Hypothyroidism is a condition that usually affects women over 50. It occurs when your thyroid gland does not produce enough thyroid hormone.
Hair growth occurs in three stages: first hair grows, then the hair rests and then it is shed before the cycle begins again. A hormone imbalance can interfere with this cycle, preventing normal hair growth.
Thinning hair is one of the symptoms of hypothyroidism. An underactive thyroid can also cause hair to fall out.
Hair loss due to hypothyroidism is remedied through treatment of the problem with your thyroid. This usually involves medication to replace the lacking thyroid hormone.
If you stop taking your medication, your hypothyroidism could return and your hair growth could stop once more.