The severity of the signs and symptoms of hyperthyroidism is related to the duration of the disease, the magnitude of the thyroid hormone excess, and the patient's age. There is also significant variability in the individual response to hyperthyroidism and individual sensitivity to thyroid hormone fluctuations generally.[1] On top of that, Graves' disease patients can undergo periods of hypothyroidism (for further information, see symptoms of hypothyroidism): finding the right dosage of thyroid hormone suppression and/or supplementation can be difficult and takes time. The body's need for thyroid hormone can also change over time, like in the first months after radioactive iodine treatment (RAI).