The thyroid gland controls your metabolism, energy, heart rate, and more. About 20 million Americans have thyroid disease, and up to 60% don't know it. Hypothyroidism (underactive) is 7x more common than hyperthyroidism (overactive).
When to See a Doctor
🩺 Routine checkupSee your doctor if you have unexplained weight changes, persistent fatigue, hair loss, or a visible neck swelling. Get urgent care for chest pain, severe shortness of breath, or sudden confusion — these can indicate a thyroid storm (rare but dangerous).
Early Warning Signs
3 symptomsUnexplained weight changes
Hypothyroidism causes weight gain; hyperthyroidism causes unexplained weight loss — both despite no change in diet or exercise.
Fatigue and sluggishness (hypothyroid)
Low thyroid hormone slows every system in the body, causing profound fatigue, brain fog, and feeling cold.
Racing heart and anxiety (hyperthyroid)
Excess thyroid hormone overstimulates the body, causing rapid heartbeat, tremors, and anxiety-like symptoms.
Common Symptoms
3 symptomsSensitivity to temperature
Hypothyroidism causes cold sensitivity; hyperthyroidism causes heat intolerance and excessive sweating.
Irregular or heavy periods
Thyroid hormones regulate the menstrual cycle. Both over and underactive thyroid can cause menstrual irregularities.
Depression or mood swings
Thyroid hormones affect neurotransmitter function. Hypothyroidism often causes depression; hyperthyroidism can cause mood swings or anxiety.
Advanced Symptoms
2 symptomsHair thinning or loss
Both underactive and overactive thyroid disrupt the hair growth cycle, causing diffuse thinning across the scalp.
Swollen neck (goiter)
Visible enlargement of the thyroid gland at the base of the throat. Can cause difficulty swallowing or breathing.
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