) and triiodothyronine (T3), may be measured to confirm the diagnosis and assess the severity of hypothyroidism.
  • Additional Tests: In some cases, additional tests may be ordered to determine the underlying cause of hypothyroidism. These tests may include measuring thyroid autoantibodies (e.g., thyroid peroxidase antibodies) to identify autoimmune thyroid diseases like Hashimoto’s thyroiditis. Imaging tests, such as ultrasound or radioactive iodine scans, may be used to evaluate the structure and function of the thyroid gland.


  • Hormone Replacement Therapy: The standard treatment for hypothyroidism involves hormone replacement therapy using synthetic thyroid hormones. The most commonly prescribed medication is levothyroxine, which is a synthetic form of T4. This medication helps restore thyroid hormone levels in the body, alleviates symptoms, and improves overall thyroid function.
  • Individualised Dosage Adjustment: The initial dosage of levothyroxine is typically based on the severity of hypothyroidism, age, weight, and other individual factors. Over time, the dosage may need adjustment through regular monitoring of TSH levels. The goal is to maintain thyroid hormone levels within the normal range to relieve symptoms and optimise overall well-being.
  • Timing and Dosage Instructions: Levothyroxine is usually taken orally once a day on an empty stomach, preferably in the morning. It’s important to follow the specific instructions provided by your healthcare provider regarding dosage, timing, and potential interactions with other medications or supplements.
  • Ongoing Management: Once treatment begins, regular follow-up appointments with your healthcare provider are essential. These visits allow for monitoring of symptoms, assessment of thyroid hormone levels through blood tests, and potential dosage adjustments to ensure optimal hormone replacement therapy.

In a Nutshell

If you suspect you have hypothyroidism or need guidance in managing your condition, it’s important to consult with a qualified healthcare professional. They can provide accurate diagnoses, prescribe appropriate treatment, and monitor your progress effectively. To find a physician specialising in thyroid disorders, visit our Find a Physician webpage. 

Take the next step towards managing your hypothyroidism and schedule an appointment with a knowledgeable healthcare provider today. Your health is important, and we’re here to support you on your journey to optimal well-being.


1. What is hypothyroidism caused by?

Hypothyroidism is primarily caused by an underactive thyroid gland, which fails to produce sufficient amounts of thyroid hormones. The most common cause of hypothyroidism is an autoimmune condition called Hashimoto’s thyroiditis, where the body’s immune system mistakenly attacks the thyroid gland. Other causes include surgical removal of the thyroid gland, radiation therapy, certain medications, congenital thyroid disorders, and iodine deficiency.

2. Is hypothyroidism serious if treated?

If properly diagnosed and effectively treated, hypothyroidism is generally not considered a serious condition. Treatment typically involves hormone replacement therapy, where synthetic thyroid hormones are prescribed to supplement the inadequate hormone production. With appropriate treatment, most individuals with hypothyroidism can lead normal, healthy lives.

3. What happens when you have hypothyroidism?

Hypothyroidism leads to a deficiency of thyroid hormones in the body, which are crucial for regulating metabolism, growth, and development. As a result, individuals with hypothyroidism may experience various symptoms, including fatigue, weight gain, sensitivity to cold, dry skin, constipation, hair loss, muscle weakness, depression, memory problems, and menstrual irregularities. However, symptoms can vary in severity and may not be present in all cases.

4. Can hypothyroidism be cured?

Hypothyroidism, in most cases, cannot be completely cured. However, it can be effectively managed with lifelong treatment. The goal of treatment is to restore the thyroid hormone levels to normal and alleviate symptoms. By taking the prescribed medication (levothyroxine) as directed by a healthcare professional, individuals with hypothyroidism can maintain a stable hormone balance.

5. Can I live long with hypothyroidism?

Yes, individuals with hypothyroidism can live long and healthy lives with proper treatment and management. The key is to regularly take the prescribed medication to maintain adequate thyroid hormone levels. It’s essential to work closely with a healthcare professional, have regular check-ups, and monitor thyroid hormone levels through blood tests. With appropriate treatment and lifestyle adjustments, most people with hypothyroidism can enjoy a normal lifespan without significant health complications.

BackReturn to all articles

Comments (0)

No comments found.

Add your comment