Thyroid Health: Understanding Hypothyroidism and Hyperthyroidism

The thyroid gland — a small, butterfly-shaped gland in the front of your neck — produces hormones (T3 and T4) that regulate metabolism, heart rate, body temperature, and energy levels. Thyroid disorders are among the most common endocrine conditions, affecting approximately 20 million Americans.

Hypothyroidism (Underactive Thyroid)

The thyroid doesn't produce enough hormone. The most common cause is Hashimoto's thyroiditis, an autoimmune condition.

Symptoms:

• Fatigue and sluggishness
• Weight gain despite normal eating
• Cold intolerance
• Constipation
• Dry skin and hair loss
• Depression
• Slow heart rate
• Brain fog

Hyperthyroidism (Overactive Thyroid)

The thyroid produces too much hormone. The most common cause is Graves' disease, also autoimmune.

Symptoms:

• Unexplained weight loss
• Rapid or irregular heartbeat
• Anxiety and irritability
• Heat intolerance and excessive sweating
• Tremors
• Frequent bowel movements
• Enlarged thyroid (goiter)

Diagnosis

Both conditions are diagnosed with a TSH (thyroid-stimulating hormone) blood test:

• High TSH → hypothyroidism (pituitary is working harder to stimulate an underactive thyroid)
• Low TSH → hyperthyroidism (pituitary reduces stimulation of an overactive thyroid)

Additional tests (free T4, free T3, thyroid antibodies) may be ordered.

Treatment

Hypothyroidism: Levothyroxine (synthetic T4) — a daily oral medication that replaces the missing hormone. Most people feel significantly better within weeks.

Hyperthyroidism: Options include anti-thyroid medications (methimazole), radioactive iodine therapy, or surgery, depending on the cause and severity.

Regular monitoring with TSH tests is essential to ensure proper dosing. Thyroid conditions are generally very manageable with appropriate treatment.