So, What Is The Link Between Thyroid Disease And Hair Loss?
Severe and prolonged hypothyroidism and hyperthyroidism can cause hair loss (often involving a diffuse pattern over the scalp), which usually becomes apparent several months after the onset of the thyroid disease. Hair growth has a long cycle (it grows approximately 0.3mm per day); hence many people only start to lose their hair after their condition undergoes treatment. Paradoxically, this makes the thyroid medication to be erroneously blamed, leading to the withdrawal of treatment, which may worsen the hair loss.
Regrowth is usual with successful treatment of the thyroid disorder, though it will take several months; be aware that growth may not be complete and that the new hair may differ in texture and color. Most cases of scalp and eyebrow hair loss caused by thyroid disorders are temporary, so be patient as the medication stimulates your hair to regrow over time.