The thyroid gland produces hormones that control metabolism, energy, and mood. A standard thyroid profile measures T3, T4 and TSH.

TSH (Thyroid Stimulating Hormone) is the most sensitive indicator. Normal range: 0.4 – 4.0 mIU/L. High TSH may indicate an underactive thyroid (hypothyroidism); low TSH suggests overactive thyroid (hyperthyroidism).

T4 is the storage hormone and T3 is the active hormone. Your doctor interprets all three together with clinical symptoms.

Common causes of abnormal readings include iodine deficiency, autoimmune disorders (Hashimoto, Graves disease) and medication. If your report is out of range, consult an endocrinologist — do not self-medicate.