Hypothyroidism and hair loss

Thinning may appear across the scalp rather than as one sharply defined bald patch. Hair can feel dry or coarse, and the outer ends of the eyebrows may become thinner. Most people with hypothyroidism notice other features such as fatigue, feeling cold, constipation, or a hoarse voice, although symptoms vary. Hair loss can also follow illness, stress, low iron, medication changes, or scalp inflammation, so hair loss alone cannot identify the cause.

Arrange a clinical assessment if shedding persists or is accompanied by other symptoms of an underactive thyroid. A clinician may review your history, examine the scalp, and request thyroid blood tests; other tests may be considered when the pattern suggests another cause. If hypothyroidism is confirmed, take prescribed thyroid replacement exactly as directed and attend planned blood-test reviews. Avoid starting high-dose supplements for hair without advice, because some can interfere with tests or treatment. Gentle washing and avoiding tight hairstyles or repeated heat can reduce breakage while the cause is being addressed.

Seek prompt medical advice for sudden or patchy hair loss, scalp pain, marked redness, scaling, or sores. Contact a clinician sooner if hair loss occurs with severe tiredness, fainting, swelling, or a major change in weight. Emergency help is appropriate for trouble breathing, chest pain, confusion, or collapse; these symptoms need urgent assessment and should not be attributed to thyroid disease.

Could thyroid testing explain my hair shedding, and should iron or other causes be assessed? What hair-loss pattern do you see on examination? When should my thyroid blood tests be repeated after treatment begins? Which supplements, shampoos, or medicines could affect my results?